File(s) under permanent embargo

Yolk corticosterone in the Gouldian Finch (Erythrura gouldiae)

journal contribution
posted on 01.01.2019, 00:00 authored by Anna MiltiadousAnna Miltiadous, S R Pryke, Mylene MarietteMylene Mariette, Kate BuchananKate Buchanan
Maternal hormones are thought to play an important role in determining the rate of evolutionary adaptation. Previous avian studies have shown that the transfer of maternally derived hormones, such as progesterone and testosterone, to the egg, affects many aspects of offspring development. In contrast, the impact of maternal corticosterone (CORT) is much less studied. CORT, the principal avian glucocorticoid hormone, is thought to be passively transferred to the egg yolk from the maternal plasma. Maternal CORT may play a role in determining the development of young birds by adaptively programming offspring for their environment. We developed a protocol which effectively quantifies yolk CORT concentrations both within and across clutches, using solid-phase extraction and radioimmunoassay. We hypothesised that Gouldian Finch (Erythrura gouldiae) mothers would differ in their yolk CORT concentrations and that maternal condition would relate to absolute yolk CORT deposition. We found variation in yolk CORT concentrations between clutches, increasing with egg number in the earlier breeding season, and negatively correlated with yolk mass. Yet, contrary to our predictions, neither maternal mass nor clutch size showed any relationship to yolk CORT concentrations or to egg or yolk mass. Our data suggest that yolk CORT varies with maternal identity for reasons which do not appear to be linked to maternal condition. Further research is needed to determine the link between maternal and egg yolk concentrations at the individual level. Such tests would be valuable for understanding the role of CORT in the reproductive effects previously observed in this threatened species.

History

Journal

Emu - Austral ornithology

Volume

119

Issue

2

Pagination

97 - 105

Publisher

Taylor & Francis

Location

Abingdon, Eng.

ISSN

0158-4197

eISSN

1448-5540

Language

eng

Publication classification

C Journal article; C1 Refereed article in a scholarly journal

Copyright notice

2018, BirdLife Australia