The endocrine disruptor 17β-trenbolone alters the relationship between pre- and post-copulatory sexual traits in male mosquitofish (Gambusia holbrooki)

It is now well-established that reproduction in wildlife can be disrupted by anthropogenic environmental changes, such as chemical pollution. However, very little known about how these pollutants might affect the interplay between pre- and post-copulatory mechanisms of sexual selection. Here, we investigated impacts 21-day exposure male eastern mosquitofish (Gambusia holbrooki) to a field-realistic level (average measured concentration: 11 ng/L) endocrine-disrupting 17β-trenbolone (17β-TB) on reproductive traits. We examined behaviour testing time spent near female behind partition, well number copulation attempts made, chasing free-swimming context. Sperm traits were also assayed for all males. found fish 17β-TB altered relationship key Furthermore, 17β-TB-exposed males had, average, higher percentage motile sperm, performed fewer than unexposed there was no overall effect either associating with or females. Taken together, our findings demonstrate potential both traits, selection contaminated wildlife.