ABSTRACT
1. The reproduction of the snail Biomphalaria glabrata, one of the intermediate hosts of Schistosoma mansoni, was evaluated under laboratory conditions by measuring egg production, number of ovipositions, number of eggs per oviposition, and hatching rate using a Latin square design with five different temperature treatments. This permitted the elimnation of occasional variation in oviposition due to manipulation or a priori group. 2. Egg production and spawning rates were higher at temperatures between 20.0 and 27.5-C than at 17.5-C. Number of eggs per spawning and hatching rate did not vary with temperature. 3. During a 3-day adaptation phase, a short-term therminal effect appeared in chich some indices of reproductive rates differed signifcantly from those of the experimental phase
Subject(s)
Animals , Biomphalaria/physiology , Oviposition , Temperature , Adaptation, Physiological , ReproductionABSTRACT
1. Reproduction in the snail Biomphalaria glabrata, a vector of Schistosoma mansoni, was measured by egg production and other paramneters such as number of clutches, eggs per clutch and egg hatching, under laboratory conditions. 2. Reproductive rates were highest in terms of total number of eggs, clutches and hatching under constant illumination, followed by conditions similar to the natural rhythm of illumination. The greatest reduction in reproduction occurred in constant darkness. in summary, reproductive rate was dependent on both the intensity of absolute illumination and the schedule of illumination exposure. 3. Seasonal variation in reproductive rate appeared to vary inversely with local temperature in Belo Horizonte, situated in a tropical zone (latitude 20 S) owing probably to a temperature prefernce of 20 to 25-C by the snail. the highest reproductive rates occurred in winter, except for the parameter eggs per clutch which was maximal in autumn. Snail reproduction appeared to be most reduced during summer. There was no linear correlation between reproductive rate and temperature