 Dragons Overhead! Dragonflies that is...
A paddling day is made all the more magical when a dragonfly pays a visit by taking a rest one's canoe gunwale or kayak deck... and even more spectacular when it decides to molt in the safety of one's gear. Such was the recent experience of Joe Anderson, Steward Specialist with the Maine Bureau of Parks and Lands, when he was out monitoring Pierce Pond. Joe's photo is below.
Newly molted dragonfly, called a teneral at this stage. Photo by Joe Anderson.
Dragonflies have a three-stage lifecycle. They begin as an egg which, depending on the kind (species) of dragonfly, is either injected into plant material by the mother dragonfly using her ovipositor, or laid with a protective jell-like coating into water. Eggs generally hatch within two to five weeks, though some species overwinter in the egg stage. When the egg hatches a tiny larva emerges. The first job of this prolarva is to find a safe place to molt - to shed its exoskeleton. Job two is to eat voraciously. This begins a cycle of eating, growing and molting. Until finally, at the final molting stage, as in the photo above, the dragonfly transitions from a nymph to an adult by shedding its exoskeleton one last time - emerging with wings and the complete ability to breathe air and live above the water.
Interesting Facts
- Dragonflies have been around for about 300 million years!
- Dragonflies are found on every continent except Antarctica.
- Wingspans of dragonflies today span up to about five inches. Long ago they spanned up to two feet!
- The three-stage life cycle of dragonflies is called Incomplete Metamorphosis
- The larval stage is an aquatic (underwater) stage and, depending on the species, can last up to two years!
- Dragonfly nymphs (those in the larval stage) eat almost anything they can catch, including other insect larva, mosquitoes, tadpoles and fishes. One dragonfly can eat hundreds of mosquitoes in one day.
- Day length and temperature help trigger the final molt of dragonflies in which they transition from a nymph to an adult.
- When the new adult emerges from its last molt it is has very light or pale coloration and it has to rest and let its body and wings harden before it can fly. It is called a teneral at this stage.
- The Globe Skimmer dragonfly (Pantala flavescens) can fly non-stop for hundreds of miles and is credited for the longest insect migration. It flies almost 4,000 miles per individual to complete and annual multi-generational migration of over 11,000 miles. It can glide on the wind to conserve its energy.
Activities for Children and the Young at Heart
- Look for dragonflies when you are exploring near or paddling on ponds and waterways. Use a field guide to learn more about the dragonflies you see. Keep your notes and drawings in a field journal or small notebook to help you remember what you've learned and to compare observations over time and through the seasons.
- Over 150 species of dragonflies live in Maine. Learn more at the University of Maine Cooperative Extension Dragonfly page and at the Maine Damselfly and Dragonfly Survey website.
- Compare Complete and Incomplete Metamorphosis. What stage is missing in Incomplete Metamorphosis? Compare the life cycle of the butterfly to the dragonfly. How are they the same? How are they different?
- Design-A-Dragonfly - do this by making a drawing, paper model, or even a paper kite or dragonfly mobile! Name and describe your dragonfly. Where does it live? What is its metamorphosis like? What does it eat? Why did you color it the way you did? What kind of eyes and mouth did you give it?
- Visit your local library or bookstore to look for storybooks about dragonflies. Can you find stories that share the knowledge of different cultures about dragonflies written by the people of that culture?
- Why do you think dragonflies got "dragon" as part of their name? What can you find out about this?
- Are dragonflies beneficial? How? To the habitat where they live? To other animals?
- Compare damselfies to dragonflies. How are they alike? How are they different?
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