Published online 28 January 1999 | Nature | doi:10.1038/news990128-8

News

Domestic violence and divorce, termite-style

Who knows the strife and discord that goes on behind apparently peaceful suburban front doors? A classic picture of domestic harmony is shattered this week with the revelation of domestic violence (up to and including mutilation) and acrimonious divorce among termites - conventionally thought to be among the nearest things that animals get to marital bliss.

Termites are monogamous and tend to stay with the same mates for a long time - up to 20 years in some species. Young termites may take several years to mature, and both parents do their fair share of the family chores.

But studies of other species that show monogamy and biparental care, such as birds and humans, suggest that domestic tranquility is a façade. Behind the net curtains is a battleground of violence, desertion and divorce. The evolutionary rationale is that animals that pair for life are likely to be very choosy about potential mates - and prepared to ditch a partner if a better prospect comes along. Why, then, does the usual picture of termite relationships remain so cosy, if not rosy?

The reason, says Janet Shellman-Reeve of Cornell University, Ithaca, New York, is that nobody has really looked. In a report in Proceedings of the Royal Society of London, she presents “the first quantitative field data on courtship strategies, mate choice and courting conflicts in termites.”

Her subjects are colonies of the termite Zootermopsis nevadensis, which makes home in logs. Termite pairs form very quickly - within two hours - as the termites reach a new log, so that defence can be organized against termites of the related species Z. augusticollis.

More than half of initial pairings ended in break-up, often accompanied by physical violence (one researcher has reported that termite couples chew off each others’ antennae, which puts slashing an unfaithful partner’s suits or spray-painting his BMW into perspective.)

Although both sexes suffered such schisms, the means of initiating the break-up tended to differ between the sexes. Males tended to walk out, deserting the female and looking for a new partner elsewhere. Females, though, generally stayed home, inviting an extra suitor into the nest. If the current partner was already there, so much the better - in nests where three termites were present, the two that were of the same sex, male or female, scrapped bitterly until one was thrown out, the fight being actively encouraged by the third termite.

The icing on this miserable and familiar-sounding picture is the fate of rejected termites, which generally go on to form pairs with termites that had also been rejected.