Surface temperatures are influenced by handling stress independently of glucocorticoid levels in wild king penguins

Lewden, A.; Ward, C.; Noiret, A.; Avril, S.; Abolivier, L.; Gerard, C.; Hammer, T. L.; Raymond, E.; Robin, J.-P.; Viblanc, V. A.; Bize, P.; STIER, A.

doi:10.1101/2023.06.16.545254

bioRxiv · 10.1101/2023.06.16.545254

Surface temperatures are influenced by handling stress independently of glucocorticoid levels in wild king penguins

Lewden, A.·Ward, C.·Noiret, A.·Avril, S.·Abolivier, L.·Gerard, C.·Hammer, T. L.·Raymond, E.·Robin, J.-P.·Viblanc, V. A.·Bize, P.·STIER, A.

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Abstract

Assessing the physiological stress responses of wild animals opens a window for understanding how organisms cope with environmental challenges. Since stress response is associated with changes in body temperature, the use of body surface temperature through thermal imaging could help to measure acute and chronic stress responses non-invasively. We used thermal imaging, acute handling-stress protocol and an experimental manipulation of corticosterone (the main glucocorticoid hormone in birds) levels in breeding king penguins (Aptenodytes patagonicus), to assess: 1. the potential contribution of the Hypothalamo-Pituitary-Adrenal (HPA) axis in mediating chronic and acute stress-induced changes in adult surface temperature, 2. the influence of HPA axis manipulation on parental investment through thermal imaging of eggs and brooded chicks, and 3. the impact of parental treatment on offspring thermals response to acute handling. Maximum eye temperature (Teye) increased and minimum beak temperature (Tbeak) decreased in response to handling stress in adults, but neither basal nor stress-induced surface temperatures were significantly affected by corticosterone implant. While egg temperature was not significantly influenced by parental treatment, we found a surprising pattern for chicks: chicks brooded by the (non-implanted) partner of corticosterone-implanted individuals exhibited higher surface temperature (both Teye and Tbeak) than those brooded by glucocorticoid-implanted or control parents. Chicks response to handling in terms of surface temperature was characterized by a drop in both Teye and Tbeak independently of parental treatment. We conclude that the HPA axis seems unlikely to play a major role in determining chronic or acute changes in surface temperature in king penguins. Changes in surface temperature may primarily be mediated by the Sympathetic-Adrenal-Medullary (SAM) axis in response to stressful situations. Our experiment did not reveal a direct impact of parental HPA axis manipulation on parental investment (egg or chick temperature), but a potential influence on the partners brooding behaviour. HighlightsO_LIExperimental increase in corticosterone does not affect king penguins surface temperature C_LIO_LIAcute handling stress increases eye but decreases beak surface temperature in adults C_LIO_LIAcute handling decreases both eye and beak surface temperatures in young chicks C_LIO_LIParental corticosterone treatment does not affect egg surface temperature during incubation C_LIO_LIChicks brooded by non-implanted partners of corticosterone parents are warmer than chicks brooded by others adults. C_LI

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Lewden, A., Ward, C., Noiret, A., Avril, S., Abolivier, L., Gerard, C., Hammer, T. L., Raymond, E., Robin, J.-P., Viblanc, V. A., Bize, P., STIER, A.. 2023-06-18. Surface temperatures are influenced by handling stress independently of glucocorticoid levels in wild king penguins. https://doi.org/10.1101/2023.06.16.545254

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