The Function of the Katydid Spermatophore and its Role in Fecundity and Insemination (Orthoptera: Tettigoniidae)

Abstract

The spermatophore of Requena verticalis Walker (Orthoptera:Tettigoniidae) consists of two parts, the sperm ampulla and the spermatophylax. The spermatophylax contains no sperm; the female eats it after mating, then removes and eats the empty sperm ampulla. Experiments were conducted to determine if female consumption of the spermatophylax prevents premature removal of the sperm ampulla, or enhances female fecundity, or both of these. Females with the spermatophylax experimentally removed ate the sperm ampulla before insemination. When mated females were given additional spermatophylax, the time until the ampulla was removed was increased relative to that in unmanipulated matings. Although females in unmanipulated matings took about 5 h to eat the spermatophylax, almost all ofthe ejaculate had left the ampulla by 3 h after mating. Inseminated females receiving no, one or two spermatophylaxes did not differ in the number of eggs produced after mating or in the weights of these eggs. Evidence is reviewed that indicates that the spermatophylax provides a nutritional as well as a protective role.