LIFE-CYCLE AND FIELD ABUNDANCE OF THE SNAIL SUCCINEA-COSTARICANA (STYLOMMATOPHORA, SUCCINEIDAE), A TROPICAL AGRICULTURAL PEST

The neotropical terrestrial snail Succinea costaricana has become a qu arantenary pest in ornamental plants (Dracaena marginata, Dracaenaceae ). Specimens were collected in Guapiles, Limon, Costa Rica, where they reached a density of 282 900 individuals/ha. In the field reproductio n is continuous (as is rainfall) and eggs, young and copulating pairs are found mainly under moist litter. The population concentrated on pl ants rather than on the soil and greatly decreased after several contr ol methods were applied. The life cycle was studied in the laboratory. The following are mean values: 7 eggs/cluster; 1.4 mm egg diameter; 0 .25 and 0.84 mm embryo and newborn shell length, respectively; 11 days (embryo development at 24 degrees C); 16 mm/min locomotion speed (you ng). The animals can reproduce at 12 weeks (lifespan: 44 weeks). The p igmentation pattern is defined after seven weeks.