Spiders: They’re kinkier than you’d expect.
"Oral sexual contact seems to be an obligate sexual behavior in this species as all males did it before, in between, and after copulations, even up to 100 times," researcher Matjaz Gregoric of the Jovan Hadzi Institute of Biology said in a news release.
Yup, that's what you're seeing below. (In case you were wondering, the female of this spider species is much larger than the male.)
The Slovenian researchers, who observed a group of Darwin's bark spiders in a lab over a two-week period, discovered that the critters have a “rich sexual repertoire,” according to a paper published Friday in the journal Scientific Reports.
That repertoire includes “sexual cannibalism,” in which some females consumed the males after breeding, and “post-mating emasculation,” meaning that the majority of males -- presumably the ones that survived -- chewed off a portion of their own sex organs within 24 hours of sex.
But all that sexual violence didn't surprise the researchers, who referred to such behavior in their paper as predictable.
What really got them excited were the revelations about spider oral sex. They wrote that the male spiders “invariably” performed some sort of sexual oral service, usually hooking a fang onto a female’s “copulatory opening” and then salivating onto her genitalia.
Humans have observed fellatio (oral sex on males) in several mammals, including fruit bats, hyenas, goats, sheep, cheetahs, primates and bears. But they're not quite convinced about the last one, describing the bears' behavior as either “abnormal” and driven by poor living conditions, or as the efforts of orphaned bears to recreate the experience of suckling their mother.
Cunnilingus-like activities (oral sex on females) are rarer in the wild kingdom, -- though scientists have observed it in so-called widow spiders, according to the paper.
So what’s the motivation for these ardent Darwin's bark males? The researchers aren’t sure yet, but they have a few theories. They floated one idea that the males are doing it to try to avoid being eaten by the females. Previous headlines on this research really latched on to that theory, but the scientists called it an unlikely possibility, noting that the male spiders perform the act even on females incapable of killing them.
They think it’s more likely that the oral contact is a sign of “male quality” that motivates the female to mate with that particular individual. It’s also possible that enzymes in the saliva somehow give the male’s sperm an advantage. But the scientists conclude that more research is needed to say anything conclusively.