Galls: wasps, mites, and midges

Is there any way to tell whether a gall was made by a wasp/mite/midge/whatever else creates them? I know it’s important to know what plant the gall is on but are there plants where, for example, only wasps create galls? Can they be identified by shape?

Sometimes I’ll see something and know it’s a gall, but other than that I have no clue what made it. Any suggestions/tips?


Galls can be tough to ID. I would recommend that you join one of the various gall projects here on iNat, where your observations will likely come into the view of someone who might know, and also where you can look through the species already observed, and see if one of them matches what you saw.

In the meantime, you may have to ID them as “insect”, and hope that covers it. Some galls are created by fungi.


It’s really hard for me. I was identifying ‘unknown’ observations to galls but I was like… what is it? Today I learned, galls are made by insects or fungi and is actually not the insect itself.

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Yes, but they count as evidence of an organism, so they are totally fine to put on iNat, like tracks, scat, nests, etc. I don’t know too much about gall ID, but some can be IDed to species for sure, eg


heartily second that. The guidance I received from a member of one such group was to submit things even if unsure as the likelihood of someone with expertise seeing it, ID-ing it. and/or correcting it is greater than if it were to sit without attention in a lengthy list of unknowns. As Susan suggests, adding, “insects,” will be helpful by attracting anyone filtering for insects to ID. If it’s fungi, they’ll probably be able to tell you that something isn’t from an insect.


I would first join a gall project as susanhewitt recommends.

If a collection project I would probably put it at Subfamily Pachypsyllinae if it were a small gall and at Family Cynipidae if a larger one. It will put them in sight of other gall enthusiasts to be corrected. Family Cecidomyiidae and Family Eriophyidae (mites) are other good possibilities as to culprits to look through to see if you can identify them.

Alternatively, put it as Phylum Arthropoda(to include possible mites) and manually add it to a gall project.

I forgot to mention aphids as well: Subfamily Eriosomatinae


Thank you for the advice everyone. Galls are such a fascinating thing, I didn’t know they could also be made by fungi! I’ll look for some gall projects and see what I can learn from them.


If you persevere, gradually you will get the hang of how best to handle your observations of galls – they are indeed fascinating things, and yes it is very often hard to know which kind of organism made them.

Definitely add all your observations of galls to one or more gall projects.

I would encourage you to just forge ahead and do not be intimidated by how little you currently know. Most of us know hardly anything about galls, but a lot of us really like them anyway! :)


Here is a list of projects✓&q=galls

Because many galls are undescribed, I have been thinking that it might be beneficial to have a gall project organized by plant and locality. For this to work, the first photo of the “plant” would have to feature the gall very prominently. The gall itself is part of the plant, so ID’ing an oak gall as “Blue oak” would be a valid choice if confusing for unsuspecting identifiers.


Thanks so much for the link! I joined a couple NA projects and one for my region as well. Also in the search results there were projects for leaf disease and egg sac/cases/etc which I’m sure will be just as fascinating :)

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There is also a leaf miner project.

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