New-born thimbleberry wasps

A month ago, I collected a few thimbleberry galls, brought them home, and split one apart to look at the larvae hidden inside. (Story, here.) I stashed them afterwards in a plastic container and set them aside in a cool spot.

This week, I opened the container. And several tiny wasps have burrowed their way out.

The larvae as they were a month ago.

Another one of the galls, this week, with exit holes.

And one of the newly-emerged wasps, Diastrophus kincaidii. About 2.5 mm long.

Another one, bent over, showing off her wings.

Wasp # 3. Wasps have that tiny waist; it seems strange that it can support the weight of the heavy abdomen.

I just checked again. There were three galls, all on the small side. And now there are a dozen new wasps, freshly emerged. I left the lid off; I don't know where they'll go, since I have no thimbleberry canes nearby. Maybe they'll find an alternate host in the raspberries.

Gourmet chickadee feed

Years ago, when I lived on a hillside overlooking Silvermere Lake, my living room windows faced a stand of thimbleberry bushes. During the winters, I watched a flock of chickadees that spent their days pounding away at the hard galls on the bare thimbleberry canes. It was hard work, but they persisted, in spite of the easier feed of of black oil sunflower seeds a few metres away. Easier, but obviously not as tasty.

On the road to Deadstick Pond, I stopped to examine a collection of galls.

Gall on bare thimbleberry stem. This one has exit holes.

Two galls, mostly intact.

And the chickadees have been working on the one on the right.

I collected a few galls to examine more closely at home.

Gall with many exit holes. I cut it in half and saw ...

Holes where the larvae had been. The centre of the gall is the original stem of the thimbleberry.

And then I cut open one of the intact galls; it had residents.

Two pretty larvae visible, hints of another deeper inside.

These are the larvae of the thimbleberry stem wasp, Diastrophus kincaidii. They are tiny; about 3 mm. long. (See UBC photos.)

Gravid female D. kincaidii prefer to ovi-posit in the  relatively soft, rapidly growing shoots of primocanes, which often host  clutches  of  eggs from  multiple female  wasps (Wangburg  1975). Green, irregularly shaped galls form as larvae begin to feed during the rst season and adults emerge from woody galls early in the summer of year two. (From Research Gate)

The galls form on the green canes (photo), which are soft, but the chickadees wait till the second winter, and break into the hardened galls, probably because the larvae now are fat and juicy. Good eating! (If you're a chickadee.)

I stashed the galls in a plastic container; I'll be watching to see what adults bore their way out.