Adrenocortical stress responses influence an invasive vertebrate's fitness in an extreme environment.
Continued range expansion into physiologically challenging environments requires invasive species to maintain adaptive phenotypic performance. The adrenocortical stress response, governed in part by glucocorticoid hormones, influences physiological and behavioural responses of vertebrates to environmental stressors. However, any adaptive role of this response in invasive populations that are expanding into extreme environments is currently unclear. We experimentally manipulated the adrenocortical stress response of invasive cane toads (Rhinella marina) to investigate its effect on phenotypic performance and fitness at the species' range front in the Tanami Desert, Australia. Here, toads are vulnerable to overheating and dehydration during the annual hot-dry season and display elevated plasma corticosterone levels indicative of severe environmental stress. By comparing unmanipulated control toads with toads whose adrenocortical stress response was manipulated to increase acute physiological stress responsiveness, we found that control toads had significantly reduced daily evaporative water loss and higher survival relative to the experimental animals. The adrenocortical stress response hence appears essential in facilitating complex phenotypic performance and setting fitness trajectories of individuals from invasive species during range expansion.
Department of Zoology, University of Melbourne, Victoria 3010, Australia. tjessop@unimelb.edu.au
Tim S
TS
Jessop
Mike
M
Letnic
Jonathan K
JK
Webb
Tim
T
Dempster
D000222:Adaptation, Physiological; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000818:Animals; D002024:Bufo marinus / Q000097:blood / Q000378:metabolism / Q000502:physiology*; D003345:Corticosterone / Q000097:blood*; D003907:Dexamethasone / Q000494:pharmacology; D004777:Environment; D005938:Glucocorticoids / Q000494:pharmacology; D006702:Homing Behavior; D006358:Hot Temperature; D058865:Introduced Species; D016014:Linear Models; D064587:Osmoregulation / Q000187:drug effects; D010641:Phenotype; D013312:Stress, Physiological
D005938:Glucocorticoids; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone
acute stress response; adaptive phenotypic performance; extreme environments; fitness; glucocorticoid hormones; survival