Scientific Name: Amphibolips confluenta Common Name(s): Spongy oak apple gall wasp Family: Cynipidae (gall wasp) Life Stage(s): Larva Location: Plano, Texas Season(s): Winter

Plant galls are structures of plant tissue that grow in response to the actions of arthropods, bacteria or fungi. These living things hijack the plant and "make" it grow something they find useful.

An "oak apple" type gall created by a parasitic wasp by laying an egg in the leaf as it was growing.

The shapes and structures of galls vary wildly, and often have no obvious correspondence to any of the other parts of the plant. (If you you have a strong trypophobia response be careful googling images of galls some make my crawl, others are etherial)

Some galls seem to be optimized to foil parasitoids who try to lay their eggs inside the pupae of other insects. A wasp would need a very long ovipositor to get to this larva suspended in the center! Somehow the wasp egg induces the tree to grow this complex structure! Amazing!

Although ants are closely related to wasps who play a large roll in the formation of plant galls, ants are *normally* only secondary fauna of galls and not gallmakers.

This is surprising to me since so many plants roll out a welcome mat for ants: extrafloral nectaries as cafeterias, hollow stems& thorns as dormitories. A resident colony of ants can be a plants personal private security detail.

For all the many symbiotic parings of ants and plants there are only a few ants that induce their own galls. As secondary fauna of galls (often created by their creepy cousins, the parasitoid wasps) ants may also act as pest control.

This raises the question: Could plants "allow" gall wasps to make these otherwise energy intensive and potentially harmful structures in hopes of attracting ants as secondary guests? It's a complex web of ecological relationships! Read more here.

Another potential player in this story of galls and wasps and ants are aphids. Aphids are the other main insect that can induce galls. The aphids live in these galls for generations (they don't live long so this is only several months) Of course, ants are famous farmers of aphids.

(Some gallmaking wasps get attacked by hyper parasitoid wasps who only lay their eggs in other gall wasps galls. To prevent this some gallmakers make the galls attractive to ants... who can deter the invaders.)

Oak Apples (or Oak Galls)

Navigating this 2020 pandemic, I have made a point to get outside and walk in my neighborhood every day. Nature always brings a balance in life, I believe, and this is my way of balancing out the uncertainty we are all experiencing right now.

I began walking in mid March, and almost every day I have come across an interesting plant and/or animal. I have been diligent in taking my cell phone…

August 10th - Oak galls continue to fascinate, and on this tree in Victoria Park, Darlaston, there’s quite a display of knopper galls, the first I’ve seen this year.

Like other oak parasites, the knopper wasp lays eggs in it’s host, secreted in a chemical that corrupts the cellular DNA of the host plant matter causing the gall too grow. In this case, the target is the acorn itself, and on this tree, one can see some acorns blighted by two such galls.

As with others, the egg hatches and ithe wasp larva eats the gall and grows safe in it’s corrupted acorn, before boring it’s way out when mature.

Also on this tree, the more conventional wasp gall - the common ‘oak apple’ of folklore, a spherical gall grown the same way.