Tuesday, January 13, 2009

Goldenrod Galls

We went out in our yard yesterday to look for goldenrods. Unfortunately, I cut most of the dried stalks this fall in an uncharacteristic bout of brush clearing. I will stay in character next year to have a greater variety of galls to look at!

We did find a few stalks that I overlooked in my brush-cutting bout:

And we found a gall on the stem of one:

My daughter Maynie (who is the official Blog Photographer) brought the stem in. Here she is with her little sister Meera posing with our find:

We opened up the gall, and here is what we found:

It's hard to tell from the picture what we saw, but it looked like the skin of a pupa. After doing some research on the internet, I found out that this is the empty pupal case of a Goldenrod Gall Moth (Gnorimoschema gallaesolidaginis). This kind of moth comes out of its pupa in the fall.

From what I read on the internet, there are three types of goldenrod galls, all caused by different insects. Our gall was an elliptical one. The round ones have a larva that overwinters by having antifreeze in its body fluids. I would like to find that one next year. It would also be fun to try to see all the different insects that live in goldenrod galls at all stages of their life cycle. Maybe something to attempt starting in the summer when our goldenrods grow back again.

Here are links to the three websites where I got most of my information on goldenrod galls:
They’ve got some gall
NNZ-Goldenrod Gall Fly

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