Honors College Theses

Publication Date



Biology (B.S.B.)

Document Type and Release Option

Thesis (open access)

Faculty Mentor

Dr. J. Scott Harrison


Widow spiders (genus Latrodectus) are well-known for their potent venom. Seven latrotoxin proteins constitute the main components of widow spider venom. The vertebrate specific (α-latrotoxin) and insect specific (α-latroinsectotoxin) latrotoxins have been well-characterized with respect to structure and function. Regulation of latrotoxin gene expression is not well understood but sex and feeding could be factors influencing production. In this study, I used quantitative qPCR to (1) characterize the expression patterns of both the insect and vertebrate specific latrotoxins in male and female brown widow spiders (Latrodectus geometricus) to characterize sex-biased expression and to (2) study expression patterns when female spiders are fed an insect and when fed a vertebrate relative to a starved condition. Sex-biased expression was strong in both genes, with an average of 30-fold higher expression in females. During the feeding experiment, α-latroinsectotoxin was upregulated upon insect feeding and α-latrotoxin expression did not change regardless of the condition.