Test of Predator Avoidance by Larvae of the Blue Ridge Two-lined Salamander (Eurycea wilderae) in Appalachian Streams


Predator avoidance is an important ecological interaction in many communities, enabling prey organisms to avoid potential negative impacts on population structure and fitness. Larval Blue Ridge Two-lined salamanders (Eurycea wilderae) are extremely abundant components of Appalachian streams and fall prey to many types of predators. In order to test the hypothesis that larval E. wilderae actively avoid important predators, we paired them against a variety of predators: Banded Sculpin (Cottus carolinae), Chattahoochee Crayfish (Cambarus howardi), and Spring Salamanders (Gyrinophilus porphyriticus), both adult and larval. We collected Eurycea larvae, crayfish, and Gyrinophilus larvae from a fishless tributary of Hazel Creek, Demorest, Habersham County, Georgia. We collected sculpins from a different, nearby tributary of Hazel Creek. We collected Gyrinophilus adults from Sosebee Cove, Union County, Georgia. We placed each predator in an aerated cage (9.5 x 8.5 x 10 cm) at one end of a 1-m metal trough. A control treatment consisted of an aerated cage without a predator. For each trial, we placed a Eurycea larva in the middle of the trough and observed it every 10 min until the point at which the larva had not moved between two observations. We then measured the distance between the larva and the cage. We ran 18‒20 replicates for each of the five treatments with no larva used more than once. Following trials, we released the larvae and predators back into their respective streams. We used ANOVA to test for differences in mean distance among treatments. We found no significant differences (F4,93 =0.470; P = 0.758). Because of their high densities, perhaps larval E. wilderae do not suffer sufficient predatory pressure from a particular predator to evolve appropriate behavioral responses.


PU Department of Biology

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