Exploring Kootenay Lake

If one were to judge all flies by the few baddies, such as the house fly and mosquito, we would miss out on the delightful ones in the yard and woods. Many folks take pleasure in watching the many species of hover flies go about their rounds. Indeed, in the U.K. there are hover fly watchers, just as there are bird watchers.

This posting is not about a hover fly, but another rather friendly group: the Long–legged Fly (Condylostylus sp.), generally also known as the Condylostylid Fly. It is tiny usually being less than 5 millimetres long; it has long legs; it is the gardner’s friend as it goes about devouring aphids and silverfish; it is fairly easy to approach; but most of all, it is amazingly colourful with metalic green, blue, and gold. There seems to be more the one species around here as I have seen them with both red eyes and green eyes.

Below are two pictures, one with greenish eyes taken this summer, and one with reddish eyes taken two years ago. The Condylostylid Fly will visit flowers for nectar, but I usually see it on leaves, where I assume it is hunting.

The ancients believed that (adult) honey bees could be produced from dead meat. References to this are found in Hebrew and Roman literature. How could this strange belief have arisen? The answer is simple and found to this day in most summer gardens.

The honey bee has a mimic: the drone fly.

It is not uncommon for various species of flies to mimic a bee or wasp. Being the look-alike of a stinging insect confers some protection from predators such as birds. Macrophotography easily enables us to tell the flies from the bees, but, when these insects are seen moving rapidly or in the distance, the differences are apparent to neither birds nor ancients. While adult honey bees emerge from larva in a hive, adult drone flies often emerge from maggots in decaying flesh. It was the honey bee mimic the ancients would have seen emerging from dead meat, not the honey bee.

The first picture shows a honey bee (Apis mellifera) collecting pollen from clover. (Why I have honey bees in my yard is unclear. Are they feral or does a neighbour keep hives?) The bee has long antennae, small eyes, and a distinct waist between the thorax and abdomen. It also has four wings, but that is more difficult to spot.

The second picture shows the drone fly (Eristalis tenax). It has short antennae, large eyes (this one is a male, so the eyes nearly touch), and no waist between thorax and abdomen. It also has only two wings.

Each of these insects is a European import that has become well established across North America.

A honey bee forages for pollen. 

Although shown here on a cedar bough, the drone fly is a pollinator and is frequently found on flowers. The hourglass pattern on the abdomen of this fly is characteristic. It neither stings nor bites so its primary protection is that it looks like something with better defences. 

I have commented a few times that ospreys of the West Arm are in retreat this summer: Ospreys’ annus horribilis, Happy herons. Of course, that doesn’t mean that they have all vanished, just that nesting has been remarkably poor. There are a few around.

Here is an osprey seen two days ago in the lakelet between Kokanee Creek Park and the Harrop ferry.

The European skipper is an invasive species. It was accidentally introduced into Ontario in 1910 and has since spread westward. That being said, one has to admit that invasive isn’t a bad word. This colourful butterfly does not seem to have displaced anything, but merely added to the richness of the fauna in the neighbourhood.

Here are two of the many European Skippers seen this afternoon in a field of tall grass and wildflowers.