Effect of temperature on growth and reproduction of the epigeic earthworm, Eudrilus eugeniae (Kinberg).

Abstract

Influence of temperature on growth and reproduction of Eudrilus eugeniae has been investigated by laboratory culturing at regulated 25.0 degreesC, 30.0 degreesC, 37.5 degreesC and 40.0 degreesC and in fluctuating (22.7-27.3 degreesC) room temperature of prevailing (winter) season over 16 weeks. All worms died during first and tenth week at 40.0 degreesC and 37.5 degreesC respectively. Weight (biomass) and growth of worms cultured at different temperature varied significantly (P <0.01). The mean growth (mg/g live weight/day) at 25.0 degreesC., 30.0 degreesC, 35.0 degreesC, 37.5 degreesC and in fluctuating temperatures was 1074.04 +/-6.07, 1554.01 +/- 192.37, 148.1 +/- 15.28, 192.83 +/- 25.8 and 1450.4 +/- 162.1 respectively. Growth declined after maturity drastically with coccon production. At 25.0 degreesC though worms are sexually mature, they failed to produce cocoons within 16 weeks whereas, at 35.0 degreesC and 37.5 degreesC they did not sexually mature. Worms attained sexual maturity at a mean weight of about 1000 mg/worm. The mean per cent maturity was higher and earlier in fluctuating temperatures and at 30.0 degreesC than at 25.0 degreesC. Cocoon production was observed only at 30.0 degreesC and in fluctuating temperatures with a mean of 0.9 and 1.5 cocoons/worm/week and the cumulative cocoon number of 10.8 and 14.7/worm over 16th week respectively. The fluctuating temperature of uncontrolled room environment and 30.0 degreesC were favorable for various life activities of the worms. Eudrilus eugeniae appears to have range of temperature optima more than 25.0 degreesC and less than 28 degreesC. The climatic conditions prevailing in whole of the peninsular India during winter season are favourable for employing this worm in intensive field scale vermiculturing practices.