Nest predation risk and deposition of yolk steroids in a cavity-nesting songbird: an experimental test

Maternal hormones can shape offspring development and increase survival when predation risk is elevated. In songbirds, yolk androgens influence offspring growth and begging behaviors, which can help mitigate offspring predation risk in the nest. Other steroids may also be important for responding to nest predation risk, but non-androgen steroids have been poorly studied. We used a nest predator playback experiment and liquid chromatography with tandem mass spectrometry (LC-MS-MS) to assess whether nest predation risk influences deposition of 10 yolk steroids. We found no clear evidence that yolk androgen deposition changed when perception of nest predation risk was experimentally increased. However, elevated nest predation risk led to decreased yolk progesterone deposition. Overall, our results suggest yolk progesterone may be more important than yolk androgens in responses to offspring predation risk and highlight new avenues for research.

Automated summary

In songbirds, androgens can influence offspring development and begging behaviors to reduce predation risk, but little is known about other steroids' effects. This study found that increased nest predation risk led to decreased yolk progesterone deposition, while yolk androgen deposition did not change significantly.