Suburban Wild: Of dragons and ladies

Dragonflies and ladybugs have captured many an imagination with their colourful characteristics

Barbara Julian

The flying dragon is perhaps everyone’s favourite insect. Big enough to be easily seen and bright as a flying jewel, the dragonfly, member of the order Odonata (“tooth-jawed”), largely escapes the insect “ick-factor.” As larvae, dragonflies are as small, brown and dull as any uncelebrated bug, but as adults they transform into what Alfred Lord Tennyson called “a living flash of light.”

Their names alone are poetry — Sedge sprite, Swift forktail, Blue dasher, Zigzag darner — and their ancestors, pre-dating birds, were the first creatures ever to take to sky from earth, some 320 million years ago. In those days everything was gigantic, ferns as broad as hillsides, horsetails tall as trees, and dragonflies two and a half feet long. Imagine that now, as you watch them flitting around our local lakes.

“Ontogeny recapitulates phylogeny”: the individual life cycle re-enacts the evolution of a species. Before becoming adults, dragonfly larvae are aquatic mud-dwellers that breathe through gills which also act as fins for swimming. Maturing, they leave water for air and grow wings, just as wings evolved in their ancestors after the gills and fins.

Dragon-like predators, the adults grab small flying insects out of the air and transfer them to crunching jaws while shooting forwards, backwards and sideways using two sets of independently moving wings. They mate head to tail in a circular formation, and the male organ has a special talent: it not only deposits sperm into the female’s abdomen but can also pull other males’ sperm out. The females deposit the eggs in water, mud or onto plants, her mating partner sometimes dive-bombing other males who might try to interfere. There’s more going on with these living flashes of light than a casual observer might realize.

There are 88 species of dragonfly in B.C. and the Yukon, more of the lyrical names including Grappletail, Western pondhawk, Sinuous snaketail and Red-waisted whiteface. A good place to find some in Oak Bay is the pond at the head of Bowker Creek at UVic.

The other insect most likely to escape people’s “ugh” reaction is the ladybird beetle. There is something endearing about its round, red, black-spotted body, so beloved of children’s book illustrators. It performs a useful service, for according to Tracey Stewart in Do Unto Animals (2015), one ladybug can eat up to 5,000 aphids in an afternoon. That is why local parks departments import them for non-chemical aphid control, although some ecologists consider this a mistake. The wild-caught commercial aphid-destroyers are a species originally imported from Asia which have out-competed the 450 native species, and in some places become a crop-harming pest themselves.

They do have the handy habit of laying their eggs among aphids however, which the hatching larvae immediately start devouring. They also need pollen, so anyone with aphids can attract ladybugs by planting geraniums and umbrella-shaped herbs. They like dandelion pollen too, however, so presumably help spread that pest even as they control the aphid. As always, relationships among the plants and animals around us are intricate.

Ladybugs have a handy ability some humans might envy. They eject a poisonous liquid from their knee joints when anything tries to molest them. These would usually be birds or spiders, not humans, because although they over-winter in people’s houses, instead of being squashed or evicted like a spider they are often considered a sign of good luck and left unharmed. It’s amazing what an advantage a cheerfully spotted red thorax can be, if it causes people to coddle you in a nest box and paint your portrait instead of squashing you under their heels.

 

 

Barbara Julian is a local writer and nature enthusiast. She writes here once a month about the wildlife in and around Oak Bay.