Emergent patterns between salamander prey and their predators

Abstract

Predator-prey interactions can impose strong selective pressures that scale up to affect the structure and function of communities and ecosystems. Salamanders are prey to a variety of predators that differ in their foraging tactics (e.g., specialists vs. generalists), morphologies, behaviors, and ecologies. Salamanders are an ideal group to explore and quantify patterns that may affect the evolution and persistence of defensive strategies. We examined patterns of predator diversity and body-size relationships of salamander species and their predators by compiling a database of observations documenting predator-prey interactions using natural history notes published in Herpetological Review (1975–2018), Herpetology Notes (2008–2018) and other outside sources. Our database contains 156 salamander predator-prey interactions comprised of 69 salamander species that were preyed upon by 89 predator species. Snakes were the most frequently reported predators (35% of predations reported), followed by salamanders (24%), and birds (16%). We found that snake predators consistently consumed salamander prey that was smaller than themselves, whereas invertebrate predators consumed salamanders across a broader body size range. Snakes are gape-limited predators and unable to eat prey that attain a certain size class, whereas invertebrate predators can use other tactics (e.g., use of venom, chewing mouthparts) to consume prey larger than themselves. These patterns can serve to help generate hypotheses on the evolution of defensive strategies in salamanders.