The ecology of marsh mosquitoes and their attraction to mallard ducks, domestic chickens and yellow-headed blackbirds at Oak Hammock Marsh, Manitoba
Fortney, Robert Gene Anthony
During the years of 1985 to 1987 a survey was carried out to determine the species of mosquitoes that were breeding and host seeking in Oak Hammock Marsh. The abundance of adult female mosquitoes in the marsh was monitored with Solid State Army Miniature (SSAM) light traps, which were used to trap host seeking adults. The abundance of raft laying species was also monitored in 1985 and 1986, using ovipools known to be attractive to Cx. tarsalis Coquillett, Cx. restuans Theobald and Cs. inornata (Williston). Larval breeding was monitored by regular sampling of 20 sampling sites within the marsh, to determine the species of mosquitoes breeding there during two summer seasons. Species abundance, as determined by trap collections of adult females, varied each year. In 1985 the abundance of only the most common species, Cs. tarsalis, Cx. restuans, Ms. perturbans (Walker), An. earlei Vargas, Cs. inornata, was monitored. In 1986 and 1987, all mosquitoes were identified and Ae. vexans (Meigen) and Ae. flavescens (Muller) were the most numerous species in the collections. In 1987 the numbers of Ms. perturbans and An. walkeri Theobald were noticeably greater than in 1986. Fourteen species werre found to breed in the marsh during the 2 years of larval sampling; Cs. inornata, Ae. flavescens and Ae. vexans were the dominant species. Cx. tarsalis egg rafts dominated, with a mean/weekly count of 16 egg rafts. Cs. inornata and Cx. restuans followed with mean/week counts of 4.4 and 3.7 repectively. Ovarian parity was studied in females of several species collected in SSAM traps during 1984-1986, to determine the physiological age of the population. A maximum of 30 live adult female mosquitoes/week were removed from the collections. Cx. tarsalis probably completed 3 generations in 1984 and 1986 while in 1985 it appeared to complete only 2 generations. One-parous individuals were collected during the second week of June, 1985 and 1986, and in the second week in July in 1984. Tri-parous females were observed in August of 1984 and July of 1986. Ms. perturbans had single generations during both years, and nullipars were collected from June or July until August. One-parous individuals were collected in the third week of July in 1985, and the last week of June in 1986. One-parous individuals of An. walkeri were collected in June, 1987. There was an increase in nullipars in the third week in July, suggesting it may complete two generations in Manitoba...