Dynamic of population-dynamics in a medically important snail species Lymnaea (Radix) Luteola (Lamarck)

Abstract

The life-cycle parameters of the snail Lymnaea (Radix) luteola and the factors influencing the same have been studied under laboratory conditions. In each month, from July 1990 to June 1991, a batch of 100 zero-day old individuals were considered for studies. The snails of April batch survived for 19.42 days while those in December batch survived for 87.45 days. The May batch individuals though survived for 65.67 days gained maximum shell size (15.84 mm in length) and body weight (419.87 mg). All individuals of April batch died prior to attainment of sexual maturity. In the remaining 11 batches the snails became sexually mature between 32 and 53 days. At this stage, they were with varying shell lengths, 9.3 mm to 13.11 mm in respect to batches. The reproduction period varied from 1-67 days. An individual laid, on an average, 0.25 (March batch) to 443.67 (May batch) eggs in its life-span. A batch of such snails would leave 24,312, 22,520, 720,268, 80,408, 76,067, 418,165, 214, 9202, 0, 0, 2,459386 and 127,894 individuals at the end of 352nd day. Since the environmental conditions were almost similar the 'dynamic' of population dynamics seems to be involved with the 'strain' of the snail individuals of the batches concerned