Term of Award

Spring 2022

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (open access)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Department of Biology

Committee Chair

Josh Gibson

Committee Member 1

Lance McBrayer

Committee Member 2

Scott Harrison

Abstract

Nasonia is a parasitoid wasp genus that serves as an emerging model for studying speciation due to an incompatibility between nuclear and mitochondrial genomes between sister taxa. Short generation times, easy rearing in a lab setting, producing large amounts of progeny, and whole genome sequencing make Nasonia is an excellent candidate for studying incomplete reproductive isolation. Nasonia have five chromosomes and exhibit haplo-diploid sex determination in which fertilized eggs develop into diploid females and unfertilized eggs develop into haploid males. Recessive phenotypes are hidden in diploid females but are laid bare in haploid males as there is no interaction between alleles. F2 male hybrids of Nasonia vitripennis and Nasonia giraulti experience high rates of mortality during development as compared to parent strains. Previous research has shown that 96% of F2 males with an incompatible allele on chromosome 5 combined with N. giraulti maternity die. F1 females experience low mortality in comparison to the high mortality that their sons, F2 males, experience. Large differences in mortality between F1 females and F2 males can be further investigated by studying F2 backcross females. I hypothesized that F1 females and F2 backcrossed heterozygous females experience similar levels of incompatibility to one another at the mortality locus as well as F2 backcrossed homozygous females and F2 males. I predicted that F2 backcross females would have intermediate mortality overall as compared to F1 females and F2 males. To test this, I conducted mortality experiments to determine differences in egg to adult survival between parent species, F2 males, and backcrossed F2 females. I found that F2 hybrids suffered greater mortality than both parent species. Egg to adult mortality was similar between F2 males and F2 females. Adult F2 females survived more than adult F2 males, but sexes were not significantly different. I also found that F1 hybrids laid significantly fewer eggs than both parent species. However, F2 backcrossed females survive much less than previously expected and suffer similar mortality to F2 males. My findings therefore indicate that there must be other interactions on the recombinant F2 backcrossed chromosome contributing to mortality in these individuals.

Research Data and Supplementary Material

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