Talk about a royal scandal. When a termite king and queen have been in power for some time, the king begins mating with his royal daughters to populate the colony. Now, researchers report that one termite species has found a way around this incest: The queen produces offspring that have only her genes. That way, when the king mates with a daughter, he's effectively still having sex with the queen.
A termite colony starts when a king and queen pair up during an annual mating flight and settle down to start a family. At first, the couple produces worker and soldier termites that care for the nest. When the colony gets big enough, the king and queen start making alates--winged termites that leave home to find mates and start colonies of their own. Finally, late in the queen's life, she lays several eggs that become secondary queens to replace her--and those queens start mating with the king to produce more workers, soldiers, and alates. This inbreeding reduces the offspring's genetic diversity and thus the colony's ability to adapt to environmental stress.
But it turns out that at least one termite species has adopted an alternative. In the Japanese termite Reticulitermes speratus, the founding queen bears her junior queens through a process called parthenogenesis, a form of asexual reproduction that produces offspring with duplicates of half of mom's genes. Some ant queens also asexually reproduce, but the resulting queens head off to start their own colonies.
Figuring out Reticulitermes's strategy wasn't easy. Entomologist Kenji Matsuura of Okayama University in Japan and colleagues first collected termites from 30 colonies at five different sites. Then they analyzed the genes of kings, queens, and other castes. The worker genomes held the real surprise: They appeared to come from only one queen despite the presence of several in the nest. Further analysis showed that the secondary queens lacked any genetic input from the king, meaning that the primary queen produced them on her own, the researchers report in today's issue of Science.
