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DIVERSITY OF AMPHIBIAN FAUNA AND THEIR ROLE IN BIOLOGICAL CONTROL OF INSECT PESTS AT CAUVERY DELTA REGIONS OF TAMIL NADU

A. Veeramani*, B. Kumaresan

Amphibians are mostly habitat specific and are highly sensitive vertebrates. So, these are called indicator species of environment and also, they play an important role in ecological cycle of the agricultural fields because they feed on insects, including many pest species of agricultural crops. They are also important food sources for many larger animals such as water birds, mammals, reptiles, and even spiders and larger insects. The amphibian fauna of the Cauvery delta region is less explored as compared to other regions like the Western Ghats range. The Cauvery belt regions has variety of crop pattern such as paddy, Cotton, sugar cane, maize, plantain, black gram, groundnut, etc. provides the ideal environment and habitats for the occurrence of amphibians. Apart from that there are natural and artificial wetlands such as ponds, pools, rivers tributaries of river Cauvery and few lakes. Such habitats are well attracted to amphibian species and may use of various purposes such as food, breeding and home ground etc. Changing of crop pattern, road kills, conversion of cultivable lands and urbanization are seriously affecting the diversity of amphibian fauna directly and indirectly. The amphibians are playing an important role of act as an agent for biological control of insect pests at cultivable lands and controlling larvae during its tadpole stage. Little studies has been initiated so far the amphibians in the study area. The Road transect method was applied for the estimation of abundance of amphibians. All Anurans species were recorded by direct sighting method and also by recording the calls from the concerned species. Dead or road killed specimens of amphibians were collected for examine the gut content to know the food remains. A total of 212 individuals of amphibians belonging to 10 species, 7 genera and 4 families were recorded from different areas of the study area. This forms the first scientific document of the amphibians of the study area. The chi-square test of amphibians recorded in the study area shows that there is significant differences among the species X²=59.5094, d_f =9, p=0.000.