Day 67: Termite queen’s got this sex thing down

They look like a happy couple, but she's got a pretty big secret ... Image courtesy of Kenji Matsuura

Termite kings are fine for fathering the workers, but when it comes to producing daughters, the queen’s got it under control, thanks …

That’s the new finding from researchers in Raleigh, North Carolina and Japan, embellished with my romantic cynicism. 

Scientifically speaking, here are the goods: the researchers have shown for the first time that it is possible for certain female termite “primary queens” to reproduce both sexually and asexually during their lifetimes. The asexually produced babies mostly grow to be queen successors –- so-called “secondary queens” -– that remain in the termite colony and mate with the king. This produces large broods of babies without the dangers of inbreeding, because the secondary queens have no genes in common with the king.

(But don’t you wonder, just a little, whether this causes any tension for the royal couple?)

The new research came out last week in the journal Science.

A single primary king and a number of secondary queens in a termite nest. (No worries, man, those aren't really your daughters.) Image courtesy of Kenji Matsuura.

Lead author Kenji Matsuura and his colleagues studied 30 natural termite colonies at five field sites. In all but one, the primary queen had been replaced by numerous secondary queens. The researchers determined most of the secondary queens were genetically identical to their mothers but were unrelated to the primary king from the same nest. 

The females are apparently using parthenogenesis, meaning they’re reproducing from eggs that haven’t been fertilized by a male. The technique has been demonstrated in plants, invertebrates including bees and wasps, a handful of reptiles and other animals.  It always yields females.

Termite babies produced through normal sexual reproduction, between either the primary or secondary queens and the king, are mostly workers and soldiers of both genders, the research shows.

“The conditional use of sex is unusual in insects and was previously unknown in termites,” said Ed Vargo, associate professor of entomology at NC State and a study co-author. “This novel use of both sexual and asexual reproduction is a way for primary queens to maximize reproductive output allowing the colony to grow bigger and faster while maintaining genetic diversity and avoiding the disadvantages of inbreeding.”

Vargo pointed out that the species of subterranean termite in the study, Reticulitermes speratus, is an important economic pest in Japan and is closely related to termites found in North Carolina.

Vargo plans to continue the research by looking for other species of female termites with dual mating systems. He adds that learning more about the genetics behind reproduction could lead to ways of preventing the production of certain castes of termites -– like the primary queens that reproduce in two ways -– or ways of knocking out certain gene functions in those castes.