Multiple blood feeding by Anopheles freeborni and Culex tarsalis (Diptera:Culicidae): spatial and temporal variation.

Multiple blood feeding in field populations of Anopheles freeborni Aitken and Culex tarsalis Coquillet was detected using a histologic technique. Examination of 333 blood engorged An. freeborni and 41 Cx. tarsalis females revealed that 13 and 10% of these females imbibed multiple blood meals, respectively. Spatial and temporal distribution of multiple blood feeding events was evaluated against the percentage of blood fed females and the abundance of female mosquitoes. The percentage of blood fed An. freeborni females was higher among those collected in pasture and riparian habitats than those collected in rice field and mixed habitats. Conversely, spatial variation of multiple blood feeding in An. freeborni was not significantly associated with rice field, pasture, riparian, or mixed habitats. The decrease of multiple blood feeding for An. freeborni through the season was correlated inversely with the increase of the abundance of adult females; but not with the percentage of blood fed females. These results confirmed that multiple blood meals in An. freeborni, and perhaps in Cx. tarsalis, are a frequent phenomenon, and that the histologic procedure is an appropriate tool for longitudinal and region-wide detection of multiple blood feeding necessary in epidemiologic studies.