<b>Corticosterone shortens foreign egg ejection distance but not latency in American Robins (</b><b><i>Turdus migratorius)</i></b>
<p dir="ltr">Obligate brood parasitic birds often face the removal of their eggs by rejector hosts; for example, in North America, American robins (<i>Turdus migratorius)</i> are robust egg rejectors of non-mimetic brown-headed cowbird (<i>Molothrus ater)</i>...
محفوظ في:
| المؤلف الرئيسي: | |
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| منشور في: |
2025
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| الموضوعات: | |
| الوسوم: |
إضافة وسم
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| الملخص: | <p dir="ltr">Obligate brood parasitic birds often face the removal of their eggs by rejector hosts; for example, in North America, American robins (<i>Turdus migratorius)</i> are robust egg rejectors of non-mimetic brown-headed cowbird (<i>Molothrus ater)</i> eggs. Recent studies have investigated the role of various hormones during the anti-parasitic egg-rejection process. Corticosterone, a steroid hormone often released in response to environmental stressors, has previously been found to increase the propensity for female American robins to reject non-mimetic model eggs. To better understand how corticosterone affects other behaviors during the egg-ejection process (i.e., distance the egg is taken from the nest, latency of rejection decision), we combined previously used techniques for non-invasive corticosterone delivery and model egg spatio-temporal tracking in American robins (<i>sensu</i> Turner et al. 2020, Turner et al. 2023). All female subjects rejected the non-mimetic eggs, and through a repeated measures design, we found that the same female robin reduced her egg ejection distance in the corticosterone treatment relative to the control. In turn, we did not find this effect for ejection latency, perhaps because all but one female already rejected the non-mimetic egg rapidly (within one hour) irrespective of the hormone treatment. Future work should examine if the other known endocrine mediators of egg rejection, including prolactin, similarly affect aspects of egg rejection behavior by this and other hosts of obligate avian brood parasites.</p> |
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