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Temperament traits and microhabitat use in bullhead, Cottus perifretum: Fish associated with complex habitats are less aggressive
Abstract
Temperament traits have been linked to fitness-related functional contexts such as dispersal or mating attractiveness, but few studies have linked inter-individual differences in habitat use to temperament traits. Therefore, we conducted a three-month field study with weekly tracking to define the individual microhabitat use of bullhead (Cottus perifretum). The species is known for its dependence on structured habitats. At the end of the field-survey, bullhead were recaptured and tested in the laboratory for five temperament traits: boldness, interest in novel food, novel environment activity, aggressiveness and activity. Repeated trait tests (activity, r = 0.439; novel environment activity, r = 0.422) and habitat complexity use (r = 0.568) indicated behavioural consistency. Overall, bullhead significantly preferred complex habitats, such as branch jams, while avoiding open water. Individual frequency in the use of complex habitats could not be attributed to size or sex differences, but was significantly negatively correlated to the level of aggressiveness. We hypothesize that this relationship was caused by a higher level of aggressive defence of less structured territories. Other temperament traits were not significantly linked to individual habitat use. To our knowledge, this study is the first to show a relationship between aggressiveness measured under laboratory conditions and the use of complex habitats in situ.
... In particular, strong links between personality and spatial dynamics have been established both by models linking exploratory behaviour (a type of movement), niche specialization and risk taking Dall et al. 2012;Quinn et al. 2012) and by empirical findings of personality-dependent dispersal (Cote et al. 2010;Clobert et al. 2012; Box 1). Personality-dependent space-use has also been recognised in foraging behaviour (Kurvers et al. 2010;van Overveld & Matthysen 2010Patrick & Weimerskirch 2014), host-parasite interactions (Boyer et al. 2010), habitat preferences (Kobler et al. 2011;Pearish et al. 2013;Leclerc et al. 2015), disease dynamics (Kortet et al. 2010;, social structures (Aplin et al. 2013; Kurvers et al. 2014) and responses to human-induced environmental changes (Cote et al. 2010;Sih et al. 2011;Chapple et al. 2012). ...
... Second, personality may be associated with different body morphologies, body sizes or metabolic rates that influence locomotion capacity (Duckworth & Badyaev 2007;Quinn et al. 2011;Larranaga et al. 2013). Third, different personalities may consistently differ in the external factors they experience and respond to or simply in the environments they inhabit (Wilson & McLaughlin 2007;Kurvers et al. 2010;Kobler et al. 2011;Pearish et al. 2013). Finally, personality may affect an individual's internal state and how it prioritises motivation for different movement types. ...
... Along similar lines, using movements of free-ranging animals to characterise personality (Ciuti et al. 2012) may be problematic since these movements may be influenced by various external factors. An apparent movement specialization may either reflect personality-dependent movement and habitat preference (van Overveld & Matthysen 2010;Kobler et al. 2011;Pearish et al. 2013), or an independent effect of the environmental heterogeneity on movement. For instance Harrison et al. (2015) showed that individual wild Burbot (Lota lota) differ consistently in several interrelated measures of space-use (home range size, site fidelity and movement distances). ...
Recent studies have established the ecological and evolutionary importance of animal personalities. Individual differences in movement and space-use, fundamental to many personality traits (e.g. activity, boldness and exploratory behaviour) have been documented across many species and contexts, for instance personality-dependent dispersal syndromes. Yet, insights from the concurrently developing movement ecology paradigm are rarely considered and recent evidence for other personality-dependent movements and space-use lack a general unifying framework. We propose a conceptual framework for personality-dependent spatial ecology. We link expectations derived from the movement ecology paradigm with behavioural reaction-norms to offer specific predictions on the interactions between environmental factors, such as resource distribution or landscape structure, and intrinsic behavioural variation. We consider how environmental heterogeneity and individual consistency in movements that carry-over across spatial scales can lead to personality-dependent: (1) foraging search performance; (2) habitat preference; (3) home range utilization patterns; (4) social network structure and (5) emergence of assortative population structure with spatial clusters of personalities. We support our conceptual model with spatially explicit simulations of behavioural variation in space-use, demonstrating the emergence of complex population-level patterns from differences in simple individual-level behaviours. Consideration of consistent individual variation in space-use will facilitate mechanistic understanding of processes that drive social, spatial, ecological and evolutionary dynamics in heterogeneous environments.
... During the two electro-fishing sessions, 334 bullhead [50-mm total length (TL) were caught (14 recaptures during the second session, for abundance estimate see Kobler et al., 2011). ...
... Once a bullhead was located, the individual PITtag code, the stream position (e.g. stream metre 1,400; marked with poles, see before) and the tracking date were noted (for more details see Kobler et al., 2011). This positioning led to an overall detection precision of less than 1 m (Kobler et al., 2011). ...
... stream metre 1,400; marked with poles, see before) and the tracking date were noted (for more details see Kobler et al., 2011). This positioning led to an overall detection precision of less than 1 m (Kobler et al., 2011). During making notes, the antenna was kept above the detected bullhead. ...
Inter-sexual differences in reproductive behaviours such as mate choice or parental care may cause sex-bias in movement distances. While this relationship has been extensively studied in birds and mammals, little is known regarding fishes. Fifty-four bullhead (Cottus perifretum), polygamous stream fish with male nest holding, were tracked by means of a portable antenna in a 2,500 m stream reach. Movement was measured at two time scales: monthly movement distance and long-term movement range. Bullhead moved furthest in February and May. In these months, movement distances diversified between the sexes. Females moved significantly furthest in February. This may be related to female mate-choice at the beginning of the reproductive period. In May, at the end of the reproductive period, males moved significantly longer distances. It is speculated that males shift to resource-richer habitats after the starvation during parental care. In general, smaller individuals moved longer distances per month. Long-term movement range did not differ between the sexes but varied considerably between individuals ranging from 1 to 1,111 m. It is concluded that movement studies should encompass an annual time scale as well as a more precise monthly time scale to present an accurate description of sex-biased movement in (annual spawning) fish.
... If several substratum categories were present, they were divided into a dominant, abundant, occasional, and rare fraction. In addition to the microhabitat parameters analyzed by Van Liefferinge et al. (2005), similar habitat characteristics as used by Kobler et al. (2011) to describe the habitat complexity were also taken into account to enhance the suitability model (Table 2). Woody debris was quantified using maximum diameter and percentage of the total cell surface (divided into a dominant, abundant, occasional, and rare fraction). ...
... The individual microhabitat scores of substratum, depth, and stream velocity of the several assessed brooks could be used to define habitat parameters that need to be improved to enlarge habitat suitability for bullheads (juveniles as well as adults). Kobler et al. (2011) showed that bullhead have a significant preference for stream patches with high habitat complexity including natural branch jams, tree roots, or pebbles. Moreover, Peters (2009) stated that the presence of gravel and stones can have a positive effect on population density of bullhead. ...
... Installing stream deflectors or introducing woody debris could induce macromeandering and the formation of pool-riffle patterns increasing habitat diversity and habitat complexity. According to Kobler et al. (2011), more woody debris will therefore increase habitat suitability for bullhead substantially. The presence of woody debris will also lead to locally higher water velocities, which are expected to scour the loamy substratum creating more suitable habitat for bullhead. ...
Microhabitat suitability models are useful tools to enhance the reintroduction success of fish. Since 2008, a translocation and reintroduction program has been carried out in Flanders to prevent substantial loss of genetic variability in the Cottus perifretum (bullhead) population, and to meet the goals set by the Habitat Directive. To this end, habitat suitability of potential headstreams was assessed on a macrohabitat and microhabitat scale prior to the reintroduction. On a macrohabitat scale, water quality, habitat structure, food availability and fish community were screened. Based on microhabitat models for bullhead in the summer period, microhabitat suitability was assessed in headstreams where macrohabitat characteristics showed a high potential for success. Both macro‐ and microhabitat assessment showed that reintroduction of bullheads in the Nellebeek, Bruelbeek and Mollendaalbeek would most likely lead to self‐sustaining populations. For the Sint‐Annabeek, the microhabitat suitability model, considering depth and stream velocity, estimates that 7.5‐9.5% of the headstream is suitable for bullhead. However, when substratum is taken into account, the microhabitat suitability index shows that only 4.3% to 5.8% of the brook is suitable. The current habitat quality and quantity in the Sint‐Annabeek is estimated to support a mean total population of 812 bullheads. However, the microhabitat suitability can be substantially improved by the artificial deposition of medium sized gravel (5‐50mm) and large gravel (50‐100mm). By doing so, the mean estimated population size could increase up to 1330 individuals. Our results show that habitat improvement is necessary prior to the reintroduction of bullheads in the Sint‐Annabeek.
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... Behavioral traits related to boldness or aggression, foraging styles, or predator avoidance have the potential to affect habitat use and resource consumption. For example, a study with bullheads (Cottus perifretum) found that less aggressive individuals (as assayed in the laboratory) showed a greater propensity to use complex habitats (i.e., branch jams) in the field (Kobler et al. 2011). In the same study, there was no correlation between habitat use in the field and individual differences in activity level measured in the laboratory. ...
... In the same way, hatchery rearing programs may select for certain behavioral types or selectively alter the way behavioral traits develop with ontogeny, resulting in hatchery stocks that differ genetically from wild populations (Huntingford 2004;Fraser 2008). In addition, habitat modifications (e.g., adding structure to streams or lakes and construction of fishways) may selectively benefit certain behavioral types that have a higher propensity to use these new habitats than others (e.g., Kobler et al. 2011). Unfortunately, at this time there is too little evidence to evaluate many of these management practices in relation to their use by (and effects on) different personality types. ...
Fish have proven to be model organisms for the study of animal personalities, and a rich literature documents consistent interindividual behavioral differences in a variety of species. However, relatively few studies have examined the ecological consequences of such consistent interindividual differences in behaviors in fish or other organisms, especially under field conditions. In this review and perspective, we discuss the factors that may lead to the formation and maintenance of behavioral types in fish populations. We then examine what is known about the effects of personality variation on individual growth and survival, breeding behaviors and reproductive success, habitat use, diet, and ontogenetic niche shifts, migration and dispersal, as well as potential consequences for species interactions and ecosystem functioning. We focus as much as possible on studies conducted under natural or seminatural conditions, as such field studies are most relevant to elucidating the ecological consequences of behavioral variation. Finally, we discuss the potential importance of consistent individual differences in behaviors to fisheries management and conservation, specifically examining consequences for recreational and commercial fishing, hatchery rearing, and stock enhancement.
... Importantly, the development and expression of behaviour may vary between individuals of the same population (Brodin et al., 2013), or even between same-aged siblings (Hudson et al., 2011), leading to the establishment of individual personalities or behavioural types (Sih et al., 2004a). Individuals may show relatively consistent differences across multiple contexts, including feeding, predator perception and dispersal (Brodin et al., 2013;Wilson and Godin, 2009), thus personality traits have often been described along a "bold/shy" continuum (Baird et al., 2006;Brodin et al., 2013;Kobler et al., 2011). Bold individuals tend to be more active (Sneddon, 2003), show a willingness to engage in risk-taking behaviour (e.g. ...
... For an individual to persist in a novel environment, it must possess traits that facilitate persistence and allow exploitation (Cote and Clobert, 2007;Cote et al., 2010;Duckworth, 2008) and it is suggested that proactive coping styles are more successful in simple, predictable environments (Huntingford et al., 2012;Kobler et al., 2011;Sneddon, 2003) because they have particular traits that enhance their fitness. For species moving out of tropical rainforests into habitats that may be more homogeneous, reactive personalities with low aggression (Koolhaas et al., 1999) may not be at a competitive advantage in that environment (Liebl & Martin, 2012), whereas proactive individuals, which are often more aggressive than reactive individuals , are likely to be more successful competitors, potentially promoting persistence in novel areas (Fig. 2), as seen in dispersing western bluebirds Sialia mexicana invading, and outcompeting, sites occupied by mountain bluebirds S. currucoides (Duckworth & Badyaev, 2007). ...
Tropical rainforests are species-rich, complex ecosystems. They are increasingly being negatively affected by anthropogenic activity, which is rapidly and unpredictably altering their structure and complexity. These changes in habitat state may expose tropical animals to novel and unpredictable conditions, potentially increasing their extinction risk. However, an animal's ability to cope with environmental change may be linked to its personality. While numerous studies have investigated environmental influences on animal personalities, few are focused on tropical species. In this review, we consider how behavioural syndromes in tropical species might facilitate coping under, and adapting to, increasing disturbance. Given the complexity of tropical rainforests, we first discuss how habitat complexity influences personality traits and physiological stress in general. We then explore the ecological and evolutionary implications of personality in the tropics in the context of behavioural flexibility, range expansion and speciation. Finally, we discuss the impact that anthropogenic environmental change may have on the ecological integrity of tropical rainforests, positing scenarios for species persistence. Maintaining tropical rainforest complexity is crucial for driving behavioural flexibility and personality type, both of which are likely to be key factors facilitating long term persistence in disturbed habitats.
... First, many studies of animal personality have used captive individuals where their space use in nature cannot be addressed. Second, many previous studies suggesting that BT affects habitat preference or space use of mammals [18,22], birds [23,24], and fish [25][26][27][28] have derived their measures of space use and BT non-independently, from the same in situ movement data. For example, activity or exploration tendency (both widely used BTs) are commonly estimated from movement data, often through dimension reduction by principal component analysis (e.g. ...
... In contrast to other examples [23,25,27,57,58], the space-use differences we observed among BTs did not result from confounding factors such as using a movement-based BT definition (e.g. activity or exploration), or from any difference among BTs in the habitat or niche they occupied, or from differences in their social context (e.g. ...
Understanding space use remains a major challenge for animal ecology, with implications for species interactions, disease spread, and conservation. Behavioural type (BT) may shape the space use of individuals within animal populations. Bolder or more aggressive individuals tend to be more exploratory and disperse further. Yet, to date we have limited knowledge on how space use other than dispersal depends on BT. To address this question we studied BT-dependent space-use patterns of sleepy lizards (Tiliqua rugosa) in southern Australia. We combined high-resolution global positioning system (GPS) tracking of 72 free-ranging lizards with repeated behavioural assays, and with a survey of the spatial distributions of their food and refuge resources. Bayesian generalized linear mixed models (GLMM) showed that lizards responded to the spatial distribution of resources at the neighbourhood scale and to the intensity of space use by other conspecifics (showing apparent conspecific avoidance). BT (especially aggressiveness) affected space use by lizards and their response to ecological and social factors, in a seasonally dependent manner. Many of these effects and interactions were stronger later in the season when food became scarce and environmental conditions got tougher. For example, refuge and food availability became more important later in the season and unaggressive lizards were more responsive to these predictors. These findings highlight a commonly overlooked source of heterogeneity in animal space use and improve our mechanistic understanding of processes leading to behaviourally driven disease dynamics and social structure.
... Ecological sexual differences can arise from these sexual differences, for example, in movement patterns or selection of resources (Shine 1991). However, individuals can differ in their patterns of microhabitat selection for reasons not only attributed to those of the mainly studied intrinsic factors (age, morphology, and sex) but also due to differences in their consistent individual behavior, known as animal personality (Bolnick et al. 2003;Klober et al. 2011). ...
One pivotal topic on habitat selection is to understand the influence of intrinsic and extrinsic factors on the selection process. Although the effect of some extrinsic variables and sex has been extensively studied, almost nothing is known about the effect of personality, particularly on snakes. Here we addressed the relative importance of extrinsic (tree-related) and intrinsic (sex and personality) factors driving microhabitat selection decisions of a nocturnal tree snake (Leptodeira annulata). We implemented a protocol to quantify the influence of personality and sex on the role of extrinsic variables on microhabitat selection. First, we conducted three behavioral experiments to extract the shyness-boldness and avoidance-exploitation personality traits of male snakes. Then, we evaluated the role of sex and personality on the effect of tree-traits (thickness, canopy cover and shelter availability) on microhabitat selection, using two-step conditional logistic regression. Snakes consistently selected tree trunks, preferably thick and with high canopy cover and shelter availability, independently of their sex of personality. For this species, only extrinsic variables determined microhabitat decisions. Our protocol will aid to quantify the role of personality on microhabitat selection of other species and understand whether this is an important variable in habitat decision-making or not.
... The resounding failure to detect a relationship between exploratory behaviour in the pool and movement in the river urges us to be cautious about assuming that an individual's behaviour in a standardized assay reflects natural behaviour in the field (Niemelä and Dingemanse, 2014). While some studies have shown that individual behaviour in a standardized open-field arena assay predicts behaviour and movement in the field (Chapman et al., 2011; Cote and Clobert, 2007; Dingemanse et al., 2003; Fraser et al., 2001; Herborn et al., 2010; Kobler et al., 2011; Wilson and McLaughlin, 2007), others have found no, or mixed, relationships between behaviour in standardized assays and natural behaviours in the field (Coleman and Wilson, 1998; Minderman et al., 2010; Wilson et al., 1993), a finding that is probably even more common but underreported due to publication bias. One potential reason for the failure to detect a relationship between exploratory behaviour in the pool and movement in the river is because exploratory behaviour in the pool reflected a response to a novel and risky environment, while movement in the river reflected behaviour in a familiar environment. ...
Species abundances and distributions are inherently tied to individuals' decisions about movement within their habitat. Therefore, integrating individual phenotypic variation within a larger ecological framework may provide better insight into how populations structure themselves. Recent evidence for consistent individual differences in behaviour prompts the hypothesis that variation in behavioural types might be related to variation in movement in natural environments. In a multiyear mark-recapture study, we found that individual sticklebacks exhibited consistent individual differences in behaviour both within a standardized testing arena designed to measure exploratory behaviour and within a river. Therefore, we asked whether individual differences in movement in a natural river were related to an individual's exploratory behavioural type. We also considered whether body condition and/or the individual's habitat or social environment use was related to movement. There was no evidence that an individual's exploratory behavioural type was related to movement within the river. Instead, an individual's habitat use and body condition interacted to influence natural movement patterns. Individuals in good condition were more likely to move further in the river, but only if they inhabited a vegetated complex part of the river; body condition had no influence on movement in those individuals inhabiting open areas of the river. Our results suggest that individual traits could help improve predictions about how populations may distribute themselves within patchy and complex environments.
... However, bullheads demonstrate a strong affinity to shelters throughout the year, therefore both males and females were expected to be equally determined to occupy and aggressively defend the available shelter. Kobler et al. (2011) found that bullhead significantly preferred complex habitats, while avoided open waters, which was not attributed to the size and sex differences. Moreover, fish aggressiveness tested in laboratory outside spawning season was not significantly related to sex. ...
... However, it was not possible to determine the sex of the specimens in autumn when sexual dimorphism of the bullhead disappeared (Kobler et al. 2012), and we were not allowed to dissect the used fish due to their protected status in Poland. Nevertheless, in autumn, which is the post-spawning period for bullheads (Mills and Mann 1983;Davey et al. 2005) as well as for gobies (Pinchuk et al. 2003), both sexes will use shelters similarly, for protection against unsuitable environmental conditions and display similar levels of aggression as it was demonstrated by Kobler et al. (2011). Therefore, we conducted the autumn treatments without determining sex in bullhead. ...
Extensive invasion of Ponto–Caspian gobies raised the question how they affect recipient ecosystems. The round and racer goby pose a threat to their native counterparts, cottid species, but the influence of other gobiids is still not sufficiently demonstrated. We experimentally assessed how monkey and western tubenose goby, two of the most widespread species across Central and Western Europe, affected time spent by bullhead in the shelter in different seasons and light conditions. Direct and indirect aggression and guarding the shelter by the fish were also checked. We observed the behaviour of single-species and mixed-species pairs in the presence of a single shelter, with bullhead as a resident and one of three species as an intruder introduced to the tank 24 h later. Neither tubenose nor monkey goby was the stronger competitor, capable of outcompeting bullhead from the shelter. Their influence on the resident bullhead was the same as that of intruding bullhead: all intruders made resident bullhead increase shelter occupancy in spring at night. Moreover, compared to the monkey goby, the tubenose goby spent more time in the shelter, occupied it similarly in both seasons, guarded it more intensely and was more aggressive. The monkey goby displayed indirect aggression more often in spring. Despite these differences, bullhead responded to the presence of both goby species similarly, especially during reproductive season.
... Bolder individuals may utilize habitats with higher risk (and reward), whereas shyer individuals may primarily utilize refuges. Only a few field studies have examined differences in habitat use between personality types, but there is evidence to support the idea that an individual's personality may affect its utilization of risky habitats (Hensley et al. 2012;Kjelvik and Mittelbach, unpublished manuscript;Kobler et al. 2011). ...
To date,most studies investigating the relationship between personality traits and fitness have focused on a single measure of fitness (such as survival) at a specific life stage. However, many personality traits likely have multiple effects on fitness, potentially operating across different functional contexts and stages of development. Here, we address the fitness consequences of boldness, under seminatural conditions, across life stages and functional contexts in largemouth bass (Micropterus salmoides). Specifically, we report the effect of boldness on (1) juvenile survivorship in an outdoor pond containing natural prey and predators and (2) adult reproductive success in three outdoor ponds across three reproductive seasons (years). Juvenile survival was negatively affected by boldness, with bolder juveniles having a lower probability of survival than shyer juveniles. In contrast, bolder adultmale bass had greater reproductive success than their shyermale counterparts. Female reproductive success was not affected by boldness. These findings demonstrate that boldness can affect fitness differently across life stages. Further, boldness was highly consistent across years and significantly heritable, which suggests that boldness has a genetic component. Thus, our results support theory suggesting that fitness trade-offs across life stages may contribute to the maintenance of personality variation within populations.
... Even though several studies demonstrated that not only predation pressure but also various other environmental factors influence personality traits in fish (e.g., habitat structure: Kobler, Maes, Humblet, Volckaert, & Eens, 2011;temperature: Biro, Beckmann, & Stamps, 2010; light intensity/turbidity: Kelley, Phillips, Cummins, & Shand, 2012;Borner et al., 2015), surprisingly few studies have made an attempt to disentangle the relative contributions of different biotic and abiotic ecological factors for the emergence of population differences in personality traits. Indeed, most studies investigating the influence of environmental factors on population differences in AP in fish focused on only one environmental factor (e.g., Archard & Braithwaite, 2011;Brown et al., 2005;Fraser & Gilliam, 1987;Harris et al., 2010), while Brydges, Colegrave, Heathcote, and Braithwaite (2008) found that the interaction between predation risk and habitat stability but not predation alone predicted differences in boldness among populations of three-spined stickleback (Gasterosteus aculeatus). ...
Understanding whether and how ambient ecological conditions affect the distribution of personality types within and among populations lies at the heart of research on animal personality. Several studies have focussed on only one agent of divergent selection (or driver of plastic changes in behaviour), considering either predation risk or a single abiotic ecological factor. Here, we investigated how an array of abiotic and biotic environmental factors simultaneously shape population differences in boldness, activity in an open field test, and sociability/shoaling in the livebearing fish Poecilia vivipara from six ecologically different lagoons in south-eastern Brazil. We evaluated the relative contributions of variation in predation risk, water transparency/visibility, salinity (ranging from oligo- to hypersaline), and dissolved oxygen. We also investigated the role played by environmental factors for the emergence, strength, and direction of
behavioural correlations. Water transparency explained most of the behavioural variation, whereby fish from lagoons with low water transparency were significantly shyer, less active, and shoaled less than fish living under clear water conditions. When we tested additional wild caught fish from the same lagoons after acclimating them to homogeneous laboratory conditions, population differences were largely absent, pointing towards behavioural plasticity as a mechanism underlying the observed behavioural differences. Furthermore, we found correlations between personality traits (behavioural syndromes) to vary substantially in strength and direction among populations, with no obvious associations to ecological factors (including predation risk). Altogether, our results suggest that various habitat parameters simultaneously shape the distribution of personality types, with abiotic factors playing a vital (as yet underestimated) role. Furthermore, while predation is often thought to lead to the emergence of behavioural syndromes, our data do not support this assumption.
... When a prey population exhibits consistent individual-level behavioral differences, as has been documented in an immensely diverse set of study systems (Bell et al., 2009;Mather & Logue, 2013), individual prey may utilize environmental refugia to different degrees, thus only providing protection for certain prey types with a specific set of phenotypic traits (Klecka & Boukal, 2014). For example, less bold or aggressive prey may be more likely to use habitat refugia (Kobler, Maes, Humblet, Volckaert, & Eens, 2011;Spiegel, Leu, Sih, Godfrey, & Bull, 2015) and thus experience higher survivorship in the presence of certain types of predators (Belgrad & Griffen, 2016). Thus, we reason that the effects of individual-level behavioral variation on predatorprey interactions will change based on the environment in which the interactions occur. ...
... Dispersers are generally more active, bolder, and more explorative than philopatric or less dispersive individuals (see Cote et al., 2010 for a similar conclusion). These patterns bring up the question of whether the propensity to disperse exists independently of personality variation or whether dispersal is an emergent property of individual variation in Utida (1972), Fairbairn (1978), O'Riain, Jarvis, and Faulkes (1996), Belthoff and Dufty (1998), Bonte, Lens, and Maelfait (2004), Krug and Zimmer (2004), Aragón, Meylan, and Clobert (2006), Jokela, Elovainio, Kivim€ aki, and Keltikangas-J€ arvinen (2008), Hoset et al. (2011), Kobler, Maes, Humblet, Volckaert, and Eens (2011), Maes, Van Damme, and Matthysen (2012, Saastamoinen, Brakefield, and Ovaskainen (2012), Edelsparre, Vesterberg, Lim, Anwari, and Fitzpatrick (2014), and Mueller et al. (2014) Aggression Positive (7) Bony fishes Arthopoda Birds Mammals Myers and Krebs (1971), Fairbairn (1978), Mehlman et al. (1995), Trefilov, Berard, Krawczak, andSchmidtke (2000), Kruuk (2009), Pintor, Sih, andKerby (2009), and Groen et al. (2012) Negative (6) Bony fishes Insects Mammals Myers and Krebs (1971), Smale (1998), Holway, Suarez, andCase (1998), Schradin and Lamprecht (2002), Guerra and Pollack (2010) Clobert, John, and Meylan (2000), Fraser, Gilliam, Daley, Le, and Skalski (2001), Dingemanse, Both, van Noordwijk, Rutten, and Drent (2003), Krackow (2003), Rehage and Sih (2004) (2012), and Aguillon and Duckworth (2015) personality. After all, heightened activity levels can lead to longer distances traveled without any need to invoke active decision-making processes by the organism. ...
Behavioral strategies combine an organism's genetic, physiological, and neurological systems into closely integrated complexes that nevertheless retain substantial environmental contingency in their expression. How does environmentally contingent and coordinated expression of behaviors evolve? While the fitness consequences of behavioral coexpression are often hypothesized to be the driving force behind the evolution of behavioral strategies, this assumes the components that comprise a strategy are ontogenetically independent. Here, we argue that because the components' coexpression at a preceding developmental stage can delineate the range of subsequent behavioral associations, correlations among behaviors can arise through developmental linkages of behavioral components independently of their eventual fitness consequences. To distinguish this explanation from the conventional explanation of behavioral correlations arising through stabilizing selection, we need to know the mechanistic bases of behavioral associations. We propose that the basic components of behavioral strategies can arise from neural trade-offs early in development. We review evidence for this idea from recent work on the neuroanatomical basis of personality variation in humans and other animals and from studies of design principles of neural network formation. We show that some behavioral associations arise not because selection favors the association per se, but because energetic and space constraints of the brain channel developmental variation into repeatable pathways that produce predictable behavioral variation across taxa. We suggest that such developmental channeling of behavioral elements should greatly facilitate adaptive evolution in complex behavioral strategies and illustrate this with evolution of dispersal strategies.
... Examples from nature include differences in host plant preference in phytophagous insects (Matsubayashi et al., 2011;Matsubayashi and Katakura, 2009) and differences in spawning site preferences in ecologically divergent stickleback fishes (Kume et al., 2010). Some evidence suggests that individuals with different personalities might prefer different habitat (Kobler et al., 2011;Wolf and Weissing, 2012;Wilson and Godin, 2009;Martin and Reale, 2008;Reale et al., 2007). If so, differences in habitat preferences could reduce the frequency of heterospecific encounters, and thereby reduce opportunities to mate. ...
... In our kelp forest study system, fish predation can reduce abundances of intermediate carnivores (other fishes) or herbivorous invertebrates (crabs, snails and urchins) [46]. With lower human predation risk, bolder fishes emerge more frequently into open areas [47], encounter and consume more prey [42], and alter prey foraging and hiding behaviour [43]. However, since these fishes are generalists that feed across trophic levels, the net ecological impacts of variation in predator boldness and predation rates across sites are difficult to predict [48], and may result in suppression or enhancement of feeding on basal trophic levels, potentially increasing or decreasing primary producer biomass. ...
Humans have restructured food webs and ecosystems by depleting biomass, reducing size structure and altering traits of consumers. However, few studies have examined the ecological impacts of human-induced trait changes across large spatial and temporal scales and species assemblages. We compared behavioural traits and predation rates by predatory fishes on standard squid prey in protected areas of different protection levels and ages, and found that predation rates were 6.5 times greater at old, no-take (greater than 40 years) relative to new, predominantly partial-take areas (approx. 8 years), even accounting for differences in predatory fish abundance, body size and composition across sites. Individual fishes in old protected areas consumed prey at nearly twice the rate of fishes of the same species and size at new protected areas. Predatory fish exhibited on average 50% longer flight initiation distance and lower willingness to forage at new protected areas, which partially explains lower foraging rates at new relative to old protected areas. Our experiments demonstrate that humans can effect changes in functionally important behavioural traits of predator guilds at large (30 km) spatial scales within managed areas, which require protection for multiple generations of predators to recover bold phenotypes and predation rates, even as abundance rebounds.
... We were also confident that, given the small home range (0.0072 km 2 in lotic systems and upwards of 500 m in lentic systems) and high site fidelity in Bluegill (reviewed in Warren 2009), the distances that we used to delineate the main lake (>3 km from the APA) and the transitional regions (0-1 km outside of the APA) should reasonably represent the fish that are resident to these regions (i.e., fish were not moving between lake regions). Fishing was standardized across similar habitat types to avoid the potential biases that are associated with ecomorphs or habitatspecific differences in the individual's behavioral phenotype (Kobler et al. 2011;Wolf and Weissing 2012). We also acknowledge that perceived predation risk may have biased our sampling towards selecting bolder individuals (i.e., shy fish likely avoided exposure in the open areas where fishing occurred), but as is detailed in the discussion this was unlikely because predation risk is relatively low for such large Bluegill in this system (e.g., Werner et al. 1983;Shoup et al. 2003). ...
In recreational fisheries it understood that individual fish exhibiting bolder personality traits have a tendency to be removed from the population (i.e., fishing mortality via harvest or catch‐and‐release mortality) while more timid individuals remain. The use of aquatic protected areas (APAs) has been promoted as a means of offsetting the negative consequences associated with fishing mortality by protecting the full suite of phenotypes. However, little work has investigated if APAs are able to maintain heterogeneity in behavioural traits in wild fish. We attempted to address this question using wild Bluegill (Lepomis macrochirus) from Lake Opinicon; a freshwater system consisting of both an APA and heavily fished areas. Bluegill were obtained via angling from three zones in the lake: the main lake area (i.e. fished), the APA (which has been in place since the 1940s), and a transitional zone between these two areas. In the laboratory, Bluegill were subjected to two behavioural assessments, a Z‐maze and a flight initiation distance (FID) test, to address differences in boldness and risk‐taking between these populations. No significant effects of capture zone were detected for any of the behavioural metrics assessed in the maze trial. However, individuals originating from the main lake population had significantly higher FID scores compared to transitional and APA derived fish indicating that they were more‐timid. Our results suggest that fisheries activities may only be acting on certain traits which may explain some of the null results presented here. Nonetheless, our study provides evidence that APAs are providing a reservoir of less timid individuals which is consistent with an evolutionarily‐enlightened management strategy.
... Microhabitat differences, like just described for N. fodiens and S. minutus, open the possibility for among-individual differences in behavioral strategies (Wolf and Weissing 2012). It has been shown for several species, including mammals, that individuals living in habitats differing in complexity also differ in behaviors like aggression or exploration (Mettke-Hofmann et al. 2002;Jensen et al. 2005;Baird et al. 2006;Kobler et al. 2011). Also, space use inside a habitat is influenced by personality (Laskowski et al. 2015;Spiegel et al. 2015;Deventer et al. 2016). ...
Phenotypic variation in behavior exists among species and populations, as well as among and within individuals. The pace-of-life syndrome hypothesis predicts covariation between life-history strategies, ranging from slow to fast, and behavior, ranging from shy, inactive, and flexible to bold, active, and less flexible. This covariation is expected to exist at multiple hierarchical levels, from the species down to the individual. We predict that fast-lived species will differ in average levels of behavior, and additionally show lower within-individual and among-individual variation than slow-lived ones. Shrews represent a highly suitable model to test these predictions, as they comprise a range of genera which differ tremendously in life-history strategy and metabolism. We performed repeated tests of boldness and aggression on 155 wild-caught individuals of five species of shrews, two species of the slow-lived genus Crocidura, two of the fast-lived genus Sorex, and one of the intermediate-paced genus Neomys. To compare not only average levels of behavior but also its variance components between those groups, we calculated coefficients of variation at within- and among-individual levels. Our results support our first prediction that, following the framework of pace-of-life-syndromes, fast-lived species should exhibit bolder behavior than slow-lived ones. However, our prediction of lower within- and among-individual variation in fast-lived species was not supported. Instead, our data suggest that other ecological factors might influence the expression of behavioral variation in shrew species, such as the variability in habitat choice and differences in anti-predator strategies.
Significance statement
The behavior and life history of animals are often structured into so-called pace-of-life syndromes (POLS), with slow-lived individuals being rather shy, inactive, and flexible and fast-lived individuals rather bold, active, and less flexible. Comparing the behavior in five species of shrews, we tested if such a gradient can also be found on the species level. While the average levels of species’ behavior indeed matched their pace of life, their individual behavior and behavioral stability did not. It was rather explained by an interplay of ecological and physiological factors, among them the variability in habitat choices and differences in anti-predator strategies. Our study shows that behavioral variation cannot be explained by just one factor like POLS at different hierarchical levels, but rather by a combination of factors including the animals’ life-history and ecological and physiological background.
... Habitat secara umumnya ialah kawasan yang digunakan oleh organisma untuk memenuhi keperluan asas, seperti makan dan membiak. Mikrohabitat pula adalah habitat yang lebih khusus dan kecil dan boleh diperhatikan dalam banyak haiwan, seperti ikan (Kobler et al 2011, Lee & Suen 2012, burung (Kirol et al. 2012) dan tumbuh-tumbuhan (Pradhan & Badola 2012). Memahami pemilihan mikrohabitat oleh haiwan boleh membantu dengan usaha pemuliharaan. ...
Bukit Fraser ialah salah satu pusat peranginan tanah tinggi yang terletak
di Banjaran Titiwangsa, Semenanjung Malaysia selain Tanah Tinggi
Cameron dan Tanah Tinggi Genting. Bersempadan antara Selangor dan
Pahang pada kedudukan latitud 30 40.6’ U dan 30 43’ U dan longitud
1010 42.0’ T dan 1010 47.0’ T di dalam daerah Raub, Pahang dengan
keluasan 2804 ha dan, disempadani Bukit Ulu Sempam (1312 m pada aras
laut), Pine Tree Hill (1448 m pada aras laut), Gunung Ulu Semangkok
(1386 m pada aras laut), Bukit Telaga dan Teranum Gap (595 m pada
aras laut) (Kiew 1998). Perubahan ketinggian sesuatu vegetasi hutan,
secara tidak langsung akan mengubah struktur hutan, fisiognomi dan
komposisi flora. Flora hutan gunung di kawasan Malesia banyak
didominasikan oleh famili-famili seperti Aceraceae, Araucariaceae,
Clethraceae, Cunoniaceae, Ericaceae, Fagaceae, Lauraceae, Myrtaceae,
Pentaphylaceae, Podocarpaceae, Symplocaceae dan Theaceae (van
Steenis 1934, 1936, 1962, 1964). Di Semenanjung Malayia, Banjaran
Titiwangsa ialah satu kawasan tanah tinggi yang banyak dilimpahi famili
Fagaceae-Lauraceae sehingga ketinggian 1500 m aras paras laut. Wyatt-
Smith (1963) menyatakan genus yang biasa bersekutu di vegetasi hutan
Fagaceae-Lauraceae seperti Agathis, Dacrydium, Podocarpus, Syzygium
dan Garcinia. Cockburn (1969) turut melaporkan di Gunung Mandi
Angin, Terengganu terdapat perubahan mendadak pada ketinggian 1140
m aras paras laut yang mana famili Guttiferae, Fagaceae dan Theaceae
lebih dominan.
... All fish were captured from similar habitat type consisting of submerged aquatic macrophytes, scattered woody debris, and soft substrate. We captured fish from similar habitat types to avoid any potential bias due to behavioral types associated with different habitat types (Kobler et al. 2011;Wolf and Weissing 2012;Lawrence et al. 2018). ...
Artificial light at night (ALAN) is one of the fastest growing anthropogenic disturbances to animals across many ecosystems, yet little is known about how ALAN influences fish and aquatic ecosystems. Our current understanding of the effects of ALAN on fish behavior and physiology tend to be based on research conducted during night, with comparatively little research on whether ALAN influences subsequent behavior during diurnal periods. We used wild-caught Bluegill Lepomis macrochirus as a model to assess whether ALAN of differing intensities comparable to what would be experienced in the wild near human-altered landscapes (i.e., 0.5 lux, 4 lux, 9 lux) alters subsequent diurnal behavior relative to controls (i.e., dark, 0 lux). We assessed a number of behavioral traits in a laboratory setting known to relate to performance and fitness in wild teleost fish including exploration, activity levels, space usage, and risk aversion. Exploration behavior, space use, and risk-taking behaviors were similar among treatments. Only locomotor activity differed among treatments with Bluegill in the 0.5 and 9 lux treatments swimming significantly less than controls after being exposed to ALAN overnight. This difference in behavior was found at light intensities commonly found at waterways today and thus may already be affecting fish communities and aquatic ecosystems.
... Juvenile salmon disperse from their streambed nest into adjacent microhabitats within a given section of stream (Einum et al., 2012). Microhabitat partitioning in freshwater fish populations can result from complex interactions between the relative quality of the individual microhabitats, as well as the competitive abilities and energy requirements of the individuals that are born among them (Auer et al., 2020;Kobler et al., 2011;Svanbäck & Bolnick, 2007;Wathen et al., 2019). This can then lead to more favourable microhabitats supporting a higher density of individuals and less favourable microhabitats supporting fewer, potentially lesscompetitive conspecifics. ...
Habitat quality can have far‐reaching effects on organismal fitness, an issue of concern given the current scale of habitat degradation. Many temperate upland streams have reduced nutrient levels due to human activity. Nutrient restoration confers benefits in terms of invertebrate food availability and subsequent fish growth rates. Here we test whether these mitigation measures also affect the rate of cellular ageing of the fish, measured in terms of the telomeres that cap the ends of eukaryotic chromosomes. We equally distributed Atlantic salmon eggs from the same 30 focal families into 10 human‐impacted oligotrophic streams in northern Scotland. Nutrient levels in five of the streams were restored by simulating the deposition of a small number of adult Atlantic salmon Salmo salar carcasses at the end of the spawning period, while five reference streams were left as controls. Telomere lengths and expression of the telomerase reverse transcriptase (TERT) gene that may act to lengthen telomeres were then measured in the young fish when 15 months old. While TERT expression was unrelated to any of the measured variables, telomere lengths were shorter in salmon living at higher densities and in areas with a lower availability of the preferred substrate (cobbles and boulders). However, the adverse effects of these habitat features were much reduced in the streams receiving nutrients. These results suggest that adverse environmental pressures are weakened when nutrients are restored, presumably because the resulting increase in food supply reduces levels of both competition and stress.
... Although the mobility of prey will affect the behavior of focal species, the presence of sit-and-wait predators in complex habitats appears to have a much stronger influence on the foraging and activity of a potential prey/focal species in these habitats (see below; Horinouchi et al. 2009;Catano et al. 2017). Another potential caveat is that the inclusion of observational studies in the meta-analysis, because we are unable to control for potential genetic or personality differences between individuals choosing to reside in open versus complex habitats (e.g., Wilson et al. 1993;Kobler et al. 2011). ...
Augmenting habitat complexity by adding structure has been used to increase the population density of some territorial species in the wild and to reduce aggression among captive animals. However, it is unknown if all territorial species are affected similarly by habitat complexity, and whether these effects extend to non-territorial species. We conducted a meta-analysis to compare the behavior of a wide range of territorial and non-territorial taxa in complex and open habitats to determine the effects of habitat complexity on 1) territory size, 2) population density, 3) rate and time spent on aggression, 4) rate and time devoted to foraging, 5) rate and time spent being active, 6) shyness/boldness, 7) survival rate, and 8) exploratory behavior. Overall, all measures were significantly affected by habitat complexity, but the responses of territorial and non-territorial species differed. As predicted, territorial species were less aggressive, had smaller territories and higher densities in complex habitats, whereas non-territorial species were more aggressive and did not differ in population density. Territorial species were bolder but not more active in complex habitats, whereas non-territorial species were more active but not bolder. Although the survival of non-territorial species increased in complex habitats, no such increase was observed for territorial species. The increased safety from predators provided by complex habitats may have been balanced by the higher population densities and bolder behavior in territorial species. Our analysis suggests that territorial and non-territorial animals respond differently to habitat complexity, perhaps due to the strong reliance on visual cues by territorial animals.
The inherently multidimensional nature of the niche has not yet been integrated into the investigation of individual niche specialization within populations. We propose a framework for modeling the between- and within-individual components of the population niche as a set of variance-covariance matrices, which can be visualized with ellipses or ellipsoids. These niche components can be inferred using multiple response mixed models, and can incorporate diverse types of data, including diet composition, stable isotopes, spatial location, and other continuous measures of niche dimensions. We outline how considering both individual and population niches in multiple dimensions may enhance our understanding of key concepts in ecology and evolution. Considering multiple dimensions as well as the within-individual component of variation can lead to more meaningful measures of niche overlap between species. The impact of a population on its food web or ecosystem can depend on the degree of individual variation (via Jensen's inequality), and we suggest how the dimensionality of individual specialization could amplify this effect. Finally, we draw from concepts in quantitative genetics and the study of animal personalities to propose new hypotheses about the ecological and evolutionary basis of niche shifts in multiple dimensions. We illustrate key ideas using empirical data from sea otters, wetland frogs, and threespine stickleback, and discuss outstanding questions about the consequences of multidimensional niche variation. Setting variation among individuals in an explicitly multivariate framework has the potential to transform our understanding of a range of ecological and evolutionary processes. This article is protected by copyright. All rights reserved.
There are generally two types of animal populations managed for conservation purposes, in situ and ex situ. The management goals for each type of population differ and this drives the manner by which the populations experience selection. Population members of different behavioral types may respond to the same stimuli in varying ways, generating potentially supportive effects for achieving conservation goals. The cumulative impact of observable phenotypic or behavioral variation predicts the potential of meeting population goals. Phenotype management is a conservation strategy that employs understanding of the varied outcomes for individuals in developing the potential for successful conservation populations. To employ phenotype management, it is useful to consider the environmental factors that drive the expression of varied behavioral types and life history trajectories. Diversity of habitat and developmental circumstance may be crucial to generating phenotypically diverse populations. Ex situ populations may be spread across numerous locations as meta-populations and members of these populations may experience a diversity of husbandry protocols, social groupings, and climates—resulting in population level behavioral diversity. A focus on habitat heterogeneity and in situ habitat restoration may support phenotypic diversity in populations of concern.
Correlated suits of behaviors (behavioral syndrome) are commonly observed in both inter- and intraspecific studies. In order to understand the genetic basis of such a correlation between species, we compared ten behaviors classified into five categories (acclimation, feeding, normal swimming, reaction to a novel object and activity in a novel environment) between two pufferfish species, Takifugu rubripes and T. niphobles. The two species showed consistent differences in nine behaviors with a significant correlation among behaviors. Quantitative trait locus (QTL) analysis using second generation hybrids revealed that different sets of small effect QTL are associated with the observed interspecific behavioral disparity. This indicates that correlations in temperament traits between them are governed by many genes with small effects, and each behavior has been selected to form particular combination patterns. One of the QTL showing small pleiotropic effect includes the Drd4 gene known for its association with behavioral traits in some animal taxa including mammals.
The Sea Lamprey (Petromyzon marinus) is invasive in the Laurentian Great Lakes. Trapping in large rivers could suppress Sea Lamprey recruitment by removing migrating adults prior to spawning. Currently, the proportion of Sea Lamprey trapped (efficiency) is too low for control purposes, possibly because trapping is biased toward certain behavioural types. We tested if individual differences in time to enter a novel environment (risk-taking) and proportion of time moving (activity) under standardized laboratory conditions were correlated with time to encounter and enter a trap in the field. 638 Sea Lamprey were tagged, assessed for risk-taking and activity in sequential trials, and released in the river to be trapped. In the laboratory, individuals differed consistently in risk-taking and activity behaviours, and more active individuals entered a simulated trap sooner than less active individuals. In the field, however, the times to first trap encounter, and capture in a trap, were not correlated with risk-taking or activity. Our study provides a novel demonstration of how patterns from small-scale behavioural studies may not extend to management-scale applications.
Across vertebrates, there is a broad correlation between neuroanatomy and the type of habitat preferred by a species. In general, species occupying habitats classified as more structurally complex have relatively larger brains and exaggerated structures related to navigating and exploiting those habitats. We empirically measured the structural habitat complexity of six species of Puerto Rican Anolis lizards, which have traditionally been classified as occupying three distinct habitat types. We also measured the volume of the whole brain as well as six structures putatively related to exploiting complex habitats in these species. We found a significant interspecific variation in structural habitat complexity, including a substantial variation between those belonging to the same ecomorph category. Despite this, we found no evidence to support the hypothesis that interspecific differences in habitat preferences, particularly differences in the relative structural complexity of those habitats, can favor a divergence in neuroanatomy. However, our findings indicate that, at a finer scale, species preferences for structural habitats vary greatly between Anolis species belonging to the same ecomorph category. This variation might contribute to the community structure of anoles by allowing multiple sympatric species of the same ecomorph category to occupy what, at a coarse scale, appears to be the same structural niche. We propose that, in the case of arboreal species, differences in the complexity of arboreal habitats alone may not be sufficient to favor divergent brain evolution. © 2014 S. Karger AG, Basel.
Abstract – Passive integrated transponder tags have been successfully applied in Cottus spp. and have enabled researchers to gather more information about the movement patterns of individual fish in the wild. In two succeeding years during springtime, a portable antenna was used to determine diel movements of bullhead (Cottus perifretum). In 2007, bullhead (N = 26) moved significantly farther distances at night (mean, 0.42 m·h−1) and dawn (mean, 0.35 m·h−1) than during daytime (mean, 0.11 m·h−1; mixed model, P P = 0.001), which may be due to foraging activities for Gammarus spp. Irrespective of diel period, smaller fish covered significantly longer distances (P = 0.001). In 2008, similar diel movement patterns were observed, but the differentiation between daytime (mean, 0.12 m·h−1) and night periods (mean, 0.18 m·h−1) was not significant (mixed model, P = 0.087; N = 49 bullhead). It is discussed that longer tracking intervals used in 2008 (three times per 24‐h instead of every two hours) were not suitable to detect the sheer magnitude of distances covered during a diel period. It is shown that this may be due to ‘site fidelity’ of some individuals: after swimming several metres at night, they returned to the exact location they previously occupied during daytime. In 2008, sex and body size were not related to diel movement. The present study is the first to present a quantitative differentiation between diel distances covered in a Cottus spp.
In laboratory experiments, variously colored strains of animals, including those with albino phenotypes, are commonly used. The melanocortin theory suggests, however, that coloration phenotypes alter animal physiology and behavior. Animals with the albino phenotype show photoreceptor degradation associated with lowered visual accuracy, escape reactions, etc., presumably accompanied by prevailing nocturnal activity and lowered aggressiveness. This assumption was tested in small groups of albino and pigmented European catfish, Silurus glanis, during the diel cycle. The frequency of agonistic interactions was observed during mutual contests for shelters, and subsequently, blood plasma, brain, gill, and liver samples were collected to evaluate stress parameters. In an experimental arena with shelters, the light/dark rhythmicity of locomotor activity and aggressiveness of the two phenotypes were comparable; the peak was observed at night, and a lower peak was observed at dawn. In an experimental stream without shelters, the peak of locomotor activity occurred at night for only the pigmented phenotype. In the evaluation of 4 antioxidants and 1 oxidative stress indicator, representing a total of 15 indices, albino fish showed significant rhythmicity for 8 indices, whereas pigmented catfish showed significant rhythmicity for 5 indices. The production of blood stress parameters with the peak during the day occurred only in albino fish. A complex model was fitted with the aim of evaluating the links between behavioral and biochemical indices. Time periodicity was modeled using a sine wave and confirmed parallel courses of agonistic interactions in the catfish groups; the peak at dawn was associated with a 4.08-fold (conf. int. 3.53-4.7) increase in such interactions. The changes in glucose and superoxide dismutase concentrations varied with phenotype, while the effects of cortisol, lactate and catalase did not. In summary, the rhythmicity of locomotor activity and changes in the aggressiveness of catfish were influenced by shelter availability, and the effect of light-induced stress was more apparent in albino fish than in pigmented conspecific fish. The results suggested that laboratory-raised animals with pigmentation patterns naturally occurring in the wild show more reasonable values during experiments than those with an albino phenotype.
We examined the effects of woody debris on the growth and behaviour of brown trout (Salmo trutta) in experimental stream channels. Two types of habitat were used in the study: a complex habitat created by placing woody debris on a gravel bed and a uniform habitat consisting of a gravel bed only. The experiment was run both outdoors with wild fish that fed on natural invertebrate drift and indoors with hatchery fish that were fed artificial food. In both treatments most of the fish lost mass. In all trials, however, the fish in the woody debris channel lost less mass than the fish in the control channel. Study of the fishes' behaviour revealed less swimming activity, less aggression, and less feeding activity in the woody debris channel than in the control channel. The results of this study indicate that the presence of woody debris decreases intraspecific competition through visual isolation, allowing fish to reduce aggressive interactions and energy expenditure.
We tested the predictions that an increase in the structural complexity of a habitat causes both a decrease in aggression and the monopolization of resources. Groups of three zebra fish (Danio rerio) were allowed to compete for food in a complex habitat with simulated vegetation and in a simple habitat with no vegetation. As predicted, both the levels of aggression by the dominant fish (P = 0.050) and the coefficient of variation of the amount of food eaten within a group (P = 0.020), a measure of food monopolization, were lower in the complex habitat than in the simple one. Fish that chased competitors more frequently ate more food in both habitats, but the relationship was stronger in the simple than in the complex habitat. Our results suggest that aggression is less useful as a mode of competition in habitats with greater structural complexity. Manipulating the structural complexity of the habitat may be a practical way of controlling the intensity of aggression and resource monopolization in groups of animals.
The spawning seasons and distributions of sympatric sculpins, namely, the small egg-type (SE) of Cottus pollux and C. hangiongensis, were investigated in a coastal river of northeastern Japan. The spawning seasons for both species last for four months, and the ovulation rate peaks in January and April for C. pollux and C. hangiongensis, respectively. The males of both sculpins nested in cavities under rocks in stony areas. C. pollux was distributed in reed marshes in summer and in stony areas during the spawning season, while C. hangiongensis was distributed in stony areas throughout the year. There was a difference in habitat use between the males and females of C. pollux during the spawning season; the males were distributed in stony areas for a longer period than the females. These results indicate that mature C. pollux shifts its habitat from marshes to stony areas for spawning.
We examined the effects of woody debris on the growth and behaviour of brown trout (Salmo trutta) in experimental stream channels. Two types of habitat were used in the study: a complex habitat created by placing woody debris on a gravel bed and a uniform habitat consisting of a gravel bed only. The experiment was run both outdoors with wild fish that fed on natural invertebrate drift and indoors with hatchery fish that were fed artificial food. In both treatments most of the fish lost mass. In all trials, however, the fish in the woody debris channel lost less mass than the fish in the control channel. Study of the fishes' behaviour revealed less swimming activity, less aggression, and less feeding activity in the woody debris channel than in the control channel. The results of this study indicate that the presence of woody debris decreases intraspecific competition through visual isolation, allowing fish to reduce aggressive interactions and energy expenditure.
Competition between hatchery-reared and wild salmonids in streams has frequently been described as an important negative ecological interaction, but differences in behavior, physiology, and morphology that potentially affect competitive ability have been studied more than direct tests of competition. We review the differences reported, designs appropriate for testing different hypotheses about competition, and tests of competition reported in the literature. Many studies have provided circumstantial evidence for competition, but the effects of competition were confounded with other variables. Most direct experiments of competition used additive designs that compared treatments in which hatchery fish were introduced into habitats containing wild fish with controls without hatchery fish. These studies are appropriate for quantifying the effects of hatchery fish at specific combinations of fish densities and stream carrying capacity. However, they do not measure the relative competitive ability of hatchery versus wild fish because the competitive ability of hatchery fish is confounded with the increased density that they cause. We are aware of only two published studies that used substitutive experimental designs in which density was held equal among treatments, thereby testing for differences in competitive ability. Additional substitutive experiments will help managers to better understand the ecological risk of stocking hatchery fish.
We quantified the space use behaviors of juvenile and adult mottled sculpin Cottus bairdii over a 3-year period in Shope Fork, western North Carolina. Our objectives were to (1) quantify home range size, (2) determine whether the fish exhibit territorial behaviors, (3) characterize the relative stability of territories, and (4) relate temporal variation in behaviors to environmental variability and population size structure. Adult behaviors were consistent with those of a strongly territorial organism. Adults exhibited nonrandom movements, restricted home ranges, and extremely low levels of spatial overlap with neighboring residents (
Repeatability is a useful tool for the population geneticist or genetical ecolo-
gist, but several papers have carried errors in its calculation. We outline the correct calcu-
lation of repeatability, point out the common mistake, show how the incorrectly calculated
value relates to repeatability, and provide a method for checking published values and
calculating approximate repeatability values from the F ratio (mean squares among groups/
mean squares within groups).
This paper describes two prototypes of portable detectors based on radio frequency identification modules and antennas commercially available in Europe and North America for reading small (2.1-mm × 11.5-mm) passive integrated transponder tags. Maximum tag detection distances ranged from 17 to 36 cm, depending on the system and orientation of the tag to the antenna. The efficiency of the detectors was field-tested with both wild juvenile brown trout Salmo trutta and adult slimy sculpin Cottus cognatus that had been marked by injection of a tag into the peritoneal cavity. By probing the water with the antenna, we were able to detect, on average, 69% of age-1 trout (fork length, 148 ± 26 mm (mean ± SD)), 82% of age-0 trout (fork length, 72 ± 8 mm), and 82% of adult sculpin (total length, 74 ± 9 mm). We did not conduct a formal study to compare the performances of the two prototypes or to determine how habitat characteristics may alter their efficiency.
Abstract – This study examined potential adverse effects of surgically implanted passive integrated transponder (PIT) tags (12 × 2.1 mm) on bullhead (Cottus gobio L.) of three different length-classes (I: 50–64 mm, II: 65–79 mm, III: 80–94 mm). During a 7-week laboratory experiment, the rate of PIT tag loss, incision closure time, survival, growth and swimming capacity were tested. The PIT tag weight to fish body weight ratio varied between 1.04% and 4.85%. The mean incision closure time differed significantly among length-classes and varied between 2.8 (I) and 4.3 (III) weeks. Nevertheless, PIT tag retention did not differ among length-classes and was ≥90%. The survival of untagged, sham-tagged and PIT-tagged bullheads was ≥90% and did not differ within or among length-classes. Finally, within each length-class, there was no difference in growth and swimming capacity among treatments. Hence, these results suggest the applicability of PIT tags for individually tagging bullheads ≥50 mm.
We investigated differences in microhabitat preference curves for bullheads, Cottus gobio L., of different size-classes during low flow periods, and evaluated the influence of such differences on habitat use through Weighted Usable Area (WUA) predictions in relation to river flow in a piedmont stream in Southwest France. Water depth, current velocity, and substratum composition were used to calculate proportional use values for each size-class (SC), and to quantify size-specific microhabitat preferences. Bullhead used non-cohesive and coarse mineral particles (pebbles, cobbles, boulders), but there was a spatial segregation of individuals from different size classes (SC1–SC4). Smaller bullhead (SC1, total length <60 mm) took refuge under cobbles, significantly preferred shallower areas, and were less prone to select high current velocities than larger bullhead (SC 2 to 4, >60 mm), the latter occurring below (or under) the largest particles, where current velocity is weakened and sand accumulates. SC1 bullhead had a more restricted range for each habitat descriptors, and were thus likely to require a more specific habitat type than other bullhead. The maximum WUA values and the related preferred discharges (0.15–0.75 m3 s–1) depended on the considered size-class. Our results suggest that ontogenetic niche shifts may play a role in the structure and dynamics of populations, by adjusting species' requirements to the spatial and temporal dynamics of environmental conditions, including abiotic and biotic conditions. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Many re-introduction programs used for conservation of populations and species threatened with extinction advocate the use of enriched rearing environments to train animals how to behave appropriately in the wild. Curiously, most of the current fish re-stocking programs have paid little attention to lessons previously learned in bird and mammal re-introductions. Many rehabilitation programs that use releases of hatchery fish observe higher mortality in released fish compared to wild, with most mortality arising shortly after release. One explanation for this mortality is based purely on selection processes; many hatchery fish normally selected out of the population thrive in the predator free, food-rich hatcheries. Alternatively, mortalities may be high because hatchery nursery environments fail to shape fish behaviour appropriately. Here, we empirically address the effect of enrichment in the early rearing environment in coastal cod (Gadus morhua). We find asymmetries in aggressive behaviour when fish reared in plain or enriched environments are allowed to interact. Furthermore, cod reared in standard, impoverished, hatchery environments spend less time in shelter, are more active, and show weaker anti-predator responses than fish reared with access to heterogeneous spatial cues. These results suggest that the constant, plain environments of fish farms may generate behavioural deficits that could reasonably be expected to be associated with lower survival in fish released into the wild.
Consistent differences in human behaviour are often explained with reference to personality traits. Recent evidence suggests
that similar traits are widespread across the entire animal kingdom and that they may have substantial fitness consequences.
One of the major components of personality is the shyness–boldness continuum. Little is known about the relative contributions
of genes and the environment in the development of boldness in wild animal populations. Here, we bred wild-caught fish (Brachyraphis episcopi) collected from regions of high- and low-predation pressure, reared their offspring in the laboratory under varying conditions
and tested boldness utilising an open-field paradigm. First-generation laboratory-reared fish showed similar behaviour to
their wild parents suggesting that boldness has a heritable component. In addition, repeated chasing with a net increased
boldness in both high- and low-predation offspring, showing that boldness is also heavily influenced by life experiences.
Differences between males and females were also sustained in the laboratory-reared generation indicating that sex differences
in boldness are also heritable. We discuss these results with reference to the potential underlying genetic and hormonal mechanisms
as well as the environmental influences that may be responsible for expression of boldness in wild animals.
Individual differences in temperament may affect how animals react to novel situations, avoid predation, invest in reproduction and behave in a variety of social contexts. Little information is available, however, about individual differences in temperament for wild animals. For bighorn sheep, Ovis canadensis, ewes captured as part of a long-term study, we compared behaviour during handling to behaviour in the field and reproductive history. We considered ‘bold’ ewes those that were frequently trapped during the summer, and assigned to each ewe a docility index based on her behaviour during handling. Measurements of temperament for the same individual at different captures were highly consistent. Temperament was not affected by reproductive status or age, nor was it related to body mass. Correlations between behaviour at the trap and in the field were weak and mostly nonsignificant, suggesting that temperament is domain specific rather than domain general. Bold ewes tended to start reproducing earlier and have higher weaning success than shy ewes. Variability in temperamental traits in the study population could be maintained by life-history trade-offs and by yearly changes in selective pressures.
The common approach to the multiplicity problem calls for controlling the familywise error rate (FWER). This approach, though, has faults, and we point out a few. A different approach to problems of multiple significance testing is presented. It calls for controlling the expected proportion of falsely rejected hypotheses – the false discovery rate. This error rate is equivalent to the FWER when all hypotheses are true but is smaller otherwise. Therefore, in problems where the control of the false discovery rate rather than that of the FWER is desired, there is potential for a gain in power. A simple sequential Bonferroni-type procedure is proved to control the false discovery rate for independent test statistics, and a simulation study shows that the gain in power is substantial. The use of the new procedure and the appropriateness of the criterion are illustrated with examples.
Aim In a selected literature survey we reviewed studies on the habitat heterogeneity-animal species diversity relationship and evaluated whether there are uncertainties and biases in its empirical support. Location World-wide. Methods We reviewed 85 publications for the period 1960-2003. We screened each publication for terms that were used to define habitat heterogeneity, the animal species group and ecosystem studied, the definition of the structural variable, the measurement of vegetation structure and the temporal and spatial scale of the study. Main conclusions The majority of studies found a positive correlation between habitat heterogeneity/diversity and animal species diversity. However, empirical support for this relationship is drastically biased towards studies of vertebrates and habitats under anthropogenic influence. In this paper, we show that ecological effects of habitat heterogeneity may vary considerably between species groups depending on whether structural attributes are perceived as heterogeneity or fragmentation. Possible effects may also vary relative to the structural variable measured. Based upon this, we introduce a classification framework that may be used for across-studies comparisons. Moreover, the effect of habitat heterogeneity for one species group may differ in relation to the spatial scale. In several studies, however, different species groups are closely linked to 'keystone structures' that determine animal species diversity by their presence. Detecting crucial keystone structures of the vegetation has profound implications for nature conservation and biodiversity management.
Consistent individual behavioural tendencies, termed "personalities", have been identified in a wide range of animals. Functional explanations for personality have been proposed, but as yet, very little consideration has been given to a possible role for sexual selection in maintaining differences in personality and its stability within individuals. We provide an overview of the available literature on the role of personality traits in intrasexual competition and mate choice in both human and non-human animals and integrate this into a framework for considering how sexual selection can generate and maintain personality. For this, we consider the evolution and maintenance of both main aspects of animal personality: inter-individual variation and intra-individual consistency.
The relevance of temperament traits for life history strategy or productivity is increasingly acknowledged. Temperament traits are often either observed in captivity or in the wild, but studies combining both observations are very rare. We examine whether exploratory behaviour in the bullhead (Cottus perifretum), assayed under laboratory conditions, predicts this behaviour under field conditions. Forty-three PIT-tagged individuals were first assayed for exploration of a novel environment in the aquarium and then released into an unfamiliar stream stretch, where they were later relocated using a mobile antenna. Explorative behaviour assayed in the laboratory was significantly positively related to the exploration in the field, thus predicting distance moved in the field release. Both in the laboratory and in the field, explorative behaviour was not related to individual body length. When bullheads that did not leave the refuge in the aquarium (laboratory assay) and, therefore, did not explore the new environment were excluded from the analysis, the correlation between laboratory and field explorative behaviour variables became weaker. However, overall, our results illustrate that exploration rate of bullheads in isolated single-individual experiments can be used to predict this behaviour in the natural ecosystem.
Movement and population of the mottled sculpin (Cottus bairdi Girard), excluding young of the year, were studied in Trout Creek, Gallatin County, Montana, between 4 August 1962 and 10 March 1963, and in the laboratory between 7 August and 21 December 1962. Finclipped fish were recaptured at an average rate of 23.9% (38.1-11.8%) for the 5 censuses. About 50% of the recaptures were within the original section (average length 46.8 ft), and about 80% were in an original section or an adjacent section (average length 153.2 ft). Upstream movement of all marked sculpins was 23.4% greater than downstream movement, but downstream movement of jaw-tagged sculpins was 16.6% greater than upstream. No mass upstream migration occurred. Home range was estimated to be less than 150 ft. Homing was not exhibited. About one-third of the displaced sculpins homed, one-third did not move, and one-third moved away from home. The longest upstream movement noted was 590 ft, and the longest downstream was 502 ft. Spatial isolation and aggressive behavior were not observed in a laboratory experiment, which suggests a lack of territoriality during the nonbreeding season. Modified Petersen population estimates ranged from 474-555 sculpins in a 234-ft section over the 5 inventories, and Schumacher-Eschmeyer estimates ranged from 480-492.
A model is developed to predict potential net energy gain for salmonids in streams from characteristics of water velocity and invertebrate drift. Potential profit was a better predictor of specific growth rate for coho salmon Oncorhynchus kisutch than for brook trout Salvelinus fontinalis or brown trout Salmo trutta. Coho salmon always achieved higher specific growth rates than either brook trout or brown trout in concurrent experiments, and maintained growth to lower resource thresholds. Fish established intraspecific hierarchies and dominant fish held positions affording maximum potential profit. The use of potential profit as an optimal foraging model was tested by predicting the potential for net energy gain at coho salmon positions from the overall pattern of flow and invertebrate drift in the stream aquarium, and ranking these positions from highest to lowest potential profit. This predicted ranking was nearly identical to the rank observed in the linear dominance hierarchy.-from Author
An electrofishing survey of daytime shelter microhabitat use of bullhead Cottus gobio in a southern English chalk stream revealed positive selection for moderate water velocity, vegetation cover and coarse substrata. Water depth, other forms of cover, shade and substratum embeddedness had no significant influence on the distribution of fish. Microhabitat use was size‐dependent, with patches occupied by adult fish containing coarser substrata and less blanket weed (Cladophora algae) than those occupied by smaller juvenile conspecifics. Differences in substratum use between size‐classes were less pronounced in parts of the stream shaded by the tree canopy. In laboratory tanks stocked at low fish density, both juveniles and adults favoured use of cobbles over pebbles. The response of fish to increased conspecific density was size‐dependent; juveniles reduced use of the coarse substratum whereas adults maintained their predominance in this habitat. An apparently greater shift by juveniles when in the presence of adults was significant at α = 0·10 only, as was an apparent reduction in interactions between size‐classes under low light intensity. The displacement of small juvenile fish from the preferred cobble substratum is consistent with the hypothesis that intraspecific competition contributes to the size‐related microhabitat shift observed in the field. Although there was a tendency for the strength of competition to be reduced at low light levels, the mechanism by which tree canopy cover affects microhabitat use remains uncertain.
The concept of behavioural syndromes hypothesizes that consistent behaviours across various situations mediate important life history trade-offs, and predicts correlations among behavioural traits. We studied the consistency of behavioural responses across three ecological situations (exploration of an environment altered with a novel object, aggression towards conspecifics, risk taking) in male collared flycatchers. We developed behavioural tests that could be applied in the birds' natural habitat, thus not requiring the capture of animals. Across individuals, we found positive covariation between exploration, aggression and risk taking, but the magnitude of these relationships varied. Variation in behaviour was also related to capture probability. Exploratory and risk-taking individuals were more likely to enter a trap than individuals with averse characteristics. Moreover, with the trapped birds, there was an association between the time needed for successful capture and exploration, and we found stronger correlations between behaviours in comparison with effects calculated from the whole sample of individuals. These patterns were independent of territory quality, male age, condition and breeding experience. Consequently, behavioural responses to different ecosocial challenges are determined by individual-specific characteristics that are manifested in correlative behaviours. Hence, behavioural types may be potential subjects for reproductive and life history adaptations. Our results have important implications for field studies of animals, because they suggest that capturing protocols may not randomly sample the observed population.
The River Bullhead (Cottus gobio) is a common species of fresh-water fish in Britain, which forms a cavity-nest and protects and aerates its eggs. The nesting behaviour involves several forms of digging: mouth-digging, the carrying away of obstructions, pectoral fin digging, and tail-digging. During the reproductive cycle, the male spends most of its time lying inside the nest with its head at the entrance. In this position it catches its food, courts females, threatens rivals, aerates its eggs, and hides from predators. Apart from actual fighting, it may threaten rivals with a number of threat displays which consist of the following components: raising the gill-covers, lowering the head, opening the mouth, darkening the head, nodding, fin-raising, and undulating the body. The various displays consist of different combinations of the above components. Courtship consists of biting the head of the female, to which she responds sexually by entering the nest. Inside the nest the male and female assume a number of postures associated with the preparation for spawning. The eggs are laid on the roof of the nest. The female does not appear to assist in parental activities. The male fans the eggs with its pectoral fins, passing a current of water around the nest. It may construct an exit so that the current passes through the nest. When the young hatch they swim to the inside corners of the nest. The frequency of the fanning activity is measured throughout the parental cycle. This behaviour is compared with that of sticklebacks. The parental cycle lasts approximately four weeks, during which time the male fans almost incessantly. The fanning frequency increases and decreases mainly as a result of changes in the speed of the beating of the pectoral fins, and in this way it differs from the fanning of sticklebacks. The similarities and differences between the reproductive behaviour of the Bullhead and the sticklebacks is summarised. Fundamentally, they are similar in many ways. A brief review of the way in which different fish species assist in the development of their eggs is given.
A model is developed to predict potential net energy gain for salmonids in streams from characteristics of water velocity and invertebrate drift. Potential net energy gain, or potential profit, is calculated for individuals of three species of juvenile salmonids in a laboratory stream aquarium, based on the energy available from drift minus the cost of swimming to maintain position. The Michaelis–Menten or Monod model is used to describe the relationship between potential profit and specific growth rate. Potential profit was a better predictor of specific growth rate for coho salmon (Oncorhynchus kisutch) than for brook trout (Salvelinus fontinalis) or brown trout (Salmo trutta). Coho salmon always achieved higher specific growth rates than either brook trout or brown trout in concurrent experiments, and maintained growth to lower resource thresholds. In each experiment, fish established intraspecific hierarchies and dominant fish held positions affording maximum potential profit. The use of potential profit as an optimal foraging model was tested by predicting the potential for net energy gain at coho salmon positions from the overall pattern of flow and invertebrate drift in the stream aquarium, and ranking these positions from highest to lowest potential profit. This predicted ranking was nearly identical to the rank observed in the linear dominance hierarchy. The results of experiments confirm ideas of other investigators about mechanisms of microhabitat selection by stream salmonids.
Underwater observations were used to examine the microhabitat utilization, feeding periodicity, home range and population size of Cottus carolinae, the banded sculpin, in the Little River of eastern Tennessee. Most sculpins resided under rocks during the day, but on tops of rocks at night. Analyses of the gut contents indicated that C. carolinae fed primarily at night. Underwater counts of individually marked sculpins suggested these fish have a small average home range, with a maximum of 47 m2. Based on a mark-recapture enclosure study and the Jolly-Seber mark-recapture method, mean density estimates for C. carolinae were 0.4 and 0.9 fish/ m2, respectively.
Microhabitat use and preferences of juvenile and adult bullhead Cottus gobio, from the River Voer, Flanders, were studied and compared across different seasons. Water depth, water velocity near the substratum, surface water velocity and substratum type used by C. gobio differed between seasons. These differences, however, were not attributable to differences in microhabitat availability. Adults appeared to prefer higher water velocities and coarser substrata than the average ones available in the basin. Although water depth appeared to have little influence on seasonal variation of microhabitat use in adult C. gobio, juveniles preferred deeper water and coarser substrata in winter, whereas in summer they appeared to use shallower water. There was a difference in microhabitat use between juvenile and adult bullhead only in summer.
SUMMARY11,555 Bullheads (Cottus gobio L.) from Windermere, 771 from the river Brathay and 542 from other waters, 2,868 in all, were caught between January 1951 and December 1955.2The fish lives on the margins of lakes and in rivers under stones where there is a sandy or gravelly bottom.3Differences in behaviour of breeding and non-breeding fish are described.4Males mature earlier in the year than females and large females lay eggs earlier in the breeding season than small ones. In the river Brathay, most fish do not breed before they are two years old, but in Windermere fast-growing fish breed when one year old. Fish from Windermere have a greater fecundity than those from the river Brathay.5Age was found from otoliths. Male fish grow faster than females in both the river Bray and Windermere and fishes of both sexes grow faster in the lake than they do in the river.6The food, which is mainly invertebrate bottom fauna, varies more with season and place than with size of fish or year of capture. In both Windermere and the river Brathay the fish feeds mostly on nymphs of Ephemeroptera and Plecoptera and larvae of Trichoptera, but in Windermere, unlike the river Brathay, Gammarus and Sialis are also commonly eaten.7The fish has many parasites, of which only one in the urinary bladder (Phyllodistomum folium) has been identified, and apparently no serious predators.
The culture of decapod crustaceans occurs worldwide. Aggressive behaviour is common in many of the species, including crayfish. This is problematic when it physically damages stock and reduces quality. Numerous biological factors influence crayfish fighting behaviour but the influence of environmental factors is not well known. This study investigated the effect of habitat complexity on the agonistic interactions of Australian freshwater crayfish, more commonly referred to locally as ‘yabbies’ (Cherax destructor Clark). Solid objects that provided structure but not shelter were used to manipulate the complexity of the environment. The number, duration and dynamic of aggressive interactions within groups of animals were observed and recorded in simple and complex environments. Habitat complexity reduced both the number of agonistic interactions and the total time spent interacting. It is suggested that the structure in the environment distracts crayfish from the presence of others or physically blocks contact between them. These results extend our knowledge of crayfish social behaviour and may provide opportunities for reducing detrimental aggressive interactions in the aquaculture industry.
There is increasing interest in individual differences in animal behaviour. Recent research now suggests that an individual's behaviour, once considered to be plastic, may be more predictable than previously thought. Here, we take advantage of the large number of studies that have estimated the repeatability of various behaviours to evaluate whether there is good evidence for consistent individual differences in behaviour and to answer some outstanding questions about possible factors that can influence repeat- ability. Specifically, we use meta-analysis to ask whether different types of behaviours were more repeatable than others, and if repeatability estimates depended on taxa, sex, age, field versus laboratory, the number of measures and the interval between measures. Some of the overall patterns that were revealed by this analysis were that repeatability estimates were higher in the field compared to the laboratory and repeatability was higher when the interval between observations was short. Mate pref- erence behaviour was one of the best studied but least repeatable behaviours. Our findings prompt new insights into the relative flexibility of different types of behaviour and offer suggestions for the design and analysis of future research.
To test the reliability of PIT tags and VIE marks as new marking techniques for the bullhead Cottus gobio, different tagging treatments were assayed. The relatively high recapture rates suggest the applicability of both marking techniques for this small benthic fish species.
The composition and abundance of Northern pike (Esox lucius L.) populations in four shallow waters was monitored during a 4–5 year period, using mark-recapture methods. In general, the populations were sampled by using a combination of fishing gear but pike that completed their first growing season (0+ pike) are captured quantitatively by electrofishing (3 kw, DC) exclusively.
Within the length range of 0–54 cm fork length, the biomasses of 0+ pike appeared to be negatively correlated with those of larger pike. It is suggested that intraspecific predation is mainly responsible for these relations. The standing stock of <54-cm pike was found to be determined by the amount of aquatic vegetation and more especially so if the different habitat preference of 0+ pike, 0+ < pike < 41 cm and 41 cm ≤ pike < 54 cm was taken into account.
It has been hypothesized that inter-specific competition will reduce species niche utilization and drive morphological evolution in character displacement. In the absence of a competitor, intra-specific competition may favor an expansion of the species niche and drive morphological evolution in character release. Despite of this theoretical framework, we sometimes find potential competitor species using the same niche range without any partitioning in niche. We used a database on test fishing in Sweden to evaluate the factors (inter- and intraspecific competition, predation, and abiotic factors) that could influence habitat choice of two competitor species. The pattern from the database shows that the occurrence of perch and roach occupying both littoral and pelagic habitats of lakes in Sweden is a general phenomenon. Furthermore, the results from the database suggest that this pattern is due to intra-specific competition rather than inter-specific competition or predation. In a field study, we estimated the morphological variation in perch and roach and found that, individuals of both species caught in the littoral zone were more deeper bodied compared to individuals caught in the pelagic zone. Pelagic perch fed more on zooplankton compared to littoral perch, independent of size, whereas the littoral perch had more macroinvertebrates and fish in their diet. Pelagic roach fed more on zooplankton compared to littoral roach, whereas littoral individuals fed more on plant material. Furthermore, we sampled littoral and pelagic fish from another lake to evaluate the generality of our first results and found the same habitat associated morphology in both perch and roach. The results show a consistent multi-species morphological separation in the littoral and pelagic habitats. This study suggests that intra-specific competition is possibly more important than inter-specific competition for the morphological pattern in the perch-roach system.
Personality affects many aspects of an individual's behaviour, life history and fitness, and has been shown to be moderately heritable in wild populations. Correlations between personality and risk-taking that lead to life history tradeoffs could act to maintain variation in personality within a population, but this has not yet been tested. In this study, we used females from a marked population of North American red squirrels in Kluane, Yukon, to determine whether personality predicts risk-taking in the wild, and whether these risk-taking behaviours result in life history tradeoffs. We measured personality in open field and mirror image stimulation tests and extracted two traits, activity and aggressiveness, using principal component analysis and mixed model techniques. Using trapping records for individuals from February to September 2005, we obtained three measures of risk-taking: the number of trapping events, the number of different trapping locations, and the maximum distance between the home territory and a trapping event. We used GLMs to determine whether the activity and aggressiveness of individuals are related to these risk-taking behaviours, and found that active squirrels were trapped significantly more frequently and at a greater number of locations. There was also a significant interaction between activity and aggressiveness to affect the maximum capture distance. To determine if there are fitness tradeoffs associated with these risk-taking behaviours, we examined female bequeathal behaviour and survival. Bequeathing a territory increases offspring probability of overwinter survival, and we found that an increasing number of trapping locations was associated with an increasing tendency to bequeath. Active females were less likely to survive until the following spring. Risk-taking is therefore predicted by personality in this population, and they affect both survival and territorial bequeathal. These fitness tradeoffs may therefore lead to the maintenance of variation in personality.
Patterns of space use related to the activity of individual Japanese fluvial sculpins, Cottus pollux, were examined during the non-breeding season, in the upper reaches of the Inabe River, central Japan. Sculpins appeared more frequently at night than in daytime. Among 31 recaptured sculpins, 30 (96.8%) showed nocturnal activity patterns, there being no fish which exhibited an entirely diurnal activity pattern. Of 21 sculpins captured both in daytime and at night, the most common pattern of space use (n = 14, 66.7%) was that in which the nocturnal home range entirely encompassed the diurnal range. Overall, nocturnal home ranges were significantly larger than diurnal ranges. Active sculpins were rarely found on sand-associated substrata in daytime, but were seen more frequently on such substrata at night.
We tested the hypothesis that increased habitat complexity would reduce intraspecific interactions among crayfish (Orconectes propinquus), and result in an increase in the consumption rate of prey at different crayfish densities. The effect of crayfish density,
food level (trout eggs), and habitat complexity on prey consumption by crayfish was quantified in the laboratory. There was
a significant difference in the consumption rate between different food levels. When food was scarce, almost all trout eggs
were consumed regardless of crayfish density or habitat complexity. When food was unlimited, there was a significant positive
linear relationship between eggs consumed per crayfish and habitat complexity. However, the relationship was not significant
when trials without habitat were deleted from the analysis. We found that habitat complexity significantly reduced intraspecific
aggression. Our findings suggest that a minimal amount of habitat complexity can reduce interactions among predators, ultimately
resulting in increased prey consumption.
Space use by the Japanese fluvial sculpin, Cottus pollux, as related to nest availability was studied in a Japanese mountain stream. Males had larger home ranges than females before breeding. A measure of nest resource limitation was L < 1="" and="" the="" same="" nest="" rock="" was="" used="" by="" two="" males="" successively="" in="" three="" cases,="" indicating="" a="" limited="" supply="" of="" suitable="" nest="" rocks="" for="" males.="" all="" males="" included="" the="" nest="" rocks="" in="" their="" home="" ranges,="" but="" the="" timing="" of="" nest="" occupation="" was="" apparently="" dependent="" on="" male="" size,="" suggesting="" the="" presence="" of="" male-male="" competition="" for="" the="" nest="" rocks.="" females,="" on="" the="" other="" hand,="" exhibited="" two="" different="" patterns="" in="" space="" use,="" independent="" of="" body="" size:="" (1)="" they="" spawned="" in="" their="" home="" ranges,="" or="" (2)="" they="" spawned="" out="" of="" their="" home="" ranges="" and="" returned.="" nest="" cavity="" area="" did="" not="" affect="" male="" reproductive="" success.="" spatial="" separation="" between="" female="" home="" ranges="" and="" nest="" location="" was="" the="" main="" reason="" for="" the="" females'="" movement="" out="" of="" their="" home="" ranges.="" the="" limitation="" in="" the="" male="" mating="" phase="" (5.7="" days="" on="" average)="" might="" also="" have="" forced="" the="" females="" to="" move="" out="" of="" their="" home="" range="" to="" spawn.="" the="" reason="" behind="" such="" temporal="" limitation="" in="" the="" male="" mating="" interval="" was="" discussed="" from="" the="" viewpoint="" of="" the="" energy="" cost="" accompanying="" male="" parental="">
I have estimated nocturnal home-range size for 24 individuals of the adult Japanese fluvial sculpin, Cottus pollux (large-egg type) by direct observation on a single night. On average, sculpin used 10.5 focal points (where they executed
ambush predation) at night and stayed for 93.1min at each point. Home-range size (mean 9.8m2, range 0.3–79.9m2), which was calculated by use of the minimum convex polygon method, was positively correlated with the number of focal points.
The swimming paths and focal points used by each sculpin often depended on the configuration of rocks on the streambed, suggesting
the importance of bottom topography to home-range use by the sculpin. More than one-third of the sculpins returned to within
1m2 of the point of original capture and release; this provided evidence of their homing ability. Comparison of nocturnal home-range
size and Schoener’s ratio (the amount of temporal autocorrelation) with the length of sampling intervals suggested that sampling
intervals of 2h through the dark period, which resulted in a 70% match with real home-range measurements and approximately
half of the data sets became independent, provide the most accurate information for predicting the nocturnal home-range size
of the sculpin.
Female zebrafish housed in aquaria with spatial complexity (plastic plants) over a 13–16-week period showed reduced levels
of aggressive behavior compared to females in bare tanks. In tanks with plants, there was no relationship between levels of
aggression and fecundity but, in bare tanks, females experiencing the highest levels of aggression showed reduced fecundity.
Our results suggest that it may be beneficial, when maintaining zebrafish at moderate to high densities or working with especially
aggressive strains, to house them in spatially complex conditions.
In fish, predation risk is often size-specific due to gape limited piscivores and visibility constraints. We have investigated whether risk-taking behaviour in perch varies in accordance with size-specific predation risk in their natural habitat. In our two study lakes, the risk of cannibalism was estimated from fishing survey data. In Lake Fisksjön, the relative risk for juvenile perch was much higher than in Lake Ängersjön in the early stages, but after reaching a body length of approximately 70 mm the situation was reversed, with higher predation risk in Ängersjön than in Fisksjön. Groups of perch, from either of the two lakes and of two age classes (0+ or 1+ years), were given the choice of foraging in an open area or hiding in the vegetation in the presence of a predator. Three measures of boldness were estimated: proportion of time spent in the open area, latency to start feeding and duration of first feeding bout. A principal component analysis was used to calculate individual boldness scores from a combination of the behaviour estimates. Differences in boldness scores within age classes corresponded well with the relative attack rates in the two lakes. In the youngest age class, perch from Fisksjön were less bold than those from Ängersjön. In the older age class, the Fisksjön perch were bolder than those from Ängersjön. Within lakes, boldness differed between age classes. Seemingly, perch adjust risk-taking behaviour to perceived predation risk.
Small animals vulnerable to predation, such as rodents, have a strong preference for sites that provide physical protection from predators. This is likely to affect not only their use of space and activity but also the ease with which they can defend a territory, since the likelihood of encountering (or losing) intruders and their willingness to compete are affected by the quality and distribution of resources and the structural complexity of the habitat. To examine how these different habitat factors interact to influence territorial behaviour in male house mice, Mus domesticus, which inhabit environments with very different levels of complexity and resource distribution, we housed male–female pairs in enclosures representing one of eight habitat types varying in ground-level structure (open/complex), overhead cover (present/absent) and distribution of protected nest sites and food (resources clumped together/scattered). Neighbouring pairs were allowed to interact five times over 3 days and we examined behaviour during the first (unfamiliar) and fifth (familiar) periods. Initially, encounter rates were two to three times higher in open habitats with overhead cover than in either complex habitats or open habitats without cover, and higher when resources were scattered than when they were clumped. Aggressive interactions between unfamiliar males were more prolonged in habitats with open ground-level structure, where pursuits followed restricted pathways. The effects of overhead cover on aggression among unfamiliar neighbours unexpectedly depended on the origin of the mice. Once neighbours learnt the outcome of their interactions, aggressive interactions were most prolonged in habitats with scattered resources and complex ground-level structure, making these habitats the most difficult to defend.
Animals often differ from one another in their willingness to take risks in a number of functional contexts related to fitness (e.g. mating, dispersal, and foraging behaviour). Although several studies have reported life history correlates and selective consequences of this variation in shy/bold behaviour, little attention has been paid to developmental processes resulting in shy/bold phenotypes. Here, we present a lifetime developmental study of shy/bold behaviour in dumpling squid, Euprymna tasmanica. Behaviour was measured in two test contexts, a threat and a feeding test, at five times across the entire life span. Across test contexts, shy/bold behaviour was not correlated at any age; while within a test context, individual shy/bold phenotypes were consistent both before and after sexual maturity. During sexual maturity, different phenotypes displayed different amounts of developmental variation; shyer animals were more plastic in feeding tests, while bolder animals were more plastic in threat ones. Our results suggest that for some animals shy/bold behaviour throughout development is uncorrelated across different contexts related to risk, while within a context, there may still be developmental constraints to changing shy/bold behaviour. This constraint within a functional context, however, may be phenotype-specific, with some phenotypes able to change more than others. These results indicate that a greater understanding of developmental pathways is needed to determine whether shy/bold phenotypes per se are the sole focus of selection. Differences in developmental plasticity between shy/bold phenotypes may also confer differential fitness in fluctuating environments.
The shy-bold continuum is a fundamental axis of behavioral variation in humans and at least some other species, but its taxonomic distribution and evolutionary implications are unknown. Models of optimal risk, density- or frequency-dependent selection, and phenotypic plasticity can provide a theoretical framework for understanding shyness and boldness as a product of natural selection. We sketch this framework and review the few empirical studies of shyness and boldness in natural populations. The study of shyness and boldness adds an interesting new dimension to behavioral ecology by focusing on the nature of continuous behavioral variation that exists within the familiar categories of age, sex and size.
Evidence is growing that an individual's propensity to take risks in the presence of a predator is correlated to behaviors
that can affect individual fitness. We examined whether risk-taking behavior predicts aggression, surface activity levels,
and mating success in male fiddler crabs, Uca mjoebergi. Risk-taking behavior was highly consistent among individuals, remained stable over time, and was unrelated to male size.
We found that males that took greater risks in the presence of a potential predator also behaved more aggressively when searching
for a new territory. In addition, bold males exhibited higher surface activity levels and spent more time courting females
compared with their shy counterparts. Although risk-taking behavior was independent of other sexually selected traits, it
accurately predicted male mating success in U. mjoebergi. We suggest nonsexually selected traits, such as risk taking, may represent important behavioral predictors of success in
other species.
Differences in bold and shy personality on sea bass Dicentrarchus labrax were investigated between a population (wild) produced from wild-brood fish and a population (selected) produced from selected-brood fish. During the experiment (112 days), fish were reared under self-feeding condition to characterize the feeding behaviour of each individual fish. Three risk-taking tests (T1, T2 and T3 of 24 h with day-night alternation) were carried out at >1 month intervals on 180 fish of each strain in order to monitor D. labrax behaviour over time and in relation to the light:dark period. A risk-taking score was evaluated via a preference choice between a safe zone (without food) and a risky zone (potentially with food) by recording the number and the duration of individual passages through an opening in an opaque divider. Results showed that fish performed passages preferentially during the night period and that wild fish were generally bolder than selected fish during T1 and T2 but showed a decrease in risk taking during T3, contrary to selected fish which showed a constant increase in their risk-taking behaviour. The phenotypic characteristics of the bold fish were different in the two strains: wild bold fish were the smallest within the wild strain and selected bold fish presented the higher growth rate within the selected strain. For both strains, these bold fish were also generally characterized by a high feed-demand activity. Fish hunger state thus seemed to be the highest motivation for risk-taking behaviour under the present conditions. Furthermore, behavioural variations over tests such as higher risk taking (number of passages) and faster exploratory responses (higher score emergence) could be interpreted as relevant indicators of the learning process and habituation. According to the results, however, no real difference in coping strategy between strains could be observed at this first stage of domestication and selection.
Individual differences in early exploratory behaviour were investigated in hand-reared juvenile male great tits, Parus major, during the first 18 weeks of their life. The juveniles differed consistently in their reaction to a novel object in a familiar environment, either when tested with different objects or when tested again after 9 weeks. Birds that approached a novel object more quickly were also quicker to visit all artificial trees present in a novel environment than birds that approached a novel object more slowly. These behavioural differences extended to the strength of foraging habits, built up during a training period in which food was always offered at the same place. After a change in the location of food, the quicker birds would keep going to the place where the food used to be. The slower birds tended to change their behaviour and stop going to the former place. The results show that juvenile male great tits differ consistently in various aspects of their exploratory behaviour at least during the first 18 weeks of life. The variation in behaviour was not likely to arise from differences in general activity or physical condition, but seems to refer to differences in the way in which information concerning the environment is collected and dealt with.
Intra-population variation in behaviour unrelated to sex, size or age exists in a variety of species. The mechanisms behind behavioural diversification have only been partly understood, but density-dependent resource availability may play a crucial role. To explore the potential coexistence of different behavioural types within a natural fish population, we conducted a radio telemetry study, measuring habitat use and swimming activity patterns of pike (Esox lucius), a sit-and-wait predatory fish. Three behavioural types co-occurred in the study lake. While two types of fish only selected vegetated littoral habitats, the third type opportunistically used all habitats and increased its pelagic occurrence in response to decreasing resource biomasses. There were no differences in size, age or lifetime growth between the three behavioural types. However, habitat-opportunistic pike were substantially more active than the other two behavioural types, which is energetically costly. The identical growth rates exhibited by all behavioural types indicate that these higher activity costs of opportunistic behaviour were compensated for by increased prey consumption in the less favourable pelagic habitat resulting in approximately equal fitness of all pike groups. We conclude that behavioural diversification in habitat use and activity reduces intraspecific competition in preferred littoral habitats. This may facilitate the emergence of an ideal free distribution of pike along resource gradients.