When is sex environmentally determined?
Abstract
THERE are several sex determining mechanisms which produce two sexes in a population (dioecy or gonochorism)1-5. In many of these, the offspring's sex is determined at or before conception, as in male or female heterogamety. In several organisms, however, the offspring's sex is determined later than conception, by some environmental influence upon the offspring. We consider here why these environmental mechanisms have been maintained; that is, why have they not been replaced with an alternative system that determines sex at conception? We propose that labile sex determination (not fixed at conception) is favoured by natural selection when an individual's fitness (as a male or female) is strongly influenced by environmental conditions and where the individual has little control over which environment it will experience. Our argument also applies to sex expression in hermaphrodites6,7.
- Publication:
-
Nature
- Pub Date:
- April 1977
- DOI:
- 10.1038/266828a0
- Bibcode:
- 1977Natur.266..828C