Displacement of Biomfhalaria glabrata by thiara granifera under natural conditions in the Dominican Republic

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

Status of Schistosomiasis Elimination in the Caribbean Region

“…Biological control using the phenomenon of competition by non-medically important snails was found to be a cost-effective, low maintenance, popular way of controlling the disease. Competitive action of the ampullarid snail M. cornuarietis through food and predation of eggs and young snails [93] or B. glabrata ’s avoidance of the prolific and rapidly colonizing parthenogenic thiarid snails T. granifera and especially M. tuberculata [94] all resulted in varying levels of displacement of B. glabrata populations. Biological control does have its limits as shown in St Lucia where B. glabrata and M. tuberculata were found to co-exist in many habitats [75], and in Guadeloupe the Thiarid snails were unable to displace B. glabrata in certain areas where rats served as S. mansoni intermediate hosts [54].…”

The biological control of snail intermediate hosts of schistosomiasis by fish

“…A renewed visit to the lakes where this species has been introduced, as has been done in Kenya, can give valuable additional information. Caution must be taken when revisiting these Puerto Rican reservoirs because on this island the competitive snail Marisa cornuarietis has successfully been introduced in the biological control against Biomphalaria glabrata (Jobin and Laracuente, 1979; also see Pointier andMcCullough, 1989, andGomez Perez et al, 1991).…”