Exploring Kootenay Lake

First, a dragonfly larva—it’s called a nymph—climbs out of the water. Second, the dragonfly adult climbs out of its the larval exoskeleton—it’s called an exuvia. Doing this is quite a trick, for once it emerges, the adult will become much larger: longer abdomen and expansive wings. All of this content was initially scrunched up inside the exuvia.

The exuvia splits open, the adult pulls itself out and then begins to pump fluid into its collapsed wings and abdomen causing them to gradually expand to full size.

This Pale Snaketail had already pulled its abdomen out of the exuvia by the time my grandson, Finn, pointed it out to me: “Granddad, do dragonflies moult?” The wings are still collapsed and the abdomen is not yet fully extended. The exuvia is the dark shape to the lower right of the dragonfly, and a few minutes before, it fitted inside this.
Gradually the wings and the abdomen expanded as fluid was pumped into them.

Expansion continued and now the wings extended beyond the end of the abdomen.

Suddenly, the wings swung out to the sides. Even so, they have creases in them and haven’t hardened.

Nevertheless, the dragonfly tries a short flight. It is still weak and quickly lands again to continue the expansion and hardening of its wings. An hour later it will be off on its way.

When a moth is named for a mythical giant, one has to suspect that it will be large. Indeed, the Polyphemus Moth is the largest moth in British Columbia, and one of our largest insects of any kind.

Polyphemus, the gigantic cyclops, lived on an Aegean island and ate humans—two for breakfast, Homer tells us.

Polyphemus, the gigantic moth, lives in southern BC forests (and elsewhere) and eats nothing—yes, nothing, the adult’s mouth is vestigial, and this results in a rather short lifespan.

The only function of the adult male Polyphemus Moth (Antheraea polyphemus) is to find females and mate. The finding is facilitated by his large feathery antenna; they are scent detectors tuned to the female’s pheromones.

Polyphemus Moths have a wing span of 9 to 14 cm; this one spanned about 12 cm. It did not stay on the spruce branch for long, but soon flew off on its quest.

I watched a (female) Bee-mimic Beetle (Trichiotinus assimilis) forage for pollen on purple yarrow.

I was not the only watcher. As you can see in the pictures below, a male Bee-mimic Beetle also spotted her.

A female Bee-mimic Beetle is collecting pollen from yarrow.

The male lands on top of her.

And, we have contact.

Dragonflies are grouped into seven families, each of which contains many members. Skimmers, one of the biggest of the families, prefer marshy areas and so are not often seen around the well drained portions of the Kootenay Lake shoreline. Yet there are marshes around here and it is there that one goes to see skimmers. Yesterday, I saw these three skimmer species around the pond at Grohman Narrows Park.

An Eight-spotted Skimmer has, as its name suggests, eight promenant black patches spread over its four wings and sometimes white patches between them. Mature males, such as this one, also have a dusty blue-grey pigment (a pruinescence) on the abdomen.

Not quite as spectacular, but perhaps more common is the Four-spotted Skimmer. The dark patches (one per wing) are much smaller. The little black streaks (the pterostigma) near the wingtips are common to many dragonflies and aren’t counted in the tally. Here are two views.

Also skimmers, but smaller than the spotted ones, are the meadowhawks. This is a White-faced Meadowhawk.