Thermal effect on the life-cycle parameters of the medically important freshwater snail species Lymnaea (Radis) luteola (Lamarck)

RESUMO

The snails Lymnaea (Radix) luteola exhibited marked variations in growth, longevity, and attaining sexual maturity at different temperatures and diets. At 10§C, irrespective of foods, pH and salinity of water, the snails had minimum life span, maximum death rate and lowest growth rate. At 15§C, the growth rate was comparatively higher and the snails survived for a few more days. But at these temperatures they failed to attain sexual maturity. Snails exposed to pH5 and 9 at 20§, 25§, 30§, 35§C and room temperatures (19.6§-29.6§C): to 0.5, 1.5 and 2.5 NaCl per thousand at 20§ and 35 §C; to 2.5 NaCl per thousand at 25§C and room temperatures failed to attain sexual maturity. The snails exposed to pH 7 and different salinity grades at 20§, 25§, 30§, 35§C and room temperatures became sexually mature between 25-93 days depending upon the type of foods used in the culture.