Phenology of the mosquito Wyeomyia smithii (Coq.) in Manitoba and Ontario
The phenology of Wyeomyia smithii (Coquillett) within the water-filled leaves of Sarracenia purpurea L. (the purple pitcher plant) was studied during 1983 in bogs near The Pas and Patricia Beach, Manitoba, and Kenora, Ontario. Larvae that overwintered developed into adults by early July, and females laid eggs in newly opened leaves, as well as in the previous year's leaves. The largest portion of the developing larvae (summer generation) entered a third-instar diapause by mid-August and remained in this instar until the following spring. A small percentage of the summer generation at each site continued their development to adults and may have given rise to another generation. The number of larvae per leaf was positively correlated with leaf size. Pupation rates as well as adult size and fecundity did not vary significantly amongst sites. Smaller and less fecund individuals emerged as the season progressed. Over-winter survival of larvae was low at Patricia Beach (9%) but relatively high at The Pas (68%) during the winter of 1983–1984; survival was moderate (32–50%) during 1984–1985 at both locations. Overwintering success is likely enhanced by an early winter snow cover which insulates the larvae from low ambient temperatures from October to December at these sites.