POTENTIAL MOSQUITO BREEDING SITES IN EMPTY SHELLS OF THE AFRICAN SNAIL, LISSACHATINA FULICA IN CALI, COLOMBIA.

Abstract

Habitat descriptions for vector larvae of public health importance are fundamental to the design of cost-effective control measures. Faced with the invasion of the giant African snail, Lissachatina fulica, the objective of the present study was to determine the role of empty giant African snail shells as mosquito breeding sites. Three experiments were performed under field conditions in four microenvironments on the banks of the Lili River in the city of Cali. Additionally, two artificial containers (motorcycle tires and plastic cups) were placed in each microenvironment. In experiments 1 and 2, the empty giant African snail shells of different sizes, which contained a previously determined water volume, were positioned in 4 selected microenvironments. In experiment 3, empty giant African snail shells of different sizes were also located in the four microenvironments during the rainy season, and the water volume in each shell was the result of natural rainfall accumulation. The variables final water volume, shell size, and mosquito density were evaluated in the three experiments, using a total of 92 shells. The dominant mosquito species identified were Limatus durhamii, Aedes albopictus, and Ae. aegpti. Experiment 1 revealed that giant African snail shells measuring less than 60 mm had limited breeding potential, whereas experiment 3 showed that shells larger than 100 mm had higher numbers of mosquito larvae. There was a significant association between shell size, water volume, and mosquito density. A total of 757 mosquitoes were identified. This is the first exploratory study under field conditions in Colombia to evaluate empty giant African snail shells as breeding sites for mosquitos of public health importance. Results of this study provide new information that should be considered in control strategies in areas with concomitant presence of giant African snails. Entomological findings and their epidemiological importance are discussed.