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Kids' Inquiry of Diverse Species

Anisoptera

What do they look like?

Immature dragonflies have six spindly legs, and a body that is only a few times longer than it is wide. They have two fairly big eyes. Some of their mouthparts are modified to shoot forward and grab prey. They breathe water through gills in their abdomen, and can squirt this water out fast to give themselves a quick jet-propelled movement. Adult dragonflies are easy to recognize. They have long thin bodies, very large eyes, and they hold their 2 pairs of wings out flat on either side. Their legs sometimes have many long stiff hairs. Immature dragonflies are usually brown or greenish, and sometimes have algae growing on them. Adult dragonflies can be very colorful, some are red, blue, yellow, or green.

  • Sexual Dimorphism
  • female larger

Where do they live?

Dragonflies are found all over the world. In Michigan there are 114 species

What kind of habitat do they need?

Immature dragonflies live in freshwater. They are most abundant an diverse in slow-moving freshwater that has no fish (small streams and ponds) but can be found in many shallow freshwater habitats. Adult dragonflies often stay near water, but sometimes travel away from water while hunting or on migration. They are fast fliers, so they tend to hunt in open areas, not in thick trees or other vegetation.

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

How do they grow?

Dragonflies hatch from eggs in freshwater, and spent at least a few months (sometimes several years) as aquatic predators. As they grow they molt (shed their whole skin at once) many times. Once they are big enough, they crawl out of the water and the adult stage emerges from the skin of the nymph. Once they have transformed into the winged adult stage, the stop growing.

Most dragonfly species spend the winter as nymphs in the water, but some migrate south, and spend the winter as adults. In few species that lay their eggs in the late summer or fall, the eggs don't hatch until spring. Dragonflies emerge from the water in the warm months of spring or summer.

How long do they live?

Dragonflies live for months at least, and some live for several years as aquatic larvae before emerging and living for a few months as adults.

How do they behave?

Dragonflies need sunny warm weather to fly, usually the temperature must be over 65°C. If it is too cold or wet, they hide in vegetation. Adult male dragonflies often establish territories along the edges of ponds or streams. They only defend the territory against other males of their species. Some large dragonfly species migrate south to warmer climates at the end of the summer. Their offspring may then migrate north the following year.

How do they communicate with each other?

Adult dragonflies communicate visually much more than most other insects. Males fight aerial duels for territory, displaying their size and speed to each other. Mating pairs probably communicate by touch, possibly chemically too

What do they eat?

Dragonflies in their aquatic stage eat many kinds of small animals: aquatic insects, tadpoles, small fish, and other invertebrates. Adult dragonflies eat flying insects, especially mosquitoes and other true flies, but also aphids, smaller dragonflies, damselflies, and just about any other insects they can grab.

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
    • eats non-insect arthropods

What eats them and how do they avoid being eaten?

Immature dragonflies avoid predators by hiding, and by jetting away if they have to. Adult dragonflies avoid predators with their quick and agile flight, and hide in vegetation when it is too cold to fly.

What roles do they have in the ecosystem?

Dragonflies are sometimes the top predators in ponds with no fish. Adult dragonflies help control populations of mosquitos and other flies.

How do they interact with us?

Dragonflies help control populations of biting flies like mosquitos.

  • Ways that people benefit from these animals:
  • controls pest population

Are they endangered?

Most dragonfly species are abundant and common, but a few use special habitats as immatures, and they are at risk because their habitats are in danger.

  • IUCN Red List [Link]
    Not Evaluated

Some more information...

There are some old stories about dragonflies stinging or stabbing people. They are not true. Dragonflies are totally harmless to people.

Contributors

George Hammond (author), Animal Diversity Web.

 
University of Michigan Museum of ZoologyNational Science Foundation

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Hammond, G. . "" (On-line), Animal Diversity Web. Accessed October 24, 2014 at http://www.biokids.umich.edu/accounts//

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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