The males of the famous cattas in Madagascar are apparently animal perfumers: researchers have discovered clear indications of sex pheromones in primates for the first time in this type of lemur. The katta males therefore smell their fluffy tails through glandular secretions on their wrists and then wave the smell to the hearts of their hearts. The scientists also gained insight into the recipe for the katta perfume and examined the effects of three substances on the females. A pheromone effect emerged.
Many insects exude them and some mammals too: volatile substances that trigger specific reproductive-related reactions in another individual of the same species. These sex pheromones primarily serve to attract partners. Although body odors also play a role in social behavior in primates, including humans, no individual substances have yet been clearly defined as sex pheromones. Until now, this was due to the complexity of the volatile compounds in body odors from primates and the difficulty in reliably performing behavioral experiments, write Kazushige Touhara from the University of Tokyo and his colleagues.
Ring-tailed mackerel flirt fluffy
The focus of her study, however, was on a primate species in which smells obviously play a major role: The Madagascar katas have clearly recognizable scent glands on their wrists. It is known that their secretion serves intra-species communication – the territory is marked by the smell and the reproductive status is also conveyed. As Touhara and his colleagues report, observations have already suggested that the males also use these scent glands to attract the attention of the females. “Only in the annual breeding season do the male lemurs rub the glands on their wrists against their fluffy tails and then swing them in front of the females. We refer to this behavior as fragrance flirting, ”says Touhara.
As part of their study, he and his colleagues have now analyzed the fragrance secretion. To do this, they collected samples of the fluid from the male wrist glands both during and outside the reproductive period. They then examined the chemical composition of the substances in the laboratory using gas chromatography-mass spectrometry. As they report, they could already recognize the samples from the mating season with their bare nose: they have a fruity-floral note, while the smell is rather tart in the non-breeding season.
The analyzes showed that three fruity-flowery odor compounds from the group of aldehydes occur more frequently in the secretions during the reproductive period. As further trials have shown, their production has to do with the male’s hormone status: if the researchers artificially raised a male lemur’s testosterone level outside the reproductive season, the amount of odor compounds increased – similar to the mating season.
Trial test with ring-tailed ladies
In order to investigate the effect of the substances on the female lemurs, the researchers presented them with scent samples and different mixtures of the substances on cotton pads at different times. “Outside of the mating season, the females were generally not particularly interested in all of the smells we tested,” reports the first author of the study Mika Shirasu. But it was different in the breeding season. The katta ladies then only sniffed at the mixtures of all three components for a remarkably long time, the researchers report.
The results suggest that the fragrances of the katas are actually pheromones. The scientists, however, emphasize that they have not yet officially been able to call the substances sex pheromones. As they explain, further studies are now required to show the extent to which they directly influence the sexual behavior of the katta women. “So far, we have not yet examined behavioral changes after a sniff in detail – but we want to clarify whether these substances affect the mating success,” says Touhara.
Source: University of Tokyo, technical article: Current Biology, doi: 10.1016 / j.cub.2020.03.037