Identification of Biological Characteristics That Enhance the Attraction of Lutzomyia longipalpis Females to Conspecific Male Sex Pheromones

Phlebotomine sand flies are the vectors of the etiological agent of leishmaniasis, the Leishmania (Kinetoplastida: Trypanosomatidae) protozoan. In Peru, the sand fly Lutzomyia verrurcarum (Townsend) is the vector of Leishmania peruviana, the causative agent of Andean cutaneous leishmaniasis. Using traditional control methods, over 1.5 million new worldwide cases of leishmaniasis are reported annually. Therefore, the development of novel control methods through an integrated pest management scheme is of great importance. The identification of appropriate targets for control is a major first step in this process, and the manipulation of chemical communication in arthropods has been shown to be a sustainable method of control. The objectives of this study were (1) to develop an operative bioassay for the characterization of the putative sex pheromones of Lu. verrucarum and (2) to define the biological characteristics of optimal sand fly respondents. Due to unavailability of Lu. verrucarum, a closely related species (Lutzomyia longipalpis Lutz and Neiva) was used in these experiments. The attraction of female Lu. longipalpis to male pheromone extracts was assayed using linear three-chamber and cage olfactometers. The time in which females spent with males and the access to a blood meal was varied among respondents, and the effect of these variables on female attraction to male sex pheromones was analyzed. Results indicated that blood-fed females with ≤ 24 hours of male exposure exhibited the highest response to male sex pheromones, and cage olfactometers were found to more effectively assess Lu. longipalpis female behavior than linear three-chamber olfactometers.