Differential reproductive responses to stress reveal the role of life-history strategies within a species

Abstract

Life-history strategies describe that 'slow'-in contrast to 'fast'-living species allocate resources cautiously towards reproduction to enhance survival. Recent evidence suggests that variation in strategies exists not only among species but also among populations of the same species. Here, we examined the effect of experimentally induced stress on resource allocation of breeding seabirds in two populations with contrasting life-history strategies: slowliving Pacific and fast-living Atlantic black-legged kittiwakes. We tested the hypothesis that reproductive responses in kittiwakes under stress reflect their life-history strategies. We predicted that in response to stress, Pacific kittiwakes reduce investment in reproduction compared with Atlantic kittiwakes. We exposed chick-rearing kittiwakes to a short-term (3-day) period of increased exogenous corticosterone (CORT), a hormone that is released during food shortages. We examined changes in baseline CORT levels, parental care and effects on offspring. We found that kittiwakes from the two populations invested differently in offspring when facing stress. In response to elevated CORT, Pacific kittiwakes reduced nest attendance and deserted offspring more readily than Atlantic kittiwakes. We observed lower chick growth, a higher stress response in offspring and lower reproductive success in response to CORT implantation in Pacific kittiwakes, whereas the opposite occurred in the Atlantic. Our findings support the hypothesis that lifehistory strategies predict short-term responses of individuals to stress within a species. We conclude that behaviour and physiology under stress are consistent with trade-off priorities as predicted by life-history theory. We encourage future studies to consider the pivotal role of life-history strategies when interpreting inter-population differences of animal responses to stressful environmental events.

The stress hormone corticosterone in a marine top predator reflects short‐term changes in food availability

“…; Schultner et al. ), and thus potentially interfere with our results. Our analyses were, however, based on changes in CORT levels rather than on absolute values, thus ruling out many of these confounding factors.…”

Migration and stress during reproduction govern telomere dynamics in a seabird

“…Based on the assumption that kittiwakes migrate to southern marine regions because conditions there are favourable, we hypothesized that time spent at these wintering grounds exhibits a positive effect on telomere length. By contrast, based on our previous observation that kittiwakes in our study colony maintain parental effort when facing stress [14], and since reproduction is costly [15], we predicted that experimentally induced stress during reproduction has a negative effect on telomere length.…”

The impact of high temperatures on foraging behaviour and body condition in the Western Australian MagpieCracticus tibicen dorsalis

“…This raises the possibility that individual birds focused primarily on self-preservation at the expense of their own offspring, distributing less food to their young and consuming more themselves at high temperatures. This trade-off has been observed in a number of bird species (Tveraa and Christensen 2002;Bleeker et al 2005;Schultner et al 2013), with studies by Erikstad et al (1998) and Ghalambor and Martin (2001) suggesting that long-lived bird species such as magpies are more likely to prioritise their own survival ahead of their young when faced with harsh environments. This has important ramifications for understanding the potential effects of long-term increases in air temperatures due to climate change; if parents reduce investment in young at high temperatures, then declines in reproductive success are likely.…”