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The structural design of the bat wing web and its possible role in gas exchange
Author(s) -
Makanya Andrew N.,
Mortola Jacopo P.
Publication year - 2007
Publication title -
journal of anatomy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 118
eISSN - 1469-7580
pISSN - 0021-8782
DOI - 10.1111/j.1469-7580.2007.00817.x
Subject(s) - stratum corneum , wing , epidermis (zoology) , anatomy , dermis , chemistry , connective tissue , thermoregulation , body surface , biophysics , biology , endocrinology , genetics , geometry , mathematics , engineering , aerospace engineering
The structure of the skin in the epauletted fruit bat ( Epomophorus wahlbergi ) wing and body trunk was studied with a view to understanding possible adaptations for gas metabolism and thermoregulation. In addition, gas exchange measurements were performed using a respirometer designed for the purpose. The body skin had an epidermis, a dermis with hair follicles and sweat glands and a fat‐laden hypodermis. In contrast, the wing web skin was made up of a thin bilayered epidermis separated by a connective tissue core with collagen and elastic fibres and was devoid of hair follicles and sweat glands. The wings spanned 18–24 cm each, with about 753 cm 2 of surface exposed to air. The body skin epidermis was thick (61 ± 3 µm, SEM), the stratum corneum alone taking a third of it (21 ± 3 µm). In contrast, the wing web skin epidermis was thinner at 9.8 ± 0.7 µm, with a stratum corneum measuring 4.1 ± 0.3 µm (41%). The wing capillaries in the wing web skin ran in the middle of the connective tissue core, with a resultant surface‐capillary diffusion distance of 26.8 ± 3.2 µm. The rate of oxygen consumption (V̇O 2 ) of the wings alone and of the whole animal measured under light anaesthesia at ambient temperatures of 24 ºC and 33 ºC, averaged 6% and 10% of the total, respectively. Rate of carbon dioxide production had similar values. The membrane diffusing capacity for the wing web was estimated to be 0.019 ml O 2 min −1 mmHg −1 . We conclude that in Epomophorus wahlbergi , the wing web has structural modifications that permit a substantial contribution to the total gas exchange.