Wasp Gall on an Oak Leaf

Hi everyone! I hope everyone is having a wonderful rest of your weekend! I haven't been able to get to my trip notes yet, so I'm posting another picture from our property. :)

Fall is Here!
As October marches towards November, the leaves are turning every shade of the rainbow and falling from the trees in ever-greater numbers. Steve and I have been oohing and ahhing over the amazing show whenever we're out and are hoping for a fall photography adventure in if we can fit it in between his projects.

Behold the Colorful, Odd Cynipid Wasp Gall
One might notice that a few leaves--especially from Oaks--have something strange attached to them. These 1/4"-1"globes are perfectly round in shape, hollow and semi-translucent when held up to the sun . Upon closer examination, there will be a small hole somewhere around the lightly fuzzy ball. What a curious thing! Whatever could it be?

This is a wasp gall! There are several species of wasps which lay their eggs in specific trees or other plants. When the larvae hatch and begin eating the plant's leaves, stems or branches, they also exude specialized growth hormones. These hormones cause rapid growth in the shape of a ball or lump of some sort depending on the species of gall wasp. The larvae sit inside this gall, which grows around them and provides protection and nutrients while they mature over the next few months. Eventually they will nibble their way out of the gall as fully-grown adults and fly away! Although they are technically parasites, they rarely do any harm to the host plant and leave only the empty galls as their calling cards.

Our property is the home to many types of wasp galls and I think this type-Cynips mirabilis---is my favorite, though the other species are very interesting and photogenic too!

If you would like to know more about some of the different types of wasp galls, here's an informative web page for you: Wasp Galls

For more pictures that include images of the various wasps and a lot more information, take a peek at this: In-Depth Article About Gall Wasps of Southern Oregon

Explored on 10/26/20; highest placement #1.