MULTIPLE BLOOD-FEEDING IN ANOPHELES FREEBORNI (DIPTERA, CULICIDAE)

The frequency of multiple blood feeding in field populations of Anophe les freeborni was determined. Fifty-six laboratory-reared mosquitoes, all known to have taken two blood meals, were used to define the limit s of the histologic procedure we used. Seventy-eight percent of known double meals were detected when the interval between meals was from 1 to 24 hr, and the time from the second meal until fixation ranged from 0 to 24 hr. At intervals outside this range, 50% of multiple meals we re detected. In field-collected An. freeborni, the most important hist ologic parameters for determination of multiple feeding were the amoun t of heme that developed around each meal, the peritrophic membrane, p artially digested blood meals, and physical blood meal separation. Exa mination of 134 blood-engorged An. freeborni collected in the held sho wed that 9.7% had imbibed multiple blood meals. These results suggest that multiple blood meals in An. freeborni are more frequent than prev iously thought, perhaps with significant epidemiologic implications.