Sexual selection and genital allometry in the Hottentot golden mole (Amblysomus hottentotus)

Abstract

Under sexual selection, genitalia typically undergo rapid and divergent evolution across species and competition between the sexes over control of fertilisation may drive the co-evolution of male and female sexual traits. Sexual selection can, therefore, influence genitalia in three fundamental but non-mutually exclusive ways: (1) cryptic female choice, (2) sperm competition and (3) sexual conflict. Golden moles (Chrysochloridae) are a highly specialised family endemic to sub-Saharan Africa. We examined intraspecific genital allometry of both male and female subterranean Hottentot golden moles (Amblysomus hottentotus). Consistent with previous studies in mammals, we found positive allometry and a high coeffi- cient of variation (CV) for male genitalia. The results for female reproductive tract length of A. hottentotus contrast with the findings of previous studies as isometry was recorded. Based on the allometric relationships of both males and females presented here, we suggest that the males do not sequester females and that in the absence of visual cues the female may use penis size as an indicator of phenotypic quality.