Thursday, June 26, 2008

Seeing spots

I've been wondering about ladybugs. Gardeners have been releasing buckets of non-native species to kill aphids for a few years; by now, are the bugs in our yards old-timers or immigrants?

So this spring I've been taking photos of every one I've seen. Yesterday I sorted through my file. Over half of them were the imported Multicoloured Asian Lady Beetle, Harmonia axyridis. And the rest; well, let's see...

I found this one in New Westminster. The Asian ladybug.

The identification depends on the pattern on the pronotum, the shield between the head and the wing covers (elytra). All Multicoloured Asians have a marking in the shape of a W (or an M, if you're looking from the tail end.) Apart from that, they're ... well, multicoloured. And variously spotted. BugGuide has 288 photos of this species alone, and almost all different in some way. Wikipedia shows 13 different patterns.

Here's another, this one from Steveston:

The pronotum is more or less like the previous one, but the head has more white, and there are fewer spots on the elytra, 14 as compared to 19 (counting that centre-front spot as 1.)

And here's another, from Crescent Beach:

Black face, 18 variable spots. And the W.

But these are different:

There's no W. Seven (two at back, where they did not show up in this photo) spots on the elytra, two angular white spots on the head, and two rectangular ones on the elytra.

It's another import: the Sevenspotted Lady Beetle, Coccinella septempunctata. I found this one in Strathcona, Vancouver.

Another Sevenspotted, from across the street here in Delta.

And how about this one, from New Westminster?

No W. No black spots on the elytra, but the two rectangular white ones at the front edge, like those of the Sevenspotted LB. An elaborate black and white pattern both on the pronotum and the head.

There are similar ladybugs on BugGuide, and some discussion as to which of the three Cycloneda species they belong to. I would guess it's theWestern Blood-red Lady Beetle, Cycloneda polita, which is native to this area.

This was the only one in my file. All the rest were introduced species. And the roses are still loaded with aphids.


  1. This has been very educational - I had no idea!


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