In C. elegans
, the two sexes are hermaphrodites and males. Hermaphrodites can either reproduce by virtue of self-fertilization or they can mate with a male and use the male derived sperm to fertilize their eggs. While virtually the entire progeny that is produced by self-fertilization is hermaphroditic, half of the cross-progeny is male.
We and many others have noticed that males disappear from laboratory cultures of some wild isolates of C. elegans
while they persist in others (Fig. 1). In collaboration with Hinrich Schulenburg
at the University of Kiel, we address the questions what might cause these differences in male maintenance and under what circumstances out-crossing or self-fertilization might be favored.