Our 2017 Theme Arthropod is the DRAGONFLY!
This year is the Museum's 21st BugFest, the largest single-day bug-centric event in the country! The theme focuses on the wonderful world of dragonflies. Museum dragonfly expert Chris Goforth created the following list of fun facts about dragonflies and tips on how to identify some of the common local species.
Dragonflies are Aquatic Insects
Many people don't know that dragonflies start off their lives underwater! Most dragonfly species lay their eggs in either ponds or streams and the juvenile dragonflies (the nymphs) that hatch from them will live in the water until they become adults. In fact, dragonflies spend most of their lives underwater! Nymphs typically spend 1-3 years underwater, but adults are only on land 3-5 weeks.
Dragonflies Undergo Hemimetabolous (aka Incomplete) Metamorphosis
Many people are familiar with the butterfly life cycle: egg, larva, pupa, and adult. The dragonfly life cycle is simpler, with an egg, nymph, and adult. While dragonfly nymphs don't look exactly like the adults, they look a lot more like the adults than a caterpillar looks like a butterfly! This is because dragonflies don't completely change form the way caterpillars do and instead go straight from a non-winged nymph to a winged adult.
Dragonfly Adults Live on Land
Adult dragonflies live outside of the water, so they undergo what's called an emergence when they transform from a nymph to an adult. The nymph typically crawls out of the water and up the stem of a plant. It puffs its body up (often by swallowing air and pumping blood into specific parts of its body) and cracks the exoskeleton open. The adult then pulls itself out of the exoskeleton and expands its wings and adult body. Once everything is fully expanded, the new exoskeleton hardens and the adult dragonfly can fly away.
Dragonflies Are Territorial
Dragonfly females choose their mates based on where they want to lay their eggs — they mate with the male they find at their chosen site. As a result, there is fierce competition between male dragonflies of the same species to control the most desirable places. Male dragonflies divide a pond or stream into territories of various qualities and the strongest, best males get the best territories along with the most mates. The weaker males take the lesser territories where fewer females are interested in laying their eggs, while the weakest males might not get to fly near the water at all! A dragonfly moves into a better territory by fighting (and beating!) the male that holds it. You'll often see males chasing each other or flying in circles facing one another. These are fighting males and whoever they decide is stronger comes back and gets to claim the territory — and the mates that come with it.
Dragonflies are Predators
Dragonflies are predators as nymphs and adults. They are often among the top predators in ponds and streams and eat other insects (including other dragonflies!), small fish, small tadpoles or frogs, and other animals. Dragonfly nymphs have a unique, long hinged mouthpart that helps them hunt, that they grab and hold their food with while they chew it up. Adult dragonflies also eat other animals, including mosquitoes, other flies, butterflies, and other dragonflies and use their long legs to help them catch food as they fly. Some species of dragonflies have been known to catch and eat hummingbirds! Dragonflies are an important balancing force in nature and help prevent prey populations from getting too big throughout their lives.
Some Dragonflies Migrate Thousands of Miles
Scientists know of a few dozen species of dragonflies that make impressive migrations each year. In North Carolina, you're most likely to see Common Green Darners, Wandering Gliders, Spot-winged Gliders, or Black Saddlebags during the fall migration as the dragonflies move from cooler areas in the north to warmer areas in the south. Green Darners likely fly south thousands of miles the way Monarch butterflies do! However, we are still learning about this behavior and still don't know where they go or whether the same individuals come back in the spring.
Visit a pond in the Triangle Area and you are likely to see some — or all — of the following species!
Common NC Piedmont Dragonfly Species
- Common Green Darner
- LARGE dragonfly, usually seen flying over the water near the shore.
- Males: Green thorax, blue abdomen.
- Females: Green thorax, green abdomen.
- Common Whitetail
- Medium dragonfly with broad abdomen, often seen perching on plants over the water.
- Males: White abdomen; black bar across center of front and hind wings.
- Females: Brown abdomen; three black spots across each wing.
- Carolina Saddlebags
- Medium dragonfly, often seen flying over water 10-15 feet from shore.
- Males and females: Deep red abdomen; burgundy spots at base of each hind wing. Often seen over grasses away from water.
- Black Saddlebags
- Medium dragonfly, often seen flying over the water 10-15 feet from shore.
- Males and females: Black abdomen with yellow spots (more obvious in females than males); black spot at the base of each hind wing. Often seen over grasses away from water.
- Blue Dasher
- Small dragonfly, often spotted perching on plants along the shoreline. Sometimes has amber spots at the base of the hind wings.
- Males: Blue to white abdomen (becomes more white as they age); bright blue-green eyes.
- Females: black abdomen; pale stripes along the sides.
- Eastern Pondhawk
- Medium dragonfly, often perched on plants near the shore; clear wings.
- Males: dusty blue, eyes deeper green than in the Blue Dashers.
- Females: bright green with black markings along the abdomen.
- Slaty Skimmer
- Medium dragonfly, often perched on plants near shore.
- Males: Deep blue to deep purple (almost black) with deep burgundy eyes.
- Females: chestnut thorax with central pale stripe; yellow abdomen with central black stripe.
- (No photo of female Slaty Skimmer available.)
- Halloween Pennant
- Medium dragonfly, most often spotted perching away from the water on tall, pointed plants.
- Males: usually red and black abdomen; orange and deep orange wings with dark spots.
- (No photo of male Halloween Pennant available.)
- Females: yellow and black abdomen and yellow wings with smoky grey spots.