A long-standing theory in evolutionary biology is that venomous predators, such as rattlesnakes, often develop complex venoms to fix the widest variety of prey. The more ecologically diverse the place, the more likely the native rattlesnake will be characterized by a deadly blood toxin stew designed to prevent prey from escaping, destroying blood clotting and breaking down tissue. However, recent fieldwork in herds of islands in the Gulf of California appears to challenge this broad assumption. According to a survey published in the journal on April 23rd, evolutionsome vipers produce poisons containing less focused toxins, despite living in very diverse environments.
Researchers from the University of South Florida’s Faculty of Integrated Biology recently jumped on 11 deserted islands in the Gulf of California. We jumped into a vast cove between the state of Baja, Mexico and the coast of the country’s northwest mainland. While there, a team led by Assistant Professor Mark Margres camped along the beach, waiting until dusk for enough cooling for rattlesnakes to appear. Eventually, Margre and his colleagues gathered venom from a 83 rattlesnake that was four feet long.
Covered collection cups. It was then safely released on the original capture site. Credit: Ricardo
Ramirez Chaparo Jacobo Reyes Velasco
“The Baja California Islands are pristine and barely touched on human activity, making them an extraordinary place for studying isolated evolutionary processes.” said in a statement.
Like many evolutionary biologists, Margres and Hearst hypothesized that biodiversity on the larger island would result in more complex rattle poisons.
“But we found the opposite pattern,” Hurst said.
Subsequent analysis of the Dogmaki revealed that islands with more competition and space are home to more specialized rattlesnake toxins. This led researchers to theorize that when competition decreases, toxic predators could actually evolve formulations that are more suitable for certain prey. New revelation may soon help experts to better understand how species evolve in increasingly fragmented natural environments.
Analyses at the University of South Chemical Cleansing Analysis and Screening (CPAS) Core Facility
Florida (USF). Photo credit: Ricardo Mirez Chaparo Jacobo Reyes Velasco
“Habitat fragmentation is like falling apart in a finished puzzle. A healthy, unharmed ecosystem is like a 1,000-piece puzzle with all the pieces in place. You can see the big picture clearly,” says Margres. “But when you start fragmenting it, if the pieces are missing or repositioned, the image is distorted. That distortion represents a disruption to ecosystem function.”
The meaning of this study goes beyond the pristine wilderness remaining at the end of the Earth. Unprecedented changes in humanity to ecosystems around the world have over the millions of years of evolution of countless species. By reducing biodiversity, humans are not only changing population numbers and food chains, but also forcing species like rattles to adapt at the molecular level.
As they move forward, Margres’ team hopes to continue exploring how the island’s systems affect habitat fragmentation and genetic diversity. They will also be testing how well existing antivenom works with rattlesnake venom collected from Vipers in the Gulf of California.
“This isn’t just rattlesnakes, it’s about understanding the basic ways in which life evolves when isolation and biodiversity begins to change,” Margres says.
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