The Environmental and Genetic Components of Sex Ratio in Menidia menidia (Pisces: Atherinidae)
Conover DO and Heins S. 1987. The Environmental and Genetic Components of Sex Ratio in Menidia menidia (Pisces: Atherinidae). Copeia. 1987(3):732-743
Comparison of sex ratios among families reared at different temperatures during larval development suggests that environmental sex determination is under the control of major sex determining genes in Menidia menidia. The response of family sex ratio to temperature within mothers was highly dependent on paternity. Moreover, the frequency distribution of family sex ratios within a temperature was multimodal: sex ratios at 15 C tended to be near 0, 0.5, or 1.0; while those at 21 C tended to be near 0, 0.25, or 0.5. The proportion of offspring that had gender determined by temperature within a family tended to be about 0, 0.25, or 0.5. Sex ratio had an inverse curvilinear relation to temperature, rather than the threshold response that has been identified in most of the other vertebrates with temperature-dependent sex determination. Sex ratio declined rapidly as temperature increased from 15-21 C, but less so at higher temperatures. The sex ratio among offspring batches from some isolated pairs of mated fish varied erratically, indicating an additional component of sex ratio variance attributable to non-genetic parental effects, or some form of environmental influence other than temperature. Photoperiod and salinity during development had no effect on sex ratio. Sex determination in M. menidia is apparently intermediate between that of the completely genetic or completely environmental forms of sex determination that have been identified in other lower vertebrates. In relation to the life history pattern of M. menidia, this observation is in accord with the predictions of sex ratio theory.
- Type
- Journal Article
- Authors
- Conover, D; Heins, SW
- Units
- FIIS
- Keywords
- Fish, Genetics, Great South Bay, Menidia, Sex Ratio, Temperature