Posts Tagged 'galls'

Gall-y

Here’s another gall for your collection:
Cypress Twig Gall Midge (Taxodiomyia cupressiananassa).
Affects Bald and Pond Cypresses. I like how they almost kinda look like the cones.
***

Yesterday, Trump mafia family members Ivanka and Jared tweeted that they were sending in their mail-in ballots, just hours after Trump railed again against mail-in balloting once again. He’s been lying about this for months to undermine the validity of mail-in ballots, while his own advertisements have been filled with claims he was using a mail-in ballot, going so far as show a close-up of his signature on the alleged mail-in ballot. (He seems to have voted in person in Florida this past weekend.)

Wisconsin’s Koch-funded denial of votes received after Election Day has been cleared by the Supreme Court, 5-3. (Amy Covid Coathanger Barrett would have made that 6-3. She becomes the third member of the radically reactionary SCOTUS supermajority who worked on Bush’s 2000 judicial coup.) In a sinister footnote to this Wisconsin decision, Injustice Kavanaugh has essentially announced his intention to not let votes be counted if it will help his master. The USPS is still run by a Trump loyalist (and private mail delivery profiteer), with all evidence suggesting that ballots are being delayed in the mail.

It now behooves us to vote in person if at all possible. I did it yesterday.

Fall Galls

You may be-galled out, but I’m certainly not. All of the above were gleaned from under a great white oak, the mother (?) of galls, on October 10. Five species of gall wasps are represented here.
Pea Gall (Acraspis pezomachoides).
Philonix nigra.
Round Bullet Gall Wasp (Disholcaspis quercusglobulus).
Andricus wendi.
Clustered Midrib Gall Wasp (Andricus dimorphus).
In this latter case, a leaf with most of the cluster still attached had also fallen.

Notes on Galls

Galls are highly specialized plant tissues whose development is induced by another organism.”

The relationship is essentially parasitic, says Britain’s Plant Galls: A Photographic Guide, but “few gall-causers seem to cause more than localised, short-term damage to their host plants.” This book continues: “Plant galls can be caused or induced by a very wide variety of organisms, including bacteria, nematodes or eelworms, and even other plants, but most of our galls are caused by insects, mites, or fungi. Although we do not know exactly how the galls are initiated, it seems clear that most gall-causers interfere with the development of the host plants’ cells, either chemically or mechanically, and cause them to develop into gall tissue.”

This Britain’s Plant Galls is good: “Many gall wasps induce no galls of their own but lay their eggs in the galls of other species. Their grubs benefit from the food and shelter found there and, although they do not harm the gall-causers directly, by competing for the food supply they can starve them to death. These ‘lodgers’ are known as inquilines. Quite a few flies have similar life styles. Parasitic species, which include many, often brightly chalcids, actually feed on and kill the rightful occupants of the galls. The female parasite tends to have a long ovipositor with which she penetrates the galls to lays her eggs in or on the host grubs. Strictly speaking, these insects should be called parasitoids because typical parasites do not kill their hosts. Parasitoids also attack the inquilines, and a large gall, such as an oak apple, can house a very large insect community, consisting of dozens of individuals of several different species.”
Here’s a good description of gall-makers in an article on the co-evolution of plants and gall-forcing herbivores like the Cynipid wasps:

“Gallers are specialized herbivores that induce the development of, and feed on, modified host plant tissues that, relative to surrounding nongall tissues, have elevated nutritive value but contain very low concentrations of toxic secondary plant metabolites.” ~ “Extreme Host Plant Conservatism during at Least 20 Million Years of Host Plant Pursuit by Oak Gallwasps” by Stone, et al. Evolution Vol. 63, No. 4 (Apr., 2009), pp. 854-869.

They somehow side-step the plant’s defenses and get better than average food out of the deal. Nice work if you can get it!

From the same article: there are about 1000 oak gall wasp species. They’re associated with oaks (Quercus) and other Fagaceae. Almost all alternate sexual and asexual generations, and each of these generations has a distinct gall — sometimes on other oak species.
You’re unlikely to ever see any of these small wasps unless you raise them yourself, so we know them by their work, the galls themselves.
I’ve logged 26 species of Cynipidae gallwasps in iNaturalist. Twenty-four of these have been in Brooklyn, all in Green-Wood Cemetery but one. (Years ago I also found an oak apple on a Cobble Hill sidewalk, but don’t seem to have preserved any memorial of it. Got my eye out for them now.)

Cecidologist: one who studies galls.

All the gall posts here at B & B.

Back To The Galls

Andricus quercusstrobilanus on swamp white oak (Quercus bicolor). There’s no common name for this gall-forcing wasp species.
Note the gap here, and the hollows within.
The individual galls brown and shrivel up as they grow. Then they fall to the ground. (I don’t think this is standard for gall wasps in general).
Since this tree had two other similar clusters, I thought it was ok to take a living sample, i.e., no exit holes for the wasp. (Many Cynipid wasps emerge in the fall as a flightless generation. Looks like this species overwinters, however.)
I cut one open.
Behold, the larva!
With something growing on it! So a gall is good protection against the vicissitudes, but it’s not foolproof. There are parasitic inquiline wasps that prey on gall wasps.
There are also parasitic wasps that prey on the parasitic wasps of gall wasps.

Even More Galls!

Andricus incertus on swamp white oak (Q. bicolor) acorn. (All the below are on various swamp white oaks as well.)
A cluster of Oak Rough Bulletgall Wasp galls (Disholcaspis quercusmamma). Note the ants and bee.
Bald-faced Hornet and Asian Lady Beetle, too. In fact, I found several with lady beetles on them. Are the galls extruding something sweet to eat?
This one is out of the ordinary, if any of these extraordinary gall structures can be called ordinary. Andricus quercusstrobilanus. (You’ll be noticing a number of these things don’t have common names.)
Oak Rosette Gall Wasp (Andricus quercusfrondosus).
And fresh versions of the same.

More Galls

This is Andricus capillatus, a Cynipidae gall wasp like all these specimens today, on a white oak.
Round Bullet Gall (Disholcaspis quercusglobulus), on the same white oak. This magnificent specimen of a tree is on a slope, with one branch sweeping down below eye-level, which is essential when searching for these things.
Here’s another Round Bullet Gall, from a previous year (and again, the same white oak). These are quite woody and persistent. Notice the exit hole. The wasp cut its way out.
Inside is the cocoon.
The empty cocoon. The wasp had to get out of here before cutting through the gall structure.
Millimeter scale.
Acraspis pezomachoides, same tree. Pea-sized.

Remember, the tree itself forms these galls in response to the irritation of the wasp. What fascinates me is how each species of wasp forces a characteristically differently-shaped gall.

Back to the Galls

The hickories and their Caryomia genus midges continue to catch my eye. I’ve now spotted eleven species in Green-Wood, mostly on pignut (Carya glabra). Here’s my first report on this phenomenon. Above is Hickory Peach-haired Gall Midge (Caryomyia persicoides) according to my gall sensei on iNaturalist. Some species are obvious, others like this one need an internal view.
Caryomyia ansericollum, with no common name.
Hickory Onion Gall Midge (Caryomyia caryaecola).
They start out green, but Hickory Smooth Gumdrop Gall Midge (Caryomyia sanguinolenta) can turn red. Sometimes there is more than one species on a leaflet. The others here are Hickory Bullet Gall Midge (Caryomyia tubicola).
Better looks at Hickory Bullet Galls.

Hickory Bumpy Woody Gall Midge (Caryomyia tuberculata).

The full run on iNaturalist.

Midge Monday

It turns out, because you have to turn the leaflets over, that hickory trees are potentially loaded with gall mites. There are several dozen hickory gall midge species in the Caryomyia genus, each forcing the tree to make a little shelter for the mite. Acting on a call from a curator on iNaturalist, I examined a few hickories in Green-Wood, which is well-represented with the glorious Carya genus of trees.
In the above pictures, the funnel-like ones are Hickory Smooth Gumdrop Gall Midges. The furry ones… well, there are several furry ones and I’ll need to cut these open to discover what they are.
Hickory Placental Gall Midge. These, like the above examples, were all on pignut (Carya glabra), which seems to be the richest host amongst Green-Wood’s hickories that I’ve seen so far. For instance, on a shagbark right next to this pignut, there were hardly any at all. In addition to pignut and shagbark, other hickories here are mockernut, bitternut, and shellbark. Green-Wood is an island of specimen trees, not a forest, so it’s cool to think these galls have made it here or survived who knows what.
Here’s some of the furry-spiky ones, on mockernut this time.
Cutting one open reveals to the iNaturalist curator that this is Purple Gumdrop Gall Midge.
Caryomyia marginata, no common name, on the same mockernut.

More Galls

I found a mother-of-gall tree! A red oak, Quercus rubra, in Green-Wood. This tree was probably brought in as a sapling a few years ago. I wonder where it was raised? Could it be that the gall-making species came in with the tree, as we’ve seen with lichens transported into the city on saplings destined to be street trees?
Everything pictured in today’s post was on this one oak — two very nearby red oaks, both looking like they were planted this year or last, were devoid of this diversity. They only had one type of gall on them.
How many gall-makers are seen here? Three, four?
Is this, for instance, one or two gall species at work?
Oops, here’s another.
And another.

Getting very little traction on iNaturalist with identification for these things. There are too many galls and not enough people interested in them.

And yet, consider the fascinating relationships of insect (wasp, mite) and plant. (And not just insects!) The plant forms these structures, which are unlike anything else they produce in the normal course of events, in response to the animal. The animal uses the plant for shelter and food, and some other animals may use the first animal, parasitizing the egg or larva inside the gall. And around and around it goes.

Monday Galls

Gallia est omnis divisa in partes tres
At the tips of a young oak, small round nestled in filamenty nests. Galls (not Gauls, pace Casesar) with exit holes. Big question in the wonderful world of galls is: what emerged, the gall inducer or the inquiline (parasite)?

Not just on the bud tips.

Possibly something in the Andricus gall wasp genus. This is a large genus. As I understand it, each species makes a unique gall. These tiny wasps stimulate the tree by chemical commands and the tree grows a gall in response. The tree is being hijacked, but not really damaged (?).

But wait! I’d originally thought this tree was a red oak but could it be be a bur oak? Will have to double check this.

If it’s a bur, then Andricus quercusfrondosus sounds like a possibility. This source notes that this species creates autumnal growths for the the agamic or asexual generation. Yes, gall wasps, which were once all called gall flies, alternate an asexual generation and a sexual generation. According to the cited piece, the agamic or sexual generation isn’t known for this species.

More complications: found a similar if not same gall on a definite red oak, which will be the subject of another day.

To summarize: galls are complicated.


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