MATING EFFORT FUNCTION OF THE SPERMATOPHORE IN THE BUSH-CRICKET POECILIMON-VELUCHIANUS (ORTHOPTERA, PHANEROPTERIDAE) - SUPPORT FROM A COMPARISON OF THE MATING-BEHAVIOR OF 2 SUBSPECIES

To analyse spermatophore function, various aspects of the mating behav iour (e.g. spermatophore mass, duration of sperm transfer, mating freq uency) were compared in two subspecies of the bushcricket P. veluchian us. Body mass was significantly different in both subspecies and had a strong effect on spermatophore mass, resulting in a large difference in absolute and relative (percentage of male body mass) spermatophore mass in both subspecies. After copulation the small P. v. minor sperma tophores were consumed much faster by the female than the larger ones of P. v. veluchianus. The time necessary for sperm transfer from the s permatophore to the female spermatheca was much shorter in the subspec ies with small spermatophores than in that with large spermatophores, and in both subspecies similar to the time required to consume the spe rmatophores. Mating frequency varied also between the subspecies and w as much higher in P. v. minor than in P. v. veluchianus. Differences i n body mass between the two subspecies therefore resulted in changes i n several aspects of mating behaviour. However, despite large differen ces in the mass of the spermatophore, its main function seems to be to ensure sperm transfer. This can be concluded from the similarity betw een the duration of sperm transfer and the time period necessary for s permatophore consumption in each of the subspecies. The spermatophore is thus considered to be male mating effort.