Behavioral Ecology and Sociobiology

, Volume 56, Issue 3, pp 270–278

The impact of behavioral and physiological maternal effects on offspring sex ratio in the common snapping turtle, Chelydra serpentina

Authors

  • Justin R. St. Juliana
    • Department of Animal EcologyIowa State University
    • Jacob Blaustein Institute for Desert ResearchBen-Gurion University of the Negev
  • Rachel M. Bowden
    • Department of Ecology, Evolution and Organismal BiologyIowa State University
    • Department of Biological SciencesIllinois State University
    • Department of Ecology, Evolution and Organismal BiologyIowa State University
Original Article

DOI: 10.1007/s00265-004-0772-y

Cite this article as:
St. Juliana, J.R., Bowden, R.M. & Janzen, F.J. Behav Ecol Sociobiol (2004) 56: 270. doi:10.1007/s00265-004-0772-y

Abstract

Theory suggests that maternal effects are especially important in organisms with environmentally-sensitive sex-determining mechanisms. However, there is no substantive body of empirical evidence to confirm this conjecture. We integrated field and laboratory studies to jointly evaluate the significance of behavioral (nest-site choice) and physiological (yolk hormone allocation) maternal effects on offspring sex ratio in the common snapping turtle (Chelydra serpentina), a species with temperature-dependent sex determination (TSD). Of the 16 microhabitat variables measured, only three (south, east, and total overstory vegetation cover) were significantly correlated with nest temperature: cooler nests were located under more vegetation cover. In turn, these microhabitat predictors of nest temperature, and nest temperature itself, may influence nest sex ratio: shadier, cooler nests were more likely to produce a higher proportion of male offspring than less shady, warmer nests. Analysis of eggs from these same nests incubated in a common garden design in the laboratory revealed that clutch sex ratio was unaffected by levels of yolk estradiol, yolk testosterone, or their interaction. Examination of both behavioral and physiological maternal effects revealed no concordant impact on offspring sex ratio. However, eggs from nests that produced male-biased sex ratios in the field yielded higher proportions of males under constant-temperature conditions in the laboratory. Our study confirms the importance of behavioral maternal effects in nature on offspring sex ratios in species with TSD, while also revealing the potential presence of a predisposition for sex-ratio production underlying TSD in this system.

Keywords

Environmental sex determinationMaternal effectsNest-site choiceTemperatureYolk hormones

Copyright information

© Springer-Verlag 2004