Studies of Populations of Adult and Immature Culicoides sanguisuga (Diptera: Ceratopogonidae)1

Abstract

The method used in making landing-rate counts of Culicoides sanguisuga (Coquillett), an abundant pest of man in the Adirondacks, is described. Landing rates were low initially at a given site, and increased to a peak 10 to 12 minutes later. Counts were highest about an hour after sunrise and at sunset. In open meadows the counts generally declined to zero during the day between the morning and evening peaks. In moist, shaded sites, protected from the wind, landing rates diminished but punkies continued to be annoying during the middle of the clay. It is suggested that the rate of moisture loss is an important factor influencing the activity of the punkie, and a close relationship between the evaporation rate and landing rate is demonstrated. Seasonal changes in populations of C. sanguisuga , as indicated by landingrate counts and light-trap collections, were comparable. The first females appeared in late May. Populations then increased rapidly and reached peak numbers in late June and early July. The numbers diminished slowly thereafter and punkies were found only in small numbers after mid-August, although occasional specimens were present into October. C. sanguisuga overwinters in the larval stage. In 1961, larval populations were high in early May, then declined during the period of pupation from late May into early June. Numbers increased thereafter owing to the appearance of recently hatched small larvae. Prepupation population levels were reached by late July.