Penetrance of symbiont-mediated parthenogenesis is driven by reproductive rate in a parasitoid wasp

Department of Entomology, University of California, Riverside, Riverside, California, United States
DOI
10.7287/peerj.preprints.2943v1
Subject Areas
Ecology, Entomology, Evolutionary Studies, Microbiology
Keywords
Wolbachia, Trichogramma, reproductive modification, asexual, sex ratio, symbiosis
Copyright
© 2017 Lindsey et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
Cite this article
Lindsey ARI, Stouthamer R. 2017. Penetrance of symbiont-mediated parthenogenesis is driven by reproductive rate in a parasitoid wasp. PeerJ Preprints 5:e2943v1

Abstract

Trichogramma wasps are tiny parasitoids of lepidopteran eggs, used extensively for biological control. They are often infected with the bacterial symbiont Wolbachia, which converts Trichogramma to an asexual mode of reproduction, whereby females develop from unfertilized eggs. However, this Wolbachia-induced parthenogenesis is not always complete, and previous studies have noted that infected females will produce occasional males. The conditions that reduce penetrance of the parthenogenesis phenotype are not well understood. We hypothesize that more ecologically relevant conditions of limited host access will sustain female-biased sex ratios. By restricting access to host eggs, we see a strong relationship between reproductive rate and sex ratio. We show that reproductive output in the first 24 hours is critical to the total sex ratio of the entire brood, and limiting oviposition in that period results in near-complete parthenogenesis that can be sustained for long periods, without any significant impact on total fecundity. Our data suggest that this phenomenon may be due to the depletion of Wolbachia when oviposition occurs relatively constantly, and that Wolbachia titers may recover when offspring production is limited. In addition to the potential to improve mass rearing of Trichogramma for biological control, findings from this study help elucidate the context dependent nature of a pervasive symbiotic relationship.

Author Comment

This is a submission to PeerJ for review.

Supplemental Information

Raw data for offspring counts and qPCR ct values

DOI: 10.7287/peerj.preprints.2943v1/supp-1

Metadata for raw_data.xlsx

DOI: 10.7287/peerj.preprints.2943v1/supp-2