A dragonfly starts life as an egg laid in or near water. Dragonfly larvae, called nymphs (also naiads), are aquatic. The egg usually hatches in 1-2 weeks. The nymph will feed and grow, shedding its skin several times. Each stage between shedding is called an instar. Depending on the species there can be 8 to 17 instars, and nymphs can take from 4 weeks to several years to grow large enough to change into adults. The last instar will crawl out of the water, shed its skin and emerge as a winged adult. This kind of insect life cycle is called “incomplete metamorphosis”.

Nymphs of damselflies breathe with 3 feather-like gills at the tip of their abdomen and can swim by wiggling their abdomen like a fish. Dragonfly nymphs have gills inside their rectum at the end of the abdomen. Muscle action moves water in and out of the rectum. They can even jet around by expelling water rapidly. They use their legs to crawl around most of the time, but can use jet-propulsion to escape enemies and even to lunge after prey.

Watch a dragonfly nymph "jetting" around. (Video = 0:33, 1.0 Mb)

Damselfly nymphs swimming. (Video = 0:20, 0.5 Mb)


Watch higher resolution versions of these videos on YouTube.
Click Here: Nymph Jetting Around! | Click Here: Nymph Swimming!

Most Manitoba dragonflies have only one generation (from egg to adult) per year. Some require four or more years for one generation. Most have offsetting generations, though, so there are always some adults around each year.

Some dragonflies emerge at night and are ready to fly the next morning. Other species emerge during the day. Many species emerge in large numbers over a very short period, often just a few hours. “Mass emergences” ensure that males and females will mature at the same time and find mates. They also overwhelm local predators and ensure survival of enough breeding adults.

The synchrony of emergences in most species and the short lifespan of adults mean that each species has its own flight season, the time of year when adults are hunting and mating. We see dragonflies around from spring to early fall, but it is a series of different species that we see, each with its own flight season of a few weeks. No one species of dragonfly is around all summer.

Dragonfly emergence!
(Video = 2:00, 3.7 Mb.)

Most adult dragonflies live only a few weeks. After spending a long time, up to several years, as a slow-moving aquatic nymph, the adult has a short, intensely active life as an aerial hunter.


Watch a higher resolution version of this video on YouTube. Click Here: Emergence!

A dragonfly can fly about an hour after it emerges, but it takes up to two weeks before it is fully mature. A newly emerged dragonfly is pale in colour without any dark markings. It is called a “teneral” or immature. It will fly off and feed until it is mature and its adult colours have developed. Then it seeks out wetland habitat to find a mate.

Males wait near wetlands for females to show up. They court them in flight, often hovering directly in front of the female. In some species, males set up territories and drive off rivals.

Prior to mating, males transfer sperm from the 9th abdominal segment to the hamulus, a secondary sex organ in the 3rd segment. A male first grabs a female with his legs and then grasps her behind her head with claspers at the tip of his abdomen. They mate in a “wheel” position where the female curls her abdomen up to take sperm from the hamuls.

After mating, in some species the male will hold onto the female and the pair will fly around together as the female lays her eggs. In others the male may release the female, but guards her from other males while she is laying eggs. Sometimes the female lays eggs alone.

Some females lay eggs simply by dropping them into water. Other species lay egg-filled strings of jelly in water. Some have an ovipositor, a needle-like tip on the abdomen, and will insert eggs into aquatic plant stems or even into damp ground near water. A female may lay several batches of eggs over her life time, totalling several thousand eggs.

Egg laying.
(Video = 0:55, 4.3 Mb.)


(Watch a higher resolution version of this video on YouTube. Click Here: Egg Laying!)

1) Basic Biology

2) Life Cycle

3) Palaeobiology

4) Biodiversity

5) Biogeography

6) Overwintering / Migration

7) Food

8) Sight and Flight

9) Cultural Significance

10) Conservation

Return to Opening Page

Fly back to NatureNorth.com