A INFLUENCIA DA DENSIDADE POPULACIONAL E A INGESTÃO DE ALIMENTOS NA BIOLOGIA REPRODUTIVA DA Biomphalaria glabrata (Mollusca) E DA QUANTIDADE DE CÁLCIO EM CARAMUJOS EXPERIMENTALMENTE INFECTADOS COM Schistosoma mansoni (Trematoda)

The aim of this study was to evaluate the influence of population density and food intake on the survival and reproduction of uninfected Biomphalaria glabrata and the effect of calcium carbonate availability on cercarial emergence from experimentally infected snails, to define conditions to maximize snails’ breeding and cercarial production for future studies about this model. The results observed in this study indicate that increased population density has a negative effect on the survival and reproductive activity of B. glabrata. In addition, the quantity of lettuce offered to the snails altered the number of eggs laid per snail. There was a significant relation between the amount of lettuce eaten per day and the number of eggs produced per snail, as well as the number of egg masses per snail, and eggs per egg mass. Furthermore, the snail’s survival was directly associated with the amount of calcium carbonate and the cercarial emergence was inversely related to the calcium carbonate amount. This study might help to understand the influence of population density and food intake on the reproductive biology of captive snail populations. In relation to cercarial emergence, calcium supplies must not be provided to Schistosoma mansoni-infected snails while maintaining S. mansoni under laboratory conditions because it decreases cercarial emergence.