Insects: Dragonfly and Damselfly

Range: worldwide except polar regions Habitat: rivers, streams, lakes, and ponds

Meet another kind of dinosaur

When you think of dinosaurs, you might think of those found in the movie Jurassic Park, but there were many other prehistoric animals that are still around today. And some lived even before dinosaurs first appeared: dragonflies and damselflies!

These two insects are in the same taxonomic family, Odonata, and look pretty similar; they are often called odonates. Dragonflies and damselflies have been popular insects for years because of their brilliant, iridescent colors and interesting hovering flying style. Some countries, such as Japan, represent the dragonfly in their art and culture. More importantly, these insects help tell us about the health of an ecosystem: their young can be severely affected by any changes in water flow and water pollution. More dragonflies in an area may indicate a healthier water ecosystem.

A spectrum of color

One thing you notice right away about dragonflies and damselflies is their wonderful array of colors. Dragonflies come in all sorts of colors like yellow, red, brown, and blue; sometimes the wings have brown spots and bands. The male damselflies typically have iridescent wings and some type of colorful blue, green, or purple body, while the females usually have a golden brown color, even on their wings. Dragonflies generally have a thicker and shorter body than damselflies, which are very slim. Both have very large compound eyes; however, damselflies have a separation between the eyes while dragonflies’ eyes are close together. Their compound eyes may be made up of 30,000 lenses, providing them with excellent vision. Talk about having one of the best pair of glasses!

Nature’s version of a helicopter

Both dragonflies and damselflies have two pairs of wings. These wings are very thin and sheer, with small veins that crisscross to add strength. Dragonflies can beat their wings together or separately. Like a helicopter, this lets them turn easily in the air, hover, and fly backward. Some dragonflies can even reach speeds of up to 20 miles per hour (30 kilometers per hour).

Damselflies, on the other hand (or wing!) are actually kind of clumsy in the air. They have weak wing muscles and beat their wings at different times, so they are slow and look a bit awkward when they fly. Damselflies rest with their wings together but not folded, while dragonflies rest with wings apart. This is a unique trait and a result of their aerial lifestyle. They have no folding mechanism because they always need to be ready to launch at a moment’s notice!

The morning routine

These helicopter-like insects live near fresh water. It is the place where the females lay eggs and where the young can develop. They live in many different habitats all over the world, except the polar regions, which are too cold and have too much frozen water. Before the odonate starts its day, it must warm up, not by doing stretching and bending but by exposing itself to the sun. You may notice that on cloudy or overcast days, odonates are rarely seen, because they need some bit of heat to function. In the mornings, they can be found on various plants while basking in the sun to absorb heat or making their own heat by shaking their wings. Once their bodies have been warmed up, it is take-off time. Dragonflies and damselflies spend most of the rest of their day flying around to catch food. In fact, they are almost always moving (how exhausting!): if they stop zipping around, they could end up as a snack for some other animal.

Insects on the menu

Odonates are carnivores, but they don’t eat the kind of meat we do. It is not chicken and beef for breakfast, lunch, and dinner but rather insects! Damselflies have legs that are located out in front of their body for grasping prey, while dragonflies have strong, biting mouthparts to eat with. Both chase smaller flying insects like mosquitoes and gnats, making them helpful to us by keeping all of those pesky insects in check that could carry diseases. Usually, once the dragonfly or damselfly has its prey, it will eat it in midair; however, if the prey is a larger insect, the odonate lands on the nearest branch to quickly gobble it up!

Life in a nymph’s shoes

The courtship of dragonflies and damselflies often requires aerial contests, as territory is fought over among males. Females only mate with males that have a territory to defend that is close to a body of water. In both damselflies and dragonflies, the male often guards the female after copulation while she lays her eggs in water. The emperor dragonfly Anax imperator and common blue damselfly Enallagma cyathigerum lay their eggs onto the stems of pondweeds to protect them from being eaten by fish.

The larva that hatches out of the egg is called a nymph. It has wing pads but no functional wings, breathes underwater with gills, and feeds on other insect larvae, tadpoles, and small fish. It is stocky and shorter than the adult and is usually a green-brown color to help blend in with its watery habitat. Water temperature can determine what time of year the eggs hatch and how quickly or slowly the nymph will grow and molt.

Like its parents, the nymph is a carnivore. It grabs prey with a unique mouthpart called a mask, which can shoot out and snatch prey in its pincers. All nymphs go through a molting sequence that can last between a few weeks to several years, depending on the species. Molting is how insects grow. During a molt, the old exoskeleton is shed to reveal the body that has grown larger underneath it. Nymphs molt between 10 to 20 times, and the time between molts is called an instar. Eventually, the nymph sheds for the last time and emerges as a full-grown adult dragonfly or damselfly, with a long skinny body, transparent wings, compound eyes, and two sharp mouthparts. The new adult needs to allow time for its new, soft exoskeleton to dry and harden before it can fly. During this time it is very vulnerable to predators.

Watch out!

Being a good-sized insect, odonates have to watch out for predators. Animals that eat dragonflies and damselflies include fish (bass, in particular), water beetles, ducks, water shrews, and water bugs. Most birds are not fast or agile enough to catch dragonflies. The nymphs are the most vulnerable, and a lot of them become a meal for ducks while they are growing or emerging into adulthood.

Whether dragonflies or damselflies are favored for their color, aerial acrobatics, or beauty, they are key insects in our ecosystems. They help us monitor the health of our fresh bodies of water, serve as an important link in the food web, protect us from other pesky and infectious insects, and bring us a sense of beauty in nature. They can arguably be called the prettiest dinosaur still living!