How Common Are Meiotically Driving Sex Chromosomes in Insects?

Abstract

Sex chromosome meiotic drive, the transmission of one of the sex chromosomes to greater than half of the progeny, is a phenomenon frequently observed within the Diptera. First recorded within the obscura group of Drosophila, it has now also been observed in the melanica, tripunctata, testacea, melanogaster, and quinaria groups of this genus. Outside of Drosophila, there are records from two mosquitoes (Aedes and Culex) and from sciarid flies and diopsids (stalk-eyed flies; Jaenike 1996) (Presgraves et al. 1997). Jaenike (1996) found that out of a random sample of nine species of Drosophila, five bore meiotically driving sex chromosomes. This growing number of records within the Diptera has led to the suggestion that sex chromosome meiotic drive may in fact be common within insects (Hurst and Hurst 1996). If this is true, meiotic drive may be an important force in insect evolution, including the evolution of sex determination mechanisms, sexual selection, and speciation (Hurst et al. 1996; Wilkinson et al. 1998). We argue here that the conclusion that sex chromosome meiotic drive is common in insects outside of the Diptera is premature. Possible cases of sex chromosome meiotic drive in other insect orders, particularly the Lepidoptera, have been included in previous reviews (Hurst and Pomiankowski 1991). However, none of these cases is proven. Indeed, recent studies suggest caution over the conclusion