LARVAL MICROHABITATS OF LUTZOMYIA-LONGIPALPIS (DIPTERA, PSYCHODIDAE) IN AN ENDEMIC FOCUS OF VISCERAL LEISHMANIASIS IN COLOMBIA

An intensive search for the larval habitats of Lutzomyia longipalpis ( Lutz & Neiva) was conducted from November 1992 to October 1993 at a sm all rural community in Colombia where American visceral leishmaniasis is endemic. Emergence traps constructed from polyvinyl chloride pipes were used to sample a variety of soil microhabitats that included edge areas of covered pigpens, cattle corrals, the base of trees, and leaf litter at sites within 40 m of a house, rocks in fields located betwe en 50 and 500 m from houses, and sites within a patch of secondary for est (rocks, base of palm trees, and leaf litter). The teneral status o f the sand flies captured in the emergence traps was confirmed by labo ratory studies that determined the rate of terminalia rotation in male L. longipalpis and the rate of cuticular growth layer formation of th e thoracic phragma in both sexes of this species. A total of 55 tenera l sand flies was captured during the study period (49 wk). Fifteen spe cimens were L. longipalpis; of these 11 (5 sand flies per square meter ) were captured near pigpens, 3 (1.4 sand flies per square meter) were captured near rock resting sites, and 1 (1.6 sand flies per square me ter) was collected at the base of a tree. The remainder of the sand fl ies were either L. trinidadensis (Newstead) or L. cayennensis (Flock & Abonnenc). Our results indicate that L. longipalpis larvae were dispe rsed widely in sites near houses, rather than concentrated in a few op timal microhabitats.