Effects of wintering under methylmercury exposure on spring reproductive onset in song sparrows (Melospiza melodia).

ABSTRACT: Exposure to methylmercury (MeHg) on breeding grounds may have numerous deleterious effects on birds, including neurotoxicity, disruption of hormones, and impaired reproduction. But it is unknown if MeHg exposure on wintering grounds can carry over and produce negative effects on the following spring breeding seasonal transition. To evaluate this, we exposed male captive song sparrows (Melospiza melodia) to environmentally relevant levels of dietary MeHg for 3 months during winter. We then photostimulated the birds with a long-day photoperiod and observed them for 21 days post-exposure. Contrary to our predictions, we found no carry-over effects of MeHg on the timing of changes in spring reproductive physiology assessed by testes mass, syrinx mass, plasma androgen concentrations, number of

SUBMITTER: Bottini CLJ 

PROVIDER: S-EPMC12145943 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature