Date-licious smell for bats

Date: December 22, 2016

Source: Forschungsverbund Berlin e.V. (FVB)

Females of the greater sac-winged bat select their mating partner by smell and unerringly choose a male which differs from them the most in genetic terms. Females with more variants of olfactory receptors of the TAAR-group have an advantage over other females. The results of this study have been released by the Nature Publishing Group in their open access journal Scientific Reports.

Researchers from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), the University of Ulm, the Museum für Naturkunde in Berlin (Leibniz-MfN) and the Fritz Lipmann Institute on Aging (Leibniz-FLI) discovered that "ladies choice" reigns in the greater sac-winged bat. Male bats from Saccopteryx bilineata are considerably smaller than females, so they are not in the position to enforce copulation. "We know that females from other species with low birth rates (like bats) are very choosy when it comes to mate selection," says Pablo Santos, lead author of the study.

So, which general criteria do female bats use to select their partner? Since bats are nocturnal animals, males cannot impress females with complex colour patterns or bizarre courtship dances. It had already been known that Saccopteryx males, beside their mating calls, present a self-made "perfume" to the females during courtship. However, what exactly counts and what makes the males irresistible in the dark -- or puts them out of the question has been a scientific mystery for more than three decades. Now it is unravelled: female bats rely on their nose and use an elaborate set of olfactory receptors.

"Male bats prepare a mixture of urine, saliva and penis secretion in two small skin bags on their wings," explains Christian Voigt, bat expert at the Leibniz-IZW. They spend up to one hour per day on cleaning and filling the bags. Owing to the body heat, the liquid begins to ferment within a short time, emitting an intense smell. Thus, each individual generates a distinctive scent, presumably revealing its MHC genotype.

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