Goldenrod Galls

These small spheres have started to appear on the goldenrod.  I now know they are created by a the Goldenrod Gall Fly, thanks to the Audubon Guides!  The fly’s larva will winter within this lump (known as a gall, of course) and emerge in spring.

I have always been a bit fascinated by the galls.  I had no idea what purpose they served and, since I typically noticed them only in winter, had no idea what plant they were on.  What I have noticed is that they are exceptionally hard.  But in deep winter, you will see that many of them have been opened, with a hole drilled into the side.  Now, understanding what is at the center of this gall, it makes sense that birds are opening them.  I had supposed that there must be seeds, but larva and glucose would be far more tasty!

Galls on a Goldenrod Stalk
Galls created by a Goldenrod Gall Fly on the stalk of a goldenrod. During winter, the larva will try to survive until spring but the contents of the gall are a tasty treat for predators who are also trying to survive through the cold.
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David Whelan
I improve information access and lead information teams. My books on finding information and managing it and practicing law using cloud computing reflect my interest in information management, technology, law practice, and legal research. I've been a library director in Canada and the US, as well as directing the American Bar Association's Legal Technology Resource Center. I speak and write frequently on information, technology, law library, and law practice issues.

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