ABSTRACT
After a study of the population dynamics of Biomphalaria glabrata snails in several breeding places in the Dominican Republic, the snail Thiara granifera was introduced in some B. glabrata habitats. T. granifera became established in one point in one habitat in the townof Quisqueya, in the east of the country. Around this point of establishment 6 points were selected in order to observe the population dynamics of both species of snails and the chemical and biological characteristics at each point. Four of these points already harbored B. glabrata. One control point was selected also harboring B. glabrata. After 14 months of observations, the results showed that T. granifera was competing with and displacing B. glabrata. This competition does not seem to be competition for food or vital space. Rather, B. glabrata avoids the presence of T. granifera and moves away to new areas, and this is possibly due to a chemical substance(s) secreted by T. granifera or by physical contact with the large number of individuals of T. granifera
Subject(s)
Animals , Adaptation, Physiological , Biomphalaria/physiology , Competitive Behavior , Snails/physiology , Analysis of Variance , Population DynamicsABSTRACT
Se presentan los resultados de un estudio preliminar de las propiedades molusquicidas del guayacil, un extracto crudo de la planta Guayacum officinale sobre Biophalaria glabrata. Los moluscos fueron expuestos a varias concentraciones de la sustancia durante periodos de 1, 6 y 24 horas y posteriormente se les permitió su recuperación según las recomendaciones de la Organización Mundial de la Salud. Los resultados indican que el guayacil posee propiedades molusquicidas con una LC50 de 0,45 ppm y una LC90 de 0,95 ppm a 24-c. Concentraciones mayores de 1 ppm resultaron en el 100 % de mortalidad, mientras que 0,1 ppm no fue letal. Todas las partes de la planta contienen el ingrediente activo. Concentraciones por debajo de 1 ppm no son letales a la flora o la fauna