Experimental enhancement of corticosterone levels positively affects subsequent male survival

Abstract

Corticosterone is an important hormone of the stress response that regulates physiological processes and modifies animal behavior. While it positively acts on locomotor activity, it may negatively affect reproduction and social activity. This suggests that corticosterone may promote behaviors that increase survival at the cost of reproduction. In this study, we experimentally investigate the link between corticosterone levels and survival in adult common lizards (Lacerta vivipara) by comparing corticosterone-treated with placebo-treated lizards. We experimentally show that corticosterone enhances energy expenditure, daily activity, food intake, and it modifies the behavioral time budget. Enhanced appetite of corticosterone-treated individuals compensated for increased energy expenditure and corticosterone-treated males showed increased survival. This suggests that corticosterone may promote behaviors that reduce stress and it shows that corticosterone per se does not reduce but directly or indirectly increases longer-term survival. This suggests that the production of corticosterone as a response to a stressor may be an adaptive mechanism that even controls survival.

Hormonally mediated maternal effects, individual strategy and global change

“…However, prolonged periods of elevated corticosterone also induce the catabolism of muscle tissue, negative nitrogen balance, reproductive suppression and immunocompetence [49,105]. Thus, the benefits of elevated corticosterone may entail a cost in terms of diminished reproduction and elevated mortality [131]. This has been demonstrated in males of the dasyurid marsupial species, Phascogale calura, where high level of corticosterone suppresses the immune system and leads to higher mortality during the breeding season [132].…”

“…This has been demonstrated in males of the dasyurid marsupial species, Phascogale calura, where high level of corticosterone suppresses the immune system and leads to higher mortality during the breeding season [132]. Indeed implantation of exogenous corticosterone stimulates activity or increases endurance in mammals [133,134], birds [135 -137], lizards [131,138,139] and turtles [140]. However, corticosterone may also have contrasting effects depending on the species and on the environmental context [141 -143].…”

Adrenocortical stress responses influence an invasive vertebrate's fitness in an extreme environment

“…We performed all analyses using the software IBM SPSS v. 20. rspb.royalsocietypublishing.org Proc R Soc B 280: 20131444 p , 0.001) coinciding with changes in environmental temperature and hydric state (figure 1e). Highest daily mean plasma corticosterone levels (117.2 + 15.1 ng ml 21 ) were recorded at 14.30, when toads were inactive in sub-ground shelters and exposed to hot environmental temperatures. As toads departed shelters at night and arrived at the dams, corticosterone levels had begun to decline (20.45; 91.9 + 16.6 ng ml 21 ) and continued to do so as toads hydrated in dams throughout the night (24.00; 60.7 + 10.2 ng ml 21 ) as environmental temperatures decreased.…”

“…In particular, the rate and duration of physiological or behavioural responsiveness, triggered by an individual's acute adrenocortical stress response phenotype, is expected to have important fitness outcomes via producing adaptive or non-adaptive phenotypic performance under environmental selection [18,19]. However, a clear demonstration that the acute adrenocortical stress response can directly mediate adaptive phenotypic performance and higher fitness under strong natural selection in free-living populations is currently lacking [19][20][21][22]. Here, we make use of an invasive vertebrate, the cane toad (Rhinella marinus), to investigate the role of the acute adrenocortical stress response in determining phenotypic performance and fitness under extreme environmental selection [12,23].…”

Do Gravid Females Become Selfish? Female Allocation of Energy during Gestation

“…At the same time, however, corticosterone may downregulate processes such as reproduction and growth that are not required for immediate survival. Chronic elevation of plasma corticosterone concentration due to shortage of prey items, high predator density, high parasite load, or poor body condition can, for example, suppress reproduction (Tilbrook et al 2000;Wingfield and Sapolsky 2003;Petes et al 2007) because high plasma corticosterone concentration increases energy expenditure for self-maintenance (McEwen and Wingfield 2003;Cote et al 2006;Lynn et al 2010). Thus, elevated plasma corticosterone concentrations in reproducing females are typically viewed as having a negative impact on reproductive investment in terms of the energy budget.…”