Inbreeding depression often affects male reproductive traits. Here, we measure inbreeding depression in sperm, body size, ornamental color patterns, and attractiveness in male guppies and ask whether different environmental conditions play a role in the severity of inbreeding depression. Male...

The avoidance of familiar individuals as mates can act to maximize the benefits of polyandry or might help to minimize inbreeding in small or highly philopatric populations. As previous mates are also familiar, the effects of familiarity and mating history can often be confounded. Here, we...