The Yard List(s), Part 15

Lots of new things to report, as usual… First, I forgot to mention this leaf mine I found on Saturday (June 13) on the old apple tree by the chicken coop:


This is so far an entirely epidermal mine: the larva is slashing open epidermal cells and drinking the fluid contents, without consuming any tissue. The “sap-feeding” early instars of gracillariid moth larvae have entirely different mouthparts from the older instars, and you can sort of see them in this backlit view:


According to the key I wrote for apple leaf mines, this should be Callisto denticulella, but I’ve never been able to rear this species to confirm. I’ll do my best this year. In any case, it’s leafminer #64 for this spring’s yard list.

Remember those pink-tipped sawfly larvae I found on a little paper birch sapling right next to my house, back in Part 10?


I mentioned that they had started to spin cocoons by June 4. Well, on Sunday morning (June 14), the adults were already starting to emerge:


As of today, 29 adults have emerged. I didn’t think I had collected quite that many! Also, a few other things that I hadn’t noticed before appeared in that jar on Sunday. One was this sawfly larva, which was quietly munching away on one of the remaining leaf fragments at the bottom of the jar:


It doesn’t have a pink-tipped abdomen, and it has a central stripe on the top of its head, so it’s a different species from the larvae I had knowingly collected back on May 31. It must been an unnoticed egg at the time I collected the leaves—and one that somehow escaped being devoured by the 29+ larvae I collected.

It also seems to be a different species from this one I found on the paper birch sapling at the southeast corner of my yard on June 5, with the distinct stripe behind its eye:


So we’ll call it sawfly #17 for the yard list.

Just to confuse things, as of yesterday it did have a pink butt, but I still think it’s a different species due to the dorsal stripes and head markings. I also think it’s quite a bit larger than the original pink-butt larvae ever got.


The other things that appeared in the jar on Sunday did not come as a surprise—several small caterpillars like this one:


When I was collecting those pink-tipped sawfly larvae back on May 31, I had noticed this group of three eggs on one of the leaves they were eating:


I was curious what kind of moth they belonged to, but not quite curious enough to put them in their own vial, so I just put them in with all the sawfly larvae. I know for certain that the caterpillars came from these eggs, because I later found an identical group of three eggs on a black birch sapling elsewhere in my yard, which I did put in an isolated vial, and identical caterpillars hatched from those.

I moved this new birch sawfly larva and these caterpillars to their own jars, and I went to get fresh paper birch leaves to feed them—from that same sapling where I collected the eye-stripe larva on June 5, and where I found the leaf-mining sawflies (Fenusa pumila) a few days ago. When I reached that sapling, I was greeted by sawfly #18—and the fifth type of sawfly larva I’ve found on paper birch this spring:


I came back with a different lens the next day to get this close-up:


And here’s how they look today:


I think these are larvae of the dusky birch sawfly, which most people still call Craesus latitarsus (Tenthredinidae) although Nematus latitarsus is technically the correct name at the moment. I haven’t reared that species but the adult looks like this:


I wasn’t the only one who showed up to check on them today.


These were the best I could do with the wind and with essentially no depth of field. It’s an ichneumon wasp looking to parasitize some sawfly larvae; I ran these photos by Gavin Broad and he says it belongs to the tribe Exenterini of subfamily Tryphoninae. I have some photos of a sawfly larva with a tryphonine egg on it here.

Leafminer #65: Pegomya hyoscyami (Anthomyiidae).  Sunday evening while we were picking greens for dinner, Julia noticed mines of this species just getting started on a spinach leaf.


As with other Anthomyiidae, the mines begin with white eggs attached to the lower leaf surface…


…which are best appreciated under high magnification:


These were some unhatched eggs on a neighboring leaf. When we find eggs or young larvae, we just make sure to eat the leaves soon; once the larvae get bigger and are making a mess of the leaves, they go to the chickens. Both Pegomya betae and P. hyoscyami mine leaves of spinach and I don’t know of a way to distinguish their mines, but I’m assuming we have the latter since that’s the species I’ve reared from our spinach in the past.


When I got the macro lens for those eggs, I couldn’t resist getting a portrait of this pygmy grasshopper that was hanging out under the spinach:


Leafminer #66: Scaptomyza flava (Drosophilidae).  A single leaf on one of the sugar snap peas had larvae of this fly mining it:


This species mostly feeds on mustards (Brassicaceae), but it occasionally dabbles in other herbaceous plants. Here’s an adult I reared from tower mustard (Turritis glabra) growing right next to the vegetable garden six years ago:


I found several more S. flava mines on kale leaves this evening:


Sawfly #19: On Monday morning while pulling up a multiflora rose stem that had popped up among the jewelweed at the edge of the leach field, I noticed some nibbling on the branches of some field horsetails (Equisetaceae: Equisetum arvense). After staring for a couple of minutes I found the well-camouflaged sawfly larvae that were responsible. They presumably belong to a species of Dolerus.


Leafminer #67: Liriomyza equiseti (Agromyzidae). There was also a single mine of this fly on one of the horsetails.


This species is known to occur throughout Canada and in Europe, but the only US state where it has been documented is California. I have a puparium from a similar mine I found in the ditch across the road the other day, so maybe I’ll be able to rear an adult and add Massachusetts to its confirmed distribution.

Earlier this spring we were given a carload of leftover native plants from a local nursery, and we planted some of the wetland species in spots in the seepy woods behind our house that we had recently disturbed by pulling up multiflora rose, Japanese barberry, Asiatic bittersweet, etc.  One of these plants was a swamp milkweed, which on Monday I noticed had many mines of Liriomyza asclepiadis on it.  On Monday evening I checked some of the common milkweed in our yard to see if I could add that species to the yard list, but no sign of it there yet.  I did, however, find another milkweed associate that I’d failed to include in my list of non-monarch insects that depend on milkweed:


Aphids. It turns out there are multiple aphid species associated with milkweed, besides the well-known bright yellow oleander aphids (Aphis nerii) that are introduced from the Mediterranean. Looks like these might be Aphis asclepiadis.

Aphids get a bad rap. I think they’re kind of charming.


Some ants were attending to the aphids on an adjacent leaf.


These pink leafhoppers (Cicadellidae: Graphocephala gothica) were on several of the milkweed plants. I see them on milkweed regularly, so I’m convinced they feed on it, but I haven’t found any information about what its host plants are supposed to be.


In my previous post I said the sawfly larvae on the red currant bush were Pristiphora appendiculata, because that’s the species I’ve found in past years. But on Monday when I checked the bush again, I found some older larvae and realized they are in fact the imported currantworm, Nematus ribesii. Some photos here show that that species inserts eggs along the veins just like the ones I found in association with the young larvae a few days ago.


The original larvae I collected have now developed distinct dark spots; here are two that have reached an impasse:


Leafminer #68, and sawfly #20: Fenella nigrita (Tenthredinidae).  Julia and I first met this species in September 2012 in the Black Hills of South Dakota, and I think the only other time I’ve found it was at the Berkshire BioBlitz in September 2018.  So I was excited to see these mines on common cinquefoil (Rosaceae: Potentilla simplex) along the south side of the house yesterday morning while we were planting our latest acquisitions there. Admittedly they’re not much to look at:


A backlit view confirmed the presence of characteristic sawfly fecal pellets, and that the larvae had already exited the mines.


Here’s one of the adults from South Dakota:


The problem with offering sawfly larvae sumac stems rather than wine corks to bore into to pupate is that I’m not 100% sure whether this wasp that emerged yesterday was a parasitoid of that first lady fern sawfly larva I collected on June 6, or emerged from some other insect that was already in the other sumac stem I had placed in the jar. Eventually I’ll cut open both stems and hopefully sort that out.


Another of yesterday’s emergences was this Cosmopterix gemmiferella from the deertongue grass mine I collected in the backyard on May 29:


Today’s slow stroll around the yard added a few more species to the list.

Leafminer #69, and sawfly #21: Metallus capitalis (Tenthredinidae).  I found a single larva of this species mining a leaf of red raspberry (Rosaceae: Rubus idaeus) in the nut orchard.


This species (like Fenella nigrita) has two generations per year; I collected mines in my yard on September 30, 2015, and this adult emerged the following spring:


Leafminer #70: Caloptilia invariabilis (Gracillariidae).  I found leaf rolls associated with small, underside tentiform mines on a pin cherry (Rosaceae: Prunus pensylvanica) right next to that raspberry, and I believe they are the work of this species rather than C. serotinella, which I found on a black cherry sapling in my yard earlier this spring.


I reared this adult from similar mines and rolls I found just outside the classroom at the Eagle Hill Institute where I taught my leafminer seminar last summer:


Sawfly #22: Acordulecera sp. (Pergidae).  I found these larvae munching on butternut leaves (Juglandaceae: Juglans cinerea) right next to the red oak where I found Acordulecera larvae on May 29. They look pretty similar, but I suspect they are a different species based on the different timing, different host, and much paler legs.


Sawfly #23: When I went to check on those gregarious larvae on the paper birch sapling today, I found yet another sawfly species—the sixth for paper birch and the fourth for that individual sapling. The yellow spots along the back make this one obviously distinct from all the others.


Leafminer #71: Phytomyza erigeronis (Agromyzidae).  This one completes the expected trio of daisy fleabane (Asteraceae: Erigeron annuus) leafminers for the yard.


It’s the first species to turn up this spring whose type locality is my yard. Here’s one of the paratypes:


Leafminer #72: Ophiomyia maura (Agromyzidae).  Yet another goldenrod leafminer. This species makes a very long, narrow mine, forming its puparium within the leaf but hidden on the lower surface.


Leafminer #73: Phytomyza plantaginis (Agromyzidae).  This one was on narrow-leaved plantain (Plantaginaceae: Plantago lanceolata).


This mine was mostly on the lower surface of a leaf that had curled so that the lower surface was on top. When almost done mining, the larva switched to the upper (= lower) surface, forming its puparium at the end of the mine.


The very narrow, white mine is distinctly different from the irregular, brownish mines of the plantain flea beetle (Chrysomelidae: Dibolia borealis) that are now abundant on broad-leaved plantain (P. major) in my yard.


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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7 Responses to The Yard List(s), Part 15

  1. Tom says:

    Those sawfly caterpillars lined up along the birch leaf look like about a two minute lunch for a bird. What is their survival strategy?

    • At least some sawfly larvae that stick their abdomens in the air like that are emitting a defense chemical that is undetectable to humans. I’ve noticed that my chickens are decidedly unenthusiastic about sawfly larvae when given the opportunity to devour some; these two facts may or may not be related!

  2. stephe59 says:

    Charley, you are the David Annenberg of leaf miners. So fascinating the diversity you are finding!

  3. Pingback: The Yard List(s), Part 17 | BugTracks

  4. Pingback: The Yard List(s), Part 18 | BugTracks

  5. Pingback: The Yard List(s), Part 24 | BugTracks

  6. Pingback: First sawflies of the season! | BugTracks

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