Effects of newt chemical cues on the distribution and foraging behavior of stream macroinvertebrates

摘要: Many amphibians possess noxious or toxic substances for self defense. These compounds have been characterized largely as chemical defenses, but may promote ecological and evolutionary processes. The California newt, Tarichatorosa, possesses a potent neurotoxin, tetrodotoxin (TTX), which serves defense, cue to conspecifics, selection pressure that has selected evolved resistance in predator. However, the potential effects of TTX upon broader community on behavior, general, overlooked. Field assays conducted during newt breeding season indicate macroinvertebrate responds adult cues by altering foraging behavior. In these assays, significantly fewer macroinvertebrates were found experimental areas with enclosed newts relative enclosures non-predatory amphibian. Laboratory bioassays showed dragonfly nymphs (Anax junius) reduced predatory behavior moved less presence cues. When exposed TTX, nymph mean angular velocities four fold velocity magnitude was threefold controls. Overall, results support hypothesis stimuli from predators, specifically, can shape species interactions at lower trophic levels potentially affect organization.