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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