Histological Observations on the Wing of the Grey-Headed Flying-Fox (Pteropus-Poliocephalus) (Chiroptera, Pteropodidae)

Abstract

The histological features of the wing membrane of Pteropus poliocephalus are described at both the light and electron microscope level. A method is described for the processing of bat wing tissue for both light and electron microscopy. The flight membrane of P. poliocephalus had a dorsal and ventral layer of epidermis with a common dermis in between. There was no hypodermis and all layers were greatly reduced in comparison with the skin of other mammals. The epidermis consisted of three layers of active keratinocytes, covered by 7-10 layers of cornified cells. Melanocytes were generally confined to the basal layer and were more numerous in the dorsal epidermis. Prominent droplets of a lipid-like substance were found in the epidermal keratinocytes and these coalesced towards the superficial layers. It is postulated that the substance contained in these droplets is a waterproofing agent. The dermis consisted mainly of collagen bundles with a network of elastin bands. An array of hair-dome complexes were found on the wing membrane surface. These receptors are similar to those described in several microchiropterans, where it is thought they provide information on airflow patterns over the wing.