earticle

영어

Body size is an important issue in ecological studies because it affects not only the structure and dynamics of food webs but also the spatial distribution and life history traits of animals. Previous studies have showed that body size of animals varies along latitudes and altitudes (i.e. Bergmann’s rule), but the patterns in ectotherms (e.g. amphibians and reptiles) show ambiguous results and thus deserve further attention. I investigated the body size variation of three ranid frogs and revealed possible mechanism causing the differences. I sampled frogs from different altitudes (low: 0-800 m, mid: 1000-1800, and high: >2000 m), measured body length and clipped a toe for skeletochronology which revealed the life-history traits of each individual. Results showed that in R. latouhii (distributes 151-1130 m), there was no significant difference of body size and life-history traits along altitude gradients. However, the body size of R. swinhoana (distributes 151-1797 m) increased with altitude, which fits the Bergmann’s rule. In this species, age is the main factors affecting body size. On the other hand, the male and female R. sauteri (distributes 408-2546 m) showed different body size patterns. Body size of males and females showed negative and no correlation with altitudes, respectively, and the different patterns can be explained by the growth rate and sex-specific longevity. Overall, results indicate body size variation along altitudes varied among species, which can probably be explained by the species or sex-specific life history traits. A model with ultimate and proximate mechanisms has been proposed to explain body size variation of animals across altitudes and even latitudes