Growth‐mortality tradeoffs and ‘personality traits’ in animals

Abstract

Consistent individual differences in boldness, reactivity, aggressiveness, and other 'personality traits' in animals are stable within individuals but vary across individuals, for reasons which are currently obscure. Here, I suggest that consistent individual differences in growth rates encourage consistent individual differences in behavior patterns that contribute to growth-mortality tradeoffs. This hypothesis predicts that behavior patterns that increase both growth and mortality rates (e.g. foraging under predation risk, aggressive defense of feeding territories) will be positively correlated with one another across individuals, that selection for high growth rates will increase mean levels of potentially risky behavior across populations, and that within populations, faster-growing individuals will take more risks in foraging contexts than slower-growing individuals. Tentative empirical support for these predictions suggests that a growth-mortality perspective may help explain some of the consistent individual differences in behavioral traits that have been reported in fish, amphibians, reptiles, and other animals with indeterminate growth.

Behavioural mediation of the costs and benefits of fast growth in a marine fish

“…However, if behaviour does not mediate trade-offs, why are behavioural traits correlated within individuals? Such correlations between aggressiveness and other behaviours would be expected when these were positively related to both growth and mortality risk (Stamps 2007). For P. amboinensis, correlations may occur because multiple behavioural traits are negatively, rather than positively, related to mortality.…”

“…Much of the current evidence for the role of behavioural traits in growth-mortality trade-offs is correlative (Stamps 2007;Biro & Stamps 2008). Importantly, correlations among behavioural traits (e.g.…”

“…If behavioural or 'personality' traits (Sih et al 2004;Reale et al 2007) of animals mediate or contribute to growth-mortality tradeoffs it is predicted that increased foraging effort will be negatively correlated with survivorship (Stamps 2007;Biro & Stamps 2008). In the 24 h after fish were settled on small patch reefs they suffered the high rates of mortality (approximately 50%) typical of many Figure 3.…”

“…It has been suggested that trade-offs between the costs and benefits of growth are mediated by behaviour, whereby rapid growth is associated with greater predation mortality because of increased foraging effort (Werner & Anholt 1993;Lima 1998;Sih et al 2004;Stamps 2007;Biro & Stamps 2008). As all animals are prey, at least during their early life history stages, greater foraging effort can increase the visibility of prey to predators with a concomitant increase in the probability of mortality.…”

“…As all animals are prey, at least during their early life history stages, greater foraging effort can increase the visibility of prey to predators with a concomitant increase in the probability of mortality. Evidence for the role of behaviour comes from a variety of sources (reviewed in Stamps 2007;Biro & Stamps 2008), including recent studies in lake systems that have shown that fast-growing rainbow trout, Oncorhynchus mykiss, that had high foraging rates were preferentially removed by predators (Biro et al 2004(Biro et al , 2006. This occurred because fast-growing fish were more likely to use habitats that were more productive in terms of food resources, but placed the fast-growing fish at greater risk of predation than the habitats used by slow-growing individuals (Biro et al 2006).…”