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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.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends.

bog

a wetland area rich in accumulated plant material and with acidic soils surrounding a body of open water. Bogs have a flora dominated by sedges, heaths, and sphagnum.

carnivore

an animal that mainly eats meat

chaparral

mid-altitude coastal areas with mild, rainy winters and long, dry summers. Dominant plant types are dense, evergreen shrubs.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

diurnal
  1. active during the day, 2. lasting for one day.
fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

freshwater

mainly lives in water that is not salty.

internal fertilization

fertilization takes place within the female's body

marsh

marshes are wetland areas often dominated by grasses and reeds.

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

migratory

makes seasonal movements between breeding and wintering grounds

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nomadic

generally wanders from place to place, usually within a well-defined range.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Climbing plants are also abundant. There is plenty of moisture and rain, but may be somewhat seasonal.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

semelparous

offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

taiga

this biome is characterized by large expanses of coniferous forest, there is an extended cold season and heavy snowfall.

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

 
University of Michigan Museum of ZoologyNational Science Foundation

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Hammond, G. . "" (On-line), Animal Diversity Web. Accessed April 23, 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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