Ten snakes, ten venoms: functional variation in prey resistance to venoms of individual rattlesnakes within a single population
Tomonori, Kodama
Graduate school of Science
Research Center for Biosystematics and Evolution
Research Organization of Life Sciences
Kyoto University
Sakyo Ward, Kyoto, Japan
Hanscom, Ryan
Department of Biology
San Diego State University
San Diego California USA
Department of Biology
University of California
Riverside, California USA
Clark, Rulon W.
Vallabhaneni, Harshita
Tobin, Ranya
Department of Biology
San Diego State University
San Diego California USA
Venom is a complex molecular phenotype with large variation in composition and function at both inter- and intra-specific levels. While previous studies have primarily focused on inter-specific and inter-population variations, few have examined the functional variation among individual snakes within a single population. To better understand the mechanisms maintaining intraspecific variation in snake venom, assessing the functional importance of individual-level variation is essential. In this study, we investigated inter-individual variation in activity of venom challenged with prey sera among individual Prairie Rattlesnakes (Crotalus viridis) at the Marathon grasslands reserve in western Texas. Venom samples were collected from each snake, and blood sera were obtained from eight sympatric mammalian prey species, including the Hispid Pocket Mouse, Merriam’s Kangaroo Rat, Ord’s Kangaroo Rat, White-footed Deer Mouse, North American Deer Mouse, Southern Plains Woodrat, Plains Pocket Mouse, and Chihuahuan Grasshopper Mouse. A serum-based metalloproteinase inhibition assay was performed to assess the potential inhibition of proteolytic activity for each snake’s venom in combination with the sera from each prey species. Results revealed considerable differences in prey specificity of metalloproteinase activity across individual snakes; some snakes exhibited up to ca. twice the activity against a specific prey species compared to others. Furthermore, the prey species most susceptible to venom varied among individual snakes. We will discuss the evolutionary and ecological implications of these findings.