Interrupted blood-feeding by Culiseta melanura (Diptera : Culicidae) on European starlings

To determine whether Culiseta melanura (Coquillett) mosquitoes tend to take multiple blood meals when birds of certain species serve as hosts, we comp ared the frequencies with which such mosquitoes fed upon caged starlings an d robins and determined whether similar volumes of blood were imbibed from each. The blood of robins (Turdus migratorius) and European starlings (Stur nus vulgaris) was marked contrastingly by injecting birds with rubidium or cesium salts. Caged birds were placed together in a natural wetland setting overnight. Mosquitoes captured nearby on the following morning were analyz ed for each of the elemental markers. Where marked robins and starlings wer e equally abundant, 43% of freshly engorged Cs. melanura fed on more than o r equal to two hosts. More Cs. melanura fed on robins than on starlings. In dividual mosquitoes tended to contain far more robin- than starling-associa ted marker, indicating that mosquitoes "feasted" on robins but only "nibble d" on starlings. Mosquitoes marked with both elements apparently fed meager ly on the starlings then abundantly on the robins. Our estimates of bloodme al volume indicate that 85% of mosquitoes that fed on marked starlings obta ined <0.5 <mu>l of blood from them. We suggest that defensive behavior by s tarlings interrupts mosquito blood-feeding and that, in a communal roost of starlings, each mosquito will tend to feed on more than one bird, thereby promoting rapid transmission of such ornithonotic arboviruses as eastern eq uine encephalomyelitis virus and West Nile virus.