Photo credit: Screenshot from Youtube video by EZlab ZRC SAZU

These kinky critters have a “rich sexual repertoire”

Spiders have a reputation for engaging in extreme sex acts. Females are known to cannibalize their male partners. Males of some species castrate themselves during mating. There have also been reports of spider bondage.

Researchers were recently surprised to find that Darwin’s bark spiders, a species found in Madagascar, engage in yet another sexual behavior: oral sex.

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Male bark spiders were reported to salivate onto the genitalia of females before, during, and even after sex, in a study published in the journal Scientific Reports. One such oral sexual encounter was captured on video:

Oral sex is rare in the animal kingdom. Fellatio-like behaviors have been observed in a few mammals, including some primates, cheetahs, dolphins, and bats. Rarer still are behaviors resembling cunnilingus, which have only been documented in dunnock birds, bonobos, fruit bats, and fruit flies. And the purpose of these types of behaviors is not always clear.

“With the data at hand, it seems premature to establish a precise adaptive significance of oral sexual contact,” the authors wrote. However, they did offer a few possible reasons why spiders might be doing it.

Oral sex could be a way for males to avoid being cannibalized by females. But the researchers think that this is an unlikely theory because males perform oral sex even on females that are incapable of killing them.

A more plausible explanation is that oral sex may signal to females whether their partner is of high quality. Or it’s possible that enzymes in the saliva could destroy the sperm of a female’s previous mate, giving the most recently mating male a better chance of fathering offspring. The authors note that these two possibilities are intriguing and require further testing.

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