Article

Nuptial gift in the spider Pisaura mirabilis maintained by sexual selection

November 2001
Behavioral Ecology 12(6):691-697

DOI:10.1093/beheco/12.6.691

Authors:

The nuptial prey gift in the spider Pisaura mirabilis has been suggested to function as a male protection against sexual canni- balism during courtship and mating. This hypothesis together with two alternatives—male mating effort and paternal investment hypotheses—were tested in a laboratory experiment with sexually inexperienced males and females. One group of males offered no gift to the female while three groups of males offered small, medium, or large sized gifts, respectively. No male was canni- balized among 82 trials. Aggression was observed only in encounters where a gift was presented. Males without a gift courted females, and 40% of these males managed to copulate, compared to 90% of males offering a gift. The copulation duration was positively correlated with gift size. In general, the female terminated the copulation and ran away with the gift. The proportion of eggs fertilized increased with copulation time. Presence or size of the nuptial gift did not affect female fecundity or spiderling size significantly. The results refute the hypotheses of sexual cannibalism and paternal investment. The nuptial gift represents a male mating effort; it entices the female to copulate, facilitates coupling during copulation, and by prolonging copulation it may increase the amount of sperm transferred. I conclude that the nuptial prey gift in Pisaura mirabilis is maintained by sexual selection. Key words: female choice, mating effort, natural selection, nuptial gift, paternal investment, Pisaura mirabilis, sexual cannibalism, sexual selection, spider. (Behav Ecol 12:691-697 (2001))

Unraveling the Significance of Draglines: Female Sexual Signalization in the Nursery-Web Spider, Pisaura mirabilis

Article

Full-text available

Sep 2023

Simple Summary Various signals are used in insects to identify mates. Signals based on visual, acoustic, or chemical communication play an important role in sexual selection. Frequently occurring chemical-based signals are the most important and understudied field of communication. Spiders use a wide variety of chemicals to find potential mates, but, until now, only a few spider-used pheromones have been identified. The nursery-web spider, Pisaura mirabilis, does not build a typical net, but leaves draglines on the ground. In our research, we investigated the role of chemical signals in female draglines influenced by factors such as spider ontogeny, nutritional status, and female mating status. Our findings indicate that the chemical signals of eggsac-carrying females were similarly sexually attractive to females not carrying eggsac. Draglines of adult and hungry females functioned, in contrast, as stimulation for male motivation to invest more silk in gift production. Chemical differences in female draglines were identified, but they did not always correspond with male behavior. We suggest the integration of behavioral and chemical approaches to better understand animal behavior in future research. Abstract Chemical signals used by animals to attract the opposite sex are well known in insects, but heavily understudied in spiders. We investigated the role of chemical signals in female draglines in a gift-giving spider, Pisaura mirabilis, using combined data from behavioral tests and high-performance liquid chromatography (HPLC). We also investigated whether the quality of sexual signalization is influenced by crucial factors, such as female spider ontogeny, nutritional status, and mating status. We found that draglines of adult (versus subadult) and hungry (versus fed) females stimulated male motivation to produce nuptial gift, and highly sexually excited males invested more silk in gift production than less sexually excited males. Unexpectedly, chemical signals of eggsac-carrying females were similarly sexually attractive to draglines of adult females not carrying eggsac. HPLC identified significant chemical differences in female draglines, but these differences did not always correspond to male behavior. The integration of behavioral and chemical approaches is required to better understand animal behavior in future research.

Dragline silk reveals female developmental stage and mediates male vibratory courtship in the nuptial gift‐giving spider Pisaura mirabilis

Article

Full-text available

Dec 2020

Male mate choice likely occurs when costs are associated with courtship or mating. For example, when males produce continuous vibrational signals, provide nutritious nuptial gifts, or are likely killed during mating, they should assess female developmental and reproductive state. Substrate‐borne vibratory courtship signals are very common in spiders serving species recognition, suppressing the female's aggression towards the male, or signalling individual quality. Males of the nursery web spider, Pisaura mirabilis, usually offer a prey item wrapped in silk as a nuptial gift to the female; the gift is commonly produced prior to female contact. When touching dragline silk deposited by a female, males tremulate their opisthosoma presumably reacting to chemical cues. Courtship energy expenditure and resource transfer should select for selective male mating decisions in this species. We hypothesized that male P. mirabilis differentiate between developmental stages of the female (sub‐adult vs. adult). Differential courtship towards virgin and mated females was not expected since females forage for nuptial gifts and might continuously signal receptivity. To test this, vibrational courtship signals of male spiders towards draglines of sub‐adult, adult unmated and mated females were recorded with a Laser Doppler Vibrometer. We found that males were less likely to perform vibrational courtship and produced less pulses when contacting silk of sub‐adult females, compared to silk produced by adult females, while their reaction towards silk of unmated and mated adult females did not differ. Reduced courtship in response to sub‐adult female silk seems beneficial since it reduces energy expenditure in the face of a not yet reproductive female. When vibratory courtship occurred, the temporal patterns and dominant frequencies of the males' vibratory signals were similar, regardless of female developmental stage or mating status. Such stable patterns suggest a role in species recognition already at a distance without direct physical contact and in reducing female aggression.

Male preferences for nuptial gifts and gift weight loss amongst the nursery web spider, Pisaura mirabilis

Article

Jul 2019

Pavol Prokop

Sexual signals produced by males are costly. Thus, sexual selection may favour males who are able to minimise these costs, but are still reproductively successful. I investigated male preferences for large and small prey used to produce nuptial gifts, which serve as sexual signals in the nursery web spider, Pisaura mirabilis. Males showed strong preferences for large prey compared to small prey for gift production, which is likely to be more attractive for females and provide males with longer copulation. These preferences were strongest in the presence of female pheromonal cues. Unexpectedly, carrying nuptial gifts did not influence male mobility measured in a 5-min-long behavioural test. Both gifts carried by males and the intact gifts showed similar decreases in mass, suggesting that males did not actively suck the content of the gift. Wrapping the gift with silk did not effectively reduce the gift’s dehydration, meaning that the function of the silk is not to protect the gift’s contents. Males in poor body condition were more likely to feed on the prey before wrapping it. This is consistent with condition dependent signalling, as males in low condition are predicted to feed on the prey as they are not able to pay the cost of gift production. Males preferred large-sized prey for gift production and males in poor body condition reduced the cost of gift production by feeding on the prey, supporting the idea that nuptial feeding is condition dependent.

Fitness effects of nuptial gifts in the spider Pisaura mirabilis: Examination under an alternative feeding regime

Article

Full-text available

Nov 2018

Nuptial feeding has variable effects on fitness within a species, partly driven by variation in female diet. We investigate nuptial feeding in the spider Pisaura mirabilis (Clerck, 1757) under a feeding regime that has not been explored: Starvation after mating and gift consumption. We vary gift size and gift number to examine the effects on mating behavior and components of female fitness. With regard to gift size, copulation duration increased with larger gift size, but no component of female fitness was affected (time to oviposition, egg sac mass, female lifespan). These results corroborate other examinations of gift size in P. mirabilis. Given a likely male benefit (prolonged copulation) for larger gift size and no demonstrated female benefit, sexual conflict stands as a likely explanation for male benefits due to large nuptial gift size. With regard to gift number, components of female fitness were not affected by the consumption of one or two extra gifts. This agrees with other studies, although we note that some experiments have found the consumption of extra gifts to increase female fitness. As for males, they were more likely to copulate when they had gifts, as in other studies. We conclude some support for sexual congruence with regard to gift number, as males and females stand to benefit simultaneously from the mere presence of the gift, and females might benefit from the consumption of multiple gifts. Thus, both sexual conflict and sexual congruence appear to be at work regarding the evolution of nuptial gifts in Pisaura mirabilis.

Resource availability, mating opportunity, and sexual selection intensity influence the expression of male alternative reproductive tactics

Article

Apr 2018

The expression of alternative reproductive tactics can be plastic and occur simultaneously depending on cues that vary spatially or temporally. For example, variation in resources and sexual selection intensity is expected to influence the pay‐off of each tactic and shape the decision of which tactic to employ. Males of the nuptial gift‐giving spider Pisaura mirabilis can adopt three tactics: offering a genuine prey gift, a ‘worthless’ non‐nutritious gift, or no gift. We hypothesized that resources and/or male body condition, and mating opportunity and sexual selection intensity, vary over the course of the mating season to shape the coexistence of alternative traits. We measured these variables in the field over two seasons, to investigate the predictions that as the mating season progresses, 1) males become more likely to employ a gift‐giving tactic, and 2) the likelihood of switching from worthless to genuine gifts increases. Prey availability increased over the season and co‐varied with the propensity of males to employ the gift‐giving tactic, but we found no support for condition‐dependent gift giving. Males responded to an increase in female availability by increasing their mating effort (gift production). Furthermore, the frequency of genuine gift use increased with sexual selection intensity, consistent with the assumption that sperm competition intensity increases with time. Our results suggest that the frequency of alternative tactics is shaped by seasonal changes in ecological factors and sexual selection. This leads to relaxed selection for the gift‐giving tactic early in the season when females are less choosy and resources more scarce, and increased selection for genuine gifts later in the season driven by mating opportunity and risk of sperm competition. This article is protected by copyright. All rights reserved.

Evolution of deceit by worthless donations in a nuptial gift-giving spider

Article

Full-text available

Jan 2014

Males of the nursery web spider Pisaura mirabilis usually offer an insect prey wrapped in white silk as a nuptial gift to facilitate copulation. Males exploit female foraging preferences in a sexual context as females feed on the gift during copula-tion. It is possible for males to copulate without a gift, however strong female preference for the gift leads to dramatically higher mating success for gift-giving males. Females are polyandrous, and gift-giving males achieve higher mating success, longer copulations, and increased sperm transfer that confer advantages in sperm competition. Intriguingly, field studies show that approximately one third of males carry a worthless gift consisting of dry and empty insect exoskeletons or plant fragments wrapped in white silk. Silk wrapping disguises gift content and females are able to disclose gift content only after accepting and feeding on the gift, meanwhile males succeed in transferring sperm. The evolution of deceit by worthless gift donation may be favoured by strong intra-sexual competition and costs of gift-construction including prey capture, lost foraging opportunities and investment in silk wrapping. Females that receive empty worthless gifts terminate copulation sooner, which reduces sperm transfer and likely disadvantages males in sperm competition. The gift-giving trait may thus become a target of sexually antagonistic co-evolution, where deceit by worthless gifts leads to female resistance to the trait. We discuss factors such as female mating rate and intensity of sperm competition that may shape the evolution of male deception, and how ecological factors may influence the evolution and maintenance of worthless gifts as an evolutionarily stable alternative mating strategy by frequency dependent selection [Cur-rent Zoology 60(1): 4351, 2014].

Biometrical and behavioural associations with offering nuptial gifts by males in the spider Pisaura mirabilis

Article

Full-text available

Jul 2017

Nuptial gifts are under strong selection in terms of female choice. It is hypothesized that nuptial gifts represent an honest signal resulting from the trade-off between self-maintenance and mating effort. Furthermore, nuptial gift size may correlate with certain personality traits, such as male ﬁghting or hunting abilities. We investigated the nuptial gifts of a gift-giving spider, Pisaura mirabilis, consisting of both exogenous (prey) and endogenous (silk) components and their relationships to male biometry (the honest signalling hypothesis) and personality traits (the personality traits hypothesis). The gift's weight in the ﬁeld was positively correlated with male size providing support for the honest signalling hy- pothesis. No differences in body condition and ﬂuctuating asymmetry between males carrying and not carrying gifts in the ﬁeld were found which does not support the honest signalling hypothesis. A sub- stantial proportion of males offered worthless gifts that were smaller and lighter than genuine gifts. Reliable personality traits of males were not identiﬁed and no behavioural or survival differences be- tween males carrying nuptial gifts, unwrapped prey and not carrying gifts in the ﬁeld were observed. These results suggest that male size serves as an honest indicator of the exogenous component of the gift (i.e. the nuptial prey).

Mutual benefit from exploitation of female foraging motivation may account for the early evolution of gifts in spiders

Article

Jul 2017

Male exploitation of female sensory or motivational biases has been proposed to account for the early evolution of nuptial gift-giving behaviour. The hypothesis is supported if females of a species positioned early in a clade respond positively to sexual signals from males of more recent species in the clade, and if these signals are not included in the courtship repertoire of its conspecific males. We tested whether such a scenario may apply to the evolution of gift-giving behaviour in the spider family Pisauridae. Presumably, the Canarian endemic Cladycnis insignis diverged on an early branch from the clade that includes the well-known nuptial gift-giving species Pisaura mirabilis. We first showed that the natural courtship and mating in C. insignis does not include gift-giving behaviour. Second, by staging female C. insignis with gift-carrying males of P. mirabilis, we found that these females accepted the gift and allowed the males to attempt mating. The duration of heterospecific ‘matings’ was much longer than conspecific matings (45–50 min versus ca. 1 min). Thus, there is scope for exploitation of the females' foraging motivation through a behavioural switch from courting without a prey gift to courting with a prey gift. Such a switch would initially have brought huge fitness benefits to these males in terms of greatly increased mating duration (advantage in sperm competition) and protection against aggressive females (shield effect), and also a benefit to the females from increased food supply.

Male spiders reduce pre- and post-mating sexual investment in response to sperm competition risk

Article

Apr 2017

The interplay between pre- and postmating responses to intrasexual competition remains enigmatic. Sperm competition models often assume a trade-off between pre- and postmating traits that enhance mate acquisition and fertilization success, respectively. However, when males court females through food donations (i.e., nuptial gifts), pre- and postmating responses may be aligned, as nuptial gifts have the dual function of facilitating both mate acquisition and sperm transfer. In the spider Pisaura mirabilis, nuptial gifts consist of silk-wrapped prey. We tested whether males respond to a competitor by altering: 1) premating investment in the gift, 2) postmating sperm investment, and 3) whether pre- and postmating responses are coupled and respond to competition in the same direction or not. Under competition risk males silk-wrapped their gifts for significantly shorter time and transferred less sperm to females, pointing to a reduction of both pre- and postmating responses. Because silk is not a target of female choice, reducing gift construction may speed up mate acquisition. In accordance with models of sperm allocation, perceived high levels of competition and/or sperm priority patterns may explain the reduced patterns of sperm transfer found in our study. Overall, our findings suggest that in competitive environments pre- and postmating traits are coupled and respond in the same direction.

Silk wrapping of nuptial gifts aids cheating behaviour in male spiders

Article

Feb 2017

Sexual traits, such as nuptial gifts, are costly and often condition-dependent. Males should be under selection to reduce these costs without impairing their reproductive success. Spider gifts consist of silk-wrapped food, but may also consist of worthless (non-nutritive) donations that successfully lead to mating, despite yielding shorter copulations. Worthless gifts may either represent a cheaper cheating strategy or the inability to produce genuine gifts due to resource limitations (i.e. poor body condition). Unless energetic constraints limit expenditure in silk, males should apply more silk to worthless gifts to compensate for their lower reproductive value. We ask whether in Pisaura mirabilis 1) worthless gifts are condition-dependent and 2) males strategically use silk based on gift type (genuine vs worthless). We tested whether male body condition explains the gift-giving strategy and compared silk amounts covering each gift type, in gifts collected from the field and produced in the laboratory by males given different feeding regimes. Our findings show that worthless gifts are not promoted by poor body condition or limited resources. They rather result from a cheating strategy evolved to opportunistically reduce the costs of genuine gifts while ensuring nutritional advantages, with cheaters gaining body mass. Males applied more silk to worthless gifts regardless of their body condition or feeding state, suggesting they can strategically adjust silk expenditure despite its costs. By masking gift contents and prolonging female feeding, silk is crucial for the maintenance of cheating, likely resulting from an evolutionary arms race between male deception and female assessment.

The shield effect: Nuptial gifts protect males against pre-copulatory sexual cannibalism

Article

Full-text available

May 2016
BIOL LETTERS

Several not mutually exclusive functions have been ascribed to nuptial gifts across different taxa. Although the idea that a nuptial prey gift may protect the male from pre-copulatory sexual cannibalism is attractive, it has previously been considered of no importance based on indirect evidence and rejected by experimental tests. We reinvestigated whether nuptial gifts may function as a shield against female attacks during mating encounters in the spider Pisaura mirabilis and whether female hunger influences the likelihood of cannibalistic attacks. The results showed that pre-copulatory sexual cannibalism was enhanced when males courted without a gift and this was independent of female hunger. We propose that the nuptial gift trait has evolved partly as a counteradaptation to female aggression in this spider species. © 2016 The Author(s) Published by the Royal Society. All rights reserved.

Sexual Selection, Ecology, and Evolution of Nuptial Gifts in Spiders

Chapter

Full-text available

Oct 2014

Nuptial gifts are an intriguing male sexually selected trait that has evolved in a wide range of forms among different animals. Wrapped prey gifts have been intensively studied in two spiders: Paratrechalea ornata (Trechaleidae), a neotropical species, and Pisaura mirabilis (Pisauridae), a Palearctic species. Interestingly, these species experience differences in their ecology but show remarkable similarities in sexual behavior, suggesting convergent evolution of the male trait. The origin of nuptial gifts probably was derived from a fecundity advantage to females and a mating advantage to males. However, the benefits to each sex might be sensitive to fluctuations in food availability, leading to antagonistic co-evolution. When food is scarce, males may deceive females by providing worthless gifts and females may counter this exploitation by limiting sperm transfer. We review studies on the function and evolution of nuptial gifts, particularly comparing the neotropical with the Palearctic species, and discuss evolutionary implications of nuptial gifts for males and females.

Extreme Male Mating Behaviours: Anecdotes in a Nuptial Gift-Giving Spider

Article

Full-text available

Feb 2015

Nuptial gifts may serve to increase male mating success, copulation duration, and fertilization success, as is known for the nuptial feeding spider Pisaura mirabilis Clerck, 1757. In this species, strong sexual selection for the gift-giving trait may lead to male strategies, such as gift enlargement or thanatosis behaviour (death feigning), which ultimately maximize male fitness. In laboratory trials, we observed male gift enlargement by inclusion of an autosomal (self-amputated) limb, female consumption of male soma during copulation, and high-injury risk thanatosis in which a male feigned death while still in copula and only attached to the female with his pedipalp, instead of hanging onto the gift with the chelicerae as is performed in a typical thanatosis. Although the observations are anecdotal, we propose functional hypotheses for these traits in the context of extreme male mating effort and cannibalism avoidance, which are characteristics of the mating system of this species. Sexual selection and sexual conflict are major evolutionary forces that shape a variety of morphological, behavioural, and physiological traits (Parker 1979). Males must compete intra-sexually over access to females or inter-sexually to attract females, and have evolved traits that serve to increase their reproductive success (Andersson 1994).

Cryptic Female Choice and Nuptial Prey Gifts in a Spider Model

Chapter

Jun 2015

Luiz Ernesto Costa-Schmidt

Reproduction is composed by a series of strategies performed by each sex in order to gain control over the outcome of the entire process. Males’ attempts to fertilize the females may deal with a hidden factor: the cryptic female choice , which is the females’ ability to control fertilization based on males’ sexual performance. A particular kind of reproductive strategy adopted by males of several invertebrate orders involves the transfer of substances or materials during the courtship and/or copulation, also known as nuptial gifts (NG). At least nine spider families have representatives that rely on the transfer of NG, all of them classified as oral gifts. Given its appeal in broad areas of behavioral ecology, NG received great attention in terms of their role in determining the outcome of sexual interactions, but little effort was applied toward the integrate analysis of the entire courtship/copulatory process. NGs are obviously just a stage of the entire mate choice process, and the empirical data available supports the idea of sexual conflict. However, I defend that only an integrated analysis will allow us to understand if NG does play some role as a source of information for cryptic female choice, or if it still remains as a way that males found to mitigate the sexual conflict issues.

Testing presence of directionality information in female spider silk trails through male trail-following behavior

Article

Full-text available

Dec 2023
BEHAV ECOL SOCIOBIOL

Mate search is challenging for solitary species. Trails represent a particularly potent, target-oriented means for finding mates, as trail-following increases encounter rates between individuals compared to random search. Embedding directionality information into the trail allows individuals to follow trails correctly to the source. Yet, directionality remains poorly understood. Spiders deposit trails during locomotion consisting of silk lines and substrate-borne chemicals. We conducted multiple experiments to test whether female silk trails convey directionality information, whether directionality is chemically or structurally encoded and depends on female phenotype. We also examined whether males interact with silk in a way that suggests information gathering. We exposed males of the cursorial spider Pisaura mirabilis to female trails deposited unidirectionally and scored their trail-following direction (i.e., same as or opposite to the females’). Tests were repeated after washing trails with a solvent to remove putative chemicals and by sourcing silk from females of different feeding regimes. While we found little evidence for male directional trail-following, we did find that unwashed trails were more likely to be followed than washed trails. Similarly, trails of relatively larger females were more likely to be followed correctly than those of smaller females. Males extensively probed and pulled on silk lines with their appendages, suggesting the gathering of chemical and tactile information. Taken together, results suggest that directional trail-following is selected only under specific contexts in this species. Chemical attributes of trails may convey information on female quality, with directional trail-following reflecting male mate choice in a system characterized by costly male nuptial gifts. Significance statement In the context of male mate search, following conspecific trails increases the chances of encountering a mating partner, especially if trails provide information about the direction the conspecific went. Yet, trail directionality remains poorly understood. Female spiders deposit silk trails as they walk. We overall show that males follow trails directionally only under a specific context. Males were more likely to follow correctly when trails were unmanipulated (compared to being washed with solvents to remove chemicals) and when they were deposited by relatively larger females (compared to smaller ones). Chemical attributes of trails may potentially indicate directionality, while decoding movement direction from trails of larger females may reflect male preferences for females of higher reproductive value.

Female state and condition-dependent chemical signaling revealed by male choice of silk trails

Article

Sep 2023

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.

Lack of Female Preference for Nuptial Gifts May Have Led to Loss of the Male Sexual Trait

Article

Full-text available

May 2023
EVOL BIOL

Evolutionary loss of sexual traits may occur if the forces that maintain those traits weaken or disappear. Females may evolve resistance or a change in preference if the male sexual trait decreases their fitness (e.g., coercive or deceptive traits). In nuptial gift-giving spiders, males offer a food gift wrapped in silk during courtship, taking advantage of female foraging motivation. Males may also produce worthless gifts, which could select for female emancipation from deception and subsequent loss of gift function. This might be the case in the two known species of the spider genus Trechaleoides (Trechaleidae). Here, we examined the females’ preference for nuptial gifts, and gift function as male mating effort and/or male protection in both species. Trechaleoides keyserlingi males offering gifts acquired significantly fewer matings than males without gifts and thus, we verified no female preference for the gift. In T. biocellata males never produced a gift, although they experienced a high risk of pre-copulatory cannibalism. To assess whether T. biocellata females possess a pre-existing sensory bias for nuptial gifts, they were presented with heterospecific T. keyserlingi males with and without gifts. No female preference was detected, and the gift did not protect males from sexual cannibalism. If silk-wrapped nuptial gifts are ancestral in the spider family Trechaleidae, a basal loss of female preference for the gift in the genus Trechaleoides could be hypothesized. This may subsequently have changed the gift’s sexual function in T. keyserlingi and led to the complete loss of the gift-giving behaviour in T. biocellata.

Adult sex ratio and male body condition affect alternative reproductive tactics in a spider

Article

Dec 2021
BEHAV ECOL

Biases in adult sex ratios can alter the intensity of sexual selection by enhancing competition for mates. Under intense competition males increase their investment in behaviors to outcompete rivals (e.g., fighting). Yet, given that in male-biased environments mating opportunities are rare males may alternatively reduce costly courtship and/or adopt alternative reproductive tactics (ARTs). Males of the spider Pisaura mirabilis adopt different mating tactics, offering females genuine nuptial gifts (prey), nutritionally worthless gifts (prey leftovers), or no gifts. To test whether behavioral shifts between gift tactics are triggered by changes in the competitive environment, we established replicate spider populations under natural conditions at varying adult sex ratios (male-biased, female-biased and equal) and sampled gift tactics repeatedly over time. We additionally explored how male individual traits, such as body size and condition, affect the expression of ARTs. In male-biased populations males produced more gifts but of low quality, suggesting competition to trigger increased mating effort to ensure mate acquisition and fertilizations, but through a worthless gift tactic. Production of gifts and of genuine gifts was favored by high body condition, pointing to energetic limitations as being central for male reproductive capacity. We hence highlight two co-existing mechanisms at play to explain ARTs in this system, the competitive social environment where expression of gift tactics is based on optimal-decision making to overcome competition, and a conditional strategy linked to the individual’s energetic state.

Condition-dependent differences in male vibratory pre-copulatory and copulatory courtship in a nuptial gift-giving spider

Article

Full-text available

Oct 2020
BEHAV ECOL SOCIOBIOL

Condition-dependent secondary sexual traits and signals are often crucial for mate choice decisions. Nuptial gifts, provided by the male to the female during mating, may represent an indicator of male condition, especially if production of the gift is energetically costly. Additionally, other signalling modalities may well play a role in mate choice in such systems. Females of the nursery web spider Pisaura mirabilis preferably mate with males that provide a prey item wrapped in silk. Apart from the nuptial gift, vibrational signals employed during courtship and mating may reveal additional information about male condition. We tested condition-dependence of male vibrational signals of well-fed versus starved males, when in contact with female dragline silk and during mating trials. Our results show that vibrational signals are produced in P. mirabilis, both during pre-copulatory courtship and during copulation. Male courtship signals were condition-dependent: males in good condition initiated signalling earlier and emitted more vibrational pulses than poor-condition males. They were also more likely to be accepted by the female for copulation. We additionally identified vibrational signals during copulation. These signals were different from pre-copulatory courtship vibrations but did not differ between the treatment groups. This study shows that vibrational communication plays an important role before and during copulation in P. mirabilis. It sets the stage for further experiments on spider biotremology associated with nuptial gift giving behaviour. Significance statement Male courtship behaviour can indicate a male’s condition and quality and be subject to female mate choice. Vibrational communication during mating plays a crucial role in many animal species. Spiders are known to be extremely sensitive towards vibrations, and there is evidence that vibratory signals are also used during courtship. Here, we study the nuptial gift-giving spider Pisaura mirabilis in which courtship entails providing a nuptial gift by the male to the female. The gift quality determines on the probability and duration of mating. We investigated the role of vibrational behaviour in this species by standardizing nuptial gifts. Our study demonstrates that vibratory signals comprise information about the male’s condition, that signals are also produced during mating and that courtship and copulatory signals are strikingly different. We suggest that vibrational communication provides important condition-dependent traits for female mate choice in addition to the nuptial gift.

Nuptial gift chemistry reveals convergent evolution correlated with antagonism in mating systems of harvestmen (Arachnida, Opiliones)

Article

Full-text available

Jun 2018

Nuptial gifts are material donations given from male to female before or during copulation and are subject to sexual selection in a wide variety of taxa. The harvestman genus Leiobunum has emerged as a model system for understanding the evolution of reproductive morphology and behavior, as transitions between solicitous and antagonistic modes of courtship have occurred multiple times within the lineage and are correlated with convergence in genital morphology. We analyzed the free amino acid content of nuptial gift secretions from five species of Leiobunum using gas chromatography–mass spectrometry. Multivariate analysis of the free amino acid profiles revealed that, rather than clustering based on phylogenetic relationships, nuptial gift chemical composition was better predicted by genital morphology and behavior, suggesting that convergent evolution has acted on the chemical composition of the nuptial gift. In addition, we found that, species with solicitous courtship produce gifts consisting of a 19% larger proportion of essential amino acids as compared to those with more antagonistic courtship interactions. This work represents the first comparative study of nuptial gift chemistry within a phylogenetic framework in any animal group and as such contributes to our understanding of the evolution of reproductive diversity and the participant role of nuptial gift chemistry in mating system transitions.

Does silk mediate chemical communication between the sexes in a nuptial feeding spider?

Article

Full-text available

Mar 2018
BEHAV ECOL SOCIOBIOL

Chemical signals play a crucial role in reproduction as a means for locating mates and/or gaining information about their quality, ultimately affecting mating system dynamics and mate choice. In spiders, one of the potential sources of chemical signalling is silk. However, while female silk is known to attract mates and/or elicit courtship, due to sex-specific roles in mate searching, male silk-related signals are often neglected. In the hunting spider Pisaura mirabilis (Pisauridae), both sexes leave silk draglines during movements while males additionally use silk to wrap nuptial gifts (food donations to females at mating). We explored the potential for both silk types (draglines and gift silk) to release signals and tested the hypothesis that chemical compounds bound to gifts’ silk serve to elicit female attraction. We conducted behavioural choice assays for dragline and gift silk, and their putative transmission mode (airborne or contact) by testing (i) male and female attraction towards draglines of the opposite sex and (ii) female attraction towards gift silk. Whereas males were attracted to female draglines (contact cues), females did not respond to male silk of any type. We suggest that females use draglines for advertisement to secure copulation and foraging of nuptial gifts. If these signals ease male mate searching, attractive male draglines are unnecessary. Overall, males may not invest in chemical stimulation but rather exploit female foraging interests through gift giving. Alternatively, they may release signals that prime other female sexual behaviours or towards which females may have evolved resistance. Significance statement Animals commonly use chemical signals to communicate during reproduction, and spiders have the potential to release such signals from their silk. We investigated whether two silk types, draglines released during movements and silk covering male nuptial gifts (prey offered to females at mating) are attractive to the opposite sex in a hunting spider. While males were attracted to female draglines, females did not respond to male silk of any type. Females may be using silk to advertise themselves to secure matings and food through reception of nuptial gifts. If males can successfully locate females, attracting females through draglines may be unnecessary. The finding that males do not release attractant signals in the silk cover of their nuptial gifts further suggests that rather than attempting to increase their attractiveness by using chemical stimulation, males may be uniquely exploiting females’ interest in food through gift giving behaviour.

Negative effects of prolonged dietary restriction on male mating effort: Nuptial gifts as honest indicators of long-term male condition

Article

Full-text available

Mar 2016

The handicap principle proposes that sexual signals must be costly to be honest. Honesty may be maintained by the costs paid by honest signallers or by the potential costs of cheating. In the latter, handicaps should emerge as a consequence of speci c biological constraints, such as life-history trade-o s. Nuptial prey-giving arthropods are good systems to investigate the honesty of sexual signals taking into account trade-o s between self-maintenance and mating e ort. We experimentally evaluated if prolonged food shortage during early adulthood imposes long-term negative e ects on gift construction by males of the spider Paratrechalea ornata. We also evaluated whether a burst of food availability improved body condition of poorly fed males, increasing their frequency of gift construction. Poorly fed males hardly constructed gifts, even after a marked increase in feeding rate, which clearly improved their body condition. Moreover, initially poorly fed males that latter received high food intake constructed lighter gifts than continuously well fed males. The long-term e ects of prolonged dietary restriction on male propensity to construct a gift and on the size of this gift may increase the honesty of this sexually selected signal. From the female’s perspective the o er of a gift may bring information on male quality.

When all males cheat post-copulatory competition limits worthless gift-giving frequency in spiders

Article

Full-text available

Dec 2024
EVOL ECOL

Environmental conditions together with agents of sexual selection (i.e., mate competition) regulate the expression of mating tactics. Likewise, alternative tactics arise when resources needed for reproduction are limited. These tactics are commonly performed by less competitive males (e.g. small size) and restricted to low frequencies in the population. Exceptionally, in the gift-giving spider Paratrechalea ornata the deceptive tactic frequencies can range between 0 and 80% throughout the mating season. Males offer nutritive gifts (prey wrapped in silk), but they can very often wrap inedible items offering worthless gifts as an alternative tactic. The gift is presented by males during courtship, and females can only recognize the content, and therefore the deception, once they have accepted the mating. Although, receiving food gifts have a positive effect on females’ fecundity, producing and offering it can be costly for males. We tested the hypothesis that the frequency shifts in worthless gift-giving are the result of the interaction between prey availability, post-copulatory competition and individual size altering the benefits and costs associated with each gift type. In the field, we found that the deceptive tactic is performed by all males regardless of their size. Small and medium males mostly produced worthless gifts under low prey availability and high post-copulatory competition; whereas large males were not affected by prey availability, producing worthless gifts only under low post-copulatory competition. To further understand how mate competition affects less competitive males, we disentangled the potential effects on medium size males by conducting experiments with constant prey availability. We found that under post-copulatory competition, males increased the production of worthless gifts compared to males exposed to pre-copulatory or no competition. In this treatment all males acquired a mating, though with reduced mating duration. Altogether, our findings support that post-copulatory competition limits the deceptive gift-giving tactic, creating the observed shifts in the frequencies throughout the mating season.

No Evidence for the Sensory Trap Hypothesis during Courtship in the Gift-Giving Spider Pisaura mirabilis (Clerck, 1757) (Araneae: Pisauridae)

Article

Full-text available

Mar 2024

Males of a gift-giving spider Pisaura mirablis silk-wrap prey and offer it a nuptial gift to the female during courtship. The sensory trap hypothesis proposes that males exploit the maternal care instinct of females by a close resemblance to a wrapped gift with an egg sac. We predict that if the sensory trap hypothesis works, then females should not feed on egg sacs and should adopt and carry them after copulation finishes. There were no differences in mating behaviour in terms of latency to copulation, copulation duration, wrapping prey/egg sacs with silk or with the likelihood of holding gifts/egg sacs by females after copula-tion. Females consumed approximately 23% of the egg sacs during copulation (mean = 0.016 g, 95% CI [0.01-0.02]). None of the females who received an egg sac during mating continued to care for it. We conclude that the production of gifts by males correlates with female foraging needs, and the silk wrapping of prey during courtship in P. mirabilis did not evolve as a sensory trap.

The role of male body size in mating success and male–male competition in a false widow spider

Article

Dec 2023
ANIM BEHAV

Advances in the reconstruction of the Spider Tree of Life: a roadmap for spider systematics and comparative studies

Preprint

Full-text available

Dec 2022

In the last decade and a half, advances in genetic sequencing technologies have revolutionized systematics, transforming the field as studying morphological characters; a few genetic markers have given way to genomic data sets in the phylogenomic era. A plethora of molecular phylogenetic studies on many taxonomic groups have come about, converging on, or refuting prevailing morphology or legacy-marker-based hypotheses about evolutionary affinities. Spider systematics has been no exception to this transformation and the interrelationships of several groups have now been studied using genomic data. About 50,500 extant spider species have been described so far, all with a conservative body plan, but innumerable morphological and behavioral peculiarities. Inferring the spider tree of life using morphological data has been a challenging task. Molecular data have corroborated many hypotheses of higher-level relationships, but also resulted in new groups that refute previous hypotheses. In this review, we discuss recent advances in the reconstruction of the Spider Tree of Life and highlight areas where additional effort is needed with potential solutions. We base this review on the most comprehensive spider phylogeny to date, representing 131 of the currently known 132 (99%) spider families. To achieve this sampling, we combined a legacy data set of six Sanger-based markers with newly generated and publicly available genome-scale data sets. We find that some inferred relationships between major lineages of spiders (such as Austrochiloidea, Palpimanoidea, Synspermiata, etc.) are robust across different classes of data. However, several surprising new hypotheses have emerged with different classes of molecular data. We identify and discuss the robust and controversial hypotheses and compile this blueprint to design future studies targeting systematic revisions of these problematic groups. We offer an evolutionary framework to explore comparative questions such as evolution of venoms, silk, webs, morphological traits, and reproductive strategies.

Arachnomadology: A Zoētic Framework for Queering Stories of Spider Sex, Life, and Death

Article

Mar 2022

Ally Bisshop

This article explores the death/life ecologies that flourish along the queered axes of spider reproductive behaviours – from cannibalistic sex to matricidal birth – and how the language and concepts used to describe these behaviours both reflect and distort heteronormative human accounts of gender/sex, life/death and thresholds between. It recalibrates storied accounts of spider sex, life and death through a critical, creative posthumanist approach to nonhuman life as zoē (Braidotti). It presents a queered reading of spider ethologies in which death is not life’s programmatic terminus, but another zoētic expression of desire: the endless reaching for affirmative becomings through (re)productive comminglings of bodies – whether by penetration, modulation, ingestion, or absorption. It argues how a spiderly weaving together of sex and death effects the conditions for the creative survival (inherence) of life itself. This zoētic analysis of spider ethologies proposes a novel figuration: the arachnomad – a sensuous assemblage of spider, web, affects and tangents – as a material model and heuristic for understanding nomadic subjectivities, and for queering the life/death relation.

Evolution of sexual conflict in scorpionflies

Article

Full-text available

Feb 2022
eLife

Sexual conflict - opposite reproductive/genetic interests between sexes - can be a significant driver of insect evolution. Scorpionflies (Insecta: Mecoptera) are models in sexual conflict research due to their large variety of mating practices, including coercive behaviour and nuptial gift provisioning. However, the role of palaeontology in sexual conflict studies remains negligible, namely due to the paucity of well-preserved fossils. Here we describe three male scorpionflies from Cretaceous and Eocene ambers. The structure of notal and postnotal organs is analysed in extant and extinct forms; a depression below the base of the notal organ in different panorpid species spatially matches the anterior fold of the female's wing. Based on disparate abdominal configurations and correlations in extant relatives, we posit that each new fossil taxon had a different mating approach along a nuptial gifting-coercive spectrum. The Eocene specimen possesses extreme female clamping abdominal armature, suggesting a degree of sexual coercion greater than in any other known scorpionfly, extinct or extant. The fossil record of abdominal modifications in male scorpionflies documents a relatively late evolution (Eocene) of long notal organs indicating oppressive behaviour toward a female during mating. Our findings reveal a wider array of mating-related morphological specialisations among extinct Panorpoidea, likely reflecting more diversified past mating strategies and behaviours in this group, and represent first steps towards gaining a deep-time perspective on the evolution of sexual conflict over mating among insects.

Evolution of nuptial-gift-related male prosomal structures: taxonomic revision and cladistic analysis of the genus Oedothorax (Araneae: Linyphiidae: Erigoninae).

Article

Nov 2021
ZOOL J LINN SOC-LOND

Sexual selection has been shown to drive speciation. In dwarf spiders (erigonines), males possess diverse, sexually selected prosomal structures with nuptial-gift-producing glands. The genus Oedothorax is suitable for investigating the evolution of these features due to high structural variation. We have re-delimited this genus based on a phylogenetic analysis. Ten species are Oedothorax s.s.; five are transferred back to their original generic placement; 25 remain unplaced as ‘Oedothorax’. Four junior synonymies are proposed: Callitrichia simplex to Ca. holmi comb. nov.; Gongylidioides kougianensis to G. insulanus comb. nov.; Ummeliata ziaowutai to U. esyunini comb. nov.; Oe. kathmandu to Mitrager unicolor comb. nov. Oedothorax seminolus is a junior synonym of Soulgas corticarius and the transfer of Oe. alascensis to Halorates is confirmed. The replacement name Ca. hirsuta is proposed for Ca. pilosa. The male of Callitrichia longiducta comb. nov. and the female of ‘Oedothorax’ nazareti are newly described. Thirty-eight Oedothorax species are transferred to other genera. Callitrichia spinosa is transferred to Holmelgonia. Three genera are erected: Cornitibia, Emertongone and Jilinus. Ophrynia and Toschia are synonymized with Callitrichia. Character optimization suggests multiple origins of different prosomal modification types. Convergent evolution in these traits suggests that sexual selection has played an important role in erigonine diversification.

Silk-borne chemicals of spider nuptial gifts elicit female gift acceptance

Article

Full-text available

Nov 2021
BIOL LETTERS

Chemical communication is important in a reproductive context for conveying information used for mate recognition and/or assessment during courtship and mating. Spider silk is a common vehicle for chemical communication between the sexes. However, despite being well described in females, male silk-borne chemicals remain largely unexplored. Males of the spider Pisaura mirabilis silk-wrap prey (i.e. nuptial gifts) that is offered to females during courtship and eaten by the female during mating. Interestingly, rejected males often add more silk to their gift which leads to successful mating, suggesting the presence of silk-borne chemicals that facilitate female gift acceptance. To test this hypothesis, we offered females standardized gifts covered with male silk that was either washed in solvents or unwashed, respectively, to remove or not any chemically active components. We scored female gift acceptance, and as expected in the case chemicals that mediate female mating behaviour are present in male silk, females were more likely to accept gifts covered with unwashed silk. Our findings suggest that silk-borne chemicals of nuptial gifts prime female responses, potentially signalling male quality or manipulating females into mating beyond their interests given the occurrence of male cheating behaviour via nutritionally worthless gifts in this system.

Differential allocation in a gift-giving spider: males adjust their reproductive investment in response to female condition

Article

Full-text available

Dec 2021
BMC EVOL BIOL

Background When males are selective, they can either reject low-quality females or adjust their reproductive investment in response to traits that indicate female quality (e.g., body size or condition). According to the differential allocation hypothesis , males increase their reproductive investment when paired with high-quality females ( positive differential allocation ) or increase their reproductive investment when paired with low-quality females ( negative differential allocation ). This hypothesis has been proposed for monogamous species with biparental care, and most empirical studies focus on birds. Here we used the polygamous spider Paratrechalea ornata , in which males offer prey wrapped in silk as nuptial gifts, to test whether males adjust their reproductive investment in gift size, pre-copulatory and copulatory courtship, and sperm transfer in response to female body condition. Results Males exposed to females in good body condition added more flies to the gift, stimulated these females longer with abdominal touches during pre-copulatory courtship, and had longer pedipalp insertions than males exposed to females in poor body condition. Female condition affected neither silk investment in nuptial gift wrapping nor the quantity of sperm transferred by males. Finally, females in good body condition oviposited faster after copulation and laid more eggs than females in poor body condition. Conclusions We provide experimental evidence that males of a gift-giving spider exhibit positive differential allocation in three key aspects of their reproductive investment: the size of the nutritious gift, duration of pre-copulatory courtship, and duration of pedipalp insertions, which is regarded as a form of copulatory courtship in spiders. This positive differential allocation is likely associated with the benefits of copulating with females in good body condition. These females are more fecund and oviposit faster after copulation than females in poor body condition, which under natural field conditions probably reduces the risk of multiple matings and thus the level of sperm competition faced by the males. As a final remark, our findings indicate that the hypothesis of differential allocation also applies to species with a scramble competition mating system, in which males heavily invest in nuptial gift construction, but not in parental care.

Empty nuptial gifts: a further step in the evolution of deception in spiders?

Article

Sep 2020

In the spider families Trechaleidae and Pisauridae, males offer nuptial gifts to females during courtship. Nutritive gifts contain recently caught prey wrapped in silk, while worthless gifts contain prey leftovers or plant parts. The presence of wrapped gifts is known in three out of 16 genera (Paratrechalea Carico, 2005, Trechalea Thorell, 1869 and Trechaleoides Carico, 2005) in Trechaleidae, suggesting that this sexual trait is of widespread occurrence in the family. Here, we report the presence of wrapped nuptial gifts in the genus Paradossenus F.O. Pickard-Cambridge, 1903. Males of P. longipes (Taczanowski, 1874) produce prey-gifts following the same sequence of behavioral units as described for other species of the family. More surprisingly, these males may also produce empty gifts consisting of a silken structure lacking contents. This is the first record of empty nuptial gifts in spiders. This novel male tactic may have evolved from worthless gifts as a further step in the evolution of deception in gift-giving spiders.

Ineffective nuptial gifts suggest female emancipation from sensory exploitation

Article

Full-text available

Mar 2021
BEHAV ECOL SOCIOBIOL

Male sensory exploitation of female gustatory pre-existing bias has been proposed for the origin of nuptial gifts in insects and spiders. This sexual trait may have been beneficial to both sexes, giving mating and survival advantages to males and providing nutritional resources for females. However, the evolution of deceptive worthless gifts is against females’ interests and may trigger a co-evolutionary change in females’ preferences. We evaluated females’ preferences for nuptial gifts and the adaptive function of the gift in the spider Trechaleoides keyserlingi. The genus belongs to the understudied Neotropical family Trechaleidae in which nuptial gifts are widespread. The family is composed of only two species, and the gift seems to be absent in the sister species, creating a relevant scenario for understanding co-evolutionary processes. In the laboratory, we found that although males invested more in nuptial gifts when encountering mated females compared to unmated, they had similar mating access and duration than males lacking a gift. We also found an absence of female choice between males offering nutritive and worthless gifts. Few females were aggressive and cannibalized males, and we did not find evidence that the gift protected males from cannibalism. In the field, 50% of the gifts were worthless items. This is congruent with the laboratory findings where males offering worthless gifts seem to better attract females, which we discuss in the context of exploitation of female gustatory bias. We therefore propose that females may have evolved indifference for the gift and that gift-giving in this species represents a currently non-functional remnant of a behaviour. Significance statement Nutritive nuptial gifts can exploit female gustatory preferences, with mutual benefits for both sexes: males can increase mating success and survival, while females increase their fecundity. But males can offer worthless gifts leading females to suboptimal matings, and in turn females can evolve indifference for the trait. The spider genus Trechaleoides is ideal to examine this process because gift-giving behaviour is present in one species and absent in the other. We examined females’ preferences for nuptial gifts and its function for males in the gift-giving species T. keyserlingi. We found that males invest in a gift but gain no reproductive advantage, as females were equally likely to mate with them regardless of whether they offered a gift or whether the gift was nutritive or worthless. We propose that females may have changed their preferences and that the gift is a remnant non-functional trait.

Empty nuptial gifts: a further step in the evolution of deception in spiders?

Article

Oct 2020

Biting and binding: an exclusive coercive mating strategy of males in a philodromid spider

Article

Sep 2020

Males typically court females extensively to convince them to mate. In some species, however, males coerce females to mate. We studied mating behaviour in the spider Thanatus fabricii and focused on behavioural and venomic adaptations. We found that males always bit and bound females before and during mating. The bitten females quickly fell into a state of immobility, during which males copulated with them. The duration of male bites increased with increasing size of the female. In contrast, male bites were shorter if the female was missing legs. Additionally, males with relatively longer legs induced longer states of immobility in females. Binding by silk prolonged the state of immobilization, allowing males to perform more insertions. After copulation, females were less successful in catching their prey (ants), suggesting that this mating strategy negatively affects female fitness. Altogether, this evidence shows that mating in T. fabricii is coercive. Males of T. fabricii had relatively larger venom glands than both conspecific females and males of closely related Philodromus species, which court females. The composition of venom, however, did not differ between the sexes. Male venom glands appear to be adapted to coercive mating rather than to foraging, as they caught fewer prey than closely related species. We suggest that coercive mating in T. fabricii may be enabled by venomic adaptation in the males.

The ecology and evolution of autotomy

Article

Full-text available

Jun 2019

Autotomy, the self‐induced loss of a body part, occurs throughout Animalia. A lizard dropping its tail to escape predation is an iconic example, however, autotomy occurs in a diversity of other organisms. Octopuses can release their arms, crabs can drop their claws, and bugs can amputate their legs. The diversity of organisms that can autotomize body parts has led to a wealth of research and several taxonomically focused reviews. These reviews have played a crucial role in advancing our understanding of autotomy within their respective groups. However, because of their taxonomic focus, these reviews are constrained in their ability to enhance our understanding of autotomy. Here, we aim to synthesize research on the ecology and evolution of autotomy throughout Animalia, building a unified framework on which future studies can expand. We found that the ability to drop an appendage has evolved multiple times throughout Animalia and that once autotomy has evolved, selection appears to act on the removable appendage to increase the efficacy and/or efficiency of autotomy. This could explain why some autotomizable body parts are so elaborate (e.g. brightly coloured). We also show that there are multiple benefits, and variable costs, associated with autotomy. Given this variation, we generate an economic theory of autotomy (modified from the economic theory of escape) which makes predictions about when an individual should resort to autotomy. Finally, we show that the loss of an autotomizable appendage can have numerous consequences on population and community dynamics. By taking this broad taxonomic approach, we identified patterns of autotomy that transcend specific lineages and highlight clear directions for future research.

Enough for all: no mating effort adjustment to varying mate availability in a gift-giving spider

Article

Full-text available

Jun 2019
BEHAV ECOL

Reproduction is costly, and because males possess a finite energetic budget, resource allocation to one mating event may constrain investment in subsequent matings. Consequently, males of many species evolved to adjust their reproductive investment in response to mating opportunities. When female availability is high, males are predicted to partition their reproductive effort among multiple partners to avoid resource depletion before mating opportunities have ceased. We tested this prediction in males of the spider Pisaura mirabilis, which mate via costly nuptial gifts consisting of silk-wrapped prey and are known to respond to social cues (rivals' presence) by adjusting their reproductive investment. We manipulated the number of females exposed to males to induce perception of high mating opportunities versus low mating opportunities, and scored male investment to premating traits (time allocated to gift construction and courtship) and traits at mating (copulation duration) during interactions with a female. We expected males facing higher mating opportunities to reduce their investment in all measured traits, but instead found no differences in male trait expression. These findings indicate lack of resource partitioning in response to variation in female availability, as males may be able to draw resources from nonreproductive traits (growth or immune defense) or may increase their food intake at mating by partially consuming the nup-tial gift. Hence, despite their associated costs, by providing a source of nutrition, nuptial prey gifts may weaken selection for adaptive plasticity in male reproductive investment.

Maintenance of deceptive gifts in a natural spider population: ecological and demographic factors

Article

Apr 2019
BEHAV ECOL

Alternative mating tactics are expected to occur predominantly when mate competition is intense, resources are in short supply, or as a result of asymmetric power relationships between individuals. Males of the nuptial gift-giving spider Pisaura mirabilis use a prevailing tactic of offering a nutritive gift (insect prey) and a deceptive tactic of offering a worthless gift (consumed prey) to prospective mates. If the male's tactic depends on precopulatory male-male competition, worthless gifts should occur primarily late in the season , when the operational sex ratio (OSR) becomes male-biased. If it depends on resource availability and/or postcopulatory sexual selection (sperm competition), worthless gifts should occur mostly early in the mating season, when prey availability is low and most females are unmated (i.e., postcopulatory sexual selection is weak). Nuptial gift construction correlated positively with prey availability and negatively with OSR, suggesting that males increase reproductive effort when resource and mate availability increase. We did not find evidence for body condition affecting male tactic use. Male size had a marked effect on the reproductive tactic employed. Males that matured early in the season were very small and employed mostly the nutritive gift tactic during their short life. Among the males that matured later and persisted through the season, relatively small males employed the worthless gift tactic whereas large males employed the nutritive gift tactic. We suggest that the existence of 2 distinct life-history strategies among males (early small and late large size) interacts with environmental and demographic conditions to maintain the deceptive tactic.

Sexual Selection in Neotropical Spiders: Examples from Selected Groups

Chapter

Nov 2017

Spiders have long been noted as classic examples of sexual behavior among arachnids, including extreme sexual dimorphism in some groups, and behavioral adaptations to diverse mating patterns. In recent decades, studies on the biology of Neotropical spiders have offered novel information on processes related to reproductive biology, including sexual selection. The present chapter synthesizes the large amount of knowledge on sexual selection and associated subjects in spiders from the Neotropics. Some of the groups considered in this review are mygalomorphs, lycosids and related, orb-weaving species, tetragnathids, social species, pholcids, and oonopids, among others. Concepts, patterns, mechanisms, and prospects on different areas of sexual selection are shown in detail for all these groups. In particular, here we highlight selected examples of the different contexts in which male–female interactions occur, such as mate choice, sexual cannibalism, sperm competition, and cryptic female choice. We outline the potential evolutionary consequences according to those contexts, with a final selection of model groups for specific experimental and comparative investigations.

Females of a gift-giving spider do not trade sex for food gifts: A consequence of male deception?

Article

Full-text available

May 2017
BMC EVOL BIOL

Background Polyandry is commonly maintained by direct benefits in gift-giving species, so females may remate as an adaptive foraging strategy. However, the assumption of a direct benefit fades in mating systems where male gift-giving behaviour has evolved from offering nutritive to worthless (non-nutritive) items. In the spider Paratrechalea ornata, 70% of gifts in nature are worthless. We therefore predicted female receptivity to be independent of hunger in this species. We exposed poorly-fed and well-fed females to multiple males offering nutritive gifts and well-fed females to males offering worthless gifts. Results Though the treatments strongly affected fecundity, females of all groups had similar number of matings. This confirms that female receptivity is independent of their nutritional state, i.e. polyandry does not prevail as a foraging strategy. Conclusions In the spider Pisaura mirabilis, in which the majority (62%) of gifts in nature are nutritive, female receptivity depends on hunger. We therefore propose that the dependence of female receptivity on hunger state may have evolved in species with predominantly nutritive gifts but is absent in species with predominantly worthless gifts. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-0953-8) contains supplementary material, which is available to authorized users.

Mating behaviour and sexual selection

Article

Jan 2011

Spider mating behaviour is varied and often surprising. In the past few decades, there has been a shift from descriptive natural history approaches to a more manipulative, theory-based dissection of the behavioural and evolutionary ecology of mating. This approach has yielded evidence in support of important underlying themes of sexual selection. In this chapter, we summarise patterns of mating behaviour in spiders, and the conditions that underlie variation in this behaviour, with an emphasis on how sexual selection theory relates to observed patterns. We end by suggesting spiders may prove particularly tractable models for testing hypotheses regarding mechanisms of sexual selection, sex-specific mating tactics, and reciprocal links between these, and ecology, demography and life history. Introduction. There are a number of traits common to the true spiders (Order Araneae) that lend unusual dimensions to their mating behaviour (e.g. Uhl and Elias, Chapter 5). Almost all spiders are predacious (for an exception see Meehan et al., 2009), and have sensory systems exquisitely tuned to vibrational and pheromonal signals. Males transfer sperm via specialised intromittent organs (males' palps), not directly connected to the gonads, into females' sperm storage organs of variable number (spermathecae), often via independent insemination tubules (Foelix, 1996). In addition, although the mating season holds risks similar to those for all sexual species (e.g. mate rejection, competitive injury, predation), male spiders (and rarely, females; Aisenberg et al., 2009, Cross et al. 2007b, Jackson and Pollard, 1990, Schutz and Taborsky, 2005) also face the additional risk of mortality through their predacious potential mate.

Focusing on Dynamics: When an Exception Becomes a Rule

Chapter

May 2024

In this chapter, we deal with the change from the exception to the rule in biological systems, both by the action of nature and by the changes that occur due to human action. We talk about the origin of life on planet Earth, the first organisms that colonized primitive environments and changed the atmosphere, giving rise to new forms of life, the appearance of eukaryotic, multicellular organisms, and the different forms of reproduction. We focus on events and changes that were initially considered teratological and that are familiar to our current vision. We also mention adaptations, plasticity, and different phenotypes that became advantages and allowed organisms to continue living in different environments. On the other hand, we point to global processes that affect humans and that in many cases are caused by humans. We discuss examples of diseases that turn into pandemics, the processes of environmental pollution, and accelerated climate change. Finally, we will discuss the changes in scientific ideas, which are closely linked to the social context at each moment in human history, the changes in the different fields of study and within society itself.

Editorial: Diet, nutrition and insect responses to environmental change

Article

Full-text available

Apr 2024

Advances in the reconstruction of the spider tree of life: A roadmap for spider systematics and comparative studies

Article

Full-text available

Oct 2023
CLADISTICS

In the last decade and a half, advances in genetic sequencing technologies have revolutionized systematics, transforming the field from studying morphological characters or a few genetic markers, to genomic datasets in the phylogenomic era. A plethora of molecular phylogenetic studies on many taxonomic groups have come about, converging on, or refuting prevailing morphology or legacy-marker-based hypotheses about evolutionary affinities. Spider systematics has been no exception to this transformation and the interrelationships of several groups have now been studied using genomic data. About 51 500 extant spider species have been described, all with a conservative body plan, but innumerable morphological and behavioural peculiarities. Inferring the spider tree of life using morphological data has been a challenging task. Molecular data have corroborated many hypotheses of higher-level relationships, but also resulted in new groups that refute previous hypotheses. In this review, we discuss recent advances in the reconstruction of the spider tree of life and highlight areas where additional effort is needed with potential solutions. We base this review on the most comprehensive spider phylogeny to date, representing 131 of the 132 spider families. To achieve this sampling, we combined six Sanger-based markers with newly generated and publicly available genome-scale datasets. We find that some inferred relationships between major lineages of spiders (such as Austrochiloidea, Palpimanoi-dea and Synspermiata) are robust across different classes of data. However, several new hypotheses have emerged with different classes of molecular data. We identify and discuss the robust and controversial hypotheses and compile this blueprint to design future studies targeting systematic revisions of these problematic groups. We offer an evolutionary framework to explore comparative questions such as evolution of venoms, silk, webs, morphological traits and reproductive strategies.

How this book came about

Chapter

Jan 2011

Marie E. Herberstein

Spiders are often underestimated as suitable behavioural models because of the general belief that due to their small brains their behaviour is innate and mostly invariable. Challenging this assumption, this fascinating book shows that rather than having a limited behavioural repertoire, spiders show surprising cognitive abilities, changing their behaviour to suit their situational needs. The team of authors unravels the considerable intra-specific as well as intra-individual variability and plasticity in different behaviours ranging from foraging and web building to communication and courtship. An introductory chapter on spider biology, systematics and evolution provides the reader with the necessary background information to understand the discussed behaviours and helps to place them into an evolutionary context. Highlighting an under-explored area of behaviour, this book will provide new ideas for behavioural researchers and students unfamiliar with spiders as well as a valuable resource for those already working in this intriguing field.

Evolution of nuptial-gift-related male prosomal structures: taxonomic revision and cladistic analysis of the genus Oedothorax (Araneae: Linyphiidae: Erigoninae)

Article

Nov 2021

In Search of an Honest Butterfly: Sexually Selected Wing Coloration and Reproductive Traits From Wild Populations of the Cabbage White Butterfly

Article

Oct 2021
ANN ENTOMOL SOC AM

Sexual selection is central to many theories on mate selection and individual behavior. Relatively little is known, however, about the impacts that human-induced rapid environmental change are having on secondary sexually selected characteristics. Honest signals function as an indicator of mate quality when there are differences in nutrient acquisition and are thus potentially sensitive to anthropogenically altered nutrient inputs. We used the cabbage white butterfly, Pieris rapae (L.) (Lepidoptera: Pieridae), to investigate differences in color and testes size in a system that is often exposed to agricultural landscapes with nitrogen addition. We collected individuals from four sites in California and Nevada to investigate variation in key traits and the possibility that any relationship between wing color and a reproductive trait (testes size) could vary among locations in the focal butterfly. Coloration variables and testes size were positively albeit weakly associated across sites, consistent with the hypothesis that females could use nitrogen-based coloration in the cabbage white as an indicator for a male mating trait that has the potential to confer elevated mating success in progeny. However, variation in testes size and in the relationship between testes size and wing color suggest complexities that need exploration, including the possibility that the signal is not of equal value in all populations. Thus these results advance our understanding of complex relationships among environmental change and sexual selection in the wild.

Metabolic cost of holding nuptial food gifts for male spiders

Article

Full-text available

Dec 2020

1. In various insect and spiders, males offer nuptial food gifts to females during copulation that enhance male fitness either directly through their effects on male fertilization success or indirectly through the nutritional benefits delivering for females. However, the physiological costs of producing these gifts remain largely unexplored. 2. We examined energetic costs of holding nuptial gifts in the gift-giving spider, Pisaura mirabilis, using stop-flow respirometry. 3. Males exhibited 37% higher metabolic rates when holding a nuptial gift than when they do not have one. 4. Our findings suggest the existence of metabolic costs associated with holding a nuptial gift for males. This confirm that male condition is particularly relevant for gift-giving and may explain the evolution of male deception for cheaper nuptial gifts.

Songs versus colours versus horns: what explains the diversity of sexually selected traits?: Diversity of sexually selected traits

Article

Full-text available

Feb 2020

Papers on sexual selection often highlight the incredible diversity of sexually selected traits across animals. Yet, few studies have tried to explain why this diversity evolved. Animals use many different types of traits to attract mates and outcompete rivals, including colours, songs, and horns, but it remains unclear why, for example, some taxa have songs, others have colours, and others horns. Here, we first conduct a systematic survey of the basic diversity and distribution of different types of sexually selected signals and weapons across the animal Tree of Life. Based on this survey, we describe seven major patterns in trait diversity and distributions. We then discuss 10 unanswered questions raised by these patterns, and how they might be addressed. One major pattern is that most types of sexually selected signals and weapons are apparently absent from most animal phyla (88%), in contrast to the conventional wisdom that a diversity of sexually selected traits is present across animals. Furthermore, most trait diversity is clustered in Arthropoda and Chordata, but only within certain clades. Within these clades, many different types of traits have evolved, and many types appear to have evolved repeatedly. By contrast, other major arthropod and chordate clades appear to lack all or most trait types, and similar patterns are repeated at smaller phylogenetic scales (e.g. within insects). Although most research on sexual selection focuses on female choice, we find similar numbers of traits (among sampled species) are involved in male contests (44%) and female choice (55%). Overall, these patterns are largely unexplained and unexplored, as are many other fundamental questions about the evolution of these traits. We suggest that understanding the diversity of sexually selected traits may require a shift towards macroevolutionary studies at relatively deep timescales (e.g. tens to hundreds of millions of years ago).

Another one bites the gift: sexual behaviour in a Trechaleoides species

Article

Dec 2019

In some spiders, nuptial gifts consist of prey or inedible items wrapped in silk by males and offered to females during courtship. Such gifts occur in the Neotropical family Trechaleidae, of which most species are semi-aquatic, associated with watercourses in riparian habitats. Here, we describe the sexual behaviour of the South American species Trechaleoides keyserlingi and report the presence of nuptial gift-giving behaviour for the first time in the genus.

Parental Investment and Sexual Selection

Chapter

Full-text available

Jan 1972

Robert Trivers

Courtship behavior and sexual cannibalism in the semi-aquatic fishing spider, Dolomedes fimbriatus (Clerck) (Araneae: Pisauridae)

Article

Full-text available

Jan 1992

Göran Arnqvist

Clutch Size in Spiders: Is More Better?

Article

Full-text available

Feb 1994

1. After controlling for phylogenetic correlation, clutch size in spiders (suborder Araneomorphae) increases with body mass. 2. Clutch mass scales isometrically with adult female body mass while individual egg mass scales with negative allometry. Clutch size therefore is a result of scaling constraints on egg size and total clutch mass. 3. There is no empirical evidence for a size-number trade-off in allocation of resources within clutches. Theory predicts that spiders are selected to maximize clutch size, with no cost of decreased egg size. Spiders are constrained from achieving an optimal clutch size.

Nuptial gift size prolongs copulation duration in the dance fly Empis borealis

Article

Full-text available

Jun 2008
ECOL ENTOMOL

1. The time that pairs of the dance fly Empis borealis (L.) (Diptera: Empididae) spent in copula was positively correlated with the volume of the nuptial gift. 2. In some cases the copulation duration was short although prey volume was large. Females engaged in these matings had more worn wings, were therefore older, and most probably had sperm already stored in the spermatheca. It is suggested that these copulations were interrupted because either the spermatheca was full of sperm and the male was not able to transmit any sperm, or because prey content was depleted (males may have fed on the prey or the prey had been used in a previous mating). The latter explanation seemed more probable. 3. A male providing a large nuptial gift may transfer larger quantities of sperm. Quantitative sperm competition is more likely than last‐male sperm predominance.

Sexual Cannibalism in Orb-Weaving Spiders: An Economic Model

Article

Full-text available

Dec 1991

Sexual cannibalism in orb-weaving spiders commonly takes place before copulation, even among virgin females. This behavior is curious because, although the female may obtain a nutritious meal, she risks remaining unmated. We present an economic model that accounts for sexual cannibalism by virgin females using stochastic dynamic programming. The model considers a female's expected reproductive output (which is a function of the number of copulations she has achieved) and her body size, both of which will depend upon her decision to either mate or cannibalize a courting male. The model demonstrates that cannibalism of courting males by virgin females can arise purely through foraging considerations and that the most important factors for the evolution of this behavior are the expected number of males encountered during the season and the distribution of mass gained from other prey items. The model also suggests a novel form of selection pressure on male body size.

Sexual cannibalism in fishing spider and a model for the evolution of sexual cannibalism based on genetic constraints

Article

Full-text available

May 1997

Several hypotheses have been proposed for the evolution of sexual cannibalism by females. Newman and Elgar (1991) suggested that sexual cannibalism prior to mating by virgin female spiders may have evolved as a result of female foraging considerations. According to this model, an adult female's decision to mate or cannibalize a courting male should be based on an assessment of the male's value as a meal versus his value as a mate. The current study provides an empirical test of the assumptions and predictions of this model in the sexually cannibalistic fishing spider. Adult females were subjected to different food treatments, and exposed to adult males in the laboratory. However, only one of the assumptions of the model and none of its five predictions were upheld. We failed to find any effects of female foraging, female mating status, female size, male size or time of the season on females' behaviour towards courting males. Females behaved stereotypically, and many females were left unmated despite numerous mating opportunities. We also demonstrate costs of sexual cannibalism in a natural population. We propose that the act of sexual cannibalism in the fishing spider is non-adaptive, and develop a model for the evolution of premating sexual cannibalism in spiders based on genetic constraints. According to this hypothesis, sexual cannibalism by adult females may have evolved as an indirect result of selection for high and non-discriminate aggression during previous ontogenetic stages. Genetic covariance between different components of aggressive behaviour may constrain the degree to which (1) juvenile and adult aggression and/or (2) aggression towards conspecifics and heterospecifics can vary independently. We briefly review the support for our model, and suggest several critical tests that may be used to assess the assumptions and predictions of the model.

Cryptic Female Choice and Its Implications in the Scorpionfly Harpobittacus nigriceps

Article

Full-text available

Dec 1983

Randy Thornhill

Female choice before mating occurs in H. nigriceps. There is considerable evidence of its occurrence during and after mating in this species. Females choose during mating by controlling mating duration and thus the number of sperm received from different mates. Postmating choice in H. nigriceps appears to include a female's ability to regulate egg laying in relation to characteristics of her mate. Female choice during and after mating in H. nigriceps almost certainly leads to stronger sexual selection on males than premating choice. All forms of female choice in H. nigriceps would result in directional selection of the criteria important in choice (male body size and its correlate, ability to obtain large prey). Female choice on the basis of body size in H. nigriceps may enhance female fitness if body size is heritable: large individuals obtain more matings (males) and more fecund (females) than small individuals, and, in general, survival and size are positively related in both sexes. Fluctuating natural selection pressures on body size within generations may generate enough genetic variation in male body size to maintain adaptive female choice in H. nigriceps.-from Author

Selective Mate Choice by Females of Harpobittacus Australis (Mecoptera: Bittacidae)

Article

Full-text available

Jan 1979

John Alcock

The evolution of edible ‘sperm sacs’ and other forms of courtship feeding in crickets, katydids and their kin (Orthoptera: Ensifera)

Chapter

Jun 1997

Darryl T. Gwynne

Insects and arachnids display the most impressive diversity of mating and social behaviour among all animals. This book investigates sexual competition in these groups, and the variety of ways in which males and females pursue, persuade, manipulate, control and help one another, enabling us to gain a better understanding of how conflicts and confluences of interest evolve together. Each chapter provides a comprehensive review of mating systems in particular insect and arachnid groups, discusses intrinsic and extrinsic factors responsible for observed mating strategies, and suggests fruitful avenues for further research. The book culminates in a synthesis, reviewing the date in terms of the theory of sexual conflict. This broad-based book will be of immense value to students and researchers interested in reproductive strategies, behavioural ecology, entomology and arachnology.

Male Mating Effort, Confidence of Paternity, and Insect Sperm Competition

Chapter

Dec 1984

Darryl T. Gwynne

Female reproductive variation in a nuptial-feeding spider, Pisaura mirabilis

Article

Jan 1986

Brautgeschenk und Umspinnen der Beute bei Pisaura mirabilis, Dolomedes fimbriatus und Thaumasia uncata (Arachnida, Araneida, Pisauridae)

Article

Jan 1988

R.O.M. Nitzsche

The World of Spiders

Article

Jun 1977

Weitere sexualbiologische Untersuchung an Spinnen

Article

Jan 1923

U. Gerhardt

Sperm Competition and Sexual Selection in Spiders and Other Arachnids

Chapter

Dec 1998

Mark A Elgar

The chapter focuses on Polyandry, which sets the stage for sperm competition, and may provide female spiders with both material and genetic benefits. The material benefits include a reduction in the costs of male harassment and, perhaps, an increase in fecundity through the provision of nuptial gifts, including the body of the male. The genetic benefits, which are modified by the patterns of sperm precedence, are less apparent in females among species with a predominantly first-male sperm priority. However, for male spiders, most of the opportunities for securing paternity appear to be related to the timing of mating, physically guarding females from rival males and blocking the genital region of the female with a plug, or increasing the duration of copulation. Moreover, the latter reduces female receptivity and increases fertilization success in competition with other males, although the mechanisms remain unknown. Therefore, the studies of sperm competition also benefit by examining precedence patterns involving more than two males. The clear sexual dimorphism and often elaborate courtship behavior of many cursorial spiders provide a rich seam of model systems to investigate the evolutionary significance of both overt and cryptic female choice.

Courtship Feeding in Katydids (Orthoptera: Tettigoniidae): Investment in Offspring or in Obtaining Fertilizations?

Article

Sep 1986

Darryl T. Gwynne

Studies indicate that courtship feeding in insects represents mating effort that evolved to ensure successful insemination. I tested this hypothesis with katydids (Requena verticalis), in which males feed females after mating by producing a sperm-free mass, the spermatophylax, from reproductive accessory glands. Although courtship feeding in this species prevents the female's removing and eating the sperm-containing ampulla before insemination has occurred, the spermatophylax is more than twice the size necessary to transfer a full complement of sperm and to transfer substances preventing female response to male sexual sounds. Thus, I reject the hypothesis that the function of "excess" maledonated nutrition is mating effort that protects the ejaculate. The size of the spermatophylax probably did not evolve only as a result of intersexual selection by premating female choice for males capable of producing larger contributions. Since feeding on spermatophylax nutrients by females increases egg size, and pos...

Prezygotic Male Reproductive Effort in Insects: Why Do Males Provide More than Sperm

Article

Mar 1986

Males' incentives for providing benefits to females and/or their offspring are ambiguous during the period prior to zygote formation. The benefits may function to increase the number of available eggs fertilized by a male and/or enhance the production and survival of his offspring. In some cases, male prezygotic investment may be an adaptation to secure fertilizations despite the fact that it incidentally benefits the female or her offspring. More often, the benefits to offspring production and survival are not simply incidental and probably account, in part, for the magnitude of the male investment. Regardless of the adaptive significance of male provided benefits, they typically reduce the females' costs of producing surviving offspring while raising the males' costs. The extent to which provisioning of benefits increases males' costs and decreases females' costs will affect the degree to which females limit male reproduction (or vice versa). If male-provided benefits (prezygotic or otherwise) are more costly than female costs of offspring production, reproductively-ready males will act as resources limiting female reproduction. From an evolutionary perspective it is important to consider the effect of male-provided benefits. The primary function of the investment (e.g., to maximize sperm transfer) is irrelevant in terms of the degree to which one sex limits the other's reproduction.

The feeding and mating behaviour of the specialized Empidinae (Diptera); observations on four species of Rhamphomyia in the high arctic and a general discussion

Article

Jul 1970
CAN ENTOMOL

J. A. Downes

Observations on the feeding and mating behaviour of Rhamphomyia spp. in the high arctic are reported. In R. nigrita Zetterstedt the males catch their prey especially in the male swarms of mosquitoes, etc., and carry it to their specific swarming (mating) site, a station controlled by a typical visual marker. In the swarm the male responds to insects hovering above, by rising to within a few inches and then holding a steady distance for some moments. The upper insect, if a male, moves away; if a female, pairing soon takes place, the prey is transferred, and the female feeds on it during mating. Apparently the female obtains insect food in no other way. The prey is rather small, and insufficient for the completion of one ovarian cycle; and the swarming flight, with mating and prey transfer, occurs repeatedly.In R. ursinella Melander hunting and mating are accomplished on the ground. The prey is very small and mating is frequent. The species is virtually non-flying, and the specialized form of the male eye, on which mating in flight depends, is considerably reduced. Similar adaptations occur in other arctic Diptera. R. nigrita, in contrast, maintains fully the normal dependence on sustained flight.The general structure of mating behaviour in the specialized Empidinae (Rhamphomyia, Empis, Hilara) is discussed. As in many Empididae, and other Diptera, mating takes place at an assembly station controlled by a visually recognized swarm marker, and the response to the female is mediated by the large ommatidia of the upper part of the male eye. The "holding flight" however signifies an interposed courtship, or display of prey by the male to the female. In most species only the male captures prey (perhaps without feeding on it himself); the female does not hunt and obtains insect food only by transfer at mating. Courtship with transfer becomes a firmly established behavioural element, and persists even in species which use objects of no value as food (ritualization of prey).The original significance of the prey, on which its role as sign stimulus in mating is based, is its significance as food required by the female for ovarian maturation. When the prey is small in relation to the requirements of the female, the mating process, including the courtship and prey transfer, is repeated (ritualized) so as to provide the female with sufficient food. It is suggested that this ritualization would develop easily once insect prey had become established as the sign stimulus for mating; and could lead on to the sex differences in habits of hunting and feeding.

Female hunger can explain variation in cannibalism despite male sacrifice in redback spiders

Article

Jan 1998

Maydianne C.B. Andrade

Male Australian redback spiders (Latrodectus hasselti Thorell: Theridiidae) place their abdomens directly over their mate's mouthparts during copulation, increasing the likelihood of sexual cannibalism. Male sacrifice may be adaptive because cannibalized males increase their paternity relative to those that are not eaten. Despite male sacrifice behavior, however, up to 50% of laboratory matings may end without sexual cannibalism. Here, I report a similar pattern in the field, where males were not cannibalized in 35% of observed matings (6/17). I examined variation in female cannibalistic behavior by evaluating the following three hypotheses for the occurrence of cannibalism from the female perspective: (1) the mistaken identity hypothesis proposes that females sometimes cannibalize males because they mistake them for prey, (2) the mate rejection hypothesis predicts that females cannibalize males who are unacceptable as mates, and (3) the feeding opportunism hypothesis predicts that hungry females are more likely to be cannibalistic. Field observations refuted the first two hypotheses: females recognized males as potential mates (i.e., nonprey), and cannibalized and noncannibalized males were not phenotypically different. The feeding opportunism hypothesis was supported. In staged field matings, cannibalistic females were hungrier than their noncannibalistic counter-parts. Moreover, a logistic regression analysis indicated that hunger was a significant predictor of cannibalism. Because redback males are below the typical prey size that females accept, well-fed females are less likely to consume their mates, despite the vulnerable mating posture. These results indicate that, although males facilitate sexual cannibalism, their fate may depend on the female's physical condition.

Nonparametric Statistics For The Behavioral Sciences

Article

Jan 1956

S. S. Siegel

Cryptic female choice and its impli-cations in the scorpion炉y Harpobittacus nigriceps

Article

Nov 1982

Randy Thornhill

Sexual Selection and Paternal Investment in Insects

Article

Jan 1976

Randy Thornhill

One way in which males offset the disparity in relative parental investment is to provide food to the female or offspring in the context of reproduction. In insects, nutritional paternal investment during reproduction may be of three major types: (1) females may receive nourishment from a glandular product of the male; (2) females received nourishment from food captured or collected by the male; and (3) the male himself may be eaten. I have shown elsewhere that the feeding of the female by the male during copulation in insects of the family Bittacidae probably evolved by female preference (i.e., intersexual selection) for males willing and capable of increasing their parental investment during reproduction. I hypothesize that female preference for greater male parental investment may have been the selective context for the evolution of all types of male investment patterns in insects. I also suggest some ways in which my argument might be tested.

Silk Investment in Gifts By Males of the Nuptial Feeding Spider Pisaura Mirabilis (Araneae: Pisauridae)

Article

Aug 1996
BEHAVIOUR

Andreas Lang

Adult males of the hunting spider Pisaura mirabilis wrap up prey with silk and pass these nuptial gifts to females prior to copulation. The females digest the nuptial gifts, including the silk, during mating. Laboratory experiments were carried out to determine the amount of silk males of P. mirabilis invest in nuptial gifts, and its possible role in sexual reproduction. The amount of silk was always small, indicating that the silk of the nuptial gift has little nutritional value for females. Males that had more time to wrap up the prey produced a larger amount of silk. Starved males required more time than satiated males to produce a given amount of silk. A larger male body size had a positive effect on the amount of silk. In general, the size of the prey used for nuptial gifts had no influence on the amount of silk. However, due to handling problem, smaller males produced no silk for very large flies. Females took more time to digest a nuptial gift with a larger amount of silk than a nuptial gift with a smaller amount of silk. A possible interpretation of the adaptive significance of wrapping is that males use silk to prolong the copulation time during mating.

The Evolution Of Insect Mating Systems

Book

Dec 1983

Sexual Selection and Nuptial Feeding Behavior in Bittacus apicalis (Insecta: Mecoptera)

Article

Jul 1976

Randy Thornhill

Field and laboratory studies of Bittacus apicalis reveal the probable occurrence and importance of intersexual selection (female choice) in these insects. Females select males on the basis of the arthropod prey which the males feed to them in the prelude to copulation, and females maximize their reproductive success, as measured by increased fecundity, by choosing males with palatable prey items 19 mm2 or larger. Female preference for increased male nutritional investment was apparently the selective context for the evolution of nuptial feeding and some of the behavior surrounding nuptial feeding in B. apicalis.

Sexual Cannibalism in the Praying Mantis Hierodula Membranacea

Article

Jan 1988

We tested the idea that sexual cannibalism increases male and female fecundity in the mantid Hierodula membranacea. Two experiments were performed, in the first we maintained females on one of three nutritional planes; high medium or low. Food intake was positively and significantly associated with: maximum mass attained, the mass of first and subsequent oothecae, and the rate at which oothecae were produced. Ootheca mass was positively correlated with maximum female mass, and the number of young hatching from oothecae was positively correlated with ootheca mass. In the second experiment we maintained females on low diets and allowed some to eat the male during mating and prevented others from doing so. Females which ate the male produced significantly heavier oothecae than those which did not. The female's nutritional state influenced her likelihood of eating the male; well fed females rarely ate males. These results confirm that under certain food regimes male and female fecundity are increased by sexual cannibalism. However, our observations indicate that males do not sacrifice themselves at mating, but attempt to avoid being eaten, suggesting that while sexual cannibalism may be adaptive for females it is unlikely to be so for male H. membranacea.

Sperm Competition in a Nuptial Feeding Spider, Pisaura Mirabilis

Article

Aug 1999

The paper tests two hypotheses about sperm priority in the spider Pisaura mirabilis. A 'phylogenetic constraints hypothesis' states that since the females have conduit spermathecae, first male priority should prevail. On the other hand, males offer nuptial prey to the females and females mate with multiple males. The evolution of these traits is most easily understood if late mating males also have a substantial fertilization success. The results indicate a compromise solution. Sterile-male technique with double-mated females indicated a first male priority pattern (P1 = ca 70%, after adjusting for sterilization damage and experimental mortality). However, the success of the fourth male of quadroublemated females was unexpectedly high (adjusted P4 = ca 24%, not different from P of 2 two-male matings). This lends support to a supplementary hypothesis of constant last male success, which may turn an initial first-male advantage into a last-male advantage, when the number of males mating with a female raises above a certain number. Independent of mating order, males may increase their share of fertilizations by long copulation times. It was tested whether female choice for symmetric males might account for differential male success. However, fluctuating asymmetry (FA) in male leg length showed no relationships with fertilization success or copulation duration.

The function of nuptial feeding in insects: Review of empirical studies

Article

Feb 1998
BIOL REV

Karim Vahed

Nuptial feeding encompasses any form of nutrient transfer from the male to the female during or directly after courtship and/or copulation. In insects, nuptial gifts may take the form of food captured or collected by the male, parts, or even the whole of the male's body, or glandular products of the male such as salivary secretions, external glandular secretions, the spermatophore and substances in the ejaculate. Over the past decade, there has been considerable debate over the current function of nuptial feeding in insects. This debate has centred on the issue of whether nuptial gifts function as paternal investment (i.e. function to increase the fitness and/or number of the gift-giving male's own offspring) or as mating effort (i.e. function to attract females, facilitate coupling, and/or to maximize ejaculate transfer), although the two hypotheses are not mutually exclusive. In the present article, evidence for the potential of nuptial gifts to function as either paternal investment, mating effort, or both is reviewed for each form of nuptial feeding in each insect taxon for which sufficient data are available. Empirical evidence suggests that many diverse forms of nuptial feeding in different insect taxa function, at least in part, as mating effort. For example, nuptial prey and salivary masses in the Mecoptera, regurgitated food in Drosophila (Diptera), hind-wing feeding in Cyphoderris (Orthoptera) and the secretion of the male's cephalic gland in Neopyrochroa (Coleoptera) and Zorotypus (Zoraptera) appear to function to entice females to copulate and/or to facilitate coupling. Nuptial prey and salivary masses in the Mecoptera also appear to function to maximize ejaculate transfer (which is also a form of mating effort), as do nuptial prey in Empis (Diptera), external glandular secretions in Oecanthus and Allonemobius (Orthoptera) and the spermatophylax in gryllids and tettigoniids (Orthoptera). Large spermatophores in, for example, the Lepidoptera and Coleoptera, also appear to be maintained by selection on the male to maximize ejaculate transfer and thereby counter the effects of sperm competition. In contrast to the large amount of evidence in support of the mating effort hypothesis, there is a relative lack of good evidence to support the paternal investment hypothesis. Certain studies have demonstrated an increase in the weight and/or number of eggs laid as a result of the receipt of larger gifts, or a greater number of gifts, in tettigoniids, gryllids, acridids, mantids, bruchid beetles, drosophilids and lepidopterans. However, virtually all of these studies (with the possible exception of studies of the spermatophylax in tettigoniids) have failed to control adequately for hormonal substances in the ejaculate that are known to affect female reproductive output. Furthermore, in at least four tettigoniids (but not in the case of two species), three lepidopterans, a drosophilid and probably also bruchid beetles and bittacids, evidence suggests that the male has a low probability of fertilising the eggs that stand to benefit from his nuptial gift nutrients. Therefore, the hypothesis that paternal investment might account for the function of nuptial gifts in general is not supported.

Nuptial feeding behaviour and female choice of mates in Harpobittacus similis (Mecoptera: Bittacidae)

Article

Nov 1984
AUST J ENTOMOL

Darryl T. Gwynne

Field experiments were conducted to investigate mating behaviour and use of nuptial prey by the scorpionfly Harpobittacus similis Esben-Petersen. Males in nature were given species of insect prey representing different body sizes and observed until they attracted females. Males commonly discarded small prey before contacting a female. With larger prey duration of pre-copulatory feeding by males was greater and they everted pheromone glands for proportinately less time than with small prey. Variability in premating behaviour by males with prey appears to be related mainly to female choice tactics; females encountering males with small prey either did not mate or terminated mating after a short period of time.

Stepfathers in Insects and their Pseudo‐parental Investment

Article

Apr 2010
ETHOLOGY

Wolfgang Wickler

Nuptial Feeding in Insects: Mating Effort versus Paternal Investment

Article

Apr 1989
ETHOLOGY

Article de synthese et de reflexion a propos de l'importance relative de l'effort reproducteur et de l'investissement parental dans l'evolution des cadeaux nuptiaux offerts par les mâles aux femelles chez les insectes.

Siegel S. Nonparametric Statistics for the Behavioral Sciences. McGraw-Hill Book Company Inc.: New York

Chapter

May 1957

Variation in nuptial gift quality in bush crickets (Orthoptera: Tettigoniidae)

Article

Dec 1994

Nina Wedell

Males of many insect species provide the female, during courtship and copulation, with a nuptial gift consisting of a prey item or synthesized material (e.g., spermatophores). The studies performed so far have mainly focused on effects of nuptial gift size on male and female reproductive success. However, the quality of the nuptial gift can differ substantially between taxa and may potentially have a large impact on male and female reproductive performance. In this study the effects of. variation in diet on nuptial gift quality is investigated in several bush cricket species with different diets. The effect of diet on nuptial gift quality (e.g., protein in the spermatophylax) and female reproductive output and, in turn, die effect of variation in spermatophylax quality on female reproductive output are investigated. Female reproductive output and male spermatophore size were mainly found to be influenced by differences in diet between species. Spermatophylax quality (i.e., protein concentration) was also correlated with differences in diet. There was a large variation in protein content of the spermatophylax widiin as well as between species. Moreover, larger spermatophylaxes had a lower protein concentration, indicating a possible trade-off between spermatophylax size and quality. Consequendy, production of larger spermatophylaxes, required for protection of the male's sperm carrying ampulla during insemination, can lead to a reduced protein concentration, because the total amount of protein may be limited. This pattern is also consistent with die idea diat the spermatophylax functions primarily to ensure sperm transfer. Finally, there was no correlation between the amount of protein in the spermatophylax and female reproductive output either across diets or within each diet category, further supporting the finding that female reproductive output is mainly affected by differences in diet.

The Mating Activities of Balloon Flies

Article

Sep 1955
Syst Zool

Edward L. Kessel

Male Crickets Feed Females to Ensure Complete Sperm Transfer

Article

Mar 1984

Scott Sakaluk

The spermatophore transferred by the male decorated cricket Gryllodes supplicans to the female during copulation includes a large gelatinous portion (spermatophylax), which the female removes and feeds on immediately after mating. Females usually removed and ate the smaller sperm-containing portion (ampulla) within 1 to 7 minutes after fully consuming or losing the spermatophylax. Complete sperm transfer requires that the ampulla remain attached for a minimum of 50 minutes; this corresponds to the average time at which females actually removed ampullae, 52.0 +/- 2.2 minutes after mating. These results indicate that nuptial feeding of the female cricket functions to deter females from removing the sperm ampulla before sperm transfer is complete.

A note on body size parameters and some life history data of Pisaura mirabilis (Araneae, Pisauridae)

111-115

A Lang
Klarenberg

Lang A, Klarenberg AJ, 1995. A note on body size parameters and some life history data of Pisaura mirabilis (Araneae, Pisauridae).In: Proceedings of the 15th European Colloquium of Arachnology (Ru ¨zicka V, ed). Ceske ´ Budejovice: Institute of Entomology; 111– 115

The life history and nuptial feeding of a nursery web spider, Pisaura lama

Jan 1993
88-93

Y Itakura

Itakura Y, 1993. The life history and nuptial feeding of a nursery web spider, Pisaura lama. Insectarium 30:88–93.

Sexual selection. Princeton, New Jersey: Prince-ton University Press Female hunger can explain variation in canni-balistic behavior despite male sacrifice in redback spiders

Jan 1994
33-42

M Andersson

Andersson M, 1994. Sexual selection. Princeton, New Jersey: Prince-ton University Press. Andrade MCB, 1998. Female hunger can explain variation in canni-balistic behavior despite male sacrifice in redback spiders. Behav Ecol 9:33–42.

Evolution of sperm priority patterns in spiders In: Sperm competition and the evolution of animal mating systems

Jan 1984
223-249

Austad
Sn

Austad SN, 1984. Evolution of sperm priority patterns in spiders. In: Sperm competition and the evolution of animal mating systems (Smith RL, ed). Orlando: Academic Press; 223–249.

The world of spiders The feeding and mating behaviour of the special-ized Empidinae (Diptera); observations on four species of Rham-phomyia in the high arctic and a general discussion

Jan 1958
769-791

Bristowe
Ws

Bristowe WS, 1958. The world of spiders. London: Collins. Downes JA, 1970. The feeding and mating behaviour of the special-ized Empidinae (Diptera); observations on four species of Rham-phomyia in the high arctic and a general discussion. Can Entomol 102:769–791.

The evolution of insect mating systems Parental investment and sexual selection. In: Sexual selection and the descent of man

Jan 1972
1871-1971

R Thornhill
Alcock

Thornhill R, Alcock J, 1983. The evolution of insect mating systems. Cambridge: Harvard University Press. Trivers RL, 1972. Parental investment and sexual selection. In: Sexual selection and the descent of man 1871–1971 (

Sexual cannibalism in spiders and other inverte-brates. In: Cannibalism: ecology and evolution among diverse taxa

Jan 1992

Ma Elgar

Elgar MA, 1992. Sexual cannibalism in spiders and other inverte-brates. In: Cannibalism: ecology and evolution among diverse taxa (Elgar MA, Crespi BJ, eds).

On the origin and basis of the male-female phenomenon. In: Sexual selection and reproductive com-petition in insects

Jan 1979
417-440

Alexander Rd Gerald

Alexander RD, Gerald B, 1979. On the origin and basis of the male-female phenomenon. In: Sexual selection and reproductive com-petition in insects (Blum MS, Blum NA, eds). London: Academic Press; 417–440.

A note on body size parameters and some life history data of Pisaura mirabilis (Araneae, Pisauridae) Ceské Budejovice: Institute of Entomology

Jan 1995
111-115

Lang A Klarenberg
Aj

Nuptial gift in the spider Pisaura mirabilis maintained by sexual selection

Abstract

No full-text available