Abstract
Grooming the body surface is indispensable for animals to survive. If foreign substance is not removed from the body, sensory organs such as eyes and skin cannot function properly and even physical condition is ruined when bacteria, mold or parasite proliferates. Insects are known to groom frequently every part of the body with the mouth and legs. However, there are some parts which are difficult to reach. In the cricket, Gryllus bimaculatus, the genital chamber housing the external genitalia is located in the terminal abdominal segment and seems to be easily soiled with feces since the anus is situated just above the genital chamber. Foreign substance may cause serious problems in producing the spermatophore, if it remains inside the genitalia, because the genitalia serves as a template for the spermatophore. Recently, we have found that there is a special membrane complex consisting of the median pouch and genital chamber floor which makes clean inside the dorsal pouch. In this review, we described the structure and function of the membrane complex in the genital chamber, its muscle and nerve innervation and the effect of its ablation. Finally, we compared the genital structures plausively involved in grooming among several species of crickets, and discussed their evolutional aspects.
