دانلود رایگان مقاله پیش بینی واگرایی تفاوت رفتاری در حیات وحش

Many animals show complex behaviours that can have important ecological and evolutionary consequences. Environmental variation can lead to divergent selection that consistently favours particular behaviours in different environments; but how predictably multiple aspects of animal behaviour diverge in response to different environmental conditions remains unclear. We tested whether populations evolving under different levels of predation risk show predictable and repeatable population-level behavioural differences in all five primary components of animal personality: aggression, sociability, boldness, activity and exploration. We formulated and tested a priori predictions of divergence for each behaviour using the adaptive radiation of Bahamas mosquitofish, Gambusia hubbsi (family Poeciliidae), inhabiting vertical water-filled caves (blue holes) where they have evolved for thousands of years in either the presence or absence of predatory fish. Mosquitofish behaviours differed consistently, and largely predictably, between predation regimes: low-predation mosquitofish showed reduced sociability and greater exploration of a novel environment compared to high-predation counterparts. However, some differences were sex dependent: only females showed greater boldness and only males displayed reduced aggressiveness in low-predation populations. Activity levels did not differ between predation regimes. All populations showed a behavioural syndrome characteristic of either proactive or reactive stress-coping styles with regard to exploration. Exploration behavioural syndromes were more similar among populations that evolved in similar predation regimes, regardless of genetic relatedness. Using laboratory-born, high-predation mosquitofish, we confirmed that exploratory behaviours have a genetic basis and show significant within-individual repeatability. Our results suggest that environmental variation, such as chronic predation risk, can lead to repeatable, and often predictable, changes in multifarious animal behaviours, and that various aspects of behaviour can diversify more or less independently of one another. Considering the ecological importance of these behaviours, the ability to forecast behavioural shifts in a rapidly changing world could serve as a valuable conservation tool.

DISCUSSION

Populations of Bahamas mosquitofish that evolved under different levels of predation risk showed consistent and largely predictable, although sometimes sex-dependent, differences in aggression, sociability, boldness and exploration. Only one behavioural category, activity, did not differ between predation regimes, and this lack of differentiation matched our prediction. Moreover, we demonstrated that exploration behaviours are repeatable within an individual (i.e. reflects personality) and show significant genetic variation within a population (i.e. heritability). In light of prior work demonstrating personality in mosquitofish (e.g. Biro & Adriaenssens, 2013; Blake & Gabor, 2014; Cote et al., 2010, 2011; Ward, 2012; Wilson et al., 2010) and a genetic basis to divergence in many traits within this study system (e.g. Anderson & Langerhans, 2015; Heinen-Kay & Langerhans, 2013; Langerhans & Makowicz, 2013; Martin et al., 2014; Riesch et al., 2013), it seems likely that observed behavioural differences between predation regimes at least partially reflect divergent evolution. Regardless of the extent to which our results reflect genetic divergence or phenotypic plasticity, our findings suggest that complex behaviours are subject to natural selection and can differ predictably in response to an ecological stressor.