Exploring Kootenay Lake

A great deal of deception is perpetrated in the fields and woods: camouflage, feigning, mimicking. Fawns sport a dappled coat so as to vanish into the sun-flecked brush. Robins feign injuries to lure predators away from a nest. Flowers lacking nectar attract pollinators by mimicking flowers that deliver.

The topic du jour is the common practice of some types of fly to mimic a bee. A year ago, I treated this same topic, Telling bees from flies, with a more nicely matched pair of images. I now take another run at it using two pictures taken this last week.

A bee has a good defence against a bird that would eat it: it stings. A fly is not similarly armed, but some adopt the survival strategy of looking as if they were: they masquerade as a bee.

Although many flies are remarkably good at such mimicry—good enough to fool birds—differences can be seen. Some are subtle and may not be obvious in the field: bees have four wings; flies only two. Others are easier to spot: flies have larger eyes and smaller antennae than bees. Below is a picture of a bee and a plausible look-alike.

This is a bumble bee, a Bombus vagans (I think). It has long antennae and smallish eyes. This one has alighted on forget-me-nots and is using its tongue to sip nectar.

This is a fly, one of the hoverflies in the genus, Criorhina. Its eyes occupy a much larger portion of the head than do those of the bee. Indeed, this male’s eyes almost touch in the middle of the head. (The particularly large eyes of the male help it to find females). The fly cannot hide is enormous eyes, but it has an interesting way to compensate for its vanishingly small antennae, and it demonstrates it in this picture. The fly will extend its forelegs and wave them about in a simulation of the constantly probing antennae of bees.

Typical oval face of the Polistes aurifer---our local paper wasp.

There seems to be almost as many species of social wasps around here as there are social bees. Most of those wasps have a fairly oval face. Certainly, that is the case for the genus, Vespula—many of the yellow jackets that build nests in the ground—and the Polistes—the paper wasps that build single-layer open-cone nests. Local examples of these can be seen on this website’s page about social wasps.

Then there are the Dolichovespula or long-faced vespula (from Greek, dolikhos = long). They are also the ones who build the large spherical nests that hang from trees and other aerial structures. For years, I have been familiar with Dolichovespula maculata—the Bald-faced Hornet. In the last few days, I spotted my first Dolichovespula arenaria—the Aerial Yellowjacket.

First, two pictures of the familiar Bald-faced Hornet showing its striking long face.

Then, two pictures of the Aerial Yellowjacket—showing its long face.
 

“My, my, who are you?” was my initial reaction to seeing my first Hummingbird Moth (Hemaris diffinis). I had read about it, but as my frequent insect-watching forays had not previously turned one up, this sighting was unexpected.

Also known as a Clearwing Moth, this creature often hovers as it collects nectar from a flower. It is also unusual for a moth in that it is active during the daytime. The adults are mainly on the wing in May, so now is the time to look for them. I show three pictures, below.

The Western Spring Azure is one of the first butterflies to emerge from a pupa in the spring. It is tiny—wings barely larger than one’s thumbnail—and easily missed when it is still. When on the ground, it raises its wings to display its camouflaged underside. When it flies—ah, then the beautiful azure topside is shown.

Each spring for a half-dozen years, I have watched this delight and tried to take a picture of it flying so as to capture the azure topside. Time after time, I have had to trash blurry shots. Finally, yesterday, I came close to the objective.

A Western Spring Azure looks inconspicuous when on the ground with its wings raised.

This flying spring azure shows the bluish topside of its left wings, but the monochrome underside of its right.

If this weren’t satisfying enough, it landed and was caught in the instant before the wings were again raised.