It’s all about trade-offs - Androgens and Prolactin on Parental Care, Gene Expression and the Immune Response in Male Parental Care Bluegill Sunfish

Dr. Adriano Alonso Pereira da Cunha

Science Educator

Abstract

Parental care is critical for reproduction in species that provide it. Hormones such as prolactin and androgens play a crucial role in parenting and reproductive behaviours. In mammals and birds, prolactin’s role in parental care is well-established; it stimulates milk production and stimulates. Androgens, on the other hand, are commonly associated with male secondary sex characteristics, territoriality, and aggressiveness in mammals and birds. Do these hormones have any similar effect on a paternal fish? 

I artificially manipulated hormone concentrations. I found that there was a trade-off between the behaviours influenced by these hormones. I tested how the gene expression in the hypothalamus is involved in these reproductive behaviours obtaining a null result. Finally, I addressed the immunocompetence handicap hypothesis (ICHH), which posits a trade-off between aggressive behaviours, and thus androgen concentration, and the immune response. My results in bluegill do not support the ICHH. I also found that prolactin did not increase the immune response as it does in some other fish, birds and mammals.