Investigating Potential Toxin Resistance in an Insectivorous Snake
Disciplines
Biology | Zoology
Abstract (300 words maximum)
The Rough Greensnake (Opheodrys aestivus) is a non-venomous colubrid native to North America. They are a harmless species with a diet consisting primarily of insects and other arthropods. Recently, a citizen scientist observed the first record of a wild Rough Greensnake consuming an adult Monarch Butterfly. This is remarkable because these butterflies are chemically defended by cardiac glycosides, toxins that they sequester from milkweed in their diet and that are lethal when ingested by organisms lacking the proper resistance. Cardiac glycoside resistance has evolved through convergent evolution in several animals (e.g., some snakes, including those that are dietary specialists upon toads that produce bufadienolide toxins) and occurs through a series of well-characterized amino acid substitutions in the genes that code for Na+/K+-ATPase. However, potential resistance has never been characterized in the Rough Greensnake. Since the toad and monarch toxins are similar, and because some snakes have a resistance to the toad toxins, there stands a possibility that some may also be capable of consuming Monarch Butterflies. To evaluate if the Monarch Butterfly is toxic to the Rough Greensnake, we conducted a polymerase chain reaction to amplify copies of ATP1A1 and ATP1A3 from a Rough Greensnake collected near the citizen science record. We then sequenced these amplicons and screened them for common amino acid substitutions known to confer resistance to cardiac glycosides. Our results contribute to a broader understanding of the evolution of toxin resistance among diverse vertebrate groups.
Academic department under which the project should be listed
CSM - Environmental Science
Primary Investigator (PI) Name
Todd Pierson
Investigating Potential Toxin Resistance in an Insectivorous Snake
The Rough Greensnake (Opheodrys aestivus) is a non-venomous colubrid native to North America. They are a harmless species with a diet consisting primarily of insects and other arthropods. Recently, a citizen scientist observed the first record of a wild Rough Greensnake consuming an adult Monarch Butterfly. This is remarkable because these butterflies are chemically defended by cardiac glycosides, toxins that they sequester from milkweed in their diet and that are lethal when ingested by organisms lacking the proper resistance. Cardiac glycoside resistance has evolved through convergent evolution in several animals (e.g., some snakes, including those that are dietary specialists upon toads that produce bufadienolide toxins) and occurs through a series of well-characterized amino acid substitutions in the genes that code for Na+/K+-ATPase. However, potential resistance has never been characterized in the Rough Greensnake. Since the toad and monarch toxins are similar, and because some snakes have a resistance to the toad toxins, there stands a possibility that some may also be capable of consuming Monarch Butterflies. To evaluate if the Monarch Butterfly is toxic to the Rough Greensnake, we conducted a polymerase chain reaction to amplify copies of ATP1A1 and ATP1A3 from a Rough Greensnake collected near the citizen science record. We then sequenced these amplicons and screened them for common amino acid substitutions known to confer resistance to cardiac glycosides. Our results contribute to a broader understanding of the evolution of toxin resistance among diverse vertebrate groups.