Effects of Latitude, Season, Elevation, and Microhabitat on Field Body Temperatures of Neotropical and Temperate Zone Salamanders

Abstract

We analyzed field body temperatures of neotropical salamanders (Feder et al. 1982b) to examine existing generalizations about salamander thermal ecology, which have been based almost entirely upon data for temperate zone species. Our findings can be summarized as follows: 1) Behavioral thermoregulation in the field is evidently uncommon among the vast majority of tropical and temperate salamander species. Body temperatures of tropical salamanders closely parallel seasonal and altitudinal changes in the thermal environment. 2) Body temperatures of salamanders show a complex relationship with latitude. Temperate zone species experience lower minimum temperatures than neotropical salamanders, but there are no consistent latitudinal trends in maximum body temperatures. Tropical plethodontids and ambysto- matids show similar rates of decline in mean body temperature with increasing elevation, but am- bystomatid temperatures are significantly warmer than plethodontid temperatures at the same ele- vation. 3) Variation in body temperature is greater seasonally for temperate salamanders than tropical salamanders. At a given time or locality, however, variation in field body temperature among members of a population is similar for tropical and temperate salamanders. 4) Interspecific thermal differences are not evident in sympatric species of tropical salamanders, and therefore may not serve as a means of niche segregation in tropical salamander communities. These latitudinal and phylogenetic differences in thermal ecology correspond to aspects of the morphology, life history, energetic, and physiological capacities of salamanders.