BIOECOLOGY OF ANOPHELES-ALBIMANUS WIEDEMAN, 1820 (DIPTERA , CULICIDAE) IN HAITI (HISPANIOLA)

Hispaniola has the highest malaria rate in the West Indies. A study of the bio-ecology of the major vector Anopheles albimanus was carried o ut in Haiti Our observations concerned the length of preimaginal stage s, biting rates and the gonotrophic cycle. A table of its complete lif e cycle, stage by stage, was produced as well as a graph illustrating its whole larval development in its natural habitat Results in the fie ld and insectarium were compared. In the laboratory the development wa s shorter except for pupae The temperature was the main factor governi ng the length of pre-imaginal development Preimaginal development decr eased from 15 days in the field to 9 days in the insectarium whereas t he temperature was a high of 4 degrees C The nycthemeral activity and seasonal variations of An. albimanus were studied, by monthly all-nigh t captures on human volunteers, during a full year in exo- and endophi lic situations. Two sampling sites were chosen for comparison, An. alb imanus were caught at every hour of the nycthemeral cycle, with a peak around midnight Monthly variations were affected by the rains. The ve ctor was more exophagous, when its density was high. The parity rate o f the biting population varied between 85.8% and 20.0%; it was low at the beginning of the rains and increased when the rains stopped and br eeding places dried out To study the gonotrophic cycle of wild An. alb imanus, several techniques were used jointly follicles dissection; fol licular relies; length of maturation of follicles. The length of the f ull cycle and of each of its components was estimated (quest of host f or blood meal maturation phase; breeding site seeking). In Haiti 41 h (nulliparous), or 21 h (parous) were necessary for females to have a c omplete maturation of the follicles. The lengthening of the gonotrophi c cycle of parous An. albimanus, in the natural field site, was estima ted to last about 4 days. For nulliparous it was 5 days, and 7 days if a pregravid stage was necessary. Considering the sporogonic cycle of Plasmodium falciparum (12 days), the wild population of An. albimanus females could become infective at the third blood feeding in Haiti.