Butterflies evolve to thwart male killers

时间:2019-03-01 04:16:00166网络整理admin

By Bob Holmes A BACTERIUM that slaughters the male offspring of its insect hosts has now provided a clear example of natural selection in action. The male-killing bacterium is a strain of Wolbachia, a widespread species that passes from one generation to the next in eggs but not sperm. Wolbachia strains infect an estimated 20 per cent of all insect species. Since males represent a dead end for the bacteria, they have evolved a variety of tricks to favour the females of their host species, including converting males into females,