Blue Dasher
Latin Name: Pachydiplax longipennis
Species: Terrestrial Invertebrate
Conservation Status: Not Evaluated
Blue dashers are one of the most common species of dragonfly found in South Carolina. Adults are typically 1-1.5 inches long with 2 sets of wings marked with dark streaks. The 2 sets of wings operate independently, enabling the dragonfly to change direction quickly and to hover in place when necessary. Males are a more vibrant blue with yellow-striped thoraces and metallic green eyes. In its larval stage, the dragonfly larva (nymph) lives in water and has 6 legs, large eyes, and a huge mouth.
Range & Habitat (map)
Blue dashers are found throughout North America, and live in and around slow moving water, marshes, and ponds. Nymphs are bottom-dwelling or benthic organisms, and are tolerant of wetlands with poor water quality and low dissolved-oxygen levels.
Diet
In their larval stage, blue dasher nymphs eat other small insect larvae and aquatic organisms, especially mosquito larvae. The nymph’s extendable jaws allow it to catch and eat prey almost as large as itself. Adult dragonflies hold their legs in a basket shape during flight so they can catch and eat small flying insects in flight. An adult blue dasher can eat hundreds of insects each day.
Life History
There are 3 stages of life for a blue dasher — egg, larvae, and adult dragonfly. A female dragonfly lays her eggs directly on the surface of the water or in aquatic vegetation, where they sink to the bottom. The larval stage of the dragonfly is the longest stage — a blue dasher can remain a nymph for as long as 4 years, and will go through several molting cycles. The nymph then crawls out of the water and goes through a metamorphosis to become an adult dragonfly.
Significance
Dragonflies are incredibly successful hunters. Despite their small size, they catch up to 95% of the prey they pursue. This makes them one of the most successful predators on earth, and also plays a big part in controlling populations of smaller insects in their ecosystem.
Threats & How You Can Help
Blue dashers are relatively tough — they can survive in impaired waters with low levels of dissolved oxygen. That makes them an indicator species. If we only find dragonfly nymphs in a creek and no other benthic organisms, that might indicate a problem with water quality in that waterway.
Additional Resources
Friends of Cortez Island – https://www.friendsofcortes.org/species-at-risk/blue-dasher-dragonfly/