The effect of temperature on the relative abundance of flies of the Drosophila affinis (sub-group) collected near Ottawa, Ontario

The relative abundance of the three species in the Drosophila affinis subgroup was not significantly correlated with changes in summer high temperatures in 1986. However, the two most abundant species in collections were the cold-adapted D. athabasca and D. algonquin respectively, which have at least one generation per year in the Ottawa area. Their predominance may be the result of below normal temperatures that occurred during the summer. The male bias in baited collections may result from the greater attraction of females to natural oviposition sites, rather than the bait.