The Yard List(s), Part 27

Time for the end-of-summer update on my project to list all the leafminers and sawfly larvae I can find in my yard, along with all the plants I’ve eaten. It’s definitely starting to get harder to add new species to the lists. On September 16 I remembered we had planted a white wood aster in the area under the old apple tree that is now engulfed in ostrich ferns, so I crawled under the ferns to see if there might be a mine of Liriomyza limopsis on the aster.

The aster was immaculate, but right next to it I noticed a little brown patch on an enchanter’s nightshade (Onagraceae: Circaea canadensis).

I took a closer look, and as I hoped, it turned out to be a leaf mine for which I’d been specifically watching all summer without success:

Leafminer #187: Mompha terminella (Momphidae). From above, I couldn’t be sure it was a mine rather than “window feeding,” in which an insect feeds externally on the lower leaf surface, leaving the upper epidermis intact…

…but a look at the lower surface revealed the frass that the larva had pushed out of the edges of the mine, as is characteristic of this species.

Here’s an adult I reared from a similar mine seven years ago:

This inspired me to look once again for mines of an undescribed Mompha species that feeds on bedstraws (Rubiaceae: Galium spp.). I’ve never found mines in the yard before, but Julia once had an adult land on her in the vegetable garden, so I know the species is here. I went over to a patch of wild madder (G. mollugo) and had a look. No mines to be found, but I noticed a brown tip on a blade of grass poking out of the wild madder patch:

Holding the blade up to the light, it seemed I had finally found a “grass miner moth” (Elachistidae: Elachista) in my yard. But on closer inspection, the frass pattern indicated a fly, and there was a metallic black puparium inside indicating Cerodontha incisa (Agromyzidae), which I’d already listed as leafminer #79 back in June.

Here’s the puparium removed from the mine:

This 1.5-mm wasp emerged from the puparium on September 19. It belongs to the genus Epiclerus in the family Tetracampidae, and is only the second tetracampid I’ve reared out of a few thousand leafminer parasitoids over the course of nearly a decade. (Thanks to Jeong Yoo for the ID; I could tell it wasn’t quite a eulophid because it has five tarsal segments, and was tentatively calling it a miscogastrine pteromalid for lack of a better option but didn’t think it really looked like one.)

You may recall that this time last year, the woolly bear caterpillars were busily cutting down the blue mistflowers (Asteraceae: Conoclinium coelestinum) by our front door (and all around our yard). Well, the plants are all doing well this year, and so far the woolly bears have left them alone. Here’s the one by the front door:

On September 17 I noticed a single leaf mine on that plant:

Leafminer #188: Liriomyza carphephori (Agromyzidae). Four of the paratypes of this species were reared from mines I found on devil’s beggar-ticks (Bidens frondosa) in our front yard on October 8, 2016, and I think this is the first mine I’ve seen in the yard since then. On both hosts, the mine typically starts out as a contorted squiggle at the tip of the leaf and then stretches out into a meandering linear mine toward the leaf base, but in this example the whole mine is bunched up at the leaf tip.

Another thing I’ve been watching for all summer is sawfly larvae on elderberry (Adoxaceae: Sambucus nigra). In the past few years I’ve found Lagium atroviolaceum (Tenthredinidae) just 50 feet or so into the woods from our yard, and right at the edge of the yard I once found a larva of another, unidentified tenthredinid among some berries as I was gobbling them up. Repeated visits this year to the various elderberry bushes the birds have planted around the edges of our yard turned up nothing, but then yesterday evening when I waded into the wild raspberry thicket to check on a persimmon sapling we had planted there this spring, I found two of the unidentified larvae on a small elderberry plant I hadn’t realized was there.

So that brings the total to 48 different sawfly larvae I’ve found in the yard this year. Unfortunately both of these larvae had ichneumon eggs attached behind their heads, so their identity may remain unknown until I can find some un-parasitized ones in some future year.

Leafminer #189: Coptotriche crataegifoliae (Tischeriidae). I found a single mine of this species today on our medlar tree. To my knowledge, this is the first tischeriid mine anyone has ever found on medlar. Medlar has traditionally been known as Mespilus germanica (Rosaceae), but some botanists treat it as Crataegus germanica, and apparently this moth agrees (though I’ve also found its mines on Amelanchier and Aronia, so this isn’t really a strong argument for accepting that medlar is just a thornless hawthorn with big, tasty fruits).

The clean appearance of this mine is explained by a tiny hole at the beginning on the lower surface, through which the larva expels all of its frass (right above the “i” and the “s” in the photo below).

I checked out a “real” hawthorn (Crataegus sp.) nearby and found one more new species for the list:

Leafminer #190: Stigmella oxyacanthella (Nepticulidae). At least, I’m pretty sure it’s this species, which I’ve reared from both hawthorn and apple in my yard in the past. The mine of this species isn’t really distinguishable from the mine of S. scintillans (#114), but S. scintillans has yellow larvae that are present from June to August, and S. oxyacanthella has green larvae that are present in September and October. I’m basing my ID on the freshness of this mine; hopefully I’ll find some green larvae in the next week or two to remove any doubt.

The apparent yellowish mottling in this backlit photo of the mine, and the darker mottling surrounding it, is actually a colony of aphids on the underside of the leaf:

I think the older ones look pretty sporty with their four green spots.

And finally, the “plants I have eaten” update…

111. Apple (Rosaceae: Malus pumila) – fruit
112. False Solomon’s seal (Asparagaceae: Maianthemum racemosum) – fruit
113. Black nightshade (Solanaceae: Solanum ptychanthum) – fruit
114. Sweet potato (Convolvulaceae: Ipomoea batatas) – root
115. Sunflower (Asteraceae: Helianthus annuus) – fruit/seeds
116. Hazelnut (Betulaceae: Corylus ‘Medium Long’) – nut

About Charley Eiseman

I am a freelance naturalist, endlessly fascinated by the interconnections of all the living and nonliving things around me. I am the lead author of Tracks & Sign of Insects and Other Invertebrates (Stackpole Books, 2010), and continue to collect photographs and information on this subject. These days I am especially drawn to galls, leaf mines, and other plant-insect interactions.
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4 Responses to The Yard List(s), Part 27

  1. lifelessons says:

    “So that brings the total to 48 different sawfly larvae I’ve found in the yard this year. Unfortunately both of these larvae had ichneumon eggs attached behind their heads, so their identity may remain unknown until I can find some un-parasitized ones in some future year.”

    I’m curious about why you couldn’t identify them if they had ichneumon eggs attached? Why would that make them unable to identify? And, I must admit that your closeup of the aphids made them seem like a cheerful little family that I would be loath to try to kill! I’ve never seen a yellow aphid and they were indeed cheery and cute with their green spots and little antennae..their kids flocking about.

    • Larvae are only known for a fraction of North American sawfly species–fewer than 20% according to Dave Smith, the North American sawfly expert, as quoted here. So the way learn who most of my sawfly larvae are is by rearing them to adults and then sending the specimens to him to examine. I just last week sent Dave all the adults that I’ve managed to rear this year; most larvae need to overwinter in soil before they will pupate and emerge as adults. I am presuming that any larvae I collect with eggs on them will not survive to adulthood and I’ll get ichneumon wasps instead.

      There is a chance that these larvae have been described before. I know, for instance, that there are several species of Macrophya that feed on elderberry, and I haven’t reviewed those descriptions yet. The ones in my yard don’t look like a match for this one though. This spring I started the project of collecting all known North American sawfly host records; I hope to finish that this winter and start making hostplant-based keys to the larvae that have been described, but even with those completed there will still be the matter of all those hundreds of species whose larvae are unknown.

  2. Anonymous says:

    Gosh, those are the prettiest aphids I’ve ever seen. I’ve been looking closely at aphids lately–different in color but none with spots. I did see an adult with wings (and I swear the three little ones around her were her progeny). I hope to find these cuties some day!

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