Absence of Daily Rhythms of Prolactin and Corticosterone in Adélie Penguins Under Continuous Daylight

Vleck, Carol M.; Hook, Jessamyn A. Van

doi:10.1093/condor/104.3.667

Cited by 9 publications

(2 citation statements)

References 29 publications

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“…For these two groups, the rate of nest predation (defined by the number of eggs/ ducklings remaining in the nest four days after implantation, and at the hatching or piping day), and the proportion of reproductive success (females having at least one egg hatching after 25 days of incubation) were determined. Because birds were under natural continuous daylight during the experiment, circadian rhythms in the plasma concentrations of these two hormones is likely to be insignificant (Vleck and van Hook 2002).…”

Section: Experimental Groupsmentioning

confidence: 99%

Corticosterone alone does not trigger a short term behavioural shift in incubating female common eiders Somateria mollissima, but does modify long term reproductive success

Criscuolo¹,

Chastel²,

Bertile³

et al. 2005

Journal of Avian Biology

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T. 2005. Corticosterone alone does not trigger a short term behavioural shift in incubating female common eiders Somateria mollissima , but does modify long term reproductive success. Á/ J. Avian Biol. 36: 306 Á/312.The trade-off between reproductive effort and adult survival in birds is modulated by several factors. Corticosterone and prolactin have additive effects on reproductive behaviour by stimulating foraging and parental behaviours, respectively. When incubation is associated with fasting, nest desertion is supposed to be activated by an unknown refeeding signal when body condition becomes critically deteriorated. The concomitant rise in corticosterone levels has been suggested to be the triggering factor. We tested the role of corticosterone on reproductive success by observing the effect of corticosterone implants on reproductive success and on plasma prolactin concentration in female common eiders Somateria mollissima . Implanted females showed a significant increase in corticosterone and a decrease in prolactin levels. Despite their enhanced daily body mass loss, females did not abandon incubation nor did they start to refeed in the four days following implantation. These data show that the experimentally induced rise in plasma corticosterone concentration alone does not trigger nest desertion. However, after 25 days of incubation, implanted females displayed a higher rate of egg loss, suggesting lower nest attentiveness towards the end of incubation. We suggest that the short-term effects of corticosterone may be dependent on the energy state of the bird. However, the late-induced change in reproductive success is indirectly linked to corticosterone, and we suggest that either a prolactin decrease, or a depletion in protein body reserves, may participate in the longterm adjustment of incubation behaviour in female eiders.F. Criscuolo (correspondence), Faculté de Médecine Necker enfants-Malades, CNRS-UPR 9078,

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Section: Experimental Groupsmentioning

confidence: 99%

Corticosterone alone does not trigger a short term behavioural shift in incubating female common eiders Somateria mollissima, but does modify long term reproductive success

Criscuolo¹,

Chastel²,

Bertile³

et al. 2005

Journal of Avian Biology

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“…Timing of blood sampling depended on the bird departure and therefore occurred at any time of the day. However corticosterone concentration is not affected by daytime in Ade´lie penguins (Vleck & Van Hook 2002, Angelier et al 2008.…”

Section: Methodsmentioning

confidence: 88%

When sea‐ice clock is ahead of Adélie penguins’ clock

Beaulieu¹,

Dervaux

Thierry

et al. 2010

Functional Ecology

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Abstract1. In Polar Regions, the extent and dynamics of sea-ice are changing. This affects the ocean productivity which consecutively impacts plankton communities and polar top predators like penguins. Yet, the underlying behavioural and physiological mechanisms remain poorly understood. 2.Here we monitored the ecophysiological responses of Ade´lie penguin (Pygoscelis adeliae) pairs during two seasons of contrasting timing of sea-ice retreat. Beside classical breeding parameters like foraging trip duration, body mass and reproductive success, we also investigated food-related stress (via plasma corticosterone concentration), nutritional state (via metabolite levels) and the use of penguins' habitat (via blood isotopic values). 3. Body mass and reproductive success remained unchanged but foraging trips were shorter when sea-ice retreated earlier. Constant plasma corticosterone concentrations indicated that none of the feeding conditions resulted in a food-related stress. However metabolite levels were lower when sea-ice retreated early, suggesting that the foraging performance and the quality ⁄ quantity of food differed. Indeed isotopic ratios indicated that coastal prey like fish contributed more to the penguins' diet when sea-ice retreated prematurely. 4. The early sea-ice retreat was related to higher chlorophyll concentrations, known to favour krill recruitment. Paradoxically, this was not associated to a higher krill contribution in the penguins' diet. We propose that a shift in the phytoplankton quality (rather than quantity), affecting krill recruitment, forced penguins to switch to more available prey like coastal fish. 5. In some Antarctic regions, sea-ice is retreating earlier and earlier. In the present study, even though the timing of sea-ice retreat and the consecutive ocean productivity differed drastically between the 2 years, Ade´lie penguins were not severely affected because they were able to adjust their at-sea behaviour and thus maintained their body condition and reproductive success unchanged. 6. This suggests that the timing of sea-ice retreat does not represent an important threat to populations of Ade´lie penguins at least as long as alternative resources are still available and other environmental parameters like winter sea-ice extent are not dramatically altered.

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Endocrine effects of exposure to artificial light at night: A review and synthesis of knowledge gaps

Grunst

2023

Molecular and Cellular Endocrinology

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Absence of Daily Rhythms of Prolactin and Corticosterone in Adélie Penguins Under Continuous Daylight

Cited by 9 publications

References 29 publications

Corticosterone alone does not trigger a short term behavioural shift in incubating female common eiders Somateria mollissima, but does modify long term reproductive success

Corticosterone alone does not trigger a short term behavioural shift in incubating female common eiders Somateria mollissima, but does modify long term reproductive success

When sea‐ice clock is ahead of Adélie penguins’ clock

Endocrine effects of exposure to artificial light at night: A review and synthesis of knowledge gaps

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