MICROSCOPIC-ANATOMICAL INVESTIGATIONS ON THE ANORECTAL REGION OF PIPISTRELLE BATS PIPISTRELLUS-PIPISTRELLUS (SCHREBER, 1774) (MAMMALIA, CHIROPTERA)

Field-studies on the olfactoric communication of Pipistrelle bats are difficult because they are mostly hidden in crevices of houses. An ind irect method of investigating is the functional morphology of glands. Scent glands are widespread within the glands entering the integument at mucocutaneous junctions in mammals, which is what we also expected to find in the pipistrelle bat. We chose the ano-rectal region for thi s study. Five male and five female adult and juvenile Pipistrelle bats found during several months of the year were microscopically investig ated. Both types of ano-rectal glands are more voluminous in males tha n in females. The sebaceous glands thus show a sexual dimorphism, but no seasonal changes. Their function could not be fully interpreted on the basis of our results. The secretory activity of the proctodaeal gl ands is less in juveniles than in adults and within the adults the sec retory activity is strongest during the mating season in autumn. Sexua l dimorphism and seasonal change in the secretory activity of these gl ands suggest that they are scent glands. Their secretion probably play s an important role during the mating season.