Where do black flies lay their eggs?

• A. Directly onto the water or on trailing vegetation near the surface of the water, near moving water.
• B. In dry soil far from water.
• C. Deep in mud away from water.
• D. On tree bark above water.

Answer: (A)

The main idea here is that black flies rely on an aquatic life stage, so their eggs must be placed where they can immediately enter water and develop. They typically lay eggs directly on the water surface or on vegetation at the water’s edge, especially in fast-moving streams. This positioning lets the hatchlings drop into or crawl into the water and attach to submerged substrates where they feed and grow. Laying eggs in dry soil far from water or deep mud away from water, or on tree bark above water, would prevent the larvae from entering the aquatic habitat they need, so those sites aren’t viable.