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Same-sex Pairing may Give Male Termites an Evolutionary Advantage, Japanese Researchers Suggest

Male Japanese termites form homosexual couples when no females are around — and when the chance arises, they take over a heterosexual couple’s nest and kill the male so that one of them can mate with the now spouseless female, scientists from Kyoto University reported in a study published this week in the research journal Animal Behaviour. The evolutionary paradox of homosexuality has long puzzled biologists, the university said in a statement entitled Homosexual Termite Regicide. “The observations support a theory that homosexual couplings in invertebrates have evolutionary advantages.”

 The statement continued: “Recent research suggests that there are benefits associated with homosexuality, at least for mammals and birds. As for invertebrates like insects, experts have considered that homosexual behavior results from an inopportune misrecognition of males as females. But lead scientist Nobuaki Mizumoto and colleagues discovered that male termites aren’t so inobservant; they behaved differently toward males and females, and when coupling with males, they didn’t act as though they were mistaking them for females.”

“There had to be some sort of benefit if this were a common behavior”

Mizumoto explained: “Japanese termites usually make nests in monogamous, heterosexual pairs. In theory, misrecognizing a female for a male in a monogamous mating system should incur considerable costs for reproduction. There had to be some sort of benefit if this were a common behavior.”

The researchers observed that homosexual male termites built nests together, just as with heterosexual couples. “Male termites aren’t able to survive on their own, but those that make nests with another male survived for much longer,” Mizumoto said. “This was especially beneficial in situations when searching for females raises the risk of being preyed upon. It’s clear that male-male pairing is a strategy for survival.”

The team found that once workers from the heterosexual couple’s colony began digging tunnels to patrol, a male-male pair would travel back through the tunnel to invade and attempt to kill the heterosexual couple’s nest, the news release said. “From genetic analyses of subsequent offspring, the scientists found that only one of the invading males had been able to mate with the female.”

“Pairing with another male isn’t the best option, but it gives mateless termites a chance to survive until they find a female, if that happens at all,” Mizutani said. “To understand this behavior further, it will be important to consider the effects of other factors such as predators.”

This post was based on a University of Kyoto news release.

12418031_10153900711084116_8462971761216697621_nDavid Braun is director of outreach with the digital and social media team illuminating the National Geographic Society’s explorer, science, and education programs.

He edits National Geographic Voices, hosting a global discussion on issues resonating with the Society’s mission and major initiatives. Contributors include grantees and Society partners, as well as universities, foundations, interest groups, and individuals dedicated to a sustainable world. More than 50,000 readers have participated in 10,000 conversations.

Braun also directs the Society side of the Fulbright-National Geographic Digital Storytelling Fellowship

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