Before one species of jumping spider, known as Evarcha culicivora, goes trolling for a mate, it firsts look to feast on blood-fattened mosquitoes. What happens next seems like something out of a bad video game: The delicacy gives the spider a special power–a sweet smell that the opposite sex finds irresistible.
In a new study, which will be published in the Proceedings of the National Academy of Sciences, researchers exposed E. culicivora specimens to the odors of others raised on blood-fed female mosquitoes and on three other diets: sugar-fed females, males and lake flies…. [The] tested spiders of both sexes were most strongly attracted to the odor of spiders reared on blood-fed female mosquitoes. But the attraction was only for spiders of the opposite sex [The New York Times]. Spiders would hang around blood-fattened spiders of the opposite sex four times longer than they would linger around those fed on another diet. The blood perfume effect might only be triggered by a gender specific hormone, the researchers suggest.
One of the study’s authors, Fiona Cross, says that if the humans had the same effect “it might be like if we all gave off an odor after eating chocolates. It would only be the people who ate the chocolates with particular centers who smelled particularly attractive. Weird” [LiveScience]. Catching these bloody mosquitoes is not easy for the spiders, so the researchers suggest the whole process is a complicated evolutionary dance. After catching to prized meal, spiders give off an odor, which the opposite sex associates attractiveness over time because of the sexiness of being able to catch such a prized meal. This in turn might have caused then to be more successful at mating. However further research is needed to confirm whether the blood perfume actually confers a reproductive advantage.
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Image: Robert R. Jackson