For many years, variations in the pattern of scales on the scutum lead to sticticus being regarded as two separate species, aldrichi in the lower Fraser and North Thompson valleys and hirsuteron, further east in the lower interior valleys (Hearle 1932). The synonym, aestivalis, was described from larvae found in the Kootenays. In years of widespread flooding, sticticus used to be one of the commonest species across the south of the Province and, with vexans, the dominant mosquito pest in the lower Fraser Valley (Hearle 1926). In the last five years, however, the Fraser has not flooded significantly and sticticus has been scarce in the valley. Swarms of about 50 males form in early evening 1 m or so above the ground, often in willow growth (Hearle 1920). Most commonly, the larvae develop in wooded river flats along with vexans and cinereus, but are seldom found in open flood water where vexans can breed in enormous numbers. Hatching occurs immediately after the eggs are flooded, generally in late Mayor early June. If, as is often the case, the river has several peaks at intervals of a week or so, each peak will produce a fresh hatch of larvae. The eggs remain viable for at least five years (Gibson 1933) so that one or two seasons can pass when the species does not appear, thus complicating control measures. Adults readily invade houses and most are small enough to penetrate 12-mesh screening (Hearle 1920). They have a flight range of several miles, and females bite viciously by day or night.
Aerial photographs of flooded areas, along with surveys of the larvae there provide a sound basis for control of this pest using selective methods.
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