Termites are often dismissed as nothing but home-destroying pests, less charismatic than bees, ants or even spiders.
In fact, termites have been doing incredible things since the time of dinosaurs, maintaining complex societies with divisions of labor, farming fungus and building cathedrals that circulate air the way human lungs do.
Now, add overthrowing the patriarchy to that list.
In a study published this week in BMC Biology, scientists reported the first discovery of all-female termite societies. Among more than 4,200 termites collected from coastal sites in southern Japan, the researchers did not find a single male.
Toshihisa Yashiro, a postdoctoral fellow at the University of Sydney and lead author of the paper, said in an email that he was utterly surprised by the discovery: I got a headache, because we believed that having both males and females is the rule in termite societies.
The complete loss of males is rare across the animal kingdom, especially in animals with advanced societies. All-female lineages have previously been documented in a few ant and honey bee species, but their colonies are already dominated by queens and female workers.
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Termites, in contrast, are known for having colonies in which males and females both participate in social activities. Dr. Yashiros research is the first, in other words, to demonstrate that males can be discarded from advanced societies in which they once played an active role.
His team collected 74 mature colonies of Glyptotermes nakajimai, a termite that nests in drywood, from 15 sites in Japan. Thirty-seven of the colonies were asexual and exclusively female, while the rest were mixed-sex. Egg-laying queens in asexual colonies stored no sperm in their reproductive organs and laid unfertilized eggs.
Genetic analyses suggested that the asexual termites evolved from ancestors that split from other G. nakajimai around 14 million years ago. The asexual termites have an extra chromosome compared with the sexual ones, suggesting the two groups may now be diverging into different species, said Nathan Lo, an evolutionary biology professor also at the University of Sydney.
Tanya Dapkey, an entomologist at the University of Pennsylvania, said that there was much to learn from successful societies in nature run without any input from males.
Edward Vargo, an entomology professor at Texas A&M University who was not involved in the study, added that determining how and why certain colonies evolved asexuality might yield insight on the big question of what is the purpose of sex and sexual reproduction.
Dr. Yashiro has a few hypotheses. To start, sexual populations of G. nakajimai do occasionally produce offspring from unfertilized eggs, which perhaps pre-adapted them to get along fine without males, he said.
Also, sexual reproduction introduces new genetic variation within a species. But the asexual termites, which are found in remote, coastal areas, might not have needed that trait to fight off parasites and pathogens. And asexuality would have been an efficient way to expand asexual populations are known to grow at twice the rate of sexual ones.
Crucial to this transition may have been a willingness, by termite queens, to cooperate when establishing colonies. In most asexual colonies the researchers studied, multiple queens, as many as 25, were found.
Furthermore, the scientists noticed that asexual colonies had fewer soldiers than sexual ones. The all-female soldiers in asexual colonies were more uniform in the size of their heads, which they use to block enemies from invading their nests. Its possible that asexual soldiers are more efficient at defense, Dr. Yashiro said.
At the end of our interview, I asked Dr. Yashiro if he had last thoughts to share. He declared, simply: For asexual Glyptotermes nakajimai, the future is female!