Entomological and mammalogical perspectives on genital differentiation.

When hypotheses concerning the evolution of animal genitalia are classified by their assumptions and arranged historically, key differences between the entomological and mammalogical approaches become clear. The former tradition emphasizes mechanism and the latter emphasizes species isolation. Consequently, studies of this subject often address different aspects of the question while using similar terminology, specifically, the term 'lock-and-hey'. Because genital variation represents a significant portion of animal diversity, it merits the attention and clarity of investigation given to other anatomical features. However, attempts to achieve the necessary level of clarity have been largely unsuccessful. This article promotes common terms for improved communication between researchers.