Dragonflies and damselflies
Also known as Odonata, Anisoptera, Damselflies, Mosquito hawks
In short
Dragonflies are fast, aerial hunters that catch midges, mosquitoes and other flying insects, and their underwater nymphs eat mosquito larvae. They cannot sting and do not bite people in any meaningful way. They only breed where there is still or slow water, so a pond or wetland is what brings them to a garden.
How it looks
Adults have very large compound eyes, a long slender abdomen and two pairs of clear or tinted wings; dragonflies are stout and rest with wings held flat and open, while the thinner damselflies fold their wings together over the body. Colours range from blue and green to red, yellow and brown. Nymphs (naiads) live underwater among plants and mud; they are six-legged and wingless, with a hinged lower jaw that shoots out to seize prey. Empty nymph skins are often left clinging to stems above the water after the adult emerges.
Signs
Adults patrolling sunny gardens, ponds or paddy fields; cast nymph skins on plant stems at the water’s edge.
Life cycle
Egg, aquatic nymph and adult, without a pupal stage. The nymph stage lasts from a few months to several years; adults typically live a few weeks.
What favours it
Sunny, sheltered still water with submerged, floating and emergent plants and perching sticks; good water quality. There are about 3,000 dragonfly species, most of them tropical. Fish such as koi and goldfish eat the nymphs.
Prevention
- Add a pond or water feature with native submerged, floating and emergent plants and a few perches.
- Keep ornamental fish out of the pond meant for wildlife.
- Avoid insecticide fogging and sprays near water.
Treatment
Start with the first step and move down only if the problem persists.
- No control needed; they are harmless to people and plants.
Pros and cons
Pros
- Adults eat large numbers of flying insects, including midges and mosquitoes.
- Nymphs eat mosquito larvae and other aquatic insects.
- Their presence indicates reasonably clean water.
Cons
- Large nymphs also eat tadpoles and small fish.
- Adults catch beneficial flying insects as well as pests.
- Of little use for indoor or non-pond collections.
Look-alikes
- Lacewings
- Lacewings are weak, fluttering fliers with small bodies and wings folded roof-like at rest.
Where you find it
Garden ponds, water gardens, bog-plant and carnivorous-plant setups outdoors, and tropical gardens near water.
Related
Sources
Written in our own words from these sources. Check a product label before using any treatment.