Abstract
Squamate reptiles sense chemical stimuli carrying information about several biological properties of the sender. Despite the fact that sex recognition is often based on colour signals, such pheromone communication occurs in many species of lizards. Epidermal gland secretions of reptiles can have pheromone properties and might play an important role in sexual signalling and territorial scent marking. The house-dwelling geckos Hemidactylus turcicus, Hemidactylus flaviviridis, and Cyrtopodion scabrum are good examples of geckos having pre-anal glands in males only. We used GC–MS chemical analysis of gland secretions, compared secretions of different species, and compared secretions from two populations of H. turcicus. Surprisingly, we detected monoglycerides of fatty acids, and one 1,3-alkanediol. These compounds have been detected once before in reptiles. In addition, carboxylic acids, alcohols, steroids, alkanes, amides, one aldehyde, carboxylic acid esters, hydrocarbons, and squalene occurred. Polyol glycerol seems to play a role in the composition of the secretions probably as an adhesive of some kind for the secretion as a whole. The data supports our hypothesis that geckos can potentially use femoral gland secretions in chemical communication. Further studies are needed to test activities of these compounds in behavioural assays to eventually identify their possible role in communication.
► We studied secretions of pre-anal glands in house-dwelling geckos. ► GC–MS analysis showed characteristic chemical structure. ► Monoglycerides and 1,3-alkanediols were detected. ► Interpopulational differences were recorded. ► The secretions are rich in glycerol.