image: A large Totonacan Rattlesnake (Crotalus totonacus) uses its tongue to sample the air in the mountains of Tamaulipas, Mexico. view more
Credit: Image credit: Jason M. Jones
Pitviper species that consume more evolutionarily diverse prey appear to produce more complex venom, according to a study. The complexity of a snake's venom, reflected in the multiple proteins found in venom, varies among species. Matthew Holding and colleagues investigated the evolutionary factors that drive this variation by examining the venoms and diets of multiple species of North American pitvipers, including rattlesnakes and copperheads. The authors characterized the protein composition and genetic transcripts found in venom glands. Next, the authors compared venom complexity with the species' diets, as measured by stomach contents previously reported in the literature. Snakes that consumed prey species farther apart from each other on a phylogenetic tree appeared to produce more complex venoms. The quantity of species consumed did not affect complexity; rather, the evolutionary distance between the consumed prey species appeared to influence venom complexity. The authors suggest that venom complexity is likely driven by subtle differences in venom targets, such as blood coagulation factors, between related but evolutionarily separated species. According to the authors, the phylogenetic diversity of an ecological community, as opposed to its species richness, plays a large role in shaping the complex traits of its members.
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Article #20-15579: "Phylogenetically diverse diets favor more complex venoms in North American pitvipers," by Matthew L. Holding et al.
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Journal
Proceedings of the National Academy of Sciences