Maternal investment in the production of male versus female neonates was approximately equal in most animal species. However, sex allocation theory predicts that under certain conditions, selection may favor the females’ ability to adjust the sex ratio of their offspring, which females tend to use more for an investment of the rare sex. The mechanism of operational sex ratio (OSR) influence on sex allocation is still unclear, and recent studies conducted on lizards have reached conflicting conclusions. Here, we selected a viviparous lizard Eremias multiocellata to test whether pregnant females could adjust the sex ratio of their offspring in response to OSRs. Our results showed that mothers did not adjust the sex ratios or phenotypes of neonates in the laboratory and field-based experiments, except tail length. However, the OSRs subsequently affected growth in both mass and SVL of the offspring in laboratory experiments; whereas only the mass was affected in the semi-nature field experiments. Our results, thus, contradict the predictions of sex allocation theory and challenge the idea that female investment in the scarcity sex might serve as a mechanism which is used for adjusting the population sex ratio.
Do operational sex ratios influence sex allocation in viviparous lizards with temperature-dependent sex determination?J. Evolution. Biol.19:
Roles of diet protein and temperature in the growth and nutritional energetics of juvenile slider turtles, Trachemys scripta.
Modelling exposure to selected temperature during pregnancy: the limitations of squamate viviparity in a cool-climate environment.
Biol. J. Linn. Soc.96:
Gestation temperature affects sexual phenotype, morphology, locomotor performance, and growth of neonatal brown forest skinks, Sphenomorphus indicus.
Biol. J. Linn. Soc.88:
Le GalliardJ.-F.FitzeP.S.CoteJ.MassotM.ClobertJ. (2005):
Female common lizards (Lacerta vivipara) do not adjust their sex-biased investment in relation to the adult sex ratio.
J. Exp. Biol.18:
Effects of gestation temperature on offspring sex and maternal reproduction in a viviparous lizard (Eremias multiocellata) living at high altitude.
J. Therm. Biol.37:
Geographic and annual variation in reproductive cycles in the Tasmanian spotted snow skink, Niveoscincus ocellatus (Squamata: Scincidae).
Aust. J. Zool.47:
Effect of gestation temperature on sexual and morphological phenotypes of offspring in a viviparous lizard, Eremias multiocellata.
J. Therm. Biol.35: