Variation Pattern of Sperm Competition in Two Bats, Pipistrellus kuhlii and Hypsugo savii (Chiroptera:Vespertilionidae) During Winter in Iran

Sperm competition is a widespread phenomenon influe ncing the quality of a whole ejaculate (i.e., propo rtion of motile, viable, morphologically normal sperm, spermconcentration and length). Bats can store fertile sperm for up to 200 days. In this study we examined relationship s between sperm competition levels by measuring spe rm quality, in two species of temperate vespertilionid bats; Pi pstrellus kuhlii and Hypsugo savii that stores sper matozoa for an extended period as a strategy that allow bats to in terrupt their reproductive cycle by hibernating. Sp erms were obtained from the epididymis of sexually mature bat s. Sperm quality and length was assessed and compar ed between the two species. Our results showed that sperm viability and motility at first did not differ in the two bats. After 2, 4 and 7 hours from sperm extraction, the differences were significant between the two examine d species. Sperm concentration, sperm normality and total sper m length in P. kuhlii were significantly higher than H. savii. Comparative studies indicate that sperm quality in P. kuhlii was significantly higher than H. savii. Our analyses revealed the associations between different male reproductiv e traits interspecies in bats and the hierarchy of sperm competition.

sperm competition, bat, Pipistrellus kuhlii , Hypsugo savii.