Demonstrating sexual selection by cryptic female choice on male genitalia: What is enough?

• DOI: 10.1111/evo.13863
• Publication Date: 2019-10-10T19:32:59Z
• Authors: William G. Eberhard; Gerlind U.C. Lehmann
• Keywords: Female sperm storage; Sex organ; Divergence (linguistics)

Rapid divergence in external genital structures occurs nearly all animal groups that practice internal insemination; explaining this pattern is a major challenge evolutionary biology. The hypothesis species‐specific differences male genitalia evolved under sexual selection as courtship devices to influence cryptic female choice (CFC) has been slow be accepted. Doubts may stem from its radical departure previous ideas, observational difficulties because crucial events occur hidden within the female's body, and alternative hypotheses involving biologically important phenomena such speciation, sperm competition, male‐female conflicts of interest. We assess current status CFC by reviewing data two which predictions have especially well‐tested, Glossina tsetse flies Roeseliana (formerly Metrioptera) roeselii bushcrickets. Eighteen confirmed 19 Roeseliana. found justifying rejection hypotheses, but none contradicted predictions. number extent tests confirming these species greater than for other generally accepted regarding functions nongenital structures. By criterion, it reasonable conclude some both likely involved CFC.