Date of Award
Frogs of the family Dendrobatidae use alkaloids as a chemical defense against predators. Alkaloids are not manufactured by frogs, but instead sequestered from a diet of arthropods. Alkaloid defenses in dendrobatids differ with geographic location, mainly because arthropod availability varies with location. It has been postulated that alkaloids also function as a defense against microbes and different frog alkaloids might be more/less effective against microbes. We assessed this hypothesis by testing the effectiveness of alkaloids in the dendrobatid frog Oophaga pumilio from five geographic locations in Costa Rica and Panama against different microbes. Alkaloids were tested against the bacteria Escherichia coli and Bacillus subtilis, and the fungus Candida albicans. Optical density assays indicated alkaloids from each location inhibited microbial growth, suggesting alkaloids function as a defense against microbes. Furthermore, there are differences in the degree of microbial inhibition among frog locations, suggesting different frog alkaloids vary in effectiveness against microbes.
Mina, Annemarie, "Geographic variation in alkaloid-based microbial defenses of the strawberry poison frog, Oophaga pumilio" (2014). Senior Honors Projects. 30.