Histochemistry of Odoriferous Secretions from Integumentary Glands in Three Species of Bats

Abstract

Secretions from the gular gland of male molossid bats (Tadarida brasiliensis and Molossus bondae) and pararhinal glands of male big brown bats (Eptesicus fuscus) were analyzed histochemically. Proteins and phospholipids were apparently absent from secretions of the glands of all three species. Sebaceous portions of the gular gland of both molossids contained unsaturated neutral lipids; older secretion in distal portions of their ducts consisted of unsaturated neutral and acidic lipids. Cholesterol and its esters and carbohydrates were not detected in sebaceous cells of gular glands. Apocrine secretions from Molossus contained neutral lipids and carbohydrates. Pararhinal glands from Eptesicus consisted of sebaceous and apocrine portions. The former contained neutral lipids and cholesterol esters throughout. Fatty acids were present in apical cells; unsaturated lipids were more prevalent in apical than in basal cells. Apocrine portions of pararhinal glands contained saturated fatty acids, but tests for carbohydrates, proteins, and phospholipids and cholesterol compounds were negative. Histochemical results indicate that at least some of the ester molecules from sebaceous glands are hydrolyzed before release from the gland. Unsaturated, probably short-chain, fatty acids thus released are the most likely components responsible for the well-known odor of these secretions.