Cloning at the hill

Courtesy of Ellen M. Vangelder

Little fire ant (Wasmannia auropunctata) colonies reveal an unexpected mode of reproduction. Denis Fournier, from the Free University of Brussels in Belgium, and colleagues studied the DNA of queens, workers, males and their sperm from 34 little fire ant nests in French Guyana, expecting to find the typical social insect haplodiploid genetic system. Instead they discovered that queens possessed only maternally derived DNA, and males possessed only paternally derived DNA.¹ Each is effectively a separate genetic lineage; the only sexually produced diploid progeny are sterile workers.

This places males "in an evolutionary dead end," says Fournier. Queens produce gynes (reproductively competent females) clonally, denying males the opportunity to pass on genes. Males are required, however, to produce workers, upon which a queen's own reproductive success depends. In response, males have evolved their own means of clonal reproduction. Fournier and colleagues propose that after fertilization, maternal ...