Do Covariances between Maternal Behavior and Embryonic Physiology Drive Sex-Ratio Evolution under Environmental Sex Determination?

Fredric J. Janzen, David M. Delaney, Timothy S. Mitchell, Daniel A. Warner

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Fisherian sex-ratio theory predicts sexual species should have a balanced primary sex ratio. However, organisms with environmental sex determination (ESD) are particularly vulnerable to experiencing skewed sex ratios when environmental conditions vary. Theoretical work has modeled sex-ratio dynamics for animals with ESD with regard to 2 traits predicted to be responsive to sex-ratio selection: 1) maternal oviposition behavior and 2) sensitivity of embryonic sex determination to environmental conditions, and much research has since focused on how these traits influence offspring sex ratios. However, relatively few studies have provided estimates of univariate quantitative genetic parameters for these 2 traits, and the existence of phenotypic or genetic covariances among these traits has not been assessed. Here, we leverage studies on 3 species of reptiles (2 turtle species and a lizard) with temperature-dependent sex determination (TSD) to assess phenotypic covariances between measures of maternal oviposition behavior and thermal sensitivity of the sex-determining pathway. These studies quantified maternal behaviors that relate to nest temperature and sex ratio of offspring incubated under controlled conditions. A positive covariance between these traits would enhance the efficiency of sex-ratio selection when primary sex ratio is unbalanced. However, we detected no such covariance between measures of these categories of traits in the 3 study species. These results suggest that maternal oviposition behavior and thermal sensitivity of sex determination in embryos might evolve independently. Such information is critical to understand how animals with TSD will respond to rapidly changing environments that induce sex-ratio selection.

Original languageEnglish (US)
Article numberesz021
Pages (from-to)411-421
Number of pages11
JournalJournal of Heredity
Volume110
Issue number4
DOIs
StatePublished - Jul 1 2019

Bibliographical note

Publisher Copyright:
© 2019 The American Genetic Association . All rights reserved.

Keywords

  • environmental change
  • microevolution
  • nesting behavior
  • pivotal temperature
  • quantitative genetics
  • reptile

Fingerprint

Dive into the research topics of 'Do Covariances between Maternal Behavior and Embryonic Physiology Drive Sex-Ratio Evolution under Environmental Sex Determination?'. Together they form a unique fingerprint.

Cite this