Thu. Dec 7th, 2023
The fascinating world of dragonflies and their importance for ecosystems

Today’s blog comes to us from Sarah Lamond, Algonquin Provincial Park naturalist.

Picture it: a warm July day in Algonquin.

You’re basking in the day’s rays and exploring an interpretive trail. Everything is perfect until you hear that telltale buzzing sound and feel that all-too-familiar pain in your scalp. The deer flies have arrived. Hitting the growing swarm, you look up at the sky and wonder: will there be no relief?

And then they arrive. The prehistoric predator. The deer fly eater. The people’s champion: dragonflies.

We often get only brief glimpses of dragonflies as they fly at speeds of over 55 km per hour, hunting for insects. But there’s so much more to their incredible lives than just hunting, something most people never know.

Green Darner Dragonfly

Believe it or not, of the approximately 7,000 species of dragonflies that exist in the world today, about 130 are found in Ontario. Each species has its own distinct colors, patterns, niches, and behaviors.

But that’s just the beginning of what makes dragonflies so amazing!

Know the Difference: Dragonfly vs. Damselfly

Dragonflies are part of the family. Odonata (meaning “the toothed ones” as they have large, toothed jaws), which includes both dragonflies and damselflies. Odonata Insects have been around for 325 million years!

While there are family similarities between dragonflies and damselflies, there are key characteristics that set them apart. Dragonflies have relatively robust bodies, and damselflies’ bodies are thin in comparison.

Side-by-side photographs of two singed insects with long, thin bodies.  On the left, a bright blue-green fly with black wings.  On the right, a dull gray dragonfly with lacy wings perches on a leaf.A species of damselfly known as a River Jewelwing sits perched with its wings closed (left), while a racket-tailed emerald, a species of dragonfly, sits with its wings open (right).

However, the easiest way to tell them apart is when they are perched. The wings of sitting dragonflies extend to each side of the body, while sitting damselflies fold their wings and hold them above their body.

At the beginning: life underwater

Dragonflies have a fascinating life journey. While we think they travel through the sky, they actually spend most of their lives underwater in their larval stage.

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When laying their eggs, adult females float on top of the water until they find the perfect spot and then begin to continually dip the tip of their abdomen into the water to release the eggs. Once the eggs hatch, the larvae can take two to six years before developing into adults.

During the larval stage, baby dragonflies molt between six and 15 times. To fuel this process, dragonflies subsist on other aquatic invertebrates, larvae, and sometimes even tiny fish! They do this with an extendable jaw, which they can fire at lightning speed to capture their prey.

Not only do they have a unique way of catching food, but their rapid movements through the water are also unique. Dragonfly larvae have gills that line the rectum and pump water through them. When they need to move quickly, they expel pressurized water from the end of their intestines, propelling them through the water at high speeds. They use this tactic both to hunt prey and to avoid becoming dinner for larger predators, such as fish and frogs.

From larva to adult

When a dragonfly nymph is finally ready to become an adult, the nymph will emerge from the water onto land and shed its old skin (known as exuvia) and emerges as a fresh, winged adult.

Two brown dragonfly nymph carcasses held in the palm of a human hand.Dragonfly exuviae (nymph) guts found dry on a rock near a river

It often takes hours before the dragonfly can begin to fly, as it must pump blood through the abdomen and through gradually expanding wing veins.

Skillful predators in the air

As adults, dragonflies only live a short time, from a couple of weeks to six months. In this short period, they focus on three things:

  • defending their territory
  • find a partner to reproduce
  • eating

Adult dragonflies hunt their prey in flight and are extremely agile fliers. They can fly forward and backward, hover in mid-flight, and even spin 360 degrees in place!

While flying, they use their six legs to grab their food in the air and then bring it up to their large jaws to feed.

Dragonflies have excellent vision compared to other insects. Its large, alien-like compound eyes are made up of nearly 28,000 individual units, known as ommatidiathat cover most of your head.

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Their field of vision, combined with their ability to fly, makes them quite adept at catching food while diving and avoiding predators (or an enthusiastic naturalist’s insect net!).

Dragonflies in Algonquin Provincial Park

Dragonflies are some of Algonquian naturalists’ favorite species to observe. For 26 years, Algonquin Provincial Park naturalist staff have been conducting an annual dragonfly and damselfly count in the first week of July.

Silhouette of a person holding an insect net standing on a pier as the sun sets in the distance.Naturalista lined the Opeongo docks in search of Stygian shadow dragons, a species that only comes out after sunset.

This count is done in a very similar way to other community scientific surveys, such as the Christmas Bird Count. During this type of survey, a designated counting circle is determined and divided into areas. Groups of naturalists and volunteers are then assigned an area, where they identify and count all the dragonflies and damselflies they see throughout the day.

To properly identify many of the species, it is necessary to catch them in an insect net and handle them for a closer look; They can then be let go without any harm coming to them.

Up to 74 species have been recorded on the day of the count! Have an idea of Odonata numbers each year is important to track long-term trends in their populations and help us reveal species declines or recoveries in the area.

Dragonflies are ecologically important!


Dragonflies are not only fascinating for their life cycle and flying style. They are important to their ecosystems and are valuable environmental indicators, as they depend on healthy aquatic ecosystems and food chains.

Changes in the population of these insects can help reveal changes in aquatic ecosystems. They are one of the top predators in the insect world and as such play an important role in controlling insect populations, particularly stinging insects and agricultural pests.

Learn for yourself

Dragonflies and damselflies are easy species to observe. You can find them practically anywhere there is water. If you want to learn more about the species you can find in Ontario, there are excellent field guides, such as Photographic Field Guide to Dragonflies and Damselflies of Southern Ontario and the Algonquin Field Guide to the Dragonflies and Damselflies of Algonquin Park and Surrounding Areas.

You can also upload photos of your dragonfly and damselfly sightings to the scientific databases iNaturalist and Odonata Central.

Sharing posts contributes to ongoing community science projects tracking these magnificent creatures in our area!