Friday seminar: Female extra-pair mating in birds: is there a universal adaptive explanation?
By Arild Johnsen, Natural History Museum, University of Oslo
Extra-pair paternity (EPP) is common in birds but its frequency varies considerably among species. Explaining this variation and understanding the adaptive significance of multiple mating to females, has been the subject of great interest and debate among avian evolutionary biologists since the advent of molecular paternity analyses. In this talk, I will address these issues by first highlighting some recent comparative work on passerine birds, questioning whether finding a single or a few variables to explain broadscale patterns of variation in EPP is likely. I will then summarise results of nearly 30 years of research on a passerine with high levels of EPP, the bluethroat. We provided some of the first evidence for genetic compatibility benefits to multiply mating females from this species twenty years ago, and have recently published compelling evidence that this arises through extra-pair mate choice for intermediate MHC-variability.