Japanese male and female termites have very sex-specific courtship behaviors known as tandem runs that mark the start of a new colony. It turns out that same-sex pairings of the same species also perform tandem runs, and members of these same-sex pairings can express opposite-sex behavior and provide the same pairing coordination seen in their heterosexual counterparts.
“Tandem running is highly coordinated, with each sex exhibiting different behaviors,” said lead author Dr. Nobuaki Mizumoto of the Okinawa Institute of Science and Technology in a statement. “The female termite always leads, and the male termite always follows closely behind. When separated, the female pauses while the male searches for her.”
The team was curious to see if and how such behavior would occur in same-sex matings. Termites not only mate to reproduce, but also to nurture one another and stay healthy. Mating quickly is also beneficial as it reduces the chance of being hunted. So being open to all sexes seems to be a good survival strategy, all the more so given that female termites can choose to reproduce by parthenogenesis without the need for a male.
The tandem runs in same-sex and opposite-sex pairings showed a similar dynamic. In female-female pairs, there was a female leader and a female follower. When the two got separated, the follower went looking for the leader, which is a typical male trait in heterosexual pairings. Likewise, in male-male matings, the male leader would stop and wait if the pair became separated. This is a typical female trait in heterosexual pairings.
Computer simulations showed that if termites in same-sex matings were restricted to their heterosexual sex role, they would either be less likely to reunite or it would take much longer.
The team originally wondered whether the driving force behind same-sex behavior in termites was due to indiscriminate mating, but the evidence here suggests that the termites change their behavior in same-sex matings. All termite species in the Neoisoptera group—including this Japanese termite—have tandem runs that are conducted by females, but more distantly related species have tandem runs that can be conducted by either males or females.
“This suggests that male and female termites, which were the ancestors of modern termites, likely had the ability to both lead and follow. That could be why the potential for female and male behaviors still exists in modern termites, allowing same-sex mating to evolve,” explained Dr. Mizumoto.
The study was published in Proceedings of the National Academy of Sciences.
