Date of Award

12-6-2019

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

School of Biological Sciences

First Advisor

Ben M. Sadd

Second Advisor

Scott K. Sakaluk

Abstract

Sexually antagonistic coevolution should lead to the rapid divergence of male and female genotypes related to the effects of ejaculatory substances on female physiology. Hence, the outcome of mating should depend on an interaction between male and female genotypes. Although mating has been shown to influence female immune responses in diverse insect taxa, a male-female genotype-by-genotype effect on female immunity post-mating remains largely unexplored. Here, we investigate both the effects of mating on female immunity and the potential for a male-by-female genotype interaction on the form and magnitude of this response in decorated crickets. Females from three distinct genotypic backgrounds were either left unmated or singly mated in a fully reciprocal design to males from the same three genotypic backgrounds. Female cellular immunity was assayed by quantifying circulating hemocytes and the presence of hemocyte microaggregations. Humoral immunity was assessed by measuring total phenoloxidase activity, an enzyme involved in melanization, and general antibacterial activity. Mated females exhibited a higher incidence of microaggregations than virgin females, indicative of a general response to mating. We also found evidence for a male-female genotype-by-genotype interaction on cellular immune measures. Specifically, the number of circulating hemocytes in mated females was contingent on an interaction between her genotype and that of her mate, and a trend of similar interaction emerged in the incidence of microaggregations. These results suggest that the ejaculates of males of different lines have diverged with respect to their effect on female immunity, and similarly, that females differ in their susceptibility to these compounds.

Comments

Imported from ProQuest Hampton_ilstu_0092N_11608.pdf

DOI

http://doi.org/10.30707/ETD2020.Hampton.K

Page Count

44

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