Behaviour is one of the most plastic traits, but local adaptations in behaviour within species are also well documented. One classic environmental factor selecting for different behavioural phenotypes is predation. Interestingly, high predation caused mortality might favour shy prey individuals with low activity (usual scenario) but also bold individuals with high activity (rare scenario).
In nine-spined sticklebacks (Pungitius pungitius), we have shown earlier that sticklebacks from high predation risk populations showed lower feeding activity, and were less bold/aggressive than their conspecifics from low predation populations, even when F1 predator- and conspecific-naive individuals were studied in lab (article; blog). Considering the current interest about how local adaptation and phenotypic plasticity induced by variation in the same environmental factors are related, we set up an experiment where perceived predation risk (chemical cues of perch, Perca fluviatilis) and energy supply (amount of food) were manipulated in a factorial design using replicated coastal marine (high predation / low intraspecific competition) and isolated pond (low predation / high intraspecific competition) stickleback F1 populations in lab.
We found strong habitat-dependence of behaviour (just like in our earlier paper): pond sticklebacks had higher feeding activity and were more risk-taking, aggressive and explorative than marine sticklebacks. The treatments were also effective: sticklebacks under high perceived predation risk were less risk-taking and aggressive, while food restriction increased risk-taking and feeding activity. However, the effect of food treatment on risk-taking was habitat-dependent, as only pond fish increased their risk-taking under energy limitation. This finding was in line with our expectations, because pond fish are giants (article, blog) with divergent growth strategy (article, blog), and thus they need more energy than marine fish while they have evolved under minimal predation caused mortality. We also found sex effects, mainly in hard-to-interpret interactions with treatments.
In sum, we showed that evolutionary history, ontogenetic experience and sex all affect behavioural variation within species, and more interestingly, the effect of ontogenetic experience on behaviour can depend on the given populations’ evolutionary history with respect to the given environmental factor.
Herczeg G, Välimäki K 2011. Intraspecific variation in behaviour: effects of evolutionary history, ontogenetic experience and sex. Journal of Evolutionary Biology, early view, DOI: 10.1111/j.1420-9101.2011.02371.x