Males as somatic investment in a parthenogenetic nematode

Mysterious males In parthenogenetic species, females produce female offspring, generally without the input of males. Given this, the production of males would seem to be a waste of resources. Grosmaire et al. report that in a particular soil nematode, males are regularly produced at a rate of about 9%. They found that the male sperm was required for egg activation, yet the sperm DNA never transmitted on to the subsequent female generation. Provided that male DNA is preferentially passed on through sibling mating, male production is evolutionarily stable. Science , this issue p. 1210