Abundance and Diet in the Frogs, Rana latouchii, at Nanjen Lake, Taiwan

Ping-Chun Lucy Hou, Yi-Ju Shih, Jao-Jinn Jong, and Meng-Shiann Juang

Department of Biology, National Cheng Kung University

Tainan, Taiwan, R.O.C.

Abstract

Rana latouchii accounts for over 40% of the observed amphibians in Nanjen Lake of Nanjenshan Reserved Area, which is the LTER site in southern Taiwan. In order to understand the role of this species in the food web of Nanjenshan forest, we estimated population abundance and analyzed diet of Rana latouchii in Nanjen Lake. We marked and recaptured frogs from a shallow ditch at least one night per month from August 1996 through July 1998. Population abundance was estimated using Jolly-Seber model A for each sampling period by the computer program JOLLY. We also flushed stomachs of at least 5 frogs each month from August 1997 through July 1998 to analyze their contents. Total of 852 frogs were marked and released during the study periods, and 44% of them were recaptured. The number of frogs captured varied greatly between months. The estimated numbers of frogs ranged from 150 to 1000 with the highest number occurred in November and December 1997. This could result from immigration of breeding males to the population. Adult Rana latouchii preyed on diverse types of food, including 7 Classes of animals. The most frequently preyed items were ants and spiders.