Predation on Green Frog eggs (Rana clamitans) by Ostracoda
Predation has long been known as a structuring force of larval amphibian assemblages with aquatic vertebrates and insect larvae being noted as important predators. However, no studies report predation by micro-predators (i.e., organisms less than one half the size of amphibian eggs) on eggs or larvae. Here we report the consumption of Green Frog (Rana clamitans) eggs by at least four species of the crustacean class Ostracoda (Dolerocypris sinensis, Cypridopsis vidua, Eucypris fuscatus, Physocypria sp.). We initially observed Green Frog egg consumption in microcosms containing sediment from stormwater management ponds. We subsequently conducted feeding studies in which we manipulated densities of three of the species and recorded time to complete consumption of a single egg. Ostracods often consumed eggs in three days (before eggs hatched), but did not appear to attack tadpoles in the microcosms. Overall density of ostracods was correlated with egg mortality in the microcosms and Eucypris fuscatus consumed eggs most efficiently during feeding trials. Because one of the ostracods we observed feeding on amphibian eggs (C. vidua) is common among temporary wetlands, and one (D. sinensis) represents the first reported occurrence of the species in North America, there is a need for further investigations of ostracod predation on amphibian eggs under field conditions.
Gray, Evan P., Schyler Nunziata, Joel W. Snodgrass, David R. Ownby, and John E. Havel. "Predation on Green Frog Eggs (Rana clamitans) by Ostracoda." Copeia 2010, no. 3 (2010): 452-456.