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영어

Although frogs are known to be important hosts for leeches, very few related studies have been conducted in South Korea. To investigate ecological characteristics of leech ectoparasitism on mountain frogs (Rana dybowskii and Rana huanrenensis) and to test if a leech infection rate (number of leeches per frog) is affected by temperature fluctuation in water pools, we have investigated 46 water pools in four different valleys within Odaesan National Park in the spring of 2010. According to morphological characteristics, we classified the collected leeches into Parabdella quadrioculata or Torix tagoi. Rana dybowskii (92%, 86 out of 94 frogs) was more infected by leeches than R. huanrenensis (88%, 77 out of 89 frogs) was. The sex, amplexus status, and condition factor (body mass/ snout-vent length) of frogs did not affect the infection rate. Among eight environmental factors, pH and DO in water pools, shortest distance to mountain from the pools, and size of the pools negatively affected the leech infection rate. We did not find any evidence that temperature fluctuation in water pools affects the leech infection rate. The leech infection rate was significantly different among valleys and specially the rate was the lowest in Gujiri valley. Considering that mountain frogs were greatly infected by leeches, leeches may increase the mortality of larval and adult frogs in wild.