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© Wikipedia commonA soldier termite (Macrotermitinae) in the Okavango Delta.
A pair of researches with Kyoto University has found how the queen of one species of termite, Reticulitermes speratus, ensures her genetic lineage continues by creating duplicate copies of herself. In their paper published in Proceedings of the National Academy of Sciences, Toshihisa Yashiro and Kenji Matsuura describe the study they carried out that showed how queens in such colonies reproduce themselves.

Scientists have known since 2009 that R. speratus queens created fatherless offspring which became queens themselves, but until now, the mechanism by which that came about has been a mystery. In this new effort, the researchers took a new look at the structure of the eggs laid by the queen to discover the difference between future queens and ordinary termites. Close inspection revealed tiny channels through the outer lining of the eggs called micropyles. The channels serve as an entry point for sperm, which the queen deposits on the eggs (after obtaining it from a male).

Interestingly, the research pair found that the number of micropyles for any given egg appeared to be random, from one to more than thirty - the average was nine. Even more interesting was that the team soon learned that sometimes there were no micropyles at all in some eggs, which would of course mean that no sperm could enter to fertilize its contents - and the egg still matured and wound up in the creation of offspring. That offspring, because it had no DNA from a male, grew into a new queen. Such a process means that the females are fully in control of both sexual and asexual reproduction.

Further study revealed that the queen only produces eggs with no microplyes when she gets older (females live on average for 11 years) thus, they serve as a means of queen replacement in a colony. This form of asexual reproduction called parthenogenesis is not unheard of in the animal kingdom - several other types of insects, lizards and even sharks use it as a form of reproduction. But this was the first time it's been seen in termites as a form of self-cloning. The authors note that because the offspring that are born as clones eventually reproduce themselves too, and so on and on, the original queen can be considered genetically immortal.

More information:

"Termite queens close the sperm gates of eggs to switch from sexual to asexual reproduction." Toshihisa Yashiro, PNAS, DOI.