The value in the details: copulatory courtship behaviour in soldier flies and bean beetles

William Eberhard's legacy attests to the value of detailed behavioural observations. The significance of this descriptive approach can be illustrated by the phenomenon of copulatory courtship, or courtship that occurs during and following copulation. Through meticulous descriptions of copulatory behaviour in numerous arthropods, Eberhard has demonstrated that copulatory courtship is common and widespread and is likely a behaviour shaped by cryptic female choice. Here I will highlight the importance of detailed observations of copulatory behaviours in both an understudied tropical species and a model organism. In the soldier fly Merosargus cingulatus, males perform copulatory courtship by waving their hindlegs and tapping the female abdomen during copulation. In the absence of this behaviour, females fail to oviposit after copulation, which is one mechanism of cryptic female choice. In the bean beetle, Callosobruchus maculatus, males tap the female body with their antennae immediately before intromission. The courtship function of this antennation behaviour is being investigated, and the results presented here support a role in copulatory courtship. These examples demonstrate that careful observations can generate novel insights, even in well-studied species.