Mark-recapture studies on the Culiseta (Diptera: Culicidae) vectors of eastern equine encephalitis virus

Natural populations of Culiseta melanura (Coquillett) and Cs. morsitans (Theobald) were marked and released at three sites associated with the Toad Harbor-Big Bay Swamp eastern equine encephalitis (EEE) virus focus in central New York. Collections of Culiseta from surveillance sites within 12.8 km of the release sites were screened for marked specimens. A total of 172 marked specimens were recaptured. The majority of recaptured mosquitoes were collected at sites associated with the swamp complex, but some were collected at seven of the eight recapture sites, up to 9.8 km from a release site. The distances traveled by 103 recaptured individuals were used to calculate the mean distance traveled and flight ranges for sexes and cohorts of both species. The mean distance traveled for females that were marked and released from resting shelters was 4 km for Cs. melanura and 5 km for Cs. morsitans. The mean distance traveled for females marked and released from a CDC + CO2 light trap was 9 km and 8 km for Cs. melanura and Cs. morsitans, respectively. The flight ranges of these species overlap the EEE epizoötic zone, and the results of these studies support the hypothesis that these species are involved in the transfer of EEE virus from swamp to upland habitats.