Viability and motility of epididymal spermatozoa in captive Pipistrellus kuhlii (Chiroptera: Vespertilionidae) in winter

Abstract

Pipistrellus kuhlii is a temperate vespertilionid bat which stores spermatozoa for an extended period of time possibly in the range of 5–6 months in both male and female reproductive organs. In this study, we measured testes and epididymis length, viability and motility of spermatozoa stored in the epididymis in a group of male P. kuhlii kept in a flight cage during autumn and winter. Change in the length of the testes and epididymis in a group of 14 Kuhl’s bats kept in a flight cage during autumn and winter showed that the growth of the testes and epididymis is reciprocal. While in mid-October testes begin to lose size, the epididymis gains length to become four times bigger than testes in mid-February. Epididymal spermatozoa removed from adult P. kuhlii males were used for a progressive motility assessment of spermatozoa by visual examination using light microscopy. The average percentage of membrane intact spermatozoa unaffected by 0.5% eosin Y solution in six monthly measurements from October ...