Predation on Florida apple snails (Pomacea paludosa) by native and non-native aquatic fauna, and predator-prey size relationships.

Florida apple snails (Pomacea paludosa) are critical to Florida wetland food webs. Past studies emphasized that large predators consumed relatively large specimens (> 20 mm shells) of these snails. Past studies also identified crayfish, fish, and turtles as predators of hatchling (≈3- 6 mm) and juvenile-sized apple snails, but quantitative relationships between these predators and a range of sizes of apple snails are scant. We identified predators not yet reported in the literature: the Seminole killifish (Fundulus seminolis), bluegill (Lepomis macrochirus), greater siren (Siren lacertina), and non-indigenous Mayan cichlid (Cichlasoma urophthalmus). We quantified the relationship between predator size and maximum snail size consumed for the following predators: crayfish (Procambarus alieni), turtles (Kinostemon bauri and Sternotherus odoratus), and redear sunfish (Lepomis microlophus). Predator size explained 60% to 78% of the variation in prey size eaten (which ranged from 4 to 22 mm shell length). When offered multiple sizes of prey simultaneously, crayfish and turtles ate snails smaller than the maximum size they were capable of consuming. All size classes of apple snails could fall prey to a variety of predators common to Florida wetlands. Understanding apple snail population ecology requires additional studies to quantify predation impacts on juvenile snails from aquatic predators. [ABSTRACT FROM AUTHOR]