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Project Noah Nature School
Sialis spp.
Adult alderflies are usually black, dark brown, or gray. They look a lot like stoneflies but are more closely related to fishflies and dobsonflies. They are generally poor fliers. At rest, the 2 pairs of heavily veined wings are held folded over the back in a rooflike (usually not flat) shape. Antennae are about half the length of the body. Alderflies lack ocelli (small, simple eyes), while fishflies and dobsonflies both have ocelli on their heads, between the compound eyes. The fourth tarsal segment (one of 5 the beadlike components of the foot) is inflated and 2-lobed.
Spotted next to the Yakima river.
Adult alderflies are usually found amid the vegetation lining the aquatic habitats their larvae require. They sometimes are attracted to lights at night. Alderflies don’t live long as adults: they mate, lay eggs, and expire soon afterward. Different species prefer different types of aquatic habitats. The larvae of many alderflies prefer slow-moving, detritus-littered waters with silty bottom sediments, such as ponds and lakes, while others require clearer, faster-flowing, better oxygenated streams.
Spotted on Oct 7, 2017
Submitted on Oct 10, 2017
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