Blue Dashers are your friends.
These small, beautiful, gem-tone dragonflies are fun to watch as they patrol the lake shore, and – big added bonus here – they can eat more than 30 mosquitoes each in a day.
Male Blue Dashers are highly decorated. They have bright blue abdomens with black tips, yellow tiger-striped thoraces and bright, reflective blue or green eyes above their white faces. Females are not as brightly colored, with striped thoraces and brown and yellow-striped abdomens.
Blue Dashers often have patches of amber color in their wings. They grow to roughly 1.75 inches long.
Blue Dashers are members of the skimmer family – the largest family of dragonflies in the world – and they are one of the most common dragonflies in North America. In fact, their range is bigger than just our country. These dragonflies are native from southern Canada to Mexico and also are found in Cuba, the Bahamas and Belize, although they are not seen in the Rocky Mountains or the Dakotas.
Blue Dashers are sometimes called the Swift Long-winged Skimmer or the Blue Pirate. The scientific name of this insect is Pachydiplax longipennis, which doesn’t mean what you might think. In Latin “longipennis” means “long wings,” (pennis is the plural of penna, which means “wing”). Although a male Blue Dasher’s wings aren’t much longer than its relatives, a female Blue Dasher has a shorter body, which does make its wings look longer in comparison.
Blue Dashers live near the shoreline of still bodies of water, which could include everything from Lake Martin to a drainage ditch or a slow-moving stream. They seem to prefer marshy, low areas in warm climates.
These dragonflies sit on their perches and help control their internal temperatures by changing their positions relative to the sun. Often on hot days, Blue Dashers will hold their abdomens straight up in what scientists call the “obelisk” position in an attempt to remain cool.
During the day, Blue Dashers are very active; at night, they roost in trees.
Males are very territorial and will chase away other males that fly over their turfs.
Mating takes place in the air and can last from several seconds to two minutes. Once a couple mates, the male will stand guard on a perch while the female flies close to the water’s surface, repeatedly releasing eggs as she touches her tail to the surface. Blue Dasher females are capable of releasing 300-700 eggs in only 35 seconds.
When the eggs hatch, the young Blue Dashers are called niaids, and they hang out in aquatic vegetation and ambush other larva that drift or swim by. Once they mature, they will crawl up on vegetation that extends above the water at night and molt their exoskeletons several times to take the familiar dragonfly shape.
Blue Dashers have a fierce, dragon-like reputation for being vicious hunters of other flying insects. Each day, these dragonflies consume insects weighing up to 10 percent of their body weight.
They hunt by ambush in air as well, remaining still on a perch and waiting for a prey insect to wander by. By prey insect, we’re speaking of almost any flying bug. These dragonflies are not picky and will catch and consume anything that flies, from moths to gnats. When a flying bug does stray nearby, a Blue Dasher dashes out and grabs it, enveloping it with its spiked legs; and then, flies back to its perch to eat.
While you can watch Blue Dashers with the naked eye, an even better way to observe them is to identify a stake-out spot – dragonflies will often use the same perch over and over during a day while hunting, Bring a pair of close-focusing binoculars and a chair for your own Blue Dasher stake-out.