Friday, November 13, 2009

Blue Dasher

Blue Dasher's (Pachydiplax longipennis) are one of the most common dragonflies in the United States. They are beginning to make their way to Canada and Mexico as well. They are a small to average sized dragonfly with a wingspan up to 3 inches, the length of their body is approximately 1 3/4 inches.  Blue Dasher's are all blue with bright aqua-blue eyes. The thorax is black with yellow striping. The females have a characteristic yellow stripe on their abdomen.

 Males are very territorial and will aggressively defend their territory from other males in the area. When a receptive female is located, mating will occur. They form a mating wheel, and while in this position a packet of sperm will be transferred to the female. Shortly thereafter she will begin depositing her eggs in the water on aquatic vegetation, or bottom sediment (picture 2). Once the eggs hatch the young nymphs will live an aquatic life, feeding on other aquatic insects. Once they reach maturity they will crawl out of the water onto a stick, rock or other solid surface to shed their skin for the last time. It takes them up to 2 hours or so to pump their wings full of fluid and gather enough strength to fly for the first time. These dragonflies can be found anywhere water is present, this could be ponds, lakes, streams, and wet boggy areas. These are one of the few dragonflies that are able to tolerate poorer water quality. Like all dragonflies they are meat eaters, and they will feed on flying insects. They capture insect using their powerful basket-like legs, right in mid-air, and carry their prey back to a perch to feed. This species has been observed orienting themselves in relation to the sun, either to cool themselves from the host summer sun, or to warm themselves on cooler days.

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