COMMON DAMSELFLIES

     During summer, I sometimes enjoy seeing a few or more metallic-green, male black-winged damselflies fluttering and dancing in shafts of sunlight low over clear-running streams in shady woodlands.  Flashing green, these striking male damselflies are fighting for territories along the streams they will use to display to females of their kind, and mate with them. 

     Black-winged and bluet damselflies commonly live along streams in southeastern Pennsylvania, and in much of the United States.  But each kind has its own niche along those waterways.  Black-wings inhabit shaded streams in woods, while bluets live in sunny meadows of the same waterways.  That diversity of niches reduces competition for food and space between these damselflies species.  But these damselflies overlap here and there because their habitats do.  There I see both kinds in a small stretch of stream, much to my pleasure.    

     These two kinds of damselflies, and their relatives, have characteristics in common, which reveals their relatedness.  Males of both are attractive with lovely colors.  Male bluets are sky-blue with black rings on their abdomens.  But females of both species are mostly light-gray, which camouflages them.

     Both genders of both species have thin abdomens, and large eyes to spot prey on the wing.  Both are entertaining to watch fluttering after flying insect prey.  And females of both species spawn into the more sluggish parts of streams where they hatched.    

     But, when at rest, black-wings hold their black wings up and over their abdomens at a 45 degree angle.  Bluets at rest, however, hold their clear wings down along the sides of their abdomens.  

     Aquatic nymphs of both species are lean, brown, which camouflages them on mud and stones, and have three, "tail-like" gills that protrude from their rears.  Those gills, of course, take oxygen from the water.  And these nymphs feed on tiny, water invertebrates.  In turn, some nymphs are eaten by fish, water snakes, turtles and other aquatic creatures.  

     Adult damselflies catch and ingest flying insects.  Some of them, however, are consumed by a variety of birds, frogs, dragonflies and other critters.

     Male black-winged damselflies and bluet damselflies are pretty, little creatures that are beneficial to us because they catch and ingest pesky, flying insects.  But I enjoy most their fluttering low over streams and by tall grasses on the shores, where their beauties are pronounced.        

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