Potential sources of sugar for the phlebotomine sandfly Lutzomyia youngi (Diptera: Psychodidae) in a Colombian coffee plantation.

Sugar-deprived Lutzomyia youngi were exposed to each of the five most numerous plant species in a Colombian coffee plantation for 24 h and then tested for the presence of fructose by the cold anthrone assay. Many flies exposed to coffee (Coffea arabica) (up to 55% in an individual test) and guamo (Inga edulis) (up to 28.0%) gave positive results. Although some flies also took sugar from red-flowered balsam (Impatiens balsamina) and bamboo (Bambusa angustifolia), none of the insects exposed to plantain (Musa paradisiaca) gave a positive result unless the plants were infested with aphids (Pentalonia sp.). Although sandflies were successfully marked in the laboratory by exposing them to coffee and guamo plants whose roots had been treated with RbCl at 5000 p.p.m., RbCl was not detected by atomic emission spectrometry in wild specimens caught in the vicinity of RbCl-labelled coffee and guamo.