Reports on Aquatic Oligochaetes (Naididae) In Paddy Fields of Moodabidri Taluk, Dakshina Kannada, South India

Abstract

The objectives of the study was to record the occurrence and abundance of microdril earthworms in the paddy field in and around Moodabidri (Dakshina Kannada), south India. 74 submerged paddy fields were surveyed during October/ November 2011 and February /March 2012. Three species namely Aulophorus vagus, Aulophorus furcata and Dero digitata belonging to the family Naididae were reported in 12 paddy fields for the first time from India. A. furcata was recorded in 8 paddy fields, D. digitata was sampled in 6 paddy fields, where as A. vagus was found only in one paddy field. The diversity of naidid worms increased with algal abundance, rotting materials, naturalrnmanures, nitrate, phosphorus and potassium in the paddy fields indicating that the algal cover is a significant factor with respect to abundance of species studied. The very high density of naidid worms particularly A. furcata was found to be due to a budding occurred during favorable condition in submerged paddy fields. Sexual reproduction seems to be adopted in these worms in response to soil desiccation. Density of naidid worms was found to improve growth conditions in the paddy