The limnological factors associated with cytotypes of the Simulium (Simulium) venustum/verecundum complex (Diptera: Simuliidae) in New York state.

A survey of cytotypes of the Simulium (Simulium) venustum/verecundum complex and of associated limnological conditions was conducted from April to October, 1978, in northern and western New York state. Water was analyzed for the following 21 factors at four sites: sodium, potassium, calcium, magnesium, chloride, sulfate, bicarbonate, nitrite, nitrate, total nitrogen, ammonium, orthophosphate (MRP), total phosphate (TSP), iron, aluminum, conductivity, silicate, dissolved oxygen, temperature, velocity, and pH.The common species and their distributions were the following: northern New York, ACD and AA-AC verecundum; western and northern New York, CC. The complex divided into two groups on the bases of pH, ionic content, and ratios of the water. Northern species occurred in mildly acidic, dilute, bicarbonate- and sulfate-dominated waters. Western species occurred in neutral, rich, bicarbonate-dominated water. Three phenological groups were found based on coldest temperature tolerated. These cytotypic differen...