Article

Female Size Influences Mate Preferences of Male Guppies

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Abstract

Guppies (Poecilia reticulata) have a promiscuous mating system in which female choice for brightly coloured males plays an important role. Consequently, much research on guppies has examined how mate choice by females has lead to the evolution of male colour patterns. Much less attention has been devoted to mate choice by males in this species. In this study, we show that male guppies are choosy when selecting a female to associate with, significantly preferring the larger female when presented with two females that differed by ≥2 mm in standard length (SL). The strength of their preference for each female increased with absolute female size. The relative sizes of the females, however, also influenced male mating preferences: males showed stronger preferences for the larger female as the difference in SL between the two females increased. Such a preference for larger females is not unexpected as fecundity generally increases with body size in female fish. Thus, males choosing to mate with the larger female should have higher reproductive success. An apparent, but non-significant anomaly, whereby males appear to prefer the smaller of the two females when the difference between female SL was <4 mm, deserves further investigation.

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... In both P. reticulata and G. affinis, males can identify female gravid status by olfactory cues (Guevara-Fiore et al., 2010;Park & Propper, 2002). To minimize the effect of individual differences in female sexual receptivity on male behavior (e.g., Dosen & Montgomerie, 2004;Jeswiet & Godin, 2011), we observed male behaviors toward gravid females. ...
... In the evening prior to the day of each trial, we randomly chose a male from a stock tank of P. reticulata or G. affinis. In both species, because males prefer to mate with larger females (e.g., Deaton, 2008;Dosen & Montgomerie, 2004), size-matched females (a P. reticulata and a G. affinis) were chosen to minimize possible effects of body sizes (within ±0.3 g of wet body weight). The male was placed in the center aquarium that was sandwiched between the two outer aquaria, one with a conspecific female and the other with a heterospecific female. ...
... More importantly, it also aimed to detect differences in male mating behaviors "toward heterospecific females" versus "toward conspecific females." We assumed that the size of the female or the size difference between the two females affected male mating behaviors (Deaton, 2008;Dosen & Montgomerie, 2004), so we observed male behaviors in a male-female pair to minimize the effect of female size. The female standard length did not significantly differ between species (t = −0.33, ...
Article
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Sexual conflict can result in coercive mating. Because males bear low costs of heterospecific mating, coercive males may engage in misdirected mating attempts toward heterospecific females. In contrast, sexual selection through consensual mate choice can cause mate recognition cues among species to diverge, leading to more accurate species recognition. Some species show both coercive mating and mate choice‐associated courtship behaviors as male alternative reproductive tactics. We hypothesized that if the selection pressures on each tactic differ, then the accuracy of species recognition would also change depending on the mating tactic adopted. We tested this hypothesis in the guppy (Poecilia reticulata) and mosquitofish (Gambusia affinis) by a series of choice experiments. Poecilia reticulata and G. affinis males both showed imperfect species recognition and directed all components of mating behavior toward heterospecific females. They tended to direct courtship displays more frequently toward conspecific than heterospecific females. With male P. reticulata, however, accurate species recognition disappeared when they attempted coercive copulation: they directed coercions more frequently toward heterospecific females. We also found that heterospecific sexual interaction had little effect on the fecundity of gravid females, which suggests that prepregnancy interactions likely underpin the exclusion of G. affinis by P. reticulata in our region.
... Pre-requisite conditions necessary for such selection to act include the availability of multiple sexually receptive females for males to choose from, females vary in quality, males have the capability to discriminate between females of varying quality, searching for and mating with certain females varies in costs, males invest in parental care, and(or) male reproductive success is sperm limited (reviewed in Edward & Chapman, 2011). Consequently, in species in which female fecundity increases with body size, males should prefer to mate with relatively larger females over small ones (e.g., Arriaga & Schlupp, 2013;Dosen & Montgomerie, 2004;Godin & Auld, 2013;Herdman, Kelly, & Godin, 2004;Hoysak & Godin, 2007;Ojanguren & Magurran, 2004), all else being equal. However, in species in which females mate multiply, larger females are more likely to be multiply mated than smaller ones, resulting in sperm competition (e.g., Herdman et al., 2004;Jeswiet, Lee-Jenkins, & Godin, 2012;Wedell, Gage, & Parker, 2002). ...
... Wedell et al., 2002). Indeed, male Trinidadian guppies are choosy and usually exhibit an overall mating preference for larger females at the population level (e.g., Dosen & Montgomerie, 2004;Godin & Auld, 2013;Herdman et al., 2004;Jeswiet et al., 2012;Ojanguren & Magurran, 2004). However, individual males vary widely in their mating preferences and individual preferences can be consistent (repeatable) over time (Godin & Auld, 2013;Jeswiet et al., 2012), as is also the case for males in other species (see references above). ...
... The large and small females were 2.4-2.7 and 1.8-2.1 cm in standard length (SL), respectively. For the mating preference trials, we chose pairs of stimulus females that differed in body length between 20% and 25% to facilitate discrimination (Dosen & Montgomerie, 2004;Jeswiet et al., 2012); that is, males could choose between a relatively large and a relatively small female as potential mates. Individual males were tested with a different pair of stimulus females in each of the two repeated mate-choice trials, and stimulus females were taken from different home tanks than those of the males to minimise any potential effects of prior familiarity with certain potential mates on mate choice (Hughes et al., 1999;Kelley, Graves, & Magurran, 1999). ...
Article
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Within populations, individual animals vary considerably in their behaviour, including mate choice and personality. There is mounting interest in the potential covariation between these two behaviours within individuals, such that personality would influence mate choice. We experimentally tested this proposition under controlled laboratory conditions using male Trinidadian guppies (Poecilia reticulata ) as a model study system. We assayed repeatedly the mating preference of individual males for females based on their body size. Additionally, we assayed repeatedly two ecologically relevant personality traits in males, namely exploration of a novel environment and boldness under a simulated predation threat. Finally, we analysed whether male mating preference and personality traits were repeatable, and tested whether the personality of individual males was correlated (covaried) with their mating preference scores. Although all but one of the measures of exploration and boldness behaviour were repeatable over time, male mating preference scores were not repeatable. Measures of male exploration and boldness were not inter‐correlated among individuals, suggesting the absence of a behavioural syndrome between exploration and boldness. Unexpectedly, males did not exhibit on average a significant mating preference for larger females over smaller ones; they chose randomly between the paired stimulus females. Overall, we found no compelling evidence for a relationship between individual personality traits and mating preference in male guppies, suggesting that personality does not predict mate choice, at least in our study population and under our experimental conditions. We discuss potential factors, other than male personality and body length, that might maintain inter‐individual variation in male mating preferences in the guppy in the wild.
... We manipulated the relative sexual attractiveness and competitiveness of observer and model males by choosing males of the same or different body length and body coloration, two sexually selected traits in the guppy (Auld, Pusiak, & Godin, 2016;Houde, 1997), in each of four treatments. Based on the findings of previous studies on male mate choice (Auld, Ramnarine, & Godin, 2017;Dosen & Montgomerie, 2004;Gasparini et al., 2013;Godin & Auld, 2013;Herdman, Kelly, & Godin, 2014;Jeswiet et al., 2012;Jeswiet, Lee-Jenkins, Ramnarine, & Godin, 2011) and male mate-choice copying (e.g. in the guppy, we predicted that focal male guppies on average (1) would initially prefer large over smaller females as mates in the absence of social information (i.e. no model males present), (2) would weaken their initial preference for a particular female and spend more time associating with the other (initially nonpreferred) female when a model male was placed near the latter female, thus simulating an apparent mate choice for this female (i.e. they would mate-choice copy), and (3) would be more likely to reverse their initial mating preference (i.e. more likely to mate-choice copy) when the model male was less or similarly sexually attractive and competitive than themselves compared to when the model male was more attractive and competitive than themselves. ...
... Females generally prefer larger and more colourful males as mates, and males generally prefer to mate with larger, more fecund females (e.g. Dosen & Montgomerie, 2004;Godin & Auld, 2013;Herdman et al., 2004; and with sexually receptive virgin or postpartum females over mated gravid females, which are generally less receptive (Guevara-Fiore, Skinner, & Watt, 2009;Guevara-Fiore, Stapley, Krause, Ramnarine, & Watt, 2010;Houde, 1997). Most adult females in natural populations, including our study population, are multiply mated (Herdman et al., 2004;Kelly, Godin, & Wright, 1999;Neff, Pitcher, & Ramnarine, 2008) and thus gravid and not sexually receptive (Houde, 1997). ...
... Following Dosen and Montgomerie (2004) and , we used gravid females with similar abdominal distention (assessed by eye), an indicator of stage of pregnancy (Houde, 1997), as stimulus females because they are generally sexually unreceptive to males (Houde, 1997) and to ensure that male mate choice would not be confounded by female sexual responses to male sexual activity and to minimize variation in male behaviour caused by any differences in female reproductive state. Although they prefer to associate and mate with virgin over gravid females when given a choice (Guevara-Fiore et al., 2009, male guppies nevertheless sexually pursue, court and mate with gravid females (e.g. ...
Article
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Copying the mate choice of another conspecific by a bystanding observer is a socially mediated alternative mating strategy to independent mate choice. Because increased sperm competition is a potential cost of mate-choice copying, males should be prudent and less likely to copy the observed mate choice of other males when the latter are more sexually attractive than themselves. We tested this hypothesis using the Trinidadian guppy, Poecilia reticulata. Focal observer males were simultaneously presented with a large and a small female as potential mates, either in the presence or absence of a nearby model male. We varied the relative differences in the body length and colour ornamentation, traits that predict male sexual attractiveness and competitiveness in the guppy, of observer and model males in each of three experimental treatments: (1) observer and model males were matched for body length and colour ornamentation; (2) the model male was larger and more colourful than the observer male; (3) the model male was smaller and less colourful than the observer male. We compared the mating preferences of focal observer males in each of the latter treatments with that of focal males in a control treatment, wherein no model male (and thus no copying opportunity) was present. As predicted, focal males copied the staged apparent mate choice of a model male in all three experimental treatments, but not in the control treatment. However, contrary to our a priori hypothesis, there were no significant differences in the likelihood or strength of the copying response in observer males among the experimental treatments. Although male guppies are known to modify their mating tactics in the presence of sexual competitors, we found no evidence for an influence of the relative phenotypes of observer and model males on mate-choice copying behaviour in focal observer males.
... gonopodium) towards the female's genital pore (Houde, 1997). Although the guppy mating system is primarily driven by female choice, males can also be choosy, and have been shown to prefer larger females (Houde, 1997;Dosen and Montgomerie, 2004;Bertram et al., 2018b), which are generally more fecund (Herdman et al., 2004). Therefore, guppies can be used to further our understanding male strategic allocation of mating effort, in addition to examining effects of endocrine disruptors (if any) on this process. ...
... Due to a known male preference for larger (and, hence, generally more fecund) females (Dosen and Montgomerie, 2004), focal males were presented sequentially with 'small' and/or 'large' females. The total length of small females ranged from 16.59 to 22.95 mm (mean ± SD = 19.52 ± 1.86 mm, Table S1), while the total length of large females ranged from 24.13 to 29.94 mm (mean ± SD = 27.13 ± 1.77 mm, Table S1). ...
... Both exposed and unexposed males showed a preference for greater female size during the first and second female presentation by courting larger females more frequently. Male preference for larger females has previously been demonstrated in guppies using simultaneous choice experiments (i.e. when males are able to make direct comparisons between potential suitors; Dosen and Montgomerie, 2004;Herdman et al., 2004). Our study, however, demonstrates that male guppies can strategically allocate reproductive effort when females are encountered sequentially. ...
... Reznick, 1983). In situations with no male-male competition, male guppies prefer to mate with larger females (Dosen and Montgomerie, 2004;Jeswiet et al., 2012;Auld and Godin, 2015;Auld et al., 2016). However, such male preference is often only observed when the difference in body length between females exceeds a certain threshold, commonly around 10% difference in body size (Dosen and Montgomerie, 2004;Jeswiet and Godin, 2011). ...
... In situations with no male-male competition, male guppies prefer to mate with larger females (Dosen and Montgomerie, 2004;Jeswiet et al., 2012;Auld and Godin, 2015;Auld et al., 2016). However, such male preference is often only observed when the difference in body length between females exceeds a certain threshold, commonly around 10% difference in body size (Dosen and Montgomerie, 2004;Jeswiet and Godin, 2011). It is thus evident that better judgment of mate quality can play a major role in maximizing reproductive fitness not only in terms of female choice but also for male mate choice in this species. ...
... Based on these measurements, we used 18 females to create three female pairs for each of the three experimental treatments: (i) large difference in body size (7 mm; 25% difference), (ii) medium difference in body size (3.4 mm; 12.5% difference) and (iii) small difference in body size (1.6 mm; 6.25% difference). To avoid potential differences in motivation to mate in the males across the three treatments and because absolute female size in the test can drive the preference for larger females (Dosen and Montgomerie, 2004), the combined body length of the two females was kept equal to 50 mm in every pair (large difference: 28.5 versus 21.5 mm; medium difference: 26.7 versus 23.3 mm; small difference: 25.8 versus 24.2 mm). ...
Article
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Understanding what drives animal decisions is fundamental in evolutionary biology, and mate choice decisions are arguably some of the most important decisions in any individual's life. As cognitive ability can impact decision-making, elucidating the link between mate choice and cognitive ability is necessary to fully understand mate choice. To experimentally study this link, we used guppies (Poecilia reticulata) artificially selected for divergence in relative brain size and with previously demonstrated differences in cognitive ability. A previous test in our female guppy selection lines demonstrated the impact of brain size and cognitive ability on information processing during female mate choice decisions. Here we evaluated the effect of brain size and cognitive ability on male mate choice decisions. Specifically, we investigated the preferences of large-brained, small-brained, and non-selected guppy males for female body size, a key indicator of female fecundity in this species. For this, male preferences were quantified in dichotomous choice tests when presented to dyads of females with small, medium and large body size differences. All types of males showed preference for larger females but no effect of brain size was found in the ability to discriminate between differently sized females. However, we found that non-selected and large-brained males, but not small-brained males, showed context-dependent preferences for larger females depending on the difference in female size. Our results have two important implications. First, they provide further evidence that male mate choice occurs also in a species in which secondary sexual ornamentation occurs only in males. Second, they show that brain size and cognitive ability have important effects on individual variation in mating preferences and sexually selected traits.
... Depending on the population, females prefer on average the more color-ornamented and(or) larger of available males as mates (e.g., Reynolds and Gross 1992;Endler and Houde 1995;Brooks and Endler 2001a;b;Dosen and Montgomerie 2004;Herdman et al. 2004;Magellan et al. 2005;Auld et al. 2016). However, male guppies possessing visually conspicuous ornamental coloration may incur the cost of a greater individual risk of mortality to predation than drabber conspecifics (e.g., Haskins et al. 1961;Endler 1978Endler , 1980Godin and McDonough 2003;Weese et al. 2010), a survival cost that can vary depending on population (Weese et al. 2010), the particular class of color (Endler 1978;Gordon et al. 2015), relative frequencies of color morphs in the population (Olendorf et al. 2006), and local habitat features (Endler 1995;Millar et al. 2006), for example. ...
... Female guppies most likely assess and respond to overall or composite male color ornamentation and male relative body size when choosing mates (Reynolds and Gross 1992;Endler and Houde 1995;Brooks and Endler 2001a, b;Dosen and Montgomerie 2004;Herdman et al. 2004;Auld et al. 2016). The visual conspicuousness (sensu Endler 1990) of the body coloration pattern of a prey depends on its overall visual contrast with the background against which it is viewed by its predators (Endler 1978(Endler , 1990(Endler , 1991Endler et al. 2022). ...
Article
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Although visual sexual signals, such as ornamental colors and courtship displays, and large body size in males are attractive to females in numerous species, they may also inadvertently attract the attention of eavesdropping predators and thus may be costly in terms of increasing individual risk of mortality to predation. Theoretically, more color ornamented and larger males should be more predation threat sensitive and suppress their sexual signaling and(or) mating effort relatively more than their less color ornamented and smaller counterparts when under predation hazard. Here, we experimentally tested this hypothesis by quantifying concurrently the rates of alternative mating tactics (courtship displays, sneak mating attempts) expressed by male Trinidadian guppies (Poecilia reticulata) varying in color ornamentation and body size under a staged immediate threat of predation. Males suppressed their overall mating effort in response to the perceived predation threat, decreasing the frequency of their (presumably more conspicuous) courtship displays significantly more on average than the frequency of their sneak mating behavior. Statistically controlling for body length, more color-ornamented males were more threat sensitive in their courtship displays, but not sneak mating attempts, under predation hazard than drabber males. Controlling for body coloration, larger males exhibited lower courtship and sneak mating efforts than smaller males in both predation treatments, but body length only influenced threat sensitivity in sneak mating behavior. These results are consistent with both the threat sensitive hypothesis and asset protection principle and highlight the phenotype dependency and adaptive plasticity of alternative mating tactics in male guppies under varying predation risk.
... Simple mathematics dictate that the larger a brood, the larger the absolute number of potential sires that can contribute to that brood (Avise and Liu, 2011): i.e., a brood of two offspring can be sired by a maximum of two fathers, while a brood of 30 offspring can be sired by a maximum of 30 different males. Several studies have furthermore shown that males prefer to mate with larger females (Bisazza et al., 1989;Ptacek and Travis, 1997;Dosen and Montgomerie, 2004;Herdman et al., 2004;Hoysak and Godin, 2007), presumably because they increase their chance of producing more offspring as these females generally carry more eggs (Schlupp, 2018). These above processes may explain the observed positive associations between female size, brood size and multiple paternity. ...
... Most previous studies in the Poeciliidae do not report a significant correlation between female size and multiple paternity (Trexler, 1997;Zane et al., 1999;Neff et al., 2008;Girndt et al., 2012;Paczolt et al., 2015;Zeng et al., 2017), although a significant relationship was found in Gambusia affinis and Poecilia latipinna (Travis et al., 1990;Greene and Brown, 1991). We expected to find a positive relationship between female size and multiple paternity, as many earlier studies have shown a male preference for larger females (including the closely related P. reticulata and P. latipinna; Bisazza et al., 1989;Ptacek and Travis, 1997;Dosen and Montgomerie, 2004;Herdman et al., 2004;Hoysak and Godin, 2007;Schlupp, 2018). But this preference, usually assessed using choice-experiments in the lab, might not reflect actual mating opportunities in natural situations. ...
Article
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Multiple paternity is a common phenomenon within the live-bearing fish family Poeciliidae. There is a great variety in brood sizes of at least two orders-of-magnitude across the family. However, little is known about the ramifications of this remarkable variation for the incidence and degree of multiple paternity and reproductive skew. Mollies (subgenus Mollienesia, genus Poecilia) produce some of the largest broods in the family Poeciliidae, making them an excellent model to study the effects of intra-specific variation in brood size on patterns of multiple paternity. We collected samples of the live-bearing fish Poecilia gillii from 9 locations in Costa Rica. We measured body size of 159 adult females, of which 72 were pregnant. These samples had a mean brood size of 47.2 ± 3.0 embryos, ranging from 4 to 130 embryos. We genotyped 196 field-collected specimens with 5 microsatellite markers to obtain location-specific allele frequencies. In addition, we randomly selected 31 pregnant females, genotyped all their embryos (N = 1346) and calculated two different parameters of multiple paternity: i.e., the minimum number of sires per litter using an exclusion-based method (GERUD) and the estimated number of sires per litter using a maximum likelihood approach (COLONY). Based on these two approaches, multiple paternity was detected in 22 and 27 (out of the 31) females, respectively, with the minimum number of sires ranging from 1 to 4 (mean ± SE: 2.1 ± 0.16 sires per female) and the estimated number of fathers ranging from 1 to 9 (mean ± SE: 4.2 ± 0.35 sires per female). The number of fathers per brood was positively correlated with brood size, but not with female size. Next, we calculated the reproductive skew per brood using the estimated number of sires, and found that in 21 out of the 27 multiply sired broods sires did not contribute equally to the offspring. Skew was not correlated with either female size, brood size or the number of sires per brood. Finally, we discuss several biological mechanisms that may influence multiple paternity and reproductive skew in P. gillii as well as in the Poeciliidae in general.
... This mirrors previous laboratory and field studies in T. dalmanni . As in other species, the likely benefit of this preference derives from mating with higher fecundity females (Olsson 1993;Dosen and Montgomerie 2004;Reading and Backwell 2007). Female eyespan reliably indicates fecundity among field caught stalk-eyed flies, where it explains a significant amount of variation in ovarian egg number, even after controlling for body size . ...
... This mirrors previous laboratory and field studies in T. dalmanni . As in other species, the likely benefit of this preference derives from mating with higher fecundity females (Olsson 1993;Dosen and Montgomerie 2004;Reading and Backwell 2007). Female eyespan reliably indicates fecundity among field-caught stalk-eyed flies, where it explains a significant amount of variation in ovarian egg number, even after controlling for body size . ...
Conference Paper
Meiotic drive is a type of selfish genetic element that, in heterozygous males, disables or destroys non-carrier sperm in order to bias its own transmission. Meiotic drive genes are predicted to spread rapidly due to this transmission advantage and even, if sex-linked, cause population extinction due to the loss of one sex. Despite this, many meiotic drive genes are found at low/moderate, stable frequencies, which implies their carriers must bear unknown costs that balance this transmission advantage. Such costs may come about as direct or pleiotropic effects of the meiotic drive gene(s) themselves, or because drive is often associated with inversions that are expected to accumulate deleterious mutations. The theme of the thesis has been to search for costs of meiotic drive in the Malaysian stalk-eyed fly, Teleopsis dalmanni. First, I assess whether the expected low quality of meiotic drive males has impacted the strength of their mate preference for high quality females. I find that male mate preference does not depend on drive status but does depend on eyespan. Male eyespan is a sexually- selected ornamental trait and drive males typically have small eyespan. I also show that drive males are unable to mate as frequently as non-drive males. Second, I study the effect of meiotic drive on the egg-to-adult viability of stalk-eyed flies. I show that drive reduces the viability of both sexes, with drive males and homozygous drive females showing the greatest loss of 5 viability compared to their non-drive counterparts. Third, I study the effect of larval food stress on the drive-associated reduction in male eyespan. I find that drive males and females have reduced eyespan, but the magnitude of this reduction does not increase under high stress. This implies that the small eyespan of drive males is unlikely to be a condition-dependent effect of the expected increased mutation load. I discuss how small eyespan may instead be part of a suite of adaptations to maintain high fertility in the face of the destruction of half of all sperm. Finally, I use experimental evolution to track the frequency of meiotic drive in cage populations and find considerable heterogeneity. While one cage is driven extinct due to the loss of males, drive frequency generally declines in other populations, disappearing entirely from some after six generations.
... Most studies of mate choice in guppies have tended to focus on female choice, with evidence that females can be highly selective in their choice of mating partners (Endler, 1980;Magurran and Seghers, 1994;Brooks and Endler, 2001). However, male guppies can also be choosy (Houde, 1997;Dosen and Montgomerie, 2004;Herdman et al., 2004) and are known to attend to both visual and chemical cues in mate assessment (Herdman et al., 2004;Guevara-Fiore et al., 2009;Crow and Liley, 2011). ...
... female 'preference' zone). Association time, in this regard, is a reliable indicator of male mate choice in Poeciliid fish (Wong et al., 2007;Walling et al., 2010;Jeswiet and Godin, 2011), and is commonly used as a measure of male mating preference in guppies (e.g., Houde, 1997;Herdman et al., 2004;Dosen and Montgomerie, 2004;Gasparini et al., 2013). In addition to association time, we also quantified the number and duration of male courtship 'sigmoid' displays directed towards each of the females over the 5 min sampling period. ...
... Mate choice is vital to sexual selection and biological evolution [8][9][10], influencing many species' reproductive success and population dynamics. It involves a range of complex and variable signals, including size, coloration, distinctive ornamental features, and movement patterns, which are often dynamic and change over time and space [11][12][13][14]. In fish, mate choice is typically driven by visual, chemical, and auditory cues, with visual signals playing a critical role in many species. ...
Article
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Visual signals are crucial for animals to obtain information about their environment, and they play a significant role in mate choice. However, individual variability and factors such as movement patterns can hinder research flexibility. A key challenge in this field is the accurate simulation of specific movements and behaviors. In this study, we investigated the western mosquitofish (Gambusia affinis) by creating 3D simulation animations using the Maya 2018 software. Meanwhile, we validated the effectiveness of this animation through dichotomous association preference tests. The results showed that our subjects could successfully identify 3D simulated mates, and both males and females demonstrated pronounced preferences for larger simulated animations. Moreover, our findings revealed that this species exhibited a notably stronger preference for 3D simulations compared to 2D animations. These findings suggest that 3D simulation technology holds significant potential for the investigation of fish mate choice, offering an efficient, precise, standardized, and easily manageable non-invasive method for future research in fish behavior.
... The individual body weight of females was 640 ± 5 mg, of males, 230 ± 5 mg. In order to exclude preferences in the sexual selection of female and male guppies by size (Dosen, Montgomerie, 2004;Herdman et al., 2004) and body coloration (Karino, Shinjo, 2004;Pilastro et al., 2004), fish of the same sex and the same size were selected, all males had an orange-red color of the body and fins, and the flag shape of the caudal fin. ...
Article
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The sexual behavior of males and the reproductive success of the guppy Poecilia reticulata were studied under experimental conditions in a temperature gradient field of 24–28°С and at a constant temperature of 26°С. The intensity of courtship of males for females in the temperature gradient field was 1.6 times higher than at 26°С, while the structure of male sexual behavior changed: the frequency of manifestation of demonstrative forms of behavior and copulations increased. On average, the individual female fecundity was 19.0% higher in the temperature gradient field than in the constant temperature regime. Temperature fluctuations experienced by fish when exposed to a temperature gradient field had a stimulating effect on the intensity of male courtship and the reproductive success of guppies.
... Moreover, most of the examples that have documented male mate choice come from arthropods (Tuschhoff and Wiens 2023), highlighting the need for further study of this form of mate choice in other animal phyla. Additionally, for many species known to exhibit both male and female mate choice, such as Drosophila melanogaster (fruit fly), Poecilia reticulata (guppy), and Xiphophorus hellerii (swordtail fish), female choice has been much better studied (Dosen and Montgomerie 2004;Byrne and Rice 2006;Tudor and Morris 2008). Thus, while numerous studies have detailed the effects of female mate choice on the evolution of populations and species, the same emphasis has not been historically placed on determining whether or how much male choice may also be impacting evolutionary trajectories. ...
Article
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While there are many studies documenting female mating preferences across taxa, male mate choice remains relatively understudied. Male mate choice often develops when there is variation in female quality and thus the fitness benefits of mating with particular females. Specifically, males tend to prefer females with traits that confer direct fitness benefits such as large body size, which may be linked with high fecundity. Prior work has shown that females of the strawberry poison frog, Oophaga pumilio, prefer males bearing certain coloration (most often the female’s own color), and that this preference can be learned through maternal imprinting. Females have been shown to prefer larger males as well. Here we test whether similar mate preferences for color and size exist in males of this species using two-way choice tests on captive bred male O. pumilio. In each test focal males were placed in an arena with two stimulus females: either both of the same size but differing in color, or both of the same color but differing in size. We found only weak evidence for behavioral biases toward particular colors and no evidence for biases toward larger females, suggesting that males of O. pumilio do not predictably choose mates based on these female traits. Despite several aspects of their natural history that suggest males have reasons to be choosy, our findings suggest that the cost of mate rejection may outweigh any fitness benefits derived from being selective of mates. Studies of additional populations, ideally conducted on wild individuals, are needed to better understand the range of conditions under which males may exhibit mate choice and the types of traits on which they base these choices. Significance statement To fully understand the fitness landscapes and evolutionary trajectories that result from sexual selection, we need to understand when and how the mate preferences of the two sexes act and interact. While female mate choice has been widely studied, male mate choice remains poorly understood. To help bridge this gap, we studied male mate preferences in the strawberry poison frog Oophaga pumilio, a small brightly colored frog for which female preferences for male color and size have been well-documented. We found no evidence that male O. pumilio exhibit mate preferences based on female size and little evidence for male mate preferences based on female color. This is surprising given that larger females are often more fecund, male O. pumilio are known to exhibit color-based behavioral biases in the context of male-male competition, and both sexes provide parental care.
... The individual body weight of females was 640 ± 5 mg, of males, 230 ± 5 mg. In order to exclude preferences in the sexual selection of female and male guppies by size (Dosen, Montgomerie, 2004;Herdman et al., 2004) and body coloration (Karino, Shinjo, 2004;Pilastro et al., 2004), fish of the same sex and the same size were selected, all males had an orange-red color of the body and fins, and the flag shape of the caudal fin. ...
... Female pheromones have been shown to co-vary positively with the condition of the emitter in few taxonomical groups, such as moths (Jaffe et al. 2007;Foster and Johnson 2011;Harari et al. 2011;Gonzalez-Karlsson et al. 2021), snakes (Shine et al. 2003), and spiders (Weiss and Schneider 2022a, 2022b) (but see (Assis et al. 2017)). From the male perspective, being able to discriminate female individual state may bring large reproductive benefits, as males could avoid courting and mating with infertile (e.g., subadult) females (Cook and Cook 1975;Lewis and Iannini 1995;McCartney and Heller 2008;Zahradnik et al. 2008;Tuni and Berger-Tal 2012), and/or select partners of highest quality (e.g., body condition, size, fecundity) (Jones et al. 2001;Dosen and Montgomerie 2004;Reading and Backwell 2007;Nandy et al. 2012;Baruffaldi and Andrade 2015). Assessing the female's mating status is particularly beneficial in polyandrous species (i.e., females mate with multiple males), where recognition and avoidance of mated females can reduce sperm competition and increase paternity success, or in systems with sperm priority patterns, where first or last males to mate may gain advantages in fertilizations (Simmons 2001;Thomas 2011). ...
Article
Male mate choice is predicted in systems with high costs of mating, as for those with male nuptial gifts and/or sexual cannibalism. We ask whether males of the nuptial gift-giving spider Pisaura mirabilis exert preferences for mates varying in their reproductive potential based on chemical information during mate search. Males were presented with binary trails consisting of silk lines and substrate-borne chemicals deposited while females were walking, from females varying in 1) body condition (high vs. low), 2) developmental state (subadult vs. adult), and 3) mating state (unmated vs. mated). If female chemical signaling co-varies with individual state, we expect males to choose trails of females that are 1) in higher body condition, indicating higher fecundity, 2) adults, which can successfully reproduce, and 3) unmated, to avoid sperm competition. We show that female signaling is condition-dependent, with males being more likely to follow trails of higher body condition females, but not dependent on female mating state. Males also tended to prefer trails of adults over subadults. Choice did not depend on male individual body condition. Our findings suggest costs to chemical signaling in nutritionally deprived females, often considered negligible, and their potential as reliable indicators of individual quality. Selection may favor male preferences for more fecund partners given the energetic investment nuptial gifts entail. Nutritional and reproductive benefits of multiple mating to females and high share of paternity for males, may instead select against signaling of female mating state, and/or male discrimination and choice.
... gamete stock or energy reserves; Edward and Chapman, 2011). In this case, male can assess the female "quality" using cues such as the female size (Dosen and Montgomerie, 2004). As we did not observe this pattern in this study, we can either hypothesize that males do not select females, or that they select females in some conditions. ...
Thesis
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Nests are widespread in the animal world and aim to protect the young from predation and adverse environmental conditions while being a privileged place to assess sexual selection. These nests, modifications of the habitat in which they are built, influence the environmental conditions and likely affect the communities and ecological processes. Among the nesting species, the sea lamprey (Petromyzon marinus L.) is an anadromous, semelparous migratory fish, whose nests consist of a mound of coarse elements downstream a pit with a fine substrate. The thesis firstly describes the reproductive behaviour of the sea lamprey by studying the link between the nests and the individuals that built them. A Capture-Mark-Recapture protocol showed that males and females visited up to 10 and 7 nests respectively, and that nests could be built by either pairs or groups of up to 5 individuals, resulting in a clearly polygynandrous mating system. Data obtained during this individual monitoring was used to set up a model providing a population size estimate via a simple nest count, a model that can be easily adapted to other populations and used via an online application. Intrasexual competition and cooperative nest building, as well as the existence of potential alternative reproductive tactics, were monitored at the scale of a nest and of an entire spawning site. Video monitoring within nests showed equal individual contributions to both nest building and mating, although aggressions perpetrated by some males suggested a hierarchy. Experimental injection of eggs into recently built nests indicated that the interaction between variables related to habitat choice (current velocity) and habitat modification (slope between the lower and upper points in the nest) affected egg retention in the nest, a major aspect of egg survival. Measurements of the maintenance of river lamprey (Lampetra fluviatilis L.) eggs in a controlled environment showed a significant role of substrate size. Finally, the link between the nest and its ecosystem was described through the study of the macroinvertebrate communities occupying the different zones and several ecosystem processes. The habitat heterogeneity created by sea lamprey generated biological heterogeneity, with an increased invertebrate diversity in the nest compared to control sites. However, nutrient retention, chlorophyll accretion and litter degradation were not affected. The general objective of this thesis is thus a better understanding of a species whose ecology and place in the ecosystem remain poorly understood, although threatened in its native range while being invasive where introduced, through the use of a characteristic structure of its life cycle: the nest.
... This could be attributed to male preferences being based on the direct benefits associated with female fertility. In contrast, female preferences are mainly based on the benefits provided by males, including protection of juvenile fish and territory, and increased survival rates of the offspring [50,51]. ...
Article
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The mating roles of males and females, to a certain extent, are dynamic and variable. Several factors influence the mate choice process. Nonetheless, the main preference features have not yet been fully understood in Aequidens rivulatus. In this study, because of its natural pairing characteristics, A. rivulatus was selected to explore the mate choice preferences of different sexes. Specifically, male and female behavioral performances were described and quantified through a “no-choice paradigm” during mate choice. A total of 12 behavioral performances were defined in male mate choice (experiment 1), whereas 14 behavioral performances were defined in female mate choice (experiment 2). According to the obtained results, unselected females did not display any proactive behaviors in experiment 1, whereas unselected males exhibited proactive behaviors in experiment 2, including quivering, nipping, tail beating, swimming up and down, and aggression. It was also found that both male and female individuals tend to express dislike rather than like. Those behaviors with higher frequencies (e.g., quivering) often mean less energy expenditure, thus easier repeatability. Moreover, principal component analysis (PCA) was employed to extract and identify mate choice preference features. Preliminary results indicated that male preferences for a mate were mainly associated with body size, behavioral intention, and appearance, whereas the intensity of female preferences was in the order of body size, appearance, and behavioral intention. In addition, sex hormone levels were associated with mate choices.
... In contrast, if higher mate encounter rates or self-attractiveness is perceived by a male through prior mating experience, he would invest more in reproductive effort given the higher fitness returns on the investment (Kemp 2006). If males encounter higher quality (e.g., larger fecundity) females, they are expected to invest more resources in their current courtship [e.g., guppy Poecilia reticulata, Dosen and Montgomerie (2004); fiddler crab Uca mjoebergi, Reading and Backwell (2007)] and/or copulation effort (Aumont and Shuker 2018). Accordingly, investment in subsequent mating is expected to decline due to energy and/or sperm depletion. ...
Article
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The effects of mating experience on male mating behavior are mediated by four factors: mating cost, such as resource depletion, perception of mating opportunities, self-perception of attractiveness, and female quality. For example, encountering females might increase male expectations of prospective mating opportunities, while copulation increases self-perception of attractiveness in males. To determine the relative importance of these factors, the effect of mating on the two components of reproductive effort (courtship and fighting effort) in Gryllus bimaculatus was examined. Calling activity before and after encountering females was measured, and copulation success was recorded. Subsequently, the intensity and outcome of male–male fighting behavior was recorded. Female encounter increased calling activity irrespective of copulation, thereby indicating that the perception of mating opportunities is important factor for the males. Changes in courtship effort of males were larger and fighting success was lower when they were previously paired with relatively heavier females. These results indicate that male reproductive effort is also affected by quality of previous mating partners.
... Males select females [23]. In fish, males of guppy, killifish, stickleback, cichlid and many other species prefer bigger females [24][25][26][27][28][29]; cichlid males prefer females with larger pelvic fins [30], halfbeak males prefer females with larger gravid spots [31], gobby males prefer females with an orange belly [32] and males of mosquitofish prefer conspecific females [19]. Many of those studies adopted the three-chamber strategy (including using digital images) for assessing the sexual preference of males. ...
Article
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The three-chamber experiment, in which one test animal can choose between two animals placed in physically inaccessible compartments, is a widely adopted strategy for studying sexual preference in animals. Medaka, a small freshwater teleost, is an emerging model for dissecting the neurological/physiological mechanisms underlying mate choice for which intriguing findings have been accumulating. The three-chamber strategy has rarely been adopted in this species; therefore, here we investigated its validity using medaka colour variants that mate assortatively. First, a total of 551 movies, in which a test male and two choice females interacted for 30 min under a free-swimming condition, were manually analysed. The sexual preference of the males, calculated as a courtship ratio, was highly consistent between human observers (r > 0.96), supporting the objectivity of this manual-counting strategy. Second, we tested two types of three-chamber apparatuses, in which choice fish were presented in either a face-to-face or side-by-side location. Test fish (regardless of sex) spent most of the time associating with choice fish in the compartments. However, their sexual preference, calculated as an association ratio, was poorly reproduced when the locations of the choice fish were swapped. Third, the sexual preferences of males quantified using the manual-counting and either of the three-chamber strategies did not correlate (r = 0.147 or 0.297). Hence, we concluded that, even for individuals of a species like medaka, which spawn every day, sexual preference could not be reliably evaluated using the three-chamber strategy. Optimization of the protocol may solve this problem; however, the explanation for the observation that animals that are ready for spawning persist with never-accessible mating partners must be reconsidered.
... At the beginning of the experiment (T0) and after the 14 and 21 days of exposure, ten male fish from each experimental group (control, 0.3 and 3 µg L − 1 ) were placed individually in a 7 L tank with a female (1:1). After 10 min of acclimatization, 15 min of recordings of each fish were made, such as recommended by Dosen and Montgomerie (2004). In the video analysis, the first five minutes were discarded (new acclimatization because of the presence of the researcher in the room to turn on the camera) and in the other 10 min, the following parameters were registered: time the male spent directed to the female (%); time (sec) until the first attempt to copulate; frequency of sigmoid displays and mate attempts. ...
Article
The iron oxide nanoparticles (IONPs) have been widely applied to nanomedicine, biology, and nanoremediation. However, its ecotoxicological effects in aquatic organisms remain unclear. The guppy (Poecilia reticulata) is a suitable model to assess the ecotoxicity, reproductive toxicity, and environmental risk of emergent pollutants, such as nanoparticles (NPs). In this study, the effects of citrate-functionalized maghemite (γ-Fe2O3) NPs on reproductive behavior and spermatogenesis of guppies were investigated over 21 days of exposure. Male guppies were exposed to maghemite NPs at environmentally relevant concentrations (0.3 and 3.0 μg L⁻¹) for 14 and 21 days, jointly with a control group (reconstituted water). The reproductive toxicity was analyzed in terms of biometric parameters, sexual behavior, and gonadal histopathology (qualitative and histomorphometric analyzes following by histopathological indices). Results indicated that the chronic exposure to maghemite NPs did not affect male reproductive behavior, but changed the spermatogenesis (increased the spermatid S1 and decreased the spermatocytes and spermatozeugmata frequency). The maghemite NPs induced histopathological damages associated with inflammatory responses and regressive alterations in the testis of guppies. The IONPs can lead to reproductive impairment in freshwater fish, indicating its potential environmental risk.
... Mate choice can be highly complex since both the number and quality of mates and rivals vary and the level of choosiness of one sex is influenced by the choosiness of the other (Johnstone et al. 1996). Generally, females are the choosy sex, but males can also be choosy in many species (Jones and Hunter 1993;Bonduriansky 2001;Dosen and Montgomerie 2004;Edward and Chapman 2011;Schlupp 2018a, b;Tina 2020;Tina and Muramatsu 2020) especially when they invest heavily in reproduction and when the quality of potential females is highly variable (Parker 1983;Gwynne 1991;Owens and Thompson 1994). There is substantial evidence that males prefer older females with more experience (Burley and Moran 1979), larger females with higher fecundity (Berglund and Rosenqvist 1993;Verrell 1994) and females with higher reproductive potential (Schwagmeyer and Parker 1990;Schwagmeyer 1995;Szykman et al. 2001). ...
Article
Many animals adjust their reproductive investment in line with their current competitive abilities. High-quality individuals may breed in the peak breeding period because they have a greater probability of finding high-quality mates, whereas low-quality individuals may breed in the off-peak period to avoid competing with high-quality rivals. We observed a wild population of the fiddler crab Austruca perplexa to investigate the waving rate of large and small males towards large and small females in the peak and off-peak breeding periods. We predicted that large males would invest more in courtship in the peak breeding period and invest less in the off-peak period, whereas small males would invest more in courtship when large males invest less. It was observed that large males waved their major claws more frequently in the peak breeding period than in the off-peak period and waved more towards large females, while small males waved more in the off-peak breeding period and their waving rates were not different towards large or small females. For small males, investing more in courtship in the off-peak breeding period may offer a greater probability of acquiring females than competing against large rival males in the peak breeding period.
... ; https://doi.org/10. 1101/2021 between females increased (Dosen and Montgomerie 2004). This led us to determine whether the strength of preference of rivulus males was influenced by hermaphrodite size. ...
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Mate choice has the potential to drive phenotypic evolution because it can determine traits that increase an individuals likelihood to reproduce (courtship behaviors, elaborate ornamentation). These traits, however, can also be detrimental for health or survival, often antagonizing the evolution of extreme phenotypes. Mangrove rivulus fish ( Kryptolebias marmoratus ) develop as self-fertilizing simultaneous hermaphrodites. Hermaphrodites overwhelmingly self-fertilize their eggs internally, but occasionally oviposit unfertilized eggs. Some individuals change sex to male after sexual maturity, essentially forgoing the reproductive assurance of selfing. In a continuing effort to understand how sex change to male is maintained this species, I designed an experiment to determine whether males act as choosers to increase their likelihood of finding unfertilized eggs for reproduction. I hypothesized that males would prefer to associate with younger hermaphrodites when given a dichotomous choice, as they lay a greater proportion of unfertilized eggs compared to older hermaphrodites. The males in this study did not show a preference for either the younger or older hermaphrodite but exhibited greater within individual variance across subtrials than among individual variation. I discuss alternative hypotheses concerning male mate choice in mangrove rivulus, which may illuminate hypotheses to be tested in this and other hermaphroditic species.
... In fish species where body size forms the basis of mate choice, reductions in average body size due to harvesting could have an impact on mating systems [15]. In many species, large body size is an indicator of good genes or generally higher fitness [26,27], and males and females in many fish species tend to prefer large sized individuals as mating partners [28][29][30]. Females of certain fish prefer large and dominant males because they produce more sperm (mandarinfish Synchiropus splendidus: [31], mosquitofish Gambusia holbrooki: [32]), promising higher reproductive success, or because larger males defend territories and offspring more effectively (threespine sticklebacks Gasterosteus aculeatus: [33], Atlantic molly Poecilia mexicana: [34]). Consequently, in some fish species females have been found to allocate more reproductive resources to large males Banggai cardinal fish Pterapogon kauderni: [35], chinook salmon Oncorhynchus tshawytscha: [36], swordtail fish Xiphophorus multilineatus: [37]). ...
Article
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Size-selective mortality is common in fish stocks. Positive size-selection happens in fisheries where larger size classes are preferentially targeted while gape-limited natural predation may cause negative size-selection for smaller size classes. As body size and correlated behavioural traits are sexually selected, harvest-induced trait changes may promote prezygotic reproductive barriers among selection lines experiencing differential size-selective mortality. To investigate this, we used three experimental lines of zebrafish (Danio rerio) exposed to positive (large-harvested), negative (small-harvested) and random (control line) size-selective mortality for five generations. We tested prezygotic preferences through choice tests and spawning trials. In the preference tests without controlling for body size, we found that females of all lines preferred males of the generally larger small-harvested line. When the body size of stimulus fish was statistically controlled, this preference disappeared and a weak evidence of line-assortative preference emerged, but only among largeharvested line fish. In subsequent spawning trials, we did not find evidence for line-assortative reproductive allocation in any of the lines. Our study suggests that size-selection due to fisheries or natural predation does not result in reproductive isolation. Gene flow between wild-populations and populations adapted to size-selected mortality may happen during secondary contact which can speed up trait recovery.
... For instance, although male rice fish in general have a more well-developed anal fin (Kawajiri and Yamahira 2011), the extent of such difference can vary among populations and may be relatively subtle (Katsumura et al. 2014). We note also that while the size of the mosquitofish, guppy and rice fish used in the present experiment were close to their reported maximum standard length (Dosen and Montgomerie 2004;Parenti 2008;Carmona-Catot et al. 2011), the half-banded barb may grow up to 7 cm (Block and Mabee 2012). However, barbs of these dimensions are not encountered in the field in Hong Kong, and captive individuals generally do not attain this size. ...
Article
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Invasive poeciliid fishes have been negatively affecting recipient ecosystems globally. However, the ecological consequences of their invasions can vary seasonally and spatially, and according to species, limiting our ability to predict their effects. It is also unclear how their impacts differ from those of native fishes. We compared the effects of the invasive mosquitofish (Gambusia affinis) and guppy (Poecilia reticulata) with those of the similar-sized native rice fish (Oryzias curvinotus) and half-banded barb (Puntius semifasciolatus) on invertebrate assemblages, primary-producer biomass, and nitrogen loadings in mesocosms during the wet and dry seasons in tropical Hong Kong. Invasive poeciliids and native fishes reduced invertebrate abundance and richness, and altered assemblage composition, but had no effects on algal biomass or nitrogen loadings. These outcomes were consistent between seasons, although the guppy effects on invertebrates were weaker in the cool dry season. The mosquitofish and the half-banded barb had the strongest influence on invertebrates, followed by the guppy, while rice fish had the smallest effects. This study adds to the scant knowledge of poeciliid invasions in tropical Asia. It reveals that invasives do not always have stronger impacts than native counterparts, and that invasive poeciliids differed in the intensity of their ecological effects.
... It is worth pointing out that the benefits for the two sexes need not be the same. For most species, the benefit for males of choosing a high-quality mate is a larger number of offspring 23,24 . On the other hand, in the case of females, the benefit of mating with a high-quality male is having more attractive and/or viable offspring 4,25,26 . ...
Article
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In mating interactions, it is common in nature for both sexes to choose simultaneously. However, this mutual mate choice and its consequences for progeny has received relatively little study; an approach where both male and female condition is manipulated is thus desirable. We compared both sexes' preferences in Tenebrio molitor beetles when individual condition varied (healthy vs infected with a fungus), and observed the direct benefits of those preferences. We predicted that: (a) females and males in good condition would prefer high quality mates; (b) preferences would be weaker when the choosing individual is in poor condition (and thus less selective given, for example, time and energetic constrains); and, (c) high quality mates would lay a larger number of total eggs and/or viable eggs than low quality mates. We found that both males and females in good condition were not more likely to choose mates that were also in good condition. However, poor-condition animals were more likely to prefer similar quality animals, while high-condition animals did not necessarily prefer mates of similar condition. Choosing sick males or females had a negative impact on egg number and viability. Our results suggest a non-adaptive mate choice in this species. Possibly, a deteriorated condition may drive individuals to invest more in attracting mates, because their chances of surviving the infection are very low. However, we do not discount the possibility that the fungus is manipulating individuals to increase its transmission during mating.
... This mirrors previous laboratory and field studies in T. dalmanni (Cotton et al. 2015). As in other species, the likely benefit of this preference derives from mating with higher fecundity females (Olsson 1993;Dosen and Montgomerie 2004;Byrne and Rice 2006;Reading and Backwell 2007). Female eyespan reliably indicates fecundity among field-caught stalk-eyed flies, where it explains a significant amount of variation in ovarian egg number, even after controlling for body size (Cotton et al. 2010(Cotton et al. , 2015. ...
Article
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Male mate preferences have been demonstrated across a range of species, including the Malaysian stalk-eyed fly, Teleopsis dalmanni. This species is subject to sex-ratio (SR), an X-linked male meiotic driver, which causes the dysfunction of Y-sperm and the production of all-female broods. While there has been work considering female avoidance of meiotic drive males, the mating decisions of drive-bearing males have not been considered previously. Drive males may be less able to bear the cost of choice as SR is associated with a low-frequency inversion that causes reduced organismal fitness. Drive males may also experience weaker selection for preference maintenance if they are avoided by females. Using binary choice trials, across two experiments, we confirmed male preference for large (fecund) females but found no evidence that the strength of male preference differs between drive and standard males. We showed that large eyespan males displayed strong preference for large females, whereas small eyespan males showed no preference. Taken together, these results suggest that, even though meiotic drive is associated with lower genetic quality, it does not directly interfere with male mate preference among available females. However, as drive males tend to have smaller eyespan (albeit only ~5% on average), this will to a minor extent weaken their strength of preference.
... Most evidences are indirect; for instance, it was found that different fish species discriminate their potential mates depending on their size (e.g. Bisazza et al. 2000;Dosen and Montgomerie 2004); also, size-assortative social grouping is widespread across animal species and seems the consequence of the ability to gauge conspecifics size (e.g. Barry et al. 2014;Pitcher 1986). ...
Article
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Several studies have investigated the ontogeny of the capacity to discriminate between discrete numerical information in human and non-human animals. Contrarily, less attention has been devoted to the development of the capacity to discriminate continuous quantities. Recently, we set up a fast procedure for screening continuous quantity abilities in adult individuals of an animal model in neurodevelopmental research, the zebrafish. Two different sized holes are presented in a wall that divides the home tank in two halves and the spontaneous preference of fish for passing through the larger hole is exploited to measure their discrimination ability. We tested zebrafish larvae in the first, second and third week of life varying the relative size of the smaller circle (0.60, 0.75, 0.86, 0.91 area ratio). We found that the number of passages increased across the age. The capacity to discriminate the larger hole decreased as the ratio between the areas increased. No difference in accuracy was found as a function of age. The accuracy of larval zebrafish almost overlaps that found in adults in a previous study, suggesting a limited role of maturation and experience on the ability to estimate areas in this species.
... Our results provide an insight into the reproductive strategies of male guppies. Consistent with previous work, we found that males preferentially pursue larger females 21 . Our results also show that the degree to which males prioritized larger females was closely predicted by our model based on size-specific differences in female profitability (that is, brood size divided by sire number). ...
Article
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Resolving the strategies by which organisms compete for limited resources is key to understanding behavioural and social evolution. When competing for matings, males in many species allocate mating effort preferentially towards higher-quality females. How males balance this against avoiding competition with rival males, who should also prefer high-quality females, is poorly understood. Kin selection theory further complicates these dynamics: males should avoid competition with close relatives especially because of added, indirect fitness costs. However, whether between-male relatedness modulates the intensity of intrasexual competition is equivocal. Here, we develop and test an analytical model describing how males should optimally allocate their mating efforts in response to information about differences in female quality, competitor presence/absence and competitor relatedness. Using freely interacting groups of Trinidadian guppies (Poecilia reticulata), we show concordance between observed and predicted mating effort allocation across all combinations of these factors. Thus, male mating effort is sensitive to variation in female quality, competitor presence and competitor relatedness, which is consistent with a kin-selected strategy of male–male competition. The fit of our model’s predictions demonstrates that males integrate assessments of female quality and competitive context in a quantitatively meaningful way, implicating a competitive strategy that has been fine-tuned to maximize inclusive fitness gains. It is unclear whether between-male relatedness modulates the intensity of intrasexual competition. A combination of modelling and empirical testing supports a kin-selected strategy of male–male competition in Trinidadian guppies.
... The removal of side-biased females is common practise in mate choice studies (e.g. Schlüter et al. 1998;Schlupp et al. 1999;Dosen and Montgomerie 2004;Hoysak and Godin 2007;Poschadel et al. 2009;Williams and Mendelson 2010;Kniel et al. 2015;Scherer et al. 2018a, b) and is important to control for females that either did not show interest in stimulus males, were frightened, and/or remained motionless in one corner of the experimental tank (Scherer et al. 2016(Scherer et al. , 2017b. The relatively high threshold of 80% was chosen to ensure that only females showing a strong side preference were excluded and to be in line with the existing literature (e.g. ...
Article
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Consistent between-individual differences in behaviour, known as personality differences, are heritable and have consequences for individual survival and reproductive success. Therefore, it is likely that personality differences are not just under natural but also under sexual selection. Indeed, the recently developed idea that individuals choose their mate based on its personality finds empirical support. However, most studies on mate choice based on personality traits are correlative pioneering work and there is a paucity of experimental studies that test for causality by disentangling personality measures from other, potentially correlated traits that may be important during mate choice. Here, we tested female preference for the apparent level and consistency of either male aggression (measured as mean distance of approach towards an animated opponent, manipulated by locating males at a fixed distance) or male boldness (measured as activity under a simulated predation threat, manipulated using a gradient in ambient water temperature) in a bi-parental West African cichlid, Pelvicachromis pulcher. Females could observe the apparent behaviour of paired stimulus males and were allowed to choose between the two stimulus males in a subsequent choice test. We found no direct effect of male apparent aggression/boldness on female choice, but an indirect effect such that female preference for the apparently bold male increased with increasing within-male pair contrast in their apparent level of boldness. Our results indicate females consider male boldness per se during mate choice, suggesting male boldness is sexually selected in our study species. Significance statement Ever since Darwin introduced the concept of sexual selection, female choice has been studied extensively. However, the hypothesis that consistent between-individual differences in behaviour (known as personality differences) affect mate choice is relatively new. Correlative studies support this idea but provide only suggestive evidence. Here, we used behavioural manipulations in order to disentangle male behaviour from other, potentially correlated male traits, allowing us to test for causality between female choice and personality differences in male aggression and boldness (both in level and consistency of behaviour) in a bi-parental cichlid. We found no overall female preference for male apparent behaviour, but female preference for the bold-appearing male increased with increasing between-male contrast in apparent boldness. Our results indicate a causal link between female choice and male boldness. In future, behavioural manipulations using a temperature gradient could provide further valuable insights.
... Furthermore, diet restriction negatively affects female fecundity (Reznick & Yang 1993) and sexual responsiveness to males (Syriatowicz & Brooks 2004). Both effects have the potential to influence the opportunity for pre-and postcopulatory sexual selection, as reduced polyandry is expected to increase the opportunity for selection on mating success (Collet et al. 2012) and changes in the variance in female fecundity across diet treatments may influence the variance in male reproductive success, for example, when more fecund females mate non-randomly with respect to male phenotype (Dosen & Montgomerie 2004). ...
Article
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Although it is often expected that adverse environmental conditions depress the expression of condition‐dependent sexually selected traits, the full consequences of environmental change for the action of sexual selection, in terms of the opportunity for total sexual selection and patterns of phenotypic selection, are unknown. Here we show that dietary stress in guppies, Poecilia reticulata, reduces the expression of several sexually selected traits and increases the opportunity for total sexual selection (standardized variance in reproductive success) in males. Furthermore, our results show that dietary stress modulates the relative importance of precopulatory (mating success) and postcopulatory (relative fertilization success) sexual selection, and that the form of multivariate sexual selection (linear vs. nonlinear) depends on dietary regime. Overall, our results are consistent with a pattern of heightened directional selection on condition‐dependent sexually selected traits under environmental stress, and underscore the importance of sexual selection in shaping adaptation in a changing world.
... Individuals also vary in important behavioural traits, such as their predator tolerance and antipredator behaviour, and other personality types (Dugatkin 1992;Godin and Dugatkin 1996;Harris et al. 2010). Males vary in their preferences for female traits (Dosen and Montgomerie 2004), and females in their preference for male traits (Houde 1988(Houde , 1994Endler and Houde 1995;Godin and Dugatkin 1995;Brooks and Endler 2001). Given the evidence for high within-population diversity in many other behaviours, it is possible-if not likely-that individual males also vary in their diel display patterns. ...
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Sexually signalling animals must trade off the benefits of attracting mates with the consequences of attracting predators. For male guppies, predation risk depends on their behaviour, colouration, environmental conditions and changing intensity of predation throughout the day. Theoretically, this drives diel patterns of display behaviour in native Trinidadian populations, where males display more under low-light conditions when their most dangerous predator is less active. Here, we observed Australian guppies in a laboratory setting to investigate their diel display pattern, and if this pattern is controlled by ambient light intensity. We also quantified individual variation in both the daily frequency and diel pattern of displays, and if such variation relates to body size, colouration and a non-sexual behaviour. Under a typical daily light regime, male guppies displayed mostly in the first hour of observation. Extending the duration of dawn-like lighting, however, resulted in an extended period of high display, demonstrating that light intensity per se is an important cue for this behaviour. These findings mirror those obtained for Trinidadian populations, suggesting that male courtship timing is likely shaped by broad, potentially generalizable features of guppy ecology. The effect of acclimation to captive conditions on male behaviour is also discussed. Whereas the temporal pattern of display appeared consistent, individuals varied in their daily display frequency, and this was correlated with variation in colour phenotype and a measure of non-sexual risk acceptance behaviour. Such relationships pose promising avenues for integrating behavioural and sensory ecology with contemporary work on behavioural syndromes and animal personality. Significance statement To limit the costs of their conspicuous colour patterns, male guppies should alter their behaviour to avoid predation. However, our understanding of how different individuals deal with this problem is lacking. Following individuals in the laboratory, we demonstrated individual variation in the daily frequency of male displays, and this was correlated with variation in colour phenotypes and non-sexual behaviour. However, all male guppies displayed more in the early hours of the day and extending the period of low lighting also extended this period of elevated display. These findings replicate and expand experiments on native populations, suggesting that male courtship timing is likely shaped by broad, potentially generalizable features of guppy ecology.
... Since bigger guppy females produce more offspring [36,37], this result may suggest assortative mating among bolder males and larger females. Indeed, male preference for larger more fecund females has been previously found in this species [38,39]. Thus, if bolder males are better at gaining access to the most preferred females (either through competition or choice), they are expected to successfully mate with large females. ...
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Background: Intra-individual stable but inter-individually variable behaviours, i.e. personalities, are commonly reported across diverse animal groups, yet the reasons for their maintenance remain controversial. Therefore, studying fitness consequences of personality traits is necessary to discriminate between alternative explanations. Results: Here, I measured boldness, a highly repeatable personality trait, and reproductive success in male guppies, Poecilia reticulata. I found that bolder males had higher reproductive success than their shyer conspecifics and they sired offspring with females who had larger clutches. Conclusions: This result provides direct evidence for fitness consequences of boldness in the guppy. It suggests that the effect may be driven by bolder males mating with more fecund females.
... Male choice is also expected to occur when males contribute with a high investment to the mating partner and/or the offspring [19,36], as they might be unavailable for mating for a long period, penalizing their potential reproductive rate [37], a pattern common in species with exclusive paternal care [19]. Since fecundity and egg size are often related to female body size [38,39], males often benefit from preferring larger females as mates [13,[40][41][42][43]. Therefore, due to their high energetic expenditures in mating investment and parental care, both females and males are expected to choose larger mates in sexually dimorphic species with exclusive paternal care. ...
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In the absence of constraints, preference for larger mates is expected to evolve, as larger individuals are typical of higher potential fitness. Large females are often more fecund and carry larger eggs (which result in higher number and better quality of offspring), whereas large males usually have more conspicuous ornaments and are better at defending resources. However, intrasexual competition can constrain the access to larger partners, especially when opportunities for mate takeover abound. Here we investigate the relationship between individual’s size and mate choice in relation to one’s own size and their respective mate’s size using the sailfin tetra, a sexually dimorphic Amazonian fish species. We show that ornaments of larger males are exponentially more conspicuous, and larger females are more fecund and carry larger eggs. Contrary to expectation, neither males nor females associated for longer with the larger of two offered potential mates. Instead, individuals of both genders chose opposite-sex individuals of similar sizes to themselves. Additionally, similar-sized pairs were more likely to spawn than couples with higher size asymmetries. Grounded on field observations, we propose that prudent choice should be particularly important in this system, since courtship is long (often taking several days), which offers opportunities for mate takeover. Intrasexual competition, however, cannot readily explain female choice for similar-sized males. We thus suggest that such preference might be best explained by avoidance of filial cannibalism.
... This mirrors previous laboratory and field studies in T. dalmanni (Cotton et al. 2015). As in other species, the likely benefit of this preference derives from mating with higher fecundity females (Olsson 1993;Dosen and Montgomerie 2004;Byrne and Rice 2006;Reading and Backwell 2007). Female eyespan reliably indicates fecundity among field-caught stalk-eyed flies, where it explains a significant amount of variation in ovarian egg number, even after controlling for body size (Cotton et al. 2010(Cotton et al. , 2015. ...
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Male mate preferences have been demonstrated across a range of species, including the Malaysian stalk-eyed fly, Teleopsis dalmanni . This species is subject to SR, an X-linked male meiotic driver, that causes the dysfunction of Y-sperm and the production all female broods. SR is associated with a low frequency inversion spanning most of the X chromosome that causes reduced organismal fitness. While there has been work considering female avoidance of meiotic drive males, the mating decisions of drive-bearing males have not been considered previously. As drive males are of lower genetic quality they may be less able to bear the cost of choice or may experience weaker selection for its maintenance if they are avoided by females. We investigated preference of drive males using binary choice trials. We confirmed that males prefer to mate with large females (indicative of greater fecundity) but found no evidence that the strength of male mate preference differs between drive and standard males. This suggests that the cost of choice does not restrict male reference among drive males. In a further experiment, we found that large eyespan males showed strong preference whereas small eyespan males showed no preference. This is likely to weaken mate preference in drive males, as on average they have reduced eyespan compared to standard males. In this respect, drive males are subject to and exert weak sexual selection. Lay summary We studied male mate preference in stalk-eyed flies. This species suffers from meiotic drive, a selfish genetic element that causes a reduction in sperm production and organismal fitness. We predicted that males with meiotic drive would show weak mate preference. Males preferred to mate with large females, but there was no difference in the strength of preference between drive and non-drive males. Males with larger eyespan showed stronger mate preference. Meiotic drive males usually have reduced eyespan so on average they exert weaker sexual selection on females, but this is mediated by eyespan, not genotype per se .
... The female body condition was positively related to the duration of the sexual sting. The mate choice theory predicts that males prefer females with high condition, because female body size or condition is usually correlated with fecundity (Bonduriansky, 2001;Dosen & Montgomerie, 2004;Barry et al., 2010;Kahn et al., 2013;Jones et al., 2014). Therefore, sexual selection would favor male mate choice if they mate with higher quality females because they have higher fecundity, and this could mean greater reproductive success for these males (Bonduriansky, 2001). ...
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In most animal species, body condition has a fundamental role in fitness. In males, sexual selection generally favors larger body size or greater weight. This may result in males with better condition performing more vigorous courtships, and biasing female preferences. The effects of body condition on mating performance have been extensively studied in different animal groups. Among arachnids, scorpions are an interesting group for evaluating the effects of these sexual traits on mating performance, since they exhibit an ancient mode of indirect sperm transfer. Scorpion males deposit a single spermatophore on the soil to transfer the sperm to the females, and therefore, the production of spermatophores involves a high cost for them. In this study, we use the scorpion Bothriurus bonariensis as a model to evaluate different patterns of sexual behavior as a function of the body condition of both males and females. We found that males with a better body condition performed the mating dance stage more quickly than males with a lower condition. In addition, males performed the sexual sting behavior for a longer time with females in a better condition. Our results suggest that a better condition provides a mating advantage to males and represents an indicator of courtship performance. Given that female quality is usually correlated with fecundity, males mating with females with a better body condition probably have higher reproductive success.
... This species' life history and mating behaviors have been exceptionally well studied (Houde 1997;Magurran 2005), which, in combination with a propensity to inhabit freshwater systems receiving agricultural waste (e.g., Phillip 1998;López-Rojas and Bonilla-Rivero 2000;Widianarko et al. 2000;Araújo et al. 2009), means that guppies are an ideal model to study the potential behavioral impacts of endocrine disruptor exposure. Although the guppy mating system is predominantly driven by female choice, with females responding to elaborate male courtship displays and avoiding coercive "sneak" mating attempts (Houde 1997), male guppies can also be choosy and are known to prefer larger females as mates (Dosen and Montgomerie 2004;Herdman et al. 2004). Because female guppy fecundity (brood size) increases with body size (Herdman et al. 2004), males gain direct fitness benefits by mating with larger females. ...
Article
Hormonally active chemical pollution threatens human and wildlife populations globally. However, despite the well-established capacity of endocrine-disrupting chemicals (EDCs) to alter reproductive traits, relatively few studies have examined the impacts of EDCs on mechanisms of sexual selection. This study investigated the effects of short-term exposure to an environmentally realistic level of 17β-trenbolone-a potent anabolic steroid used in livestock production worldwide-on male mate preference, reproductive behavior, and morphology in the guppy (Poecilia reticulata). Male guppies prefer to mate with larger females because such females are generally more fecund. Hence, males gain direct fitness benefits by being choosy. Here, we found no significant effect of 17β-trenbolone exposure on male courting behavior, with both unexposed and exposed males courting larger females more often. However, exposure to 17β-trenbolone significantly altered the amount of coercive copulatory behavior ("sneak" matings) performed. Specifically, while both unexposed and exposed males demonstrated a preference for larger females by conducting more sneaking attempts toward these females, exposed males carried out a greater number of sneaks toward large females than did unexposed males. Further, exposure resulted in increased male condition index (i.e., mass relative to length). Together, our results show for the first time that 17β-trenbolone can alter reproductive behavior and morphology in male fish at concentrations as low as 4 ng/L, highlighting the potential for disruption of reproductive processes in wildlife exposed to this potent agricultural contaminant.
... Indeed, males often prefer larger mates and through this choice increase fitness benefits (Bonduriansky, 2001;Dosen & Montgomerie, 2004;Reading & Backwell, 2007). For example, male Atlantic mollies (Poecilia mexicana) prefer large females over small ones (Plath et al., 2006) and males of the snail species Littorina subrotundata prefer large and virgin females (Zahradnik et al., 2008). ...
Article
Mate choice is often a role assigned to females. Already Darwin realised that males are eager to copulate, and females are choosy. However, male mate choice is not as rare as assumed. Males should choose females if females vary in quality, i.e., fecundity. Indeed, males often choose larger mates and through this preference increase fitness benefits. In addition, if mating costs reduce the number of copulations a male can potentially perform, he should be choosy. Bedbug females vary in their fecundity and female size is positively related to fecundity. Male bedbugs are limited in seminal fluid availability and, hence, the number of consecutive matings they can perform. Traumatic insemination gives males full control over mating, therefore low female mating resistance could further allow males to be choosy. Here, using mate choice arenas, we investigated if male bedbugs prefer to mate with large females. We observed mating behaviour and measured female fecundity to investigate potential male fitness benefits. Males chose to mate with large females 1.8 times more often than small females and large females laid significantly more eggs than small females. Our study provides first evidence for male mate choice based on female body size in bedbugs and males can increase their fitness by mating large females. It has to be further established if male mate choice is driven by mating costs in terms of ejaculate investment and if such male mate choice based on female size could be a driver of sexual size dimorphism in bedbugs.
... Our design tested male preference for the larger of a pair of stimulus females that were presented to the males before and after experiencing high or low mating success. In the first trial, males did not show any specific preference in relation to female size (Fig. 2), which is surprising given that most previous studies have found a preference for larger females (Abrahams, 1993;Baerends, Brouwer, & Waterbolk, 1955;Dosen & Montgomerie, 2004;Herdman et al., 2004). Interestingly, after their mating experience, unsuccessful males did not discriminate among females by size, but males that experienced high mating success showed a strong adjustment of their preferences, becoming choosier in favour of larger females. ...
Article
High mating effort leads to choosiness because each mating event reduces future reproductive potential. Many studies have shown that males adjust their sexual behaviour relative to female fecundity and encounter rate. However, little is known about the effects of a male's past mating experiences. We used guppies, Poecilia reticulata, to investigate how males change their sexual behaviour after experiencing high or low mating success. Each male was tested with two differently sized unreceptive females before and after encountering either four indiscriminate receptive virgin females or four nonreceptive pregnant females. Males that experienced high mating success with receptive females decreased their courtship displays but increased the frequency of sneaky behaviour, whereas low mating success males previously repetitively rejected by nonreceptive females showed an increase in courtship and a decrease in sneaky copulation attempts. Mating history also influenced male choosiness, with successful males showing stronger preferences for larger females than unsuccessful males. This overall adjustment in behaviour may be attributed to a reduction of resources, such as energy and gametes, as well as prior social interaction with receptive and nonreceptive females. Males that adjust their effort and choosiness based on their recent mating history and their own condition could optimize reproductive trade-offs.
... males effectively stop growing after maturation). Larger females are more fecund, produce larger offspring (Reznick 1983, Bronikowski et al. 2002, and are preferred by males (Dosen andMontgomerie 2004, Herdman et al. 2004). Males, on the other hand, are selected for (relatively) fast maturation, to avoid loss of reproductive opportunities and are thought to gain little from larger size. ...
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Sexual dimorphism in behaviour and personality has been identified in a number of species, but few studies have assessed the extent of shared genetic architecture across the sexes. Under sexually antagonistic selection, mechanisms are expected to evolve that reduce evolutionary conflict, resulting in genotype-by-sex (GxS) interactions. Here we assess the extent of sexual dimorphism in four risk-taking behaviour traits in the Trinidadian guppy, Poecilia reticulata, and apply a multivariate approach to test for GxS interactions. We also quantify the among-individual and genetic covariances between personality and size and growth, which are known a priori to differ between the sexes. We found significant sexual dimorphism in three of the four behaviours, although rmf between sex-specific homologous traits was significantly <+1 for only one behaviour. Using multivariate models, we then estimated sex-specific genetic (co)variance matrices (G m and G f ) and tested for asymmetry of the cross-trait cross-sex genetic covariance structure (submatrix B). While G m and G f were not significantly different from each other overall, their respective leading eigenvectors were poorly aligned. Statistical support for asymmetry in B was found, but limited to a single trait pair for which the cross-sex covariances differed (i.e., COVA(m,f) ≠ COVA(f,m)). Thus, while single- and multi-trait perspectives evidence some GxS, the overall picture is one of similarity between the sexes in their genetic (co)variance structures. Our results suggest behavioural traits related to risk-taking may lack the sex-specific genetic architecture for further dimorphism to evolve under what is hypothesised to be antagonistic selection.
... However, selection on female (maternal) weight is expected. Like many fish species, female guppies exhibit indeterminate growth, with fecundity increasing as a function of size (Bronikowski et al. 2002) and, when given the choice, male guppies will choose to mate with larger females (Dosen and Montgomerie 2004;Herdman et al. 2004). Thus, we can at least speculate that the evolution of personality traits in guppies will depend on selection on size through maternal fitness, particularly at the juvenile stage where maternal influence is strongest, highlighting another mechanism by which morphological and behavioural traits may co-evolve. ...
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We found that both additive genetic and maternal effects are important determinants of risk-taking behaviour traits in guppies, although the former are only evident in adult fish. Not accounting for the maternal effects resulted in much higher h2 estimates in some cases raising the possibility that current estimates for personality traits are upwardly biased. Robust evidence of additive genetic variance was found for adult traits but maternal effects are also present, though with generally much smaller effect sizes than in juveniles. In contrast, our models did not provide statistical support for additive variance in juvenile behaviours. Rather our results indicate, among-family variance arises principally from maternal identity effects, as well as maternal effects occurring via variation in maternal weight and brood size. Moreover, the specific maternal traits influencing offspring behaviour differed between juveniles and adults, suggestive of a shift in the mechanism through which maternal effects influence behaviour over ontogeny. Offspring size is a plausible candidate trait for mediating maternal effects on behaviour in some cases but not all. Our study highlights the benefit of employing the hybrid approach for estimating maternal effects at different stages over offspring ontogeny, and of using animal models to estimate both the additive genetic structure and maternal effects for personality traits. We suggest that wider efforts to characterise maternal effects, and especially to test their genetic basis, could greatly benefit our understanding of the evolutionary dynamics of animal personality.
... Interestingly, males and females can show preferences -seemingly for the same trait -, body size, but likely for very different reasons. Male preferences seem to be related to a direct benefit, via increased fecundity (although a direct link to fitness remains to be shown; (Dosen & Montgomerie 2004a, Dosen & Montgomerie 2004b, whereas female preferences for large males are thought to be due to indirect, genetic benefits (Reynolds & Gross 1992). ...
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Although the majority of studies on mate choice focus on female mate choice, there is growing recognition of the role of male mate choice, too. Male mate choice is tightly linked to two other phenomena, female competition for males, and ornamentation in females. In the current paper I review the existing literature on this in a group of fishes, Poeciliidae. In this group male mate choice appears to be based on differences in female quality, especially female size, which is a proxy for fecundity. Some males also have to choose between heterospecific and conspecific females in the unusual mating system of the Amazon molly. In this case, they typically show a preference for conspecific females. While male mate choice is relatively well documented for this family, female ornamentation and female competition are not.
... Male mate choice requires female characters that indicate potential benefits, either direct or indirect, for males (Servedio and Lande 2006). Thus on top of being attracted to females that are likely receptive or previously unmated (Guevara-Fiore et al. 2010;Gaskett et al. 2004;Ojanguren and Magurran 2004) males may show preferences for females bearing attributes that reflect fecundity, such as a large body size (Kraak and Bakker 1998;Dosen and Montgomerie 2004;Herdman et al. 2004;Arriaga and Schlupp 2013), abdominal distention (Rowland 1982;Nuttall and Keenleyside 1993;Reinhardt et al. 2008) or particular (e.g. carotenoid) colouration (Amundsen and Forsgren 2001). ...
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In the majority of sexual species, there are asymmetries in reproductive effort, with males typically investing more in securing matings and females investing more in producing offspring. This causes males to mate less discriminately than females. Yet males may also become choosy if the following conditions are met: (a) that females vary in their reproductive value, (b) that males can perceive this variation, and (c) that mating with one female reduces the possibility of mating with another. These conditions may be met in the livebearing Goodeidae, a clade of Mexican fish whose females are often brightly coloured and whose males display costly ornaments and courtship as the only means to obtain matings. Males of the black-finned goodeid (Girardinichthys viviparus) have relatively simple, yet costly courtship behaviour, with mating probability depending on the duration of one-to-one courtship episodes, thus by courting one female they must ignore others. We evaluated whether the decision to court a female depends on her phenotype. Three variables of female phenotype were positively linked to the duration of male visits and to the frequency of displays performed by males: belly area, hue (“orangeness”) and size. Since fecundity and offspring survival were also a positive function of female size, we conclude that male G. viviparus evaluate the potential female reproductive value and allocate their courtship effort accordingly. Since male courtship effort is also influenced by female colouration, we suggest that our findings may help explaining the recurrent evolution of sexually dimorphic female colouration in this clade. Significance statement Amongst sexually reproducing species, females often invest heavily on offspring and mate only after selecting partners carefully, while males invest little on offspring but mate indiscriminately. In other cases, males carry the burden of raising offspring and are choosy. Thus, we see female mate choice in species with a bias towards maternal investment, and male mate choice in species with a bias towards paternal investment. Here we report male mate choice in a species with predominantly maternal investment; a viviparous fish whose females are choosy and whose males invest heavily on courtship. Males made longer visits to the wider bellied, and more orange-looking females, and larger (but not more orange) females produced more offspring which survived better, thus some attributes of females linked to their reproductive value influence how much time and effort males devote to court them.
... Throughout the whole testing time (10 min before starting the first mate-choice test until the last mate-choice test was over), Test females that showed side biases during the first mate-choice test, that is, those that spent more than 80% of their choosing time on the same side, even though we had switched the position of the stimulus cages, were excluded from the analysis in accordance with other studies (Dosen & Montgomerie, 2004;Hoysak & Godin, 2007;Kniel, Dürler, et al., 2015;Kniel, Schmitz, et al., 2015;Kniel et al., 2016;Schlupp & Ryan, 1997;Williams & Mendelson, 2010). ...
Article
Previous studies have shown that zebra finch females copy the mate choice of other females by choosing a mate of the same phenotype as the one chosen by another female (model). Little is known about the influence of the model female on the mate choice of the observing female. Therefore, we investigated the role of the model female in mate-choice copying by manipulating her phenotype. Test females could choose between an unadorned male and an artificially adorned male, that is, wearing a red feather on the forehead. During a 2h observation period, test females could observe a single male in one cage and a male–female pair in another cage. In treatment one, the single male was unadorned and both the male and the female of the pair (model female) were adorned. In treatment two, the single male was adorned, the male of the pair unadorned and the model female adorned. Afterwards, test females could again choose between two new males, one adorned and one unadorned. In treatment one, test females first showed no preference for one of the two males, but avoided adorned males after the observation period. In treatment two, test females lost an initial preference for unadorned males after the observation period. In both treatments, test females did not copy the mate choice of the adorned model female. Adorned model females seemed to have a negative influence on the attractiveness of their mates' phenotype. Test females might have recognised model females as females of a different phenotype within their species which are adapted to different environmental conditions, or even have recognised model females as a female of another species. Our study demonstrates the important role of the model female in the complex public information network in zebra finches.
Article
The presence of bystanders can influence the behaviour of a forager, which has mainly been studied in primates and birds. We tested the effect of the absence and presence of an unfamiliar audience (females, males, and their combination) near or far from a food patch, on the foraging behaviour of guppies (Poecilia reticulata). Our investigation includes both males and females, recognising that different social dynamics and reproductive strategies between the sexes could lead to varied responses to audience effects. For each focal fish, we measured the latency to start feeding, bite frequency, time spent near the audience, and overall mobility. Both males and females started feeding faster when food was close to any audience type. Specifically, females exhibited a faster feeding response in the presence of a female audience. Males reduced their feeding rate in the presence of male and mixed audiences, while both sexes increased their consumption when food was close to the audience. Focal fish, irrespective of their sex, spent more time in the vicinity of the audience zone when the audience was present but, surprisingly, females spent less time with a female audience compared to others. Only females increased their mobility when the food patch was far from any audience. Here we show that guppies adjust their foraging behaviour in the presence of an audience. The specific responses observed varied between the sexes, reflecting the distinct social trade-offs faced by each sex.
Article
Male chum salmon display a courtship behaviour involving an actively “quivering” against female, which is essential for female orgasm. Because generally male prefer larger female, we determined whether the elements of quivering such as the number, the amplitude, and the distance are affected by female body size. Additionally, quivering changes towards oviposition; therefore, we also identified the essential time for the male to succeed in his courtship behaviour. We conducted two experiments to measure quivering parameters: (i) measuring the number and the amplitude of quivering by the acceleration data logger and (ii) measuring the distance between sexes during quivering by observation of recorded video. From the first experiment, there was no significant relationship between the ratio of female‐to‐male body lengths and the number and the amplitude of quivering, while an important relationship between the body length ratio and the distance between sexes from the second experiment. Therefore, we think the distance is more significant than the number or vigour of quivering for male choice, and males quiver more closely to a larger female to increase reproductive success. In addition, when the body length ratio of the sexes is 1.01, the distance during quivering is the shortest. So, there is a possibility that the reproduction of chum salmon is based on size‐assortative mating. And both experiments also showed that male quiver passively as spawning approaches. We suggest that males may not quiver actively for smooth mating as females spawning approaches.
Article
Males often perform mate choice with the aim of maximizing reproductive success. To identify profitable mates, the males of some animals are known to use visual and chemical cues derived from females. In this study, we aimed to examine mate discrimination by male guppies (Poecilia reticulata) using chemical cues received from females under different reproductive statuses, i.e., virgin females, pregnant females, females after copulation with another male, and post-partum females. We conducted a dichotomous choice experiment for each combination of chemical stimuli from females under different reproductive statuses. In experiment 1, in which females were removed from water that was subsequently used as a chemical stimulus, male preferences did not differ significantly in all combinations of chemical stimuli from females under different reproductive statuses. However, in experiment 2, in which females remained within bottles containing the water used as a chemical stimulus, with the exception of one combination of chemical stimuli, significant differences in male preferences were detected for chemical stimuli derived from females under different reproductive statuses. Overall, males generally showed a preference for chemical stimulus received from females after copulation with other males. The findings of this study indicate that male guppies can discriminate the reproductive status of females based solely on chemical cues that may disappear or degenerate within a short period of time, thereby facilitating profitable mate choice.
Article
Although many pharmaceutical compounds (and their metabolites) can induce harmful impacts at the molecular, physiological and behavioural levels, their underlying mechanistic associations have remained largely unexplored. Here, we utilized RNA-Seq to build a whole brain transcriptome profile to examine the impact of a common endocrine disrupting pharmaceutical (17α-ethinyl estradiol, EE2) on reproductive behaviour in wild guppies (Poecilia reticulata). Specifically, we annotated 16,791 coding transcripts in whole brain tissue in relation to the courtship behaviour (i.e. sigmoid display) of EE2 exposed (at environmentally relevant concentration of 8 ng/L for 28-days) and unexposed guppies. Further, we obtained 10,960 assembled transcripts matching in the non-coding orthologous genomes. Behavioural responses were assessed using a standard mate choice experiment, which allowed us to disentangle chemical cues from visual cues. We found that a high proportion of the RNAseq reads aligned back to our de novo assembled transcriptome with 80.59% mapping rate. Behavioural experiments showed that when males were presented only with female visual cues, there was a significant interaction between male treatment and female treatment in the time spent in the preference zone. This is one of the first studies to show that transcriptome-wide changes are associated with the reproductive behaviour of fish: EE2 exposed male guppies that performed high levels of courtship had a gene profile that deviated the most from the other treatment groups, while both non-courting EE2 and control males had similar gene signatures. Using Gene Ontology pathway analysis, our study shows that EE2-exposed males had gene transcripts enriched for pathways associated with altered immunity, starvation, altered metabolism and spermatogenesis. Our study demonstrates that multiple gene networks orchestrate courting behaviour, emphasizing the importance of investigating impacts of pharmaceuticals on gene networks instead of single genes.
Article
While the importance of male mate choice is increasingly recognized, it continues to be an understudied aspect of sexual selection. Here, the effect of female body size on male mate choice was evaluated in the annual killifish Austrolebias reicherti, a species with marked sexual dimorphism in which males are more conspicuous than females. In dual-choice mate choice trials with unequal sized females we found that males spent significantly more time with larger females. Furthermore, larger females spawned more and larger eggs when spawning was allowed in non-choice trials. Therefore, male selection is probably attributable to the higher reproductive success of larger females. To our knowledge, this is the first study that provides evidence of both male mate choice in annual fishes and its possible fitness advantages. The implications of male mate choice for sexual selection in these fish highlight the need for further studies.
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Males can gain fitness benefits by preferentially courting and mating with virgin females if they represent a lower risk of sperm competition. When females mate multiply, but do not remate frequently, males can experience a lower level of sperm competition when mating with virgins. Male preference for virgins has been demonstrated many times in invertebrates but rarely in vertebrates. In this study, I tested if Anolis apletophallus males preferentially courted virgin females more than non-virgin females, in two-choice trails where the virgin was smaller than the non-virgin, and trails where the females were size-matched. In both trails males preferentially courted the virgin females more than non-virgin females. This suggests males can discriminate between females based on their reproductive history and that they do not use body size as a cue. Males most likely used visual signals from the female, although these signals could not be identified in this study. This is only the second study to show male preference for virgins in vertebrates. Although it is possible that male preference for virgins is relatively rare in vertebrates, I argue that certain life history traits, namely, where large females do not have reproductive benefits, and or when sperm is stored between subsequent reproductive events this preference function can evolve. Future studies focusing on such systems are likely to be fruitful with respect to this male mating preference and may help us to better understand the evolution of male mating preferences and female traits.
Article
On rare occasions, during mating season among sharks, ‘mating scars’ appear on female sharks’ bodies caused by the males holding onto them. The low frequency of sharks bearing such scars indicates that those markers are not part of regular mating efforts. These scars are mostly deeper cuts and punctures, indicating a more forceful motivation such as coercive mating from the male’s side. We discuss scenarios based on mating scars from three Carcharhinid species, describe and explain the arrangement of these bite scars, and consider plausible mating strategies used by males, including coercive mating.
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Consistent individual differences in behavioral tendencies (animal personality) can affect individual mate choice decisions. We asked whether personality traits affect male and female mate choice decisions similarly and whether potential personality effects are consistent across different mate choice situations. Using western mosquitofish (Gambusia affinis) as our study organism, we characterized focal individuals (males and females) twice for boldness, activity, and sociability/shoaling and found high and significant behavioral repeatability. Additionally, each focal individual was tested in two different dichotomous mate choice tests in which it could choose between computer-animated stimulus fish of the opposite sex that differed in body size and activity levels, respectively. Personality had different effects on female and male mate choice: females that were larger than average showed stronger preferences for large-bodied males with increasing levels of boldness/activity (i.e., towards more proactive personality types). Males that were larger than average and had higher shoaling tendencies showed stronger preferences for actively swimming females. Size-dependent effects of personality on the strength of preferences for distinct phenotypes of potential mating partners may reflect effects of age/experience (especially in females) and social dominance (especially in males). Previous studies found evidence for assortative mate choice based on personality types or hypothesized the existence of behavioral syndromes of individuals’ choosiness across mate choice criteria, possibly including other personality traits. Our present study exemplifies that far more complex patterns of personality-dependent mate choice can emerge in natural systems.
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Brighter red three-spined stickleback, Gasterosteus aculeatus, males have been shown to be preferred by females in the laboratory but in the field, these males did not receive more eggs. Instead, they had heavier eggs in their brood. We investigated the hypothesis that sexual selection for red coloration in male sticklebacks acts through mate choice by preferred males, who can afford to be choosy, for high-quality females which lay heavier eggs. We assume here that heavier eggs provide a direct fitness advantage. In simultaneous choice tests males were presented with two females differing in size. The number of zigzags directed to and the time spent orienting to each female were measured. After the test the females laid eggs, which we counted and weighed. Bigger (i.e. longer and heavier) females laid significantly more and heavier eggs than smaller females. For all 23 males pooled together, the preferred female was the bigger of the two in 17 cases, laid more eggs in 18 cases, but laid heavier eggs in only 13 cases. When bright and dull males were analysed separately, we found that bright but not dull males spent more time oriented to the bigger female, and to the female that laid more eggs. Females preferred by bright males tended to lay heavier eggs than nonpreferred females, although this result was not quite significant. We conclude that in nature this preference for bigger females results in brighter males receiving on average heavier eggs. Assuming higher survival of bigger offspring, we propose that this can explain how brightness can be sexually selected in spite of brighter males not receiving more eggs.
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Female mate-copying has been shown to occur between heterospecifics: female sailfin mollies Poecilia latipinna copy the choice of their gynogenetic associates, Amazon mollies P. formosa. Female mate-copying thus contributes to the maintenance of this asexual-sexual species complex by providing an advantage to male sailfin mollies that mate with Amazon females; because of mate-copying these males increase their attractiveness to conspecific females. Here we show that male mate-copying, an unreported phenomenon, also occurs and that it can reverse male preferences for conspecific females. Male mate-copying should also contribute to the maintenance of gynogens and might be advantageous in allowing males a means to rapidly assess female receptivity although sometimes resulting in heterospedfic matings.
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The only anesthetic registered in North America for use in fisheries science is 3-aminobenzoic acid ethyl ester methanesulfate (tricaine or MS-222). Although MS-222 is a very effective anesthesia for several fish species, its application in the field is limited because U.S. Food and Drug Administration guidelines demand a 21-d withdrawal period after exposure to MS-222 before fish can be released and enter the food chain. As a consequence, carbon dioxide (CO2) has been used as a substitute anesthetic; however, induction and recovery times with CO2 are long, and anesthesia is shallow in comparison with MS-222. We compared the efficacy of MS-222 to that of clove oil, a naturally occurring substance, for use as an anesthetic for juvenile and adult rainbow trout Onchorhynchus mykiss. Clove oil was as effective as MS-222 in inducing anesthesia in both age-groups. Furthermore, exposure to either clove oil or MS-222 at the concentrations tested was not detrimental to critical swimming speed of juvenile or adult rainbow trout. We propose that clove oil be considered as an alternative to MS-222 for use as a fish anesthetic.
Article
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It is becoming increasingly clear that mate preferences are not static, but can vary as a function of ecological conditions and the state of the choosing individual. This applies not only to females, the sex that has usually been the subject in research on mate preferences, but also to males. Under certain conditions, males should be selective in their choice of breeding partner. In the two-spotted goby, Gobiusculus flavescens, a small marine fish, breeding females develop conspicuous yellow-orange bellies, which they actively display to males during courtship. We have recently shown that males prefer more colourful females as mates. In this study, we test if the size of a male affects his preference for colourful females. Using three-compartment mate-choice aquaria, we recorded the interest shown by a male in two females differing in coloration but similar in size. Large and small males were equally eager to court females, but only large males showed a greater interest in the more colourful females. We suggest that small males are unselective because they usually obtain few mating opportunities, as a result of being unsuccessful in mate attraction or male contest competition. This study provides the first demonstration that the size of a male affects his preference for female colour.
Article
Full-text available
Brighter red three-spined stickleback,Gasterosteus aculeatus, males have been shown to be preferred by females in the laboratory but in the field, these males did not receive more eggs. Instead, they had heavier eggs in their brood. We investigated the hypothesis that sexual selection for red coloration in male sticklebacks acts through mate choice by preferred males, who can afford to be choosy, for high-quality females which lay heavier eggs. We assume here that heavier eggs provide a direct fitness advantage. In simultaneous choice tests males were presented with two females differing in size. The number of zigzags directed to and the time spent orienting to each female were measured. After the test the females laid eggs, which we counted and weighed. Bigger (i.e. longer and heavier) females laid significantly more and heavier eggs than smaller females. For all 23 males pooled together, the preferred female was the bigger of the two in 17 cases, laid more eggs in 18 cases, but laid heavier eggs in only 13 cases. When bright and dull males were analysed separately, we found that bright but not dull males spent more time oriented to the bigger female, and to the female that laid more eggs. Females preferred by bright males tended to lay heavier eggs than nonpreferred females, although this result was not quite significant. We conclude that in nature this preference for bigger females results in brighter males receiving on average heavier eggs. Assuming higher survival of bigger offspring, we propose that this can explain how brightness can be sexually selected in spite of brighter males not receiving more eggs.
Article
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In this study we compared the insemination efficiency of two alternative mating tactics (courtship and sneak mating) in the guppy Poecilia reticulata by quantifying the number of sperm delivered during a copulation. During a single copulation, guppies delivered between zero and 92% of the sperm available, as determined by mechanically stripping the males' sperm reserve at rest. The absolute number of sperm delivered after courtship was three times larger than that delivered through sneak mating; nonetheless, the variance was large with both tactics and the two distributions largely overlapped. The number of sperm available at rest increased with male size. With both tactics, the number of sperm delivered was positively correlated with the sperm available. Contrary to courtship copulations, in sneak copulations there was no correlation between the number of sperm delivered and male size. However, once the data were standardized for sperm reserve, small males delivered a larger proportion of their available sperm during sneak copulation. The rate of sexual acts (sigmoid and thrust rate) before copulation was not correlated with the number of sperm available. After the occurrence of a copulation in both the courtship and sneak copulation groups, the sexual activity of the male decreased in proportion to the amount of sperm he previously inseminated.
Article
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Current theory in sexual selection is extended to predict within-sex variability with regard to selectivity towards mates in different mating systems. Generally, the sex that invests more in the care of each offspring should be more selective of mates than the sex investing less. Within each sex, individuals of low male quality should be less selective than individuals of high quality, but there should be less variation in selectivity among individuals of the sex investing more. When only one sex contributes parental care, however, individuals of that sex should be uniformly selective, while the other sex is expected to mate indiscriminately. Using feral pigeons (Columba livia), these hypotheses are tested for the case in which both sexes contribute substantial parental care, but in which females contribute more than males. As predicted, females were found to be more selective of mates than males were. On certain criteria, males of lower quality were less selective of mates than males of higher quality.
Article
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Males are competitive, sexually indiscriminate, and pushy, whereas females are passive, choosy, and coy. This familiar generalization about the sexual behavior of animals and humans is grossly overstated and potentially misleading, yet has its roots in empirical observation of at least some species. One of the triumphs of modern sociobiology (1, 2) is that evolutionary theory can explain why the sexes differ in their behavior along these lines in so many cases. To state the generalization more accurately, it is frequently, if not usually, the case that for every receptive female in the mating pool of a population, there is more than one male ready to inseminate her. This typical imbalance in the operational sex ratio (OSR; ref. 3) in turn stems from the basic facts of reproductive physiology: sperm are small and cheap, whereas the time and energy burdens of egg production, gestation, and parental care typically fall more heavily on females with the result that fewer females than males are available in the mating pool at any given time (4). Consequently, competing inter alia often benefits males most strongly, whereas being discriminating in mate choice often benefits females most strongly, leading to an evolutionary process of sexual selection expected to result in the evolution of secondary sexual traits in males: weapons that help them win in competition with one another and ornaments that help them win the attentions of females.
Article
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It is well known that female mate choice decisions depend on the direct costs of choosing (either because of search costs or male-imposed costs). Far less is known about how direct fitness costs affect male mate choice. We conducted an experiment to investigate male mate choice in a fish, the Pacific blue-eye (Pseudomugil signifer). Preferred females were larger, probably because larger females are also more fecund. Males, however, were consistent in their choice of female only when the costs of associating with prospective mates were equal. By contrast, males were far less consistent in their choice when made to swim against a current to remain with their initially preferred mate. Our results suggest that males may also respond adaptively to changes in the costs of choosing.
Article
We examined both female and male mate choice in the sailfín molly, Poecilia latipinna. Female mollies preferred larger males over smaller ones when comparing males from their own populations. Although the expression of this preference depends on a female's receptive state, the level of female preference does not appear to be associated with any other attribute of the female or of the males. When presented with males of the same size from different populations, females preferred native over foreign males in some but not all population combinations. These results cannot be explained by a bias for higher size-specific rates of courtship displays that is shared by all females. Males preferred larger over smaller females; larger males exhibited stronger preferences, and preference for the larger female also increased as the disparity in size between the two object females increased. We found no evidence that males preferred native over foreign females when encountered singly or in size-matched combinations. These results indicate that discrimination among populations arises because females exercise divergent directional preferences for size-specific trait values that are associated with differences among males in these values. This result implies an active role for sexual selection in contributing to the maintenance of the behavioral or morphological distinctions among males observed within and among populations.
Article
This study tested the effect of differences in the extent of orange pigment in the color pattern of male guppies on the sexual responsiveness of females. Fish used in this study were descendants of a single natural population from the Paria River of Trinidad. Males from this population have unusually large, brilliant orange spots. I used three experimental approaches to test for discrimination by females among males based on the relative area of orange in color patterns: 1) the time to mating when a male was presented to a virgin female; 2) the frequency of sexual responses of females to passing, nondisplaying males; and 3) the proportion of a male's courtship displays that elicited a female sexual response. In all three experiments, females appeared to discriminate against males with less-than-average amounts of orange in their color patterns. In at least one experiment, however, the increase in female responsiveness with increasing amounts of orange leveled off and possibly decreased at high levels of orangeness. This suggests that there may be no advantage of increased amounts of orange above a certain level. These results suggest that female choice is a mechanism for the evolution of color patterns in guppies and may have contributed to the distinctive color pattern of the Paria population.
Article
Sexual competition is associated closely with parental care because the sex providing less care has a higher potential rate of reproduction, and hence more to gain from competing for multiple mates. Sex differences in choosiness are not easily explained, however. The lower-caring sex (often males) has both higher costs of choice, because it is more difficult to find replacement mates, and higher direct benefits, because the sex providing more care (usually females) is likely to exhibit more variation in the quality of contributions to the young. Because both the costs and direct benefits of mate choice increase with increasing parental care by the opposite sex, general predictions about sex difference in choosiness are difficult. Furthermore, the level of choosiness of one sex will be influenced by the choosiness of the other. Here, we present an ESS model of mutual mate choice, which explicitly incorporates differences between males and females in life history traits that determine the costs and benefits of choice, and we illustrate our results with data from species with contrasting forms of parental care. The model demonstrates that sex differences in costs of choice are likely to have a much stronger effect on choosiness than are differences in quality variation, so that the less competitive sex will commonly be more choosy. However, when levels of male and female care are similar, differences in quality variation may lead to higher levels of both choice and competition in the same sex.
Article
This study tested the effect of differences in the extent of orange pigment in the color pattern of male guppies on the sexual responsiveness of females. Fish used in this study were descendants of a single natural population from the Paria River of Trinidad. Males from this population have unusually large, brilliant orange spots. I used three experimental approaches to test for discrimination by females among males based on the relative area of orange in color patterns: 1) the time to mating when a male was presented to a virgin female; 2) the frequency of sexual responses of females to passing, nondisplaying males; and 3) the proportion of a male's courtship displays that elicited a female sexual response. In all three experiments, females appeared to discriminate against males with less-than-average amounts of orange in their color patterns. In at least one experiment, however, the increase in female responsiveness with increasing amounts of orange leveled off and possibly decreased at high levels of orangeness. This suggests that there may be no advantage of increased amounts of orange above a certain level. These results suggest that female choice is a mechanism for the evolution of color patterns in guppies and may have contributed to the distinctive color pattern of the Paria population.
Article
Male convict cichlids Cichlasoma nigrofasciatum presented three females simultaneously were found to prefer larger females, even if a female's size exceeded their own. This indicates that some mechanism other than male choice, such as female choice or intrasexual competition, must contribute to male-larger assortative pairing in convict cichlids. Despite a preference for larger females, males continued to consort with smaller females when available, and a female's attractiveness was a function of her size relative to other females.
Article
Four species of poeciliid fish occur sympatrically in the drainage trenches of Georgetown, British Guiana: they are Poecilia vivipara Bloch and Schneider, P. (=-Lebistes) reticulata Peters, P.(= Micropoecilia) picta Regan, and P. (= Micropoecilia) parae Eigenmann. /// Vier Poeciliiden-Arten leben sympatrisch in den Entwässerungsgräben von Georgetown, Britisch Guiana: Poecilia vivipara Bloch und Schneider, P. (= Lebistes) reticulata Peters, P. (=Micropoecilia) picta Regan und P. (= Micropoecilia) parae Eigenmann.
Book
Why have males in many species evolved more conspicuous ornaments and signals such as bright colours, enlarged fins, and feather plumes, as well as larger horns and other weapons than females? Darwin's explanation for such secondary sex traits, the theory of sexual selection, became his scientifically perhaps most controversial idea. It suggests that the traits are favoured by competition over mates. After a long period of relative quiescence, theoretical and empirical research on sexual selection has erupted during the last decades. This book describes the theory and its recent development, reviews models, methods, and empirical tests, and identifies many remaining open problems. Among the topics discussed are the selection and evolution of mating preferences; relations between sexual selection, species recognition, and speciation; constraints on sexual selection; the selection of secondary sex differences in body size, weapons, and in visual, acoustic, and chemical signals. The rapidly growing study of sexual selection in plants is also reviewed. Other chapters deal with alternative mating tactics, and with the relationships among sexual selection, parental roles, and mating systems. The present review of this very active research field will be of interest to students, teachers, and research workers in behavioural and evolutionary ecology, animal behaviour, plant reproductive ecology, and other areas of evolutionary biology where sexual selection is a potential selection factor. In spite of much exciting progress, some of the main questions in the theory of sexual selection yet remain to be answered.
Article
Previous research on natural populations of guppies in Trinidad established that guppies are exposed to geographically varying levels and types of predation. We examined the association between three predation "treatments" and several life history parameters. There were three modes of predation or treatments: (1) Crenicichla: high predation intensity, predominantly on adult guppies; (2) Rivulus: moderate predation intensity, predominantly on juveniles; and (3) Aequidens: low predation intensity on all size classes. We found in a survey of 16 localities that guppies from the Crenicichla treatment appear to have increased reproductive investment relative to the other treatments, and they achieve this in two ways. Guppies from Crenicichla treatments devote a larger percentage of their body weight to developing offspring (Reproductive Allotment) and have shorter interbrood intervals than the other treatments. They also produce more and smaller off-spring and begin to reproduce at a smaller size than the other two treatments. Guppies from Aequidens localities tend to be intermediate between Crenicichla and Rivulus localities, or tend to resemble guppies from Rivulus localities in the various life history statistics. The results of field data from two seasons, within-stream comparisons, an introduction experiment, and a selection experiment are all qualitatively consistent with the field survey and theoretical predictions. The data therefore make a strong case for the direct role of predators in molding guppy life history patterns.
Article
This book describes the sexual behavior of guppies and examines how mate choice by females leads to the evolution of the conspicuous colors and the courtship displays for which guppies are widely recognized. The author shows that female guppies prefer males with bright color patterns, especially those with orange spots, and that the mating preferences of females lead to sexual selection on both color patterns and courtship displays of males. Houde's work addresses a number of areas that are of interest in sexual selection, including the remarkable degree of plasticity and evolutionary lability of sexual behavior in guppies, geographic variation in mating preferences, possible mechanisms for the evolution of female mating preferences, and the role of sexual selection in speciation. In conclusion, the author explores the implications of her findings for behavioral ecologists who study sexual selection in other species.
Article
A systematic examination was made of isolating mechanisms, as set out by Mayr, that might serve to maintain reproductive isolation between the marine (trachurus) and the freshwater (leiurus) threespine sticklebacks. Field work was conducted in a small British Columbia coastal stream, the Little Campbell River, for years and complemented with laboratory experiments. Other streams were included late in the investigation. Leiurus permanently occupies the upper reaches of the stream; trachurus is anadromous and enters the lower reaches to breed in freshwater. Between the breeding grounds of the two, where numbers of both are greatly reduced, hybridization occurs. But it is restricted to a narrow zone.The two species are easily distinguished. Thus, morphological analysis provided firm circumstantial evidence that hybrids are plentiful and that backcrossing occurs, predominately to leiurus. Hybridization was confirmed by rearing offspring under uniform conditions in the laboratory with crosses in all combinations. Such offspring were also used to demonstrate considerable genetic divergence (much of it polygenetic) between leiurus and trachurus.Behavioural experiments demonstrated the absence of ethological isolation and hybrids performed courtship and parental care normally.Nor was genetic incompatibility found in the reared hybrids (F1's or backcrosses); all were vigourous. Seasonal isolation is only partially developed with early spawning migrants of trachurus making a major contribution to hybridization (in the Little Campbell River).Since behavioural and genetic blocks to hybridization are not present, there is no means to prevent hybridization where leiurus and trachurus come together. However, coexistence between the two species is very low. Evidence from observation and experiment in the field and from preference tests showed that ecological isolation is a very powerful barrier to hybridization. The two species show numerous adaptations to the distinctly different habitats they frequent, and each shows a strong affinity for its own habitat. In localities with intermediate or contiguous habitats, coexistence and interbreeding occur. Hybridization is a function of the environment.No selection against hybrids could be detected within the hybrid zone (or with laboratory reared hybrids); yet, one is forced to assume that it is present outside the zone. The very narrow zones as well as the reversed cline that were found indicate there is intense selection against hybrids. What these selective forces are remains to be found. Hybrid zones will probably continue to be poorly understood until a critical analysis of hybrid inferiority is made.Genotypes of either species that remain in the hybrid zone are at a strong selective disadvantage. Hence, reinforcement of ecological isolation probably occurs, and Moore's criticism concerning the spread of such reinforced genotypes would not apply to such cases. Mayr distinguishes between pre- and postmating mechanisms stating that the mode of operation of natural selection will be different for the two. But in threespine sticklebacks one premating mechanism (ecological isolation) and one postmating mechanism (hybrid inferiority) cannot be distinguished. This is so because ecological isolation is the cause of hybrid inferiority.Leiurus and trachurus are reproductively isolated, have well developed isolating mechanisms, and exhibit considerable genetic divergence. The two, then, fulfill the species definition of Mayr. There is no evidence that introgression occurs. Indeed a reversed cline showing a progressive increase in morphological divergence between the two species as the hybrid zone is approached together with the narrow hybrid zone demonstrates that selection severely restricts gene flow. Collections and observations from other streams corroborate those from the study area. Reproductive isolation between leiurus and trachurus seems to be widespread, throughout their range.
Article
Sexual competition is associated closely with parental care because the sex providing less care has a higher potential rate of reproduction, and hence more to gain from competing for multiple mates. Sex differences in choosiness are not easily explained, however. The lower-caring sex (often males) has both higher costs of choice, because it is more difficult to find replacement mates, and higher direct benefits, because the sex providing more care (usually females) is likely to exhibit more variation in the quality of contributions to the young. Because both the costs and direct benefits of mate choice increase with increasing parental care by the opposite sex, general predictions about sex difference in choosiness are difficult. Furthermore, the level of choosiness of one sex will be influenced by the choosiness of the other. Here, we present an ESS model of mutual mate choice, which explicitly incorporates differences between males and females in life history traits that determine the costs and benefits of choice, and we illustrate our results with data from species with contrasting forms of parental care. The model demonstrates that sex differences in costs of choice are likely to have a much stronger effect on choosiness than are differences in quality variation, so that the less competitive sex will commonly be more choosy. However, when levels of male and female care are similar, differences in quality variation may lead to higher levels of both choice and competition in the same sex.
Article
Guppies were observed in 4 rivers in Trinidad. In 2 mountain headstreams guppies were evenly distributed across and along the river. Guppies in a lowland river and a 'midstream' river occurred in small schools close to the water's edge. Male guppies in the headstream performed more frequent sigmoid displays and displays of longer duration than males in the turbid lowland river and the midstream river. Males in the turbid low and river exhibited higher frequencies of gonopodial thrusts than males in the oher 3 rivers. There is a likely genetic basis to the observed behavioral differences between populations.-from Authors
Article
[A description is given of the courtship of the viviparous cyprinodontid fish Lebistes reticulatus and an ethological analysis is attempted of the behaviour of the male during these performances. Several courting activities are distinguished. They most frequently occur in the order: searching, approaching the ♀, following, posturing, luring, sigmoid, this series ending either by a display jump or by a copulation attempt. This sequence corresponds to an increase of the intensity of the sexual drive; the order is not rigidly fixed, it is for instance to a considerable extent influenced by changes in the external situation. The courtship consists of two phases: 1°. a preliminary one in which the ♂ tries to lead the ♀ away from a concentration of guppies, involving the series of activities already mentioned and ending with a display jump; 2°. a more advanced stage, including the same activities but ending with a copulation attempt. In correspondence with the function in the first phase the body axes of ♂ and ♀ are aligned with each other but during the second phase (which we called checking) the ♂ halts the advance of the ♀ by placing its body axis perpendicularly to hers. By making genital smears we could distinguish copulation attempts during which real copulation took place from merely superficial gonopodial contacts. True copulations appeared to be always followed by a characteristic activity: the post copulatory jerking. The material we used was far from a pure breed and consisted of mixtures of different races, at least of iridescens, aureus, oculatus and variabilis. Therefore, the marking pattern in the (non-reproductive) ♂.♂ varied considerably from fish to fish. However, during courtship, the ♂ ♂ we studied assumed the same pattern of black markings, whereas at the same time most of the existing individual differences faded away. Six different groups of markings were distinguished during courtship, they were named 1, 2, 3, 4, 5 and 6. Quantitative studies of the occurrence of these patterns show that 3 and 5 are the only patterns occurring exclusively in combination with another pattern, namely 3 with 2 and 5 either with 4 or 6, whereas 1, 2, 4 and 6 can all occur alone. Moreover, pattern 1 can occur with 2+3, 4 or 6; 2 can be combined with 4; combinations of 2 and 6 and of 4 and 6, however, are rare and if present are incompletely developed. It is suggested that the different colour patterns correspond to different internal factors or combinations of internal factors. In that case the simultaneous presence of 2 and 6 or of 4 and 6 must indicate the contemporary influence of two internal factors that are in principal incompatible with each other. The order of the different combinations of black markings during courtship was also studied quantitatively. The results suggest that after a preliminary phase in which pattern 1 is predominate a phase follows in which pattern 4 dominates. In between both phases pattern 2 or combinations of 2 and 4 are often seen. After a longer or shorter period of courtship the 4-phase is succeeded by a 6-phase. Further quantitative studies were made to find out how often every activity is combined with every combination of marking patterns. These figures indicate that pattern 2 corresponds with aggressive behaviour, both 4 and 6 with courting behaviour, which reaches the highest level at 4.5 and 6.5. Successful copulations marked by post-copulatory jerking are, however, only performed when 6.5 is shown. This pattern, therefore, must correspond to the highest level of the sexual motivation. The sigmoid display is seen with the 4- as well as with the 6-pattern; however, the sigmoid activity in both phases shows the above mentioned difference in orientation. In the preliminary phase with the 4-pattern the sigmoid posture is directed away from the ♀ and in the advanced phase with the 6-pattern it is displayed perpendicularly to the body axis of the ♀, the orientation of the activities and the position of the patches, therefore, work together to make the latter very conspicuous to the ♀. Obviously the fixed motor pattern (
Article
In sticklebacks, Gasterosteus aculeatus, males have conspicuous nuptial coloration, whereas females are cryptically coloured. Usually females are the choosy sex in mate choice, but under certain conditions males may be choosy too. Females signal their spawning readiness, among others, by displaying a head-up courtship posture while pointing at the preferred male. We tested the male's preference for this posture by offering males a simultaneous choice of two stylized dummies of ripe females, one in head-up posture and one horizontal. The males directed relatively more courtship to the head-up dummy, and tended to do the more so the more intense the blue iris of their own eyes (corrected for differences in male length). Because the blue eye colour is a criterion of female choice in this population, attractive males tended to be choosier. Upon repeated presentation of the dummies to the same males on subsequent days, the malcs' preference for the head-up dummy disappeared, but there was no change in total courtship activity. When confronted with a different, more realistic pair of dummies, the same males showed again a preference for the head-up posture suggesting that male preference can be influenced by experience.
Article
Two experiments involving a sample of Japanese medaka, a sexually dimorphic killifish, examined whether male mate choice may occur even in promiscuous mating systems where males provide no parental care and male fitness increases with each successive mating. In Exp 1, a male was allowed to court 3 females simultaneously, and the order of courtship displays directed toward each female, spawning order, and the number of eggs released by each female were recorded. Exp 2 determined whether males preferred to court the larger of 2 females by controlling for the effect of female behavior. Results show that when simultaneously confronted with 3 females, males directed more of their courtship effort toward larger females. It is suggested that male preferences for more fecund females will occur in any mating system where males even occasionally have the opportunity to choose between 2 or more females. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
The influence of standard length (SL) and maximum body width on the attractiveness of female to male convict cichlids was examined in a choice apparatus. Preliminary experiments showed that maximum body width (abdominal swelling), ovary mass and ovary volume of females increased significantly over the 7-d post spawning period. Variation in body width explained a moderate amount of the variation in ovary mass and volume. Therefore, body width is a suitable indicator of gravidity. Male convict cichlids were offered a simultaneous choice between two females that varied in standard length (SL) and/or gravidity. Choice was determined by amount of time the male spent near each female. Males chose the larger of two females when both were gravid but showed no choice when neither was gravid. In general, males chose the gravid female when one was gravid and the other was not, regardless of the difference in SL between them. Choice of female by males was not influenced by female behaviour in the test apparatus. We suggest that mate choice by convict cichlid males is based primarily on female gravidity and secondarily on female SL.
Article
Male convict cichlids Cichlasoma nigrofasciatum presented three females simultaneously were found to prefer larger females, even if a female's size exceeded their own. This indicates that some mechanism other than male choice, such as female choice or intrasexual competition, must contribute to male-larger assortative pairing in convict cichlids. Despite a preference for larger females, males continued to consort with smaller females when available, and a females attractiveness was a function of her size relative to other females.
Article
Territorial male threespine sticklebacks, Gasterosteus aculeatus, were presented simultaneously with two gravid female stickleback dummies that differed only in degree of abdominal distention. Males directed most (approximately 60%) of their courtship behaviour (zigzags and leads) to the more distended dummy. However, when presented with the same two dummies consecutively, males directed similar amounts of courtship to each. Males probably prefer the more distended females because distention indicates greater fecundity or spawning readiness.
Article
Selection generally favours male competition for females, and female mate choice of males. If, however, females vary in quality, and if males are limited in the maximum number of females with which they can mate, then selection should also favour male mate choice. We report on male mate choice in two species of fishes with different mating systems: the threespine stickleback, which has male parental care, and the coho salmon, which has female parental care. In both species, males allocated their mating effort in direct proportion to female quality.
Article
Current theories of mate choice predict that the level of choosiness of males and females will depend on their relative investment in parental care. Males often invest less than females and are expected to be less choosy, especially in lekking species where males contribute only sperm. Our study of the haplochromine cichlid fish Astatotilapia flaviijosephi, a maternal mouthbrooder, provides the first experimental evidence for male mate choice in a lekking species. In this species the number of eggs spawned is positively correlated with female weight, thus making larger females potentially better mates. In the laboratory, we conducted a simultaneous choice experiment where males had the opportunity to associate with, and court, each of two females that differed in size. Males preferred to court the larger female and spent more time courting during experimental trials involving larger females. This selective allocation of courtship effort to more attractive (i.e. heavier) females suggests that there may be constraints on males in fertilizing multiple females, thus compelling them to be choosy.Copyright 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.
Article
Mate choice and mating success were investigated in a natural population of the redlip blenny, Ophioblennius atlanticus (Pisces: Blenniidae). Male mating success was correlated significantly with male size and with the inner surface area of the male's nest. Females preferred to mate with large males; they approached the territories of large males more often, their probability of spawning after entering the nest was greater, and they released more eggs when spawning with larger than with smaller males. Large males may be preferred because they spend more time guarding and therefore lose a smaller proportion of egg batches per reproductive period. In addition, last batches have half the hatching success of batches laid earlier. Since large males guard longer per reproductive period, a female may decrease the probability of being the last to spawn in a nest by mating with larger males. Females may prefer nests with larger surface area because such nests can hold more egg batches, and the predation risk to individual egg batches may therefore decrease. Feeding rate is reduced during guarding and the effect of this cost on future reproduction may constrain increased guarding investment by small males. Male preference for larger females was observed directly; females accepted in a nest were larger than females chased from the nest. A computer simulation showed that males mating selectively should obtain eggs at a faster rate than males mating indiscriminately.
Article
Mate choice by males has been recognized at least since Darwin's time, but its phylogenetic distribution and effect on the evolution of female phenotypes remain poorly known. Moreover, the relative importance of factors thought to underlie the evolution of male mate choice (especially parental investment and mate quality variance) is still unresolved. Here I synthesize the empirical evidence and theory pertaining to the evolution of male mate choice and sex role reversal in insects, and examine the potential for male mating preferences to generate sexual selection on female phenotypes. Although male mate choice has received relatively little empirical study, the available evidence suggests that it is widespread among insects (and other animals). In addition to 'precopulatory' male mate choice, some insects exhibit 'cryptic' male mate choice, varying the amount of resources allocated to mating on the basis of female mate quality. As predicted by theory, the most commonly observed male mating preferences are those that tend to maximize a male's expected fertilization success from each mating. Such preferences tend to favour female phenotypes associated with high fecundity or reduced sperm competition intensity. Among insect species there is wide variation in mechanisms used by males to assess female mate quality, some of which (e.g. probing, antennating or repeatedly mounting the female) may be difficult to distinguish from copulatory courtship. According to theory, selection for male choosiness is an increasing function of mate quality variance and those reproductive costs that reduce, with each mating, the number of subsequent matings that a male can perform ('mating investment') Conversely, choosiness is constrained by the costs of mate search and assessment, in combination with the accuracy of assessment of potential mates and of the distribution of mate qualities. Stronger selection for male choosiness may also be expected in systems where female fitness increases with each copulation than in systems where female fitness peaks at a small number of matings. This theoretical framework is consistent with most of the empirical evidence. Furthermore, a variety of observed male mating preferences have the potential to exert sexual selection on female phenotypes. However, because male insects typically choose females based on phenotypic indicators of fecundity such as body size, and these are usually amenable to direct visual or tactile assessment, male mate choice often tends to reinforce stronger vectors of fecundity or viability selection, and seldom results in the evolution of female display traits. Research on orthopterans has shown that complete sex role reversal (i.e. males choosy, females competitive) can occur when male parental investment limits female fecundity and reduces the potential rate of reproduction of males sufficiently to produce a female-biased operational sex ratio. By contrast, many systems exhibiting partial sex role reversal (i.e. males choosy and competitive) are not associated with elevated levels of male parental investment, reduced male reproductive rates, or reduced male bias in the operational sex ratio. Instead, large female mate quality variance resulting from factors such as strong last-male sperm precedence or large variance in female fecundity may select for both male choosiness and competitiveness in such systems. Thus, partial and complete sex role reversal do not merely represent different points along a continuum of increasing male parental investment, but may evolve via different evolutionary pathways.
Mate choice by the male convict cichlid
  • D B Nuttall
  • M H A Keenleyside
Nuttall, D. B. & Keenleyside, M. H. A. 1993: Mate choice by the male convict cichlid. Ethology 95, 247—256.
Parental investment, mate choice, and mate quality Reproductive biology of poeciliid fishes Male and female mate choice in the redlip blenny: why bigger is better
  • R Bonduriansky
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Sex roles, ornaments, and evolutionary explanation Mutual mate choice and sex differences in choosiness