Les Jones

Way cool

Galls are so bizarre. We had an infestation of these galls (i can't remember the specific name) in the shrubs outside of our apartment.

There are some pictures here

Beautiful!

Keep this up and cat blogging will become so passe.

Kinda creepy.

Thanks, guys.

Chris: That's wild. I've never seen those before. In picture 17, is that the critter erupting from the top of the gall?

Yep. There was a 1-2" larva inside each one -- they almost look like Monarch butterfly larva.. I talked to an entomologist or someone at some point that told me what they were..

They hatch from an egg inside a branch and immediately start secreting a hormone that promotes cell-growth in the surrounding plant tissue. Eventually it forms a coccoon of the live tissue that it keeps on its back, sorta like a hermit crab has a shell.

Very weird. Then eventually, they attach to something and the cocoon seals up. I can't remember what they turn into, though.

That's my kind of post! It might be worthwhile to point out that the gall wasp is a tiny thing that most people would mistake for a gnat, if they noticed it at all.

Chris, your insect is a bagworm moth larva, and those are not galls, just protective cases the caterpillar builds from dead plant parts and silk it secretes from its mouthparts. The adults are nondescript medium-sized moths.

Do they taste good?

Yours,
Wince

Interesting.. so the plant material is just dead? How disappointing.

Is that the definition of gall -- it has to contain live tissue?

Galls are formed by a live plant, typically as a reaction to chemicals injected by an insect along with an egg. Bagworm cases are constructed by the insect from plant materials. I'm not sure if they use live or dead tissues during construction, but it's definitely dead once it's silked to the case.

I'm not sure where you got that stuff about hormones promoting cell growth. That sounds like how galls form, but those cases the bagworms drag around are not galls. Perhaps a bagworm uses a gall to start its case, then adds on additional plant material as it grows and needs a bigger case. I've never heard that, but it's possible.

If you know caddisflies (a/k/a "stickbait"), they build their cases the same way. Some species use twigs and bits of leaves, and some use rocks, but they all cement their case together with silk. Moths evolved from caddisflies, and some species retain the habit of dragging a case around for protection. Moths that eat wool, the ones mothballs are intended to ward off, are case-builders. If you ever get an infestation of them, you may find little tubes of lint creeping slowly across a wall with a tiny caterpillar inside. The cocoons of moths and butterflies (and wasps) are essentially these same cases constructed entirely of silk, without the interwoven bits of debris.

I for one welcome our Oak Gall Wasp Overlords...
cool post

One of the freakier things you'll find on any blog that's still Rated-G

my galls started out clear .... I thought they resembled pearl onions very closely ...and the more mature ones I mistook for opportunistic plants because of the windseed like matrix inside the dried paper gall. I'd been doing shishkabob and really did wonder if the opaque/clear seemingly gelatinous filled "balls" were edible. Wow ...wasps ...who'd a thunk it

I just discovered these this year around and in some of my trees in central Pennsylvania. I have found several attached and growing on the ground so it appears it does not need the Oak tree itself to form these Galls. I am 50 years old and have never seen these before and had trouble finding out what they are. They look very much like plant growth and never suspected they are insect related.