Dispersal of Viable Algae and Protozoa by Horse Flies and Mosquitoes (Diptera: Tabanidae, Culicidae)

Algae and protozoa of 28 different genera were cultured from external “washings” of 14 species of aseptically collected adult horse flies and mosquitoes. Algae predominated, with 7 genera of blue-greens, 15 of greens, and 1 genus of diatoms; 5 genera of flagellate protozoa were identified in the cultures, although no rhizopods or ciliates were found. Analysis by “t” test showed that the horse flies carried significantly more algae and protozoa than the mosquitoes. Five tabanid species yielded 21 genera; 9 mosquito species of 4 genera yielded 17. Known dispersion distance of some of the Diptera studied suggest that the numerous algae and protozoa which they carried could be transported overland from 1 aquatic or moist habitat to another. The data suggest that some Diptera contribute substantially to the passive dispersal of large numbers of different algae and protozoa.