Journal ofChemicaIEcology, Vol. 16, No. 1, 1990 CHEMICAL PROPERTIES OF FEMORAL GLAND SECRETIONS IN THE DESERT IGUANA, Dipsosaurus dorsalis ALLISON C. ALBERTS Research Department Zoological Society of San Diego P.O. Box 551, San Diego, California 92112 (Received February 1, 1989; accepted March 17, 1989) Abstract--This study investigates the chemistry of femoral gland secretions in the desert iguana, Dipsosaurus dorsalis (Lacertilia: Iguanidae), and dis- cusses their possible functional significance. Electrophoretic and proton NMR studies indicated that the secretions are composed of approximately 80 % pro- tein and 20% lipid material. Individual differences in polyacrylamide gel banding patterns of femoral gland proteins were found. Reflectance spectros- copy revealed that the secretions strongly absorb longwave ultraviolet light, a feature that may be important in the localization of secretion deposits in the environment. Key Words--Desert iguana, Dipsosaurus dorsalis, femoral glands, contact pheromones, ultraviolet light, signal localization. INTRODUCTION The femoral glands of lizards are follicular skin glands present in a row on the ventral surface of the hindlegs and open to the exterior through femoral pores. Femoral glands are present in many, although not all, families of lizards. Although the existence of femoral glands has been documented for over 200 years (Linnaeus, 1758), little is known of either the chemical nature of the secretion or its functional significance. Each gland consists of several branching tubules leading to a separate pore through which a solid plug of exudate is secreted. The secretion is holocrine in nature, and, at least in some species, is composed of cells that undergo trans- formation and subsequently move down through the secretory duct of the glands 13 0098-0331/90/0100-0013506.00/0 9 1990Plenum Publishing Corporation