On Wed, 3 Oct 2001, Thomas G. Cleaver (tom.cleaver@louisville.edu) sent me this article (original URL: http://sciboard.louisville.edu/news/scinews/bioins/fireants.htm): WHY FIRE ANTS KILL THEIR QUEENS 6/8/93 For most species of ants, each colony has a single queen. At various times during the year, the ants of the colony will throw a party, then send out their royalty (winged males and females) on a mating flight. If a female finds a mate, she becomes a queen; the "king" becomes a has been, and dies. The new queen looks for a good spot, digs a nest, and lays a few eggs. The first offspring are nurtured by the queen therough the egg, larva, and pupa stages. When they become adults, they forage for food -- a new colony has been formed. Fire ants are found in tropical and semitropical climates, including the southern US. They are particularly nasty and destructive. One reason is that they can sting as well as bite; another reason is that they build very large nests. The reason that their nests get so big is that they can have many queens in the same colony. The idea seems to be, if one queen is good, twenty is better. So fire ants go for a few big nests rather than lots of little ones. Also, this saves the stay-at-home queens from risking their lives in the hostile outer world. Scientists have recently discovered that fire ants commit regicide -- they kill their queens. Queens, apparently, don't get any respect, at least if they have the wrong genes. If a queen carries the gene called PGM-3, she will be killed as soon as she reaches adulthood. This is very peculiar as this gene is associated with especially high fecundity (this means she can lay a lot of eggs). Why would the fire ants kill off their best egg layers? The answer is a mystery. Some scientists theorize that if one queen layed too many eggs, she would dominate the nest with her genes, and thus reduce genetic diversity. But that's really just a guess.