Feeding and Activity Patterns in the Salamander Desmognathus ochrophaeus (Amphibia, Urodela, Plethodontidae)

Abstract

The feeding and activity patterns of D. ochrophaeus were studied near the northwestern limit of its geographic range to determine the main factors influencing feeding. Salamanders were less active and ingested less prey when the temperature was low (5.degree.-0.degree. C), and they remained in subterranean refugia when the minimum daily temperature was below 0.degree. C. The specific habitat was an important determinant of feeding activity; salamanders inhabiting seepage banks initiated activity and feeding earlier in the spring and remained active later in the fall than streamside salamanders. Feeding success of salamanders in seepage banks showed no consistent correlation with either temperature or precipitation, but in streamside habitat feeding success was positively correlated with precipitation. For the entire study period diets were qualitatively similar in the 2 habitats, although there were important time-specific differences. Feeding success was consistently dependent on a moist substrate. Oligochaetes and dipteran larvae were the major prey consumed by salamanders in both habitats, although diets were more variable and diverse in streamside salamanders. The quantity of prey ingested was highly variable and showed greatest variability when conditions for feeding were most favorable. It is suggested that the high variability in feeding under favorable habitat conditions results because the salamanders do not actively forage but eat only nearby prey; large quantities of prey are thus ingested infrequently. The physical habitat is limiting on D. ochrophaeus by prohibiting foraging activity or by restricting prey availability.