Using vehicle-mounted nets for studying activity of Arabian sand flies (Diptera: Psychodidae)

Vehicle-mounted nets were used on 15 nights in northern Oman to collect 2,216 sand flies. The composition of the catch was compared with that of 100 sticky traps, which were used twice a month over a 15-mo period to collect 3,099 sand flies. Sticky trap catches showed no obvious seasonal change in abundance. The vehicle nets collected up to 260 flies per night, with a mean of 148. This compared with the catch of the 100 sticky traps, which had an overall mean of 115 flies per night. The vehicle nets collected seven species of sand flies (four Phlebotomus and three Sergentomyia). Phlebotomus alexandri Sinton, the presumed vector of visceral leishmaniasis in Oman, made up 29% of the catch. In contrast, the sticky traps collected mainly Sergentomyia spp., and P. alexandri was only 4% of the catch. Overall, catch of both methods had a sex ratio of 1:1, but both collected a higher proportion of female P. alexandri. The vehicle nets collected only a few blood-fed flies, the greatest number being 33 P. alexandri (8% of the females for this species). However, some females were collected at each stage of the gonotrophic cycle; the smallest number was in stage II. All the flies developing eggs beyond stage II had had a blood meal, so that there was no sign of autogeny in these species. Ten percent of the females were parous. The vehicle-mounted net placed on the side of the vehicle at 0.3 to 1.8 m above the ground caught a greater number of Sergentomyia clydei Sinton than an identical net mounted on top of the vehicle at 1.8 to 2.8 m, in which the rest of the species, including P. alexandri, mainly were caught.