Intersex production in the Wolbachia-infected parasitoid wasp, Trichogramma kaykai

Sexually aberrant individuals, displaying both male and female characteristics, are rare in occurrence but are documented throughout the animal kingdom. In parasitoid wasps of the genus, Trichogramma, such individuals typically appear as a result of rearing Wolbachia-infected, thelytokous wasps at high temperatures. Sexually aberrant Trichogramma have been referred to interchangeably in the literature as gynandromorphs, sexual mosaics, and intersexes. However, accurately used, the terms “gynandromorph” and “sexual mosaic” describe an individual composed of a mixture of genetically distinct tissues corresponding to the sexual phenotypes observed, while “intersex” refers to an individual having a uniform genetic constitution but with some tissues exhibiting sexual phenotypes conflicting with the associated genotype. Here, we investigate the production of sexually aberrant offspring by thelytokous T. kaykai. Aberrant individuals were rare, but each was characterized as one of 11 morphotypes ranging from very feminine to very masculine. Overall, the production of aberrant individuals increased with both temperature and time from the onset of maternal oviposition. However, while the production of males also increased with temperature and time, the degree of masculinity of aberrant individuals did not; the different morphotypes appearing to be produced at random. We conclude that the aberrant individuals produced by Trichogramma kaykai are actually intersexes, and not gynandromorphs.