Diet of Larval Red Salamanders (Pseudotriton rubber) Examined Using a Nonlethal Technique

Stream salamanders may play important roles as predators within streams, but we know little about actual predation by stream salamanders on other organisms. Because larval stream salamanders are more abundant within streams than adults, feed and forage throughout the year, and may spend multiple years in streams before transformation, larvae may play a more important role than adults in trophic
interactions within streams. We conducted a study using larval Red Salamanders (Pseudotriton ruber) to determine (1) the prey composition of larval salamanders, (2) whether feeding rates are affected by stream water temperature, (3) whether larval size affects the diversity of prey items, and (4) whether nonlethal stomach flushing is an effective technique for examining the diet of larval salamanders. We found that larvae
consumed a wide diversity of prey items including individuals of the families Chironomidae (36.52% of prey items) and Sphaeriidae (15.17%) as well as terrestrial prey (7.87%) and other salamanders (2.25%). We also found that feeding rates were negatively correlated with stream water temperature, and larger larvae consumed a wider diversity of prey items than smaller individuals. Our results also suggest that nonlethal stomach flushing did not affect survivorship. These findings suggest that larval Red Salamanders are generalist predators that can play important trophic roles in stream ecosystems.
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Abstract/Description: Stream salamanders may play important roles as predators within streams, but we know little about actual predation by stream salamanders on other organisms. Because larval stream salamanders are more abundant within streams than adults, feed and forage throughout the year, and may spend multiple years in streams before transformation, larvae may play a more important role than adults in trophic interactions within streams. We conducted a study using larval Red Salamanders (Pseudotriton ruber) to determine (1) the prey composition of larval salamanders, (2) whether feeding rates are affected by stream water temperature, (3) whether larval size affects the diversity of prey items, and (4) whether nonlethal stomach flushing is an effective technique for examining the diet of larval salamanders. We found that larvae consumed a wide diversity of prey items including individuals of the families Chironomidae (36.52% of prey items) and Sphaeriidae (15.17%) as well as terrestrial prey (7.87%) and other salamanders (2.25%). We also found that feeding rates were negatively correlated with stream water temperature, and larger larvae consumed a wider diversity of prey items than smaller individuals. Our results also suggest that nonlethal stomach flushing did not affect survivorship. These findings suggest that larval Red Salamanders are generalist predators that can play important trophic roles in stream ecosystems.
Subject(s): herpetology