ECOLOGY OF THE INTRODUCED SNAIL MELANOIDES TUBERCULATA (GASTROPODA: THIARIDAE) IN RELATION TO BIOMPHALARIA GLABRATA IN THE MARSHY FOREST ZONE OF GUADELOUPE, FRENCH WEST INDIES

Abstract

Melanoides tuberculata was introduced to several types of aquatic habitat occurring in the marshy forest zone, Guadeloupe, as a competitor of the snail host, Biomphalaria glabrata, of Schistosoma mansoni. Colonization by the competitor was successful in all habitats, but the impact on the snail host was variable according to the site. Evolution of global prevalences, intensities and abundances of Schistosoma mansoni in the reservoir host, Rattus rattus, did not show any significant changes during the eight years following the introduction of the competitor. The analysis of size distribution of M. tuberculata in a release plot showed that maximum reproduction took place during the rainy season between June and November. The thiarid snail needed 4.5 months to reach a size of 10 mm, 14 months to reach 15 mm, and more than 30 months to reach 20 mm. Calculated life expectancies were 0.74 year at the first year of age, 0.9 year at the second year, and 0.5 year at the third year.