Honors Theses

Date of Award


Document Type

Undergraduate Thesis

Degree Name




Faculty Mentor

Jason L. Strickland


Jonathan H. Perez, Jeremiah A. Henning


Phenotypic variation is a common occurrence throughout the animal kingdom and can occur both interspecifically and intraspecifically. Interspecific variation evolves in response to differential selection between species whereas intraspecific variation is commonly expressed as sex-based or population-based differences. Both interspecific and intraspecific phenotypic differences occur frequently in venomous species including arachnids, and can often result in differences in venom yield, potency, and protein. The North American tarantulas (Theraphosidae: Aphonopelma), include approximately 35 species and little is known about their venom. To test for interspecific and intraspecific venom variation, we collected individuals from three species and generated proteomic profiles and Illumina venom gland RNA-seq libraries for 62 total individuals. These represent the first venom protein profile and venom gland transcriptome for A. hentzi (Texas Brown Tarantula), A. anax (Texas Tan Tarantula), and A. gabeli (Chihuhuan Grey Tarantula). We found both transcriptomic and proteomic evidence of interspecific differences. Specifically, we found similar toxin families between the species, but differences in the relative abundance of the families and differences in expression of individual transcripts. Furthermore, we found transcriptomic and proteomic evidence of sex-based venom variation in two of the species, A. gabeli and A. anax. Overall, toxin family identification was difficult as there were very few known toxin sequences for comparison for the family Theraphosidae. The general lack of knowledge on the ecology, and especially the venom, of these organisms underscores the necessity of this project.


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