SEXUAL SIZE DIMORPHISM AND FEEDING ECOLOGY OF COMMON GREEN FROGS (Hylarana erythraea) IN PHU LOC, THUA THIEN HUE PROVINCE

Abstract

The Common Green Frog, Hylarana erythraea (Schlegel, 1837), is an important species in both terrestrial and aquatic ecosystems. However, information on sexual size dimorphism (SSD) and the feeding ecology of this species in Vietnam is currently lacking. We used the stomach-flushing method to obtain food items from 223 stomach specimens. The results showed that the average snout-vent length was significantly larger in adult females than in adult males, with an SSD index of 0.57. The most important prey categories of H. erythraea were Coleoptera, unidentified insect larvae, Odonata, Orthoptera, and Araneae (occurrence frequency 65.45 %, representing 65.89 % of the number of items, and 81.04 % of the total volume). The mouth width and snout-vent length had significant effects on the prey size and on the volume of food items. However, air temperature and relative humidity did not have significant effects on the prey volume or size of individual food items. These results supported the hypothesis that “the mouth size is the limiting factor on the food size” in anuran species.