MALE SECONDARY GENITALIA MIMIC THE FEMALE EGG DURING OVIPOSITION FOR SPERM DISPLACEMENT IN THE NON-TERRITORIAL DAMSELFLY ISCHNURA ASIA TICA (BRAUER) (ZYGOPTERA: COENAGRIONIDAE)

摘要

The 9 sperm storage organs of / asiatica include the bursa copulatrix and the sper-matheca. The spermatheca is joined to the base of the bursa copulatrix by a sperma-thecal duct. At the tip of the cJ's secondary genitalia, there is a pair of horns which might be used to remove sperm from the 9 sperm storage organs. Since each horn of the 8 genitalia is shorter than the spermathecal duct, the spermatheca might be inaccessible to 8 8. However, sperm reduction occurs both in the bursa copulatrix and inthe spermatheca during copulation. This suggests an alternative mechanism by which the 8 can cause a decline in the spermathecal sperm. In order to investigate the mechanism of sperm reduction, an interrupted copulation experiment was conducted in the field. The extent of sperm reduction in the spermatheca was related to the width of the head of the secondary genitalia of the mated 8. 9 9 have mechano--receptive sensilla which communicate the presence of an egg to the muscles surrounding the sperm storage organs for fertilization. Therefore, the head of the secondary genitalia might mimic the movement of the egg that stimulates the sensilla to induce spermathecal sperm ejection by the 9.