Dragonflies, Pacific Northwest
The Dragonflies are a large predatory insect that is generally found around lakes and streams, they are quite common on the coast of BC. They are best known for their beautiful colors and the way their body and wings sparkle when they are hovering over the water.
Dragonflies have long, thin colorful bodies, large eyes and two pairs of transparent wings. As with other species of insect, the dragonfly also has six legs but it is unable to walk on solid ground. In flight, the adult dragonfly can propel itself in six directions which are upward, downward, forward, back, and side to side.
The dragonfly larvae are aquatic. The dragonfly larvae or nymph is capable of producing a painful bite for humans, so don’t attempt to catch them in your hands. Better still, just observe them and let them be.
Both the dragonfly and its larvae are carnivorous animals and they feed exclusively on other small animals. The main prey of the dragonfly are mosquitoes, bees, and other small invertebrates. The larvae feed mainly on aquatic insects and their eggs. The dragonfly is itself, preyed upon by a number of predators including birds, fish, toads, and frogs.
Female dragonflies lay their eggs in water. The dragonfly eggs then hatch into nymphs. which is how most of the dragonfly’s life is spent. The dragonfly nymphs live beneath the water’s surface, catching insects and vertebrates such as tadpoles and fish.
The larval stage of some dragonflies may last as long as five years. When the larva is ready to metamorphose into an adult, it climbs up a reed or other emergent plant. The exposure to air causes the larva to begin breathing. The skin splits at a weak spot behind the head and the adult dragonfly crawls out of its old larval skin, pumps up its wings and is ready for flight.
Mature males are bright red on the face, thorax, and abdomen. Each side of the thorax may be marked with a pair of yellow spots. The wings have some red veins along the outer edge and are shaded with brown near the body. Females are a dull red and the wings may appear a translucent gold color. Immature males are brown instead of red and the spots on the thorax are white rather than yellow.
This species is found from southern British Columbia down the pacific northwest coast all the way to Chile. They can be found on the southeast coast of Vancouver Island from Campbell River south.
This dragonfly can be found near marshes, ponds and small lakes.
They fly from mid-May to mid-August. They like to perch bare branches or bask on rocks to absorb the heat early in the day. This species is one of the first dragonflies to emerge each year. I always look forward to seeing them in the spring, they seem to bring the sun with them.
After mating the female typically flies off alone, without the male attached, to lay her eggs in lakes and ponds. She does this by dipping the tip her abdomen on the surface of the water.
The Larvae live in debris on the bottom of ponds and lakes. They do not actively pursue prey but wait for it to pass by, a strategy which affords them protection from other predators. Larvae emerge as adults at night.
The face below the eyes is marked with yellow. The thorax is greenish-brown with fine hairs and a metallic luster. A bold yellow stripe extends diagonally from the dorsal area along each side of the thorax.
The wing vein at the front of the wing is yellow, the rest are black. The abdomen is black with yellow bands on the dorsal area of each segment. Legs on this species are unusually long.
Females in the family Macromiidae lack an ovipositor that is used to deposit eggs. Populations from the South Coast are darker. The larvae have a prominent horn between the antennae along with large eyes and long legs. The abdomen is broad, round and has high, slightly arched dorsal hooks.
Members of the order Odonata are carnivorous. Adults capture prey by hawking or flying back and forth over an area. Dragonfly larvae can prey on a range of organisms like small fish, amphibian larvae, other aquatic invertebrates including their own species or those of other dragonflies or damselflies.
This species can be confused with the Pacific spiketail dragonfly, the spiketail eyes meet at a single point on top of the head and those of the cruiser are broadly joined. The eyes are a blue color on the spiketail and grey to dark green on the cruiser.
The male common whitetail has wide, black bands on its wings, there is a broad band near the wing tip and a small narrow band at the base of the wing. The head, eyes, and thorax of the male are dark brown, and faint pale stripes are visible on each side of the thorax.
The immature males have all the same markings except they lack the white markings on the abdomen and have small white spots that run along the sides.
The face, eyes, and thorax of the female common whitetail are brown, and the thorax has two white stripes on the sides which become yellow at the ends. The female’s abdomen is brown with white or pale yellow spots on each side. The spots form diagonal lines. The wing pattern of the female is completely different from the males, she has three dark spots or patches on each wing.
The males are very territorial during the breeding season. An adult male will patrol his territory and drive off all other males he encounters. The success of the male’s defense of his territory usually depends on age, with older, more mature males generally being more successful than young, immature males.
Most males are only able to defend their territories for a few hours per day though, this sometimes leads to more than one male defending the same territories at different times of the day.
The female will visit breeding sites every few days, usually around midday looking for males. after copulation, the female will immediately begin oviposition. The female taps the water with her ovipositor to lay up to 50 eggs with each tap. She may deposit up to 1,000 eggs in total. The male will protect the female during her egg laying by flying just above her.