Remember a few days ago when I showed photos of a Cameraria larva mining in a red maple leaf and wondered if both maple-feeding species have such dark larvae?
(The second photo is a backlit close-up of the mine at the right side of the first photo.) Well, take a look at this mine I found on September 5 on a sugar maple (Acer saccharum) behind the chicken run:
I think we have our answer. I reviewed my photos of mines from which I’ve reared the two species, and I’m pretty sure the dark larva (Leafminer #161 for my yard list) is Cameraria aceriella, and the pale larva with dark markings (Leafminer #172) is C. saccharella. I went back to check on the red maple mines, and unfortunately I won’t be able to track their progress. The larger mine had progressed some but then a predator had torn open the upper epidermis and removed the larva:
The larva in the smaller mine had been devoured by the larva of a eulophid wasp, which had now pupated in the middle of the mine:
There were a few other Cameraria mines on nearby red maple leaves, but the larvae in them look the same as the ones on sugar maple. I’ll try an keep an eye on the situation.
Leafminer #173: Tischeria quercitella (Tischeriidae), on red oak (Fagaceae: Quercus rubra). At last, the BugTracks mascot (see the banner at the top of this blog) has made an appearance in my yard!
Leafminer #174 / Sawfly #44: Profenusa thomsoni (Tenthredinidae), on gray birch (Betulaceae: Betula populifolia). Earlier this season, I had found mines of two other introduced leaf-mining sawflies on the paper birch sapling at the edge of my yard, but I hadn’t checked the gray birch sapling next to the black walnut in the “upper nut orchard” until now. There were several old, tattered mines of P. thomsoni on it.
Leafminer #175: Aspilanta argentifera (Heliozelidae), on the clump of sweetfern (Myricaceae: Comptonia peregrina) on the other side of the walnut. I’ve now found three of the six species in this newly described genus in my yard this year. Let’s see if I can also find A. viticordifoliella on Virginia creeper; the other two don’t occur anywhere near New England.
Leafminer #176: Ectoedemia ?similella (Nepticulidae), on red oak. This mine more or less matches the description of E. similella, but there are two undescribed Ectoedemia species known from oaks in the eastern US (at least one of them occurring in Massachusetts), and I’m not sure how their mines differ. The single mine I found already had an exit slit (at lower right in the photo below)…
…so I was surprised to discover that the larva hadn’t left yet.
Within a few hours, the larva did find its way out of the leaf:
Leafminer #177 / Sawfly #45: Profenusa sp. (Tenthredinidae), on the same red oak sapling. To decide between P. alumna and P. lucifex I’d need a close look at the larva and count the segments on the antennae and legs, although only P. lucifex has been documented feeding this late in the season.
I found another one of those lower-surface Marmara mines on tall blue lettuce, this one on a plant growing by the door to the shed. It appeared to me at the time that this mine entered the leaf midrib and continued to the base (evidently entering the stem, but there was no visible mine there). Now that I look at the photos, though, it appears that the midrib mine just passes by the leaf blade mine without interacting with it, and I think the larva is still in the blade where one of the main lateral veins meets the midrib. I’ll have to take another look at that today. None of the other mines I’ve been monitoring has shown any sign of entering the midrib. I do think the mine on the midrib is another Marmara though (same species or a different one, I couldn’t say).
The midrib mine is easier to see in this photo I took without the flash (this is a section closer to the base of the leaf):
And here’s the midrib mine disappearing into the stem:
Next to the shed, at the south end of the yard, is part of a big white pine tree that we cut down several years ago to let in more light. Because the pine was crooked, and because it fell on top of a small black cherry tree that is still alive, it isn’t lying flat on the ground, and there is now a tangle of dense vegetation growing through and around the two fallen trees. This jumble of dead and living vegetation, which we’ve enhanced by piling brush under and next to the pine, is a great wildlife habitat feature, and the catbirds are especially fond of it. It’s also a good place for unwanted plants to get a foothold before we notice them, and after inspecting the tall blue lettuce I noticed a big Oriental bittersweet vine (Celastraceae: Celastrus orbiculatus) twining up some of the branches of the bent-over black cherry (which are now vertical and acting like trunks). I uprooted the vine and pulled it free from the cherry, then laid it down on the ground to check it for evidence of the one leafminer I’ve ever seen on bittersweet. I wasn’t disappointed.
Leafminer #178: Sumitrosis rosea (Chrysomelidae). This native beetle mines leaves of a variety of legumes (Fabaceae), but somehow it has decided that bittersweet (both native and nonnative) and wood nettle (Urticaceae: Laportea canadensis) are also acceptable hosts. I found several old, long vacated mines on this bittersweet vine.
Here’s another mine where the larva (at right) died for some reason while it was very young; at left you can see the oval eggshell embedded in a small pit in the leaf chewed by the mother beetle.
On the same bittersweet vine, I found two examples of what seemed to be aborted underside tentiform mines of a gracillariid moth. I figured they must have been a cherry-feeding species and that the female had goofed and laid a few eggs on the vine that was twined around the cherry; the larvae had developed a little bit before dying due to the unsuitable host. This sort of thing is known as “xenophagy.”
Note the object at the lower edge of the “mine” in the above photo, which looks about right for an eggshell of a gracillariid. Here’s the same “mine” backlit:
And here’s the other “mine”:
I found one other interesting thing on one of the bittersweet leaves, which it is now clear was the same phenomenon:
These mine-like features were not made by larvae feeding inside the leaves; they are places where a leafhopper inserted rows of eggs side by side! If you didn’t notice them before, look back at the two backlit views and you can see that the first “mine” has punctures indicating the insertion points of three eggs; the second one has six, and in the upper-surface view of the third example, there are seventeen. As for the “eggshell,” I think it’s actually a scale insect. It’s amazing how often they happen to position themselves at the edges of leaf mines so that they appear to be eggs. Take, for example, the one at the beginning of a Cosmopterix clemensella mine on a sedge leaf (there is a close-up of the scale here):
Leaf (stem) miner #179: Ophiomyia sp. (Agromyzidae), on wild carrot / Queen Anne’s lace (Apiaceae: Daucus carota). I was excited to find this mine on the evening of September 5:
No Ophiomyia is known to feed on wild carrot, but Julia and I found a bunch of similar mines on an isolated clump at Black Rock Forest in New York late last August while conducting our survey for leaf-mining moths there. The puparia in those mines were all black, and only eulophid wasps emerged from them. The puparium in the above mine (visible as a bulge along the upper margin of the stem) was whitish; unfortunately it turned out to be empty already.
In this close-up, the pair of little black anterior spiracles of the puparium are visible poking through the stem epidermis at far left, and there is a longitudinal opening associated with those—along with a more conspicuous transverse slit to the right of them—indicating that the fly has already emerged. I spent a good chunk of yesterday pulling up wild carrot stems around the yard, and I found six stems with intact puparia (plus one more empty one, and one or two that seemed to still have larvae in them). To give a sense of how sparsely distributed these mines are, this is how many stems I had to inspect to find a half dozen of them (note Brenda in the background; she followed me around for most of the time that I was pulling them up, and was often literally underfoot):
All of the mines were confined between two nodes in the stem as in the example shown above. John van der Linden has observed similarly constrained stem mines (both agromyzid and Marmara) on Ageratina altissima, Polymnia canadensis, and Veronicastrum virginicum in Iowa.
When I found the first mine yesterday morning, I ran inside to get a camera, and in my hurry to get back outside I didn’t bother to put my shoes back on. This turned out to be a mistake, as my right pinky toe soon met with an unseen bee, who left this in it:
Leafminer #180: Keiferia sp. (Gelechiidae), on clammy groundcherry (Solanaceae: Physalis heterophylla var. heterophylla). While Brenda and I were nibbling berries and pulling up wild carrot stems between the two largest rows of red raspberries, I noticed some mines on the perennial groundcherries growing beneath them. These groundcherries pale in comparison with the annual ones that are also in our yard, in terms of both quantity and deliciousness of fruit, but I guess they’ve earned their keep now.
Running the mines through my Physalis key, they would seem to be the work of the undescribed Keiferia species that has been reported only on the glandular-haired variety of P. heterophylla. Elsewhere in the yard, as I passed another patch of clammy groundcherry, I thought I spotted the first flower of the season out of the corner of my eye, but it turned out to be a big yellow crab spider waiting for lunch to drop by:
When I came around to the driveway in my wild carrot-pulling / stem miner-hunting expedition, Julia exclaimed that the garden loosestrife (Primulaceae: Lysimachia vulgaris) in the adjacent perennial bed was all sawfly-eaten. Sawfly larvae show up on these plants every year, and I’d been watching for them, but I guess I hadn’t looked in a while:
Sawfly #46: Monostegia abdominalis (Tenthredinidae). This sawfly, like garden loosestrife, is introduced from Europe. I’ve never seen it feeding on native Lysimachia species, like the fringed loosestrife (L. ciliata) growing wild on the other side of our yard. I think it’s great that the plant and the sawfly have found each other here; garden loosestrife spreads pretty aggressively, and it’s nice to have something keeping it in check. There were no green leaves left on any of the plants yesterday, and I thought I was going to have to settle for a photo of one of the shed larval skins that were draped over some of the remaining leaf fragments, but then I spotted this one straggler munching away on a leaf that had a little bit of green left on it:
I’ll close with a few miscellaneous sightings from yesterday that are neither sawflies nor leafminers. Toward the southeast corner of the front yard, there is a little aspen sapling that started out this spring as an unambiguous bigtooth aspen (Populus grandidentata), and has gradually turned into a quaking aspen (P. tremuloides) over the course of the season. I’ve been checking it regularly because it has already yielded two sawfly species that I haven’t found elsewhere in the yard, and a week or so ago I noticed that a clutch of red-humped caterpillars (Notodontidae: Schizura concinna) were beginning to defoliate it. These show up in the yard every year; sometimes on cherry, other times on persimmon. When I checked on them yesterday, there were a few hanging out in plain sight…
…but most of them were hanging out on the underside of a leaf, where they were in varying stages of becoming “mummified” by braconid wasp larvae spinning cocoons inside them.
A few goldenrod plants were displaying the lovely reddish galls of Schizomyia racemicola (Cecidomyiidae) among their flowers.
And several inches of a branch on one of our asparagus plants was encrusted with hundreds of eggs of some sort of owlet moth (Noctuidae).