During which months are black fly adults most abundant?

The correct answer is that black fly adults are most abundant in May and June. During these months, environmental conditions such as temperature, rainfall, and the availability of breeding habitats coincide to create optimal conditions for the emergence and activity of black fly adults.

Black flies, particularly species in the Simuliidae family, have a lifecycle that includes an aquatic larval stage, which typically develops in flowing waters during the spring months. As temperatures rise and the water flow conditions are favorable in late spring, adult black flies emerge and are most active in May and June. During this period, adult populations peak as they search for hosts to feed on, often coinciding with the peak activities of many wild and domestic animals that serve as hosts.

The other months do not align with the peak abundance of black fly adults. For instance, while June might still see black flies present, their population typically starts to decline as the season progresses into summer, and warmer, drier conditions become less favorable for their lifecycle. Therefore, focusing on May and June accurately reflects the most abundant period for black fly adults.