Table of Contents
International Journal of Evolutionary Biology
Volume 2012, Article ID 593438, 7 pages
Research Article

Noncompetitive Gametic Isolation between Sibling Species of Cricket: A Hypothesized Link between Within-Population Incompatibility and Reproductive Isolation between Species

1Department of Entomology, Kansas State University, 123 W. Waters Hall, Manhattan, KS 66506, USA
2Department of Neurobiology, Physiology and Behavior, University of California, Davis, CA 95616, USA

Received 2 July 2012; Revised 20 October 2012; Accepted 22 October 2012

Academic Editor: Rob Kulathinal

Copyright © 2012 Jeremy L. Marshall and Nicholas DiRienzo. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Postmating, prezygotic phenotypes are a common mechanism of reproductive isolation. Here, we describe the dynamics of a noncompetitive gametic isolation phenotype (namely, the ability of a male to induce a female to lay eggs) in a group of recently diverged crickets that are primarily isolated from each other by this phenotype. We not only show that heterospecific males are less able to induce females to lay eggs but that there are male by female incompatibilities in this phenotype that occur within populations. We also identify a protein in the female reproductive tract that correlates with the number of eggs that she was induced to lay. Functional genetic tests using RNAi confirm that the function of this protein is linked to egg-laying induction. Moreover, the dysfunction of this protein appears to underlie both within-population incompatibilities and between-species divergence—thus suggesting a common genetic pathway underlies both. However, this is only correlative evidence and further research is needed to assess whether or not the same mutations in the same genes underlie variation at both levels.