Fishfly

Fishflies belong to the same order as dobsonflies and alderflies (Megaloptera) and share the same general body plan of long, veined wings and a soft, elongated body, but they are considerably smaller and males lack the exaggerated tusk-like jaws that make dobsonflies so distinctive. Several genera, including Chauliodes and Nigronia, are grouped under the common name fishfly.

Like their relatives, fishflies begin life as aquatic larvae that live among submerged debris, rocks, and vegetation in streams and along lake margins, where they hunt smaller invertebrates. Adults are short-lived and mainly nocturnal, often gathering near lights close to water in spring and early summer.

Fishflies play a similar ecological role to dobsonflies and stoneflies, serving as both predators and prey within freshwater food webs, and their larvae are sometimes used as fishing bait much like hellgrammites.

• Moderate-sized insect with two pairs of smoky, mottled or plain, net-veined wings held tent-like over the body
• Antennae often feathery or comb-like (pectinate) in males of some species, unlike the simple antennae of dobsonflies
• Mandibles short and roughly equal in both sexes, without the extreme elongation seen in male dobsonflies
• Body typically brown, gray, or blackish
• Larvae resemble small hellgrammites but often lack the terminal hooked prolegs or have a single long filament at the tip of the abdomen
• Lookalikes: dobsonflies (larger, males with long mandibles) and alderflies (smaller, single wing pair appearance at rest)

Fishflies occur widely across North America near streams, rivers, and the shallow, weedy margins of ponds and lakes. Larvae live in slower currents and debris-rich areas than dobsonfly hellgrammites often prefer, tolerating a somewhat broader range of water conditions. Adults emerge in spring and early summer and stay close to their natal waters, resting on streamside vegetation by day and flying to lights at night.

Adult fishflies feed little during their brief flight period, focusing energy on finding mates. Males of some species use their feathery antennae to detect female pheromones. Larvae are active predators that crawl or swim among submerged debris hunting midge larvae, small crustaceans, and other soft-bodied invertebrates, and they in turn provide food for fish and other aquatic predators, making them a meaningful part of freshwater food chains.

Females glue flat masses of eggs to leaves, bark, or structures overhanging water. Hatchling larvae drop into the water and develop over roughly one to two years through several instars while hunting among submerged debris. Mature larvae crawl onto land to pupate in damp soil or under bark near the water's edge, later emerging as adults that live only a few weeks to mate and lay eggs.