Seasonal incidence and horizontal distribution patterns of oviposition by Aedes aegypti in an urban environment in Trinidad, west Indies.

The oviposition patterns of Aedes aegypti in ovitraps placed along 5 horizontal transects were monitored weekly for 52 wk (January to December 1988) in St. Joseph, Trinidad. Of the 2,550 ovitraps exposed, 270 were lost and 1,177 (52%) out of 2,280 were used by gravid females, containing 38,118 eggs. During the dry season 43% (16,265 eggs) of the eggs were collected whereas during the wet season 57% (21,853 eggs) were collected. Ovitraps exposed under eaves, under houses and in the open yard attracted similar oviposition occurrences and proportions of eggs. Inspections of the 52 properties within St. Joseph revealed that 17 (House Index = 32.7%) harbored Ae. aegypti pre-adult stages. The container index was 5.5%. This study revealed no evidence of behavioral changes in the container preferences of Ae. aegypti in St. Joseph, Trinidad, after 12 years of treating with fenthion and temephos.