Things are really picking up now… First of all, I collected something from the arborvitae hedge at the end of the day yesterday that I didn’t get around to investigating until this morning.
There were two of these little white cocoons attached to the foliage, and I had a feeling they were related to some of the needle mines on those shrubs. This morning I checked my key to Thuja leaf mines, and as I thought, both of the species of needleminers I’ve found in this hedge before—Coleotechnites thujaella (Gelechiidae) and Argyresthia thuiella (Argyresthiidae)—pupate inside their mines. But there are three other species that spin a cocoon outside the mine (also differing from the first two in that they deposit frass within the mine instead of pushing it all outside). Of these three, there is one that spins a white, spindle-shaped cocoon and occurs in northeastern North America: Argyresthia aureoargentella. So that’s miner #17 for this year’s yard list. The only published distribution records I have found for this species are Ontario, Quebec, New Brunswick, and Maine, so this might be the first record from Massachusetts; however, on BugGuide there is a photo of an adult from Pennsylvania, so finding one here isn’t surprising.
When I headed out into the front yard this morning, I decided to check on some of the fruit trees. We have several apples and pears that were sent to us as bare-rooted sticks in the mail six years ago by Julia’s family’s neighbor in Ohio, who has a small orchard and develops his own varieties. On the variety he named “Dave’s delight,” of which I think ours is the only one in existence besides the parent tree, I noticed a stem mine I hadn’t seen before (this photo is rotated 90 degrees):
It didn’t seem to go anywhere from there, but I checked the other side of the tree and found not only a much longer mine, but the characteristic Marmara bark flap under which the cocoon is spun:
So I raced back inside to get some forceps and a vial, and very carefully peeled back the flap, revealing an intact cocoon:
With any luck, I’ll have an adult Marmara elotella (Gracillariidae) within a few weeks. So that’s #18. Additional species piled up as I slowly made my way around the yard…
#19: Orchestes mixtus (Curculionidae). This weevil is essentially identical to O. pallicornis (shown on black cherry in my previous two posts), but feeds on plants in the birch family (Betulaceae). Today I found mines on our cultivated hazelnut, variety “Medium Long,” which is believed to be a hybrid of the European Corylus avellana and the native C. americana.
I also found one on black birch (Betula lenta) that was a little further along:
#20: Sumitrosis inaequalis (Chrysomelidae). I saw several adults of this species, whose larvae mine leaves of various plants in the aster family (Asteraceae). Most of them were resting on rough-stemmed goldenrod (Solidago rugosa). These beetles overwinter as adults, like their fellow hispine (tribe Chalepini) Chalepus walshii that I wrote about yesterday.
#21: Marmara ?fulgidella (Gracillariidae). These mines are in the bark of our young Chinese chestnuts (Fagaceae: Castanea mollissima). Marmara fulgidella was described from adults reared from oak, and mines later found on American chestnut (C. dentata) were assumed to be made by the same species but this has not been proven. In fact, it seems certain that there is a different species on chestnut, because M. fulgidella spins its cocoon outside the mine, and Dave Wagner has found mines on American chestnut with the cocoon under a bark flap as in M. elotella and M. fraxinicola*. I wasn’t able to tell for sure whether any of these Chinese chestnut mines were still occupied, but I didn’t see any bark flaps.
#22: Japanagromyza viridula (Agromyzidae). I found several mines just getting started on a red oak (Fagaceae: Quercus rubra) sapling. This fly is called the “oak shothole leafminer” because of the holes that open up in the leaves as a result of feeding by adult females. They use their ovipositors to stab the young leaf and then turn around to drink the juices from the wounds. As the leaf continues to expand, a hole opens around a tiny necrotic disc that forms around each puncture (upper right in the photo below). Holes also open up around eggs that are inserted in the leaf (lower left).
In this closer crop you can see the tiny white (because it’s backlit) puncture from the ovipositor near the right edge of the necrotic disc.
There are often multiple holes per leaf. Eventually the necrotic discs drop out, leaving just the “shotholes” as evidence.
Japanagromyza viridula seems to have just one generation per year, but unlike most agromyzid flies with this type of life cycle, adults emerge within a few weeks after the larvae exit their mines, rather than the following spring.
One black birch (Betulaceae: Betula lenta) sapling had a number of mines like this, which as I explained the other day are characteristic of casebearer moths (Coleophoridae: Coleophora). I spent quite a while searching for the larva(e) responsible for these mines before suddenly spotting two at once—and they were two different species!
#23: Coleophora comptoniella (Coleophoridae). There are two birch-feeding species that live in a “spatulate” case with a bivalved apical opening; the larger (~1 cm) case rules out C. lentella.
Check out the second half of this post to see what this larva was up to last fall. And here’s an adult of Coleophora comptoniella I reared from paper birch (B. papyrifera) last spring:
#24: Coleophora serratella (Coleophoridae). This species is recognized by its smaller, trivalved case.
#25: Pegomya rubivora (Anthomyiidae). This one is mostly a borer (feeding in deeper tissues of the stem, where its tunnel is not externally visible), but the young larva mines a spiral around the shoot, girdling it and causing it to droop.
A close-up of the spiral mine:
This is a stem of black raspberry (Rosaceae: Rubus occidentalis). I first met this fly last June in Vermont, where a whole patch of black raspberry was similarly affected. I collected a bunch of stems and had a single adult emerge this spring:
#26: Agromyza aristata (Agromyzidae). A small American elm (Ulmaceae: Ulmus americana) at the edge of my yard had three mines of this fly. This is yet another species that appears only in the spring, overwintering as a pupa.
#27: Marmara n. sp. (Gracillariidae). That same elm had bark mines of Marmara #5 for my yard; this is a species that has been reared but has not yet been described and named.
#28: Phytomyza solidaginophaga (Agromyzidae). This species had been conspicuously missing from my spring leafminer lineup, and I had been specifically looking for it for the past couple of weeks. Finally I found three mines on Canada goldenrod (Asteraceae: Solidago canadensis) at the end of my long walk around the yard; they were already empty, as they should be: This species appears only in mid-May in Massachusetts, and that is the only way I know to distinguish its mine from that of P. astotinensis, which can be found from June to October.
Then this afternoon, when I finished mowing some paths through our meadowy lawn, I inspected a clump of deertongue grass (Poaceae: Dichanthelium clandestinum) and found three more species!
#29: Cosmopterix gemmiferella (Cosmopterigidae). What actually caught my eye at first was this narrow, pale stripe, which turned out not to be a mine (I’m not sure what caused it):
But the tip of the leaf happened to be twisted in such a way that it revealed the characteristic pupation mine of C. gemmiferella. This species apparently overwinters as a larva in the plant’s basal rosette, mining the leaves into early spring. When finished feeding, the larva exits its mine and moves up to one of the lower stem leaves, in which it makes a short, inconspicuous mine, where it spins its cocoon. In the close-up below, you can see where the larva entered the leaf at upper right, and its cocoon is the elongate white patch at lower left.
This species has previously only been found on much smaller-leaved Dichanthelium species. Here is one I reared from D. acuminatum, found in the woods behind my house:
#30: Leucospilapteryx n. sp. (Gracillariidae). Not 20 feet from the mines of the undescribed Marmara on elm was a leaf mine of another undescribed moth species. Dave Wagner told me once that it belongs to an undescribed genus, but the adult always looked like a Leucospilapteryx to me, and Don Davis has it listed in that genus in a list of Gracillariidae he shared with me last fall, so that’s what I’m calling it for now. It makes an underside tentiform mine like some of the ones on black cherry made by Caloptilia serotinella (a few posts back).
This larva recently finished its “sap-feeding” stage, in which it fed in an epidermal mine visible only on the lower leaf surface; it has now begun to consume the mesophyll and spin silk that causes the leaf to buckle. A backlit photo reveals the shape of the larva inside:
#31: Chalepus bicolor (Chrysomelidae). Both adults and larvae of this species are apparently specific to grasses in the genus Dichanthelium, whereas C. walshii feeds on a number of grass genera but is very rarely found on Dichanthelium. Adults of C. bicolor feed in a similar way to C. walshii but don’t make those neat rectangular patches.
Although I was confident that this was feeding sign of C. bicolor, I checked some other patches of deertongue grass until I finally saw an adult. It was feeling skittish and only allowed me to get one blurry photo:
So here’s a better one, from the archives:
Today’s yard exploration also turned up sawfly larva #2 for the season, feeding in small groups on red oak leaves:
I’ve reared similar larvae to adults a few times, and they belong to the Acordulecera dorsalis complex (Pergidae)—a confusing group of species that no one has gotten around to sorting out yet. The adult below was collected as a larva on red oak at the 2016 Connecticut BioBlitz and emerged as an adult the following spring (this is why it takes me a while to finalize my lists for bioblitzes):
As for the edible plants list, it looks like it will soon be eclipsed by the leafminer list, but I added three more today:
56. Staghorn sumac (Anacardiaceae: Rhus typhina) – branchlets
57. Fox grape (Vitaceae: Vitis labrusca) – tendrils
58. Apple mint (Lamiaceae: Mentha suaveolens) – leaves (tea)
It never would have occurred to me to eat sumac branchlets, but one of Arthur Haines’ books describes how you can peel off the bark of tender young shoots and eat the cores, so I gave it a try. They were pretty tasty.
* Eiseman, Charles S., Donald R. Davis, Julia A. Blyth, David L. Wagner, Michael W. Palmer, and Tracy S. Feldman. 2017. A new species of Marmara (Lepidoptera: Gracillariidae: Marmarinae), with an annotated list of known hostplants for the genus. Zootaxa 4337(2): 198–222.