The Yard List(s), Part 4

May has started off with a string of beautiful, sunny days, and more new birds have been announcing their arrival each day. On the 1st it was the blue-headed vireo; on the 2nd a ruby-throated hummingbird joined the myriad bees, wasps, and flies buzzing around the plum trees that had just burst into bloom, while a blue-gray gnatcatcher wheezed from the trees around the edges of the yard; yesterday the morning started off with the song of a black-throated green warbler, followed before long by ovenbird, common yellowthroat, black-and-white warbler, chestnut-sided warbler, gray catbird, eastern towhee, and barn swallow; and this morning a rose-breasted grosbeak and Baltimore oriole have already joined the chorus (those two always seem to arrive together).

Amid all these arrivals, the season’s eighth leafminer species has made its presence known in my yard: plantain flea beetle (Chrysomelidae: Dibolia borealis). As with the Chrysoesthia sexguttella that are still swarming inside the hoop house, it is the adults rather than the leaf-mining larvae that are now appearing. Unlike those moths, though, these beetles are not newly emerging from pupae; they have been hunkered down as adults since early last summer. I woke up this morning thinking how odd it is that the tiny beetles that are now nibbling the plantain leaves in the lawn were already adults last July when we bought the little fuzzy day-old chicks that are now full-grown hens, laying enough eggs every day to feed me and Julia as well as several neighbors.

After nibbling on plantain leaves for a few weeks, the beetles will begin laying eggs on them, and in June the trails of the larvae mining inside them will be obvious.

When full-grown, the bright yellow-orange larvae will exit their mines and burrow into the ground to pupate, emerging as adults in July.

The new adults may nibble on plantain leaves for a little while, but soon they will go into hiding until the following spring.

Dibolia borealis is among that small minority of native North American species that have become more common and widespread since Europeans arrived here. Over five hundred years ago, they would have fed only on the native Plantago species, which are spotty in their distribution. But they have expanded their diet to include the European P. major, which is now ubiquitous in lawns and other disturbed areas. In Helen Reed’s study of this species at Cornell University nearly a century ago*, she stated that both adults and larvae of D. borealis appear to feed exclusively on P. major, although she found that captive larvae would mine into leaves of another European import, P. lanceolata, when given no other choice. I did find a single mine on P. lanceolata in my yard three years ago, but it is clear that this is not a preferred host.

Meanwhile I, adaptable creature that I am, have so far eaten 35 different plant species in my yard this spring. The latest additions:

31. Tall blue lettuce (Asteraceae: Lactuca biennis) – leaves
32. Carrot / Queen Anne’s lace (Apiaceae: Daucus carota) – roots
33. Virginia waterleaf (Hydrophyllaceae: Hydrophyllum virginianum) – leaves
34. Tower mustard (Brassicaceae: Turritis glabra) – leaves, flowers
35. Shepherd’s purse (Brassicaceae: Capsella bursa-pastoris) – leaves, flowers, fruits

Asparagus, you’re next!

* Reed, Helen. 1927. Some observations on the leaf-mining flea-beetle Dibolia borealis Chevrolat. Annals of the Entomological Society of America 20(4): 540–549.

Sawfly Surprise

As I’ve mentioned a few times before, I’m starting to work on a hostplant-based guide to sawfly larvae that will be arranged similarly to my leafminer guide. In addition to reviewing the existing sawfly literature, I’ve been sporadically collecting larvae to rear, and I plan to do a lot more of that this year. Since the hosts are known for only about a quarter of the North American sawfly species, raising them to adults will often be necessary to figure out what species I’ve found. For the past few years, I’ve been keeping an eye out for sawfly larvae to collect while surveying for galls and leaf mines on Nantucket. Here’s a striking one I collected there on September 5, munching on the edge of a leaf of beaked hazelnut (Betulaceae: Corylus cornuta):

Five days later, it had molted to its final instar:

And by September 13, it had spun this cocoon among the crumpled paper at the bottom of the rearing container:

On April 1, something emerged from the cocoon—but instead of an adult sawfly, it was 44 beautiful little green wasps:

Although I’m used to them being more nondescript, I eventually recognized these as tetrastichine eulophids. Evidently the larvae are internal parasitoids, since there was no external evidence that anything was amiss with the sawfly larva. Lacking a reared adult sawfly, I have to rely on existing sawfly hostplant records to determine the identity of the larva, but it seems like there’s a pretty good chance it was Arge pectoralis (Argidae), a species more commonly found on birch but also recorded from hazelnut and alder (all plants in the birch family). Tetrastichus trisulcatus is the only tetrastichine eulophid that has been reported as parasitizing this or any other Arge species, and it is apparently a sawfly specialist, but sawfly parasitoids are of course more poorly known than sawflies themselves, so the wasps that came swarming out of that cocoon may or may not have been T. trisulcatus.

The Yard List(s), Part 3

Spring continues to lurch along here in northern Massachusetts. This morning I woke up once again to the sight of fresh snow (though not a continuous blanket like last time), but in the meantime the daffodils, hyacinths, Scilla, and Forsythia have been blooming, along with a few native-ish wildflowers we’ve planted around the yard, including this single sprig of Dutchman’s breeches (note the evidence of nectar robbing near the tips):

Not far from the Dutchman’s breeches along the east side of our house, there are some clumps of a woodland sedge (Carex sp.) that I haven’t yet gotten around to identifying.

Given my mission to find as many leafminers in my yard as possible this year, I took a close look at them the other day, and I soon found what I was after:

Flipping this leaf over, I found the telltale pile of expelled frass at one end…

…confirming that this is a leaf mine of Cosmopterix clemensella (Cosmopterigidae). I first reared this species eight years ago, and I have reared it many times since from various sedge species, but I had never before bothered to look for it in my own yard. Like the other leafminers I’ve found so far this spring, this one was made by a larva that overwintered. Cosmopterix clemensella evidently does not require a period of cold temperatures to complete its development. Here is a larva I collected on November 12, 2015…

…which pupated by January 8…

…and emerged as an adult on January 20.

Incidentally, right next to that sedge clump along the side of my house, I spotted feeding sign of another micro-moth, this one on heart-leaved aster (Symphyotrichum cordifolium).

Four springs ago I found a similar fold in the edge of a leaf of white wood aster (Eurybia divaricata)…

…which I collected to see who was responsible. The larva ended up constructing a tubular leaf shelter, from which it can be seen peeking out here:

It emerged as an adult in mid-June, revealing itself to be Dichomeris bilobella (Gelechiidae).

I don’t know that it’s the same species hiding in a folded hear-leaved aster leaf next to my house, but I’d bet it’s at least a Dichomeris of some sort. I’m going to leave that one where it is, but I’m currently trying to rear another Dichomeris species that starts out life as a leafminer in early autumn, then transitions to feeding externally from a web, which it continues to do for at least several weeks the following spring. More on that later, perhaps.

And on the “how many different plants can I find to eat in my yard” front, on average I’ve been able to add at least one a day throughout the month of April:

26. Giant chickweed (Caryophyllaceae: Myosoton aquaticum or Stellaria aquatica, depending on whom you ask) – leaves
27. Bok choy (Brassicaceae: Brassica rapa) – leaves, flowers
28. Bittercress (Brassicaceae: Barbarea vulgaris) – leaves
29. Sedum / orpine / live-forever (Crassulaceae: Hylotelephium telephium) – leaves
30. Peppermint (Lamiaceae: Mentha × piperita) – leaves

Although stinging nettle was added to the list early on, there is now enough of it to make a substantial contribution to meals. We added it to some potato-leek soup for last night’s dinner, and it featured prominently in this morning’s omelet. Yum.

The Yard List(s), Part 2

Yesterday afternoon I spotted the sixth leafminer species of the season for my yard list. The mine was a subtle one, which I probably wouldn’t have noticed if I hadn’t been lying face-down in my lawn and nibbling dandelion greens.

See it? This sneaky species forms a clean, whitish mine right over the midribs of dandelion leaves. Here’s a closer view:

I first noticed this type of mine in a small, isolated plant growing along my driveway on April 21, 2016. Rather than picking the leaf right away, I watched the mine develop over a couple of weeks. When I first spotted it, the plant was just beginning to grow its second leaf:

By May 5, that second leaf was larger than the original one, and the larva had abandoned the first leaf (at right in the photo below) in favor of the new one (at left).

On further investigation, I discovered that the larva had also abandoned the second leaf, mining into the underside of the plant’s third leaf, where it had just formed a puparium right next to the midrib.

Mind you, this larva was not capable of exiting the plant and then reentering; each transition to a new leaf was accomplished by mining down one petiole to the base and then entering the base of another petiole. Given how early in the season this species shows up, I suspect that eggs may be laid in the fall, with young larvae overwintering in the crowns of the plants. I’ve documented something similar in the related fly Ophiomyia congregata (Agromyzidae) on the related plant Nabalus (formerly Prenanthes; common names include white lettuce and rattlesnake-root). This dandelion miner is O. nasuta—here’s the adult that emerged from the mine along my driveway, on May 20 or 21:

On larger-leaved dandelion plants, there may be no upper-surface portion to the mine at all, as in this example I found in my yard on April 24, 2017. It’s essentially invisible except for the puparium itself. This is another one I only found because I was munching on dandelion greens.

Since my last post I’ve also added four more species to the list of plants I’ve eaten from my yard this spring:

22. Early winter cress (Brassicaceae: Barbarea verna) – leaves
23. Garlic (Amaryllidaceae: Allium sativum) – leaves
24. Parsnip (Apiaceae: Pastinaca sativa) – roots
25. Hairy bittercress (Brassicaceae: Cardamine hirsuta) – leaves

I hadn’t really tried (or really identified) hairy bittercress before, but it occurred to me while weeding it out of a strawberry patch that it might be worth eating. I found this page about it and agree with the assessment that it would be more accurate to call this plant “Not-so-hairy and pleasantly-mild spicycress.” After sautéing a big pile of it, it made a great addition to some parsnip soup.

Nevertheless, Julia and I thought it would be nice to have more than just weeds to eat later in the season, so yesterday we finished rabbit-proofing the fences around our vegetable gardens. And not a moment too soon, it turned out, as we found this baby bunny inside the garden where we’ll soon be planting beans:

 

Green Wasps from a Green Island

Last October I picked up a fallen black cherry (Prunus serotina) leaf from my yard because it had a good example of the “green island” phenomenon I’ve written about here and here. Apparently, endosymbiotic Wolbachia bacteria in certain leaf-mining larvae manipulate levels of  plant hormones (cytokinins) with the result that the portion of the leaf being mined stays green when the rest of the leaf is changing color in the fall. By this time of the year, photography fatigue was setting in, and the leaf sat on my desk drying and curling for a few days before I got around to taking some pictures of it.

Mines of two different moth larvae are visible in the photo above. To the left is a contorted linear mine of Stigmella prunifoliella (Nepticulidae), without any associated green island. The Stigmella larva completed its development and exited the mine to spin a cocoon on the ground. The green patch to the right corresponds exactly with an underside tentiform mine of a Phyllonorycter species (Gracillariidae), probably P. propinquinella. (There is also an old, brown mine of another Phyllonorycter larva at the upper edge of the leaf adjacent to the Stigmella mine, but it doesn’t look like much in this photo.)

Here are closer views of the upper and lower surfaces of the green Phyllonorycter mine:

The lower surface is wrinkled because at a certain point in its development, the larva began spinning silk inside the mine, and this contracted as it dried. The resulting tentiform mine makes it much more difficult for a parasitoid or predator to reach the larva because the larva now has a three-dimensional space in which to move around. Some parasitoids, however, attack these larvae when they are young and the mine is still flat, then complete development when their host is nearly mature.

In taking these photos, I noticed a couple of tiny holes in the upper surface of the mine, which suggested some sort of predator or parasitoid had gotten at the moth larva inside. So I tore open the mine to see if I could figure out what had happened.

In this interior view of the mine, we can see that the moth larva kept its living space clean by collecting all of its blackish frass into a neat bundle. At left is a parasitoid wasp larva, which has just finished devouring the moth larva. It, too, has kept its living space—the inside of the moth larva—clean, by saving up all of its waste products until it was finished feeding. It has now deposited them in a little cluster of brown meconial pellets.

Three days later, I was surprised to find not one but two wasp pupae inside the mine.

So the leafminer was actually devoured from within by not one but two wasp larvae. If you look back at the first photo showing the inside of the mine, you can see the head of the second larva (a little out of focus) just peeking out from the flap of leaf epidermis where the tip of the second pupa’s abdomen is hidden in the above photo.

A few weeks later, I put this leaf in the fridge for the winter. I took it back out on February 21. On March 30, both of the wasps emerged as adults.

These wasps, which are a little over 1 mm long, belong to the tribe Entedonini of the family Eulophidae. I’m fairly sure they belong to the genus Chrysocharis, of which Christer Hansson has so far identified six species among the wasps I’ve reared from leafminers in my yard. All of them specialize in parasitizing leafminers, and it has been interesting to learn how each Chrysocharis species is further specialized: one emerges exclusively from cocoons of nepticulid moths; one seems to specialize in linear mines (of agromyzid flies and occasionally moths); one has been reared almost exclusively from mines of agromyzid flies on monocots; another parasitizes leaf-mining flies, moths, or beetles, but only on grasses and sedges; one attacks various flies and moths but seems to favor moist to wet habitats; and one shows no apparent preferences, having been reared from a variety of leaf-mining flies, moths, beetles, and sawflies, as well as the occasional gall wasp or midge that forms flat, mine-like leaf galls.

Here is an adult of Phyllonorycter propinquinella that escaped parasitism, though another larva mining in the same leaf was not so lucky. It emerged in early September from a leaf I had collected a few days earlier.

The Yard List(s)

This year Julia and I decided to take a break from traveling and—for once—experience our yard through all the seasons without missing anything. Given the stay-at-home orders of late, and my almost complete lack of employment opportunities as a result, it looks like we picked the right year for it! Since 2013 I have been haphazardly keeping lists of the flora and fauna on our property (which includes our yard as well as several acres of seepy woods that were logged just before we moved here). The tallies currently stand at 239 vascular plant species,  130 vertebrates, and 742 invertebrates. If I had been making this a priority, these numbers would not be at all impressive; people who regularly set up lights in their yards at night to attract moths have counted 7-800 or more species, and that’s just one insect order.

I have no plans to attempt a complete all-taxa biodiversity inventory of our property, but I did think it would be fun to see how many species of leafminers I can find in the yard in one year, and to make an effort to notice when each species first makes an appearance. Since I’ve started work on a guide to sawfly larvae, I’m going to try to keep track of them too, although I won’t be able to put names on them right away. And while I’m keeping tabs on all the plants to see what bugs are eating them, I’m curious to see how many species of plants I can find to eat in my yard over the course of a year (both wild and cultivated).

Well, leafminer season of course begins on January 1, since I’ve got larvae of both Argyresthia thuiella (Argyresthiidae) and Coleotechnites thujaella (Gelechiidae) overwintering in the arborvitae hedge along the road. A few weeks ago, adults of Chrysoesthia sexguttella (Gelechiidae) started showing up in our hoop house—here’s one I found clinging to some lambsquarters (Amaranthaceae: Chenopodium album) I was picking yesterday for our breakfast omelet:

Larval mines of this species were extremely abundant on the maple-leaved goosefoot (Chenopodiastrum simplex) in our hoop house last July, so I’m not surprised to see all these adults now.

And last week while weeding the Japanese pachysandra out of one of our wildflower/shrub gardens, I found two species of moth larvae mining basal leaves of heart-leaved aster (Asteraceae: Symphyotrichum cordifolium). Landryia impositella (Scythrididae) makes blotch mines that have no frass inside, because when not feeding it retreats to a web spun on the underside of the leaf.

The adults will appear in June. Evidently this species overwinters either as eggs or young larvae.

The other miner in the heart-leaved aster was Bucculatrix staintonella (Bucculatricidae). It makes linear mines with frass deposited in a central line.

The above photo was taken on January 6 last year—I collected the leaf on January 1. So clearly this species overwinters as a larva, thawing out and feeding whenever it’s warm enough. As with Landryia impositella, adults of Bucculatrix staintonella appear in June.

So that’s five species of leaf-mining moth found in my yard this year as of April 7. No sawfly larvae yet, although in our seepy woods there are leaf-mining larvae of Metallus ochreus (Tenthredinidae) that have overwintered in leaves of dewberry (Rosaceae: Rubus hispidus). A few days ago I started seeing adults of what I presume are Dolerus species, whose larvae feed on grasses and horsetails. Here’s one from April 2015:

And how many different plants have I eaten from my yard so far this spring? Let’s see…

1. Jerusalem artichoke (Asteraceae: Helianthus tuberosus) – tubers
2. Oxeye daisy (Asteraceae: Leucanthemum vulgare) – leaves
3. Common dandelion (Asteraceae: Taraxacum officinale) – leaves, flowerbuds
4. Common plantain (Plantaginaceae: Plantago major) – leaves
5. Common chickweed (Caryophyllaceae: Stellaria media) – leaves
6. Stinging nettle (Urticaceae: Urtica dioica) – leaves
7. Chives (Amaryllidaceae: Allium schoenoprasum) – leaves
8. Leeks (Amaryllidaceae: Allium ampeloprasum) – leaves
9. Evening primrose (Onagraceae: Oenothera biennis) – leaves
10. Lambsquarters (Amaranthaceae: Chenopodium album) – leaves
11. Miner’s lettuce (Montiaceae: Claytonia perfoliata) – leaves
12. Spinach (Amaranthaceae: Spinacia oleracea) – leaves
13. Lettuce (Asteraceae: Lactuca sativa) – leaves
14. Curly dock (Polygonaceae: Rumex crispus) – leaves
15. Common wood-sorrel (Oxalidaceae: Oxalis stricta) – leaves
16. Kale (Brassicaceae: Brassica oleracea) – leaves
17. Heart-leaved aster (Asteraceae: Symphyotrichum cordifolium) – leaves
18. Common blue violet (Violaceae: Viola sororia) – leaves
19. Ground ivy (Lamiaceae: Glechoma hederacea) – leaves
20. Oregano (Lamiaceae: Origanum vulgare) – leaves
21. Thyme (Lamiaceae: Thymus vulgaris) – leaves

Most of these are just nibbles at this point, rather than constituting a large part of a meal, but it’s a wider array of menu options than I expected to find in my yard when spring has just barely started here on our mountain near the Massachusetts / New Hampshire border. More coming soon, no doubt!

 

Adventures in Taxonomy

Apparently today is “Taxonomist Appreciation Day,” so I suppose it’s an appropriate time to write a little something about my latest paper, which I discovered had been published right after I clicked “publish” on my previous blog post. I never intended to become involved in taxonomy at all, but as a naturalist, it gets really hard to make sense of the world when so many of the species I’m studying don’t have names. If I meet a species that no one has gone to the trouble to describe and name, how can I tell how it relates to anything anyone has found before? Once there are names to which to attach observations, I can start to understand patterns in the habits and host plants (or host insects) of different species, and how these differ from species to species. Somebody needs to do the hard work of deciding what the limits are between similar species, and illustrating (in words and pictures) what the differences are. As summarized here, I’ve now had the pleasure of collaborating with various taxonomists to give names to over 60 species of insects whose natural history I’ve written about. This latest paper* doesn’t describe any new species, but it makes several taxonomic changes involving the names of leaf-mining moths in the family Gracillariidae.

It all started in March of 2017, when Julia and I stopped in Arizona on our way home from checking out the “super bloom” in southern California. Although nothing had leafed out yet in the canyons we visited, we found a number of different active mines in the leaves of evergreen trees and shrubs, and we had good success in rearing adults from most of them. These included a Cameraria species on Arizona madrone (Ericaceae: Arbutus arizonica)…

…and another Cameraria on silverleaf oak (Fagaceae: Quercus hypoleucoides):

When we got home and I started trying to identify all the leaf mines we had found using the keys I’d written, I found that most of them were new to science. These two species were among the few that had names (or at least, that had names that could be linked to leaf mines that had been described in the literature). To my surprise, they were Phyllonorycter arizonella and P. cretaceella. But they both were clearly Cameraria, based both on the leaf mines (flat, on the upper surface, with a longitudinal crease along one margin when complete) and the adult wing pattern (the black edging was on the outer edge of the white markings). I checked the original descriptions; both were species that Annette Braun had described in 1925 from specimens she reared in Arizona, and no one had published anything about them since. She described both species in the genus Lithocolletis, which is now considered a junior synonym of Phyllonorycter but in 1925 also included all the species that are now placed in Cameraria. The genus Cameraria was actually described in 1902—it was named for the Kentucky lepidopterist V. T. Chambers (“camera” being Latin for “chamber”)—but it was decades before the name was adopted for North American species, and most species of “Lithocolletis” didn’t receive their currently recognized names until Don Davis transferred them to Cameraria and Phyllonorycter in the 1983 Check List of the Lepidoptera of America North of Mexico.

Phyllonorycter species mostly make leaf mines on the undersides of leaves, and rather than remaining flat they usually become strongly wrinkled and “tentiform.” I decided to review the leaf mine descriptions of all the other North American Cameraria and Phyllonorycter species to see if any others were on the “wrong” side of the leaf. I found a number of other examples of Phyllonorycter species that sometimes or always make upper-surface mines, but based on features of the larvae and adults (larvae becoming round in cross section in later instars, rather than remaining flat; adult forewings with black edging on the inner margins of the white markings, rather on the outer margins), they appeared to be proper Phyllonorycter species. However, among the Cameraria species there were two that formed underside tentiform mines, and a little investigation suggested that they actually belonged in Phyllonorycter. One was C. leucothorax, which mines leaves of tanoak (Notholithocarpus densiflorus) and canyon live oak (Quercus chrysolepis) in Oregon and California. I’ve never reared it, but this is probably its mine:

The other was Cameraria affinis, an eastern species that mines leaves of honeysuckles and snowberries (Caprifoliaceae: Lonicera and Symphoricarpos).

I wrote to Don Davis about this, and he agreed that all four species were misplaced and should be transferred as I suggested, changing their names to Cameraria arizonella, C. cretaceella, Phyllonorycter affinis, and P. leucothorax. I thought I would just write a short note to set things right, but he felt that something more detailed was warranted, including illustrations of the male and female genitalia of each species, which he offered to provide. He had never seen specimens of C. arizonella (the six that Julia and I reared may be the only ones beyond Annette Braun’s original five, which are in Philadelphia now), so I sent him a male and female of that species, along with whichever sex he was missing for P. affinis. He had reared his own series of C. cretaceella in New Mexico in 1989, and fortunately he already had what he needed for P. leucothorax as well.

When I submitted the manuscript to Zootaxa, I suggested Terry Harrison as a possible reviewer. This turned out to be a very good idea, because when Terry was looking over the manuscript and illustrations, he was struck by the resemblance of Phyllonorycter affinis—in both wing pattern and genitalia—to the species he calls P. mariaeella. As it happens, last October when I visited Harvard University with Julia to give a slideshow about leafminers to the Cambridge Entomological Club, we showed up early and spent a few hours photographing V. T. Chambers’ type specimens that are housed at the Museum of Comparative Zoology. Unfortunately there is no type specimen for P. mariaeella—whatever existed may have been devoured by dermestid beetles, as happened to many of Chambers’ specimens while he was still alive—but filed under that name there are three specimens reared by Mary Murtfeldt in Kirkwood, Missouri. She was the namesake of P. mariaeella, and the species was described from specimens she reared at that same location, so these were as close to type specimens of P. mariaeella as could be hoped for.

Here’s one she reared from snowberry:

And one of two she reared from honeysuckle:

Annette Braun, in her 1908 revision of the genus “Lithocolletis“, had distinguished affinis and mariaeella based on the forewing fasciae (white markings) being “nearly straight”
in the former and “distinctly bent outward near the middle” in the latter. Terry dissected a series of Illinois specimens showing a full range of variation in these markings and found that they all had matching genitalia. David Lees at the Natural History Museum in London was kind enough to send photos of one of the affinis type specimens and its genitalia, and these too matched Terry’s specimens from Illinois as well as Mary Murtfeldt’s specimens from Missouri, and these in turn matched Chambers’ description of mariaeella. Since Chambers described mariaeella in 1875 and affinis was described in 1876 (by Frey & Boll, a couple of German lepidopterists studying material from Texas), mariaeella has priority, and Don and I have designated affinis as a synonym. One less leaf-mining moth to worry about!

The other reviewer I suggested for this manuscript, Steven Whitebread, noticed another possible synonymy when reviewing our illustrations. This is one of the type specimens of Phyllonorycter gemmea, another Frey & Boll species, but one collected in Massachusetts rather than Texas (and that, I suppose, is why part of its type series is deposited in Cambridge, MA rather than in London):

It was allegedly reared from black locust (Fabaceae: Robinia pseudoacacia), but Frey & Boll had some mix-ups with the leaves they had collected and they weren’t sure what type of mine it had come from. They described three different types of mines they had found on black locust, which clearly correspond with three other gracillariids: Chrysaster ostensackenella, Macrosaccus robiniella, and Parectopa robiniella. Braun (1908) incorrectly cited Frey & Boll as having said that Phyllonorycter gemmea makes an upper-surface mine, which is how this species ended up getting mentioned in this “wrong side of the leaf” paper. Chambers was convinced that this moth hadn’t come from black locust at all, and I’m inclined to agree. Steven suggested that it might be synonymous with P. diversella, a leafminer of huckleberry (Ericaceae: Gaylussacia baccata) that Annette Braun described decades later. It does seem plausible that if Frey & Boll had a bunch of mixed-up leaves, they could have mistaken a huckleberry leaf for a leaflet of black locust. But as I considered this possibility, I found two other species that Braun described—P. martiella from birch, and P. viburnella from arrowwood—that also have a similar wing pattern, and the only way to sort this out will be to dissect the specimen in the above photo (which is the only specimen in the type series that still has an abdomen) and compare its genitalia with those of specimens reared from huckleberry, birch, and arrowwood. A bit beyond the scope of this paper—one of many taxonomic issues that still need to be worked out involving species that already have names, let alone the countless ones that remain to be described.

And so, a big thanks to all taxonomists—past, present, and future—for your ongoing work to help the rest of us make sense of the complexity of nature!

* Eiseman, Charles S. and Donald R. Davis. 2020. Wrong side of the leaf: assigning some Lithocolletinae species (Lepidoptera: Gracillariidae) to their proper genera. Zootaxa 4751(2): 201–237.

Mallow Munchers

Three years ago, Don and Mignon Davis described a new species of moth, Telamoptilia hibiscivora (Gracillariidae), whose larvae mine leaves of swamp rosemallow (Malvaceae: Hibiscus moscheutos) along the Atlantic Coast*. Specimens were known from Maryland, Louisiana, Texas, and adjacent Mexico, dating back to 1932—sometimes these things take a little time. Swamp rosemallow isn’t a plant I normally encounter in my wanderings, but nonetheless I added T. hibiscivora to my mental list of species to watch for—and, of course, to my complete guide to North American leafminers.

Last spring, when Kelly Omand asked me about some beetles that were emerging from swamp rosemallow seeds she had collected on Nantucket, I immediately made checking those plants a priority for my next visit to the island. In September Julia and I followed Kelly’s directions to the plants and found them in bloom:

More importantly, we found a thriving population of Telamoptilia hibiscivora, with multiple larvae often mining a single leaf.

The above photos show the upper and lower surface of the same three mines. Each mine begins as a linear track on the underside of the leaf, then becomes a greenish, interparenchymal blotch: leaving some green tissue adjacent to both the upper and lower epidermis, with the result that the mines are less distinct than leaf mines typically are. But the older larva continues to nibble away at the cells in the blotch, so that it develops more distinct whitish or brown patches. Here’s a backlit leaf with at least three larvae visible inside:

As noted by Davis & Davis, the mature larva exits its mine “and forms an elliptical, white to brownish white cocoon usually on the leaf surface.”

A detail they didn’t mention is that the finished cocoon is decorated with a few “frothy bubbles” as in certain other gracillariid moths (see this post for more examples).

The original description noted that larvae pupate only when subjected to cold temperatures, and that the pupal stage overwinters, so once everybody had finished mining and spun their cocoons, into the fridge they went. I emptied out the bug fridge a little less than a month ago, and yesterday the first adult Telamoptilia hibiscivora emerged:

And just like that, the species’ known distribution was extended by 500 miles or so.

Thanks to the “Leafminers of North America” project I created on iNaturalist, I recently learned of the existence of similar mines on saltmarsh mallow (Kosteletzkya pentacarpos) in Everglades National Park. Another new species of Telamoptilia, or a new host record for T. hibiscivora? Someone down there will have to investigate.

As for the beetles that live in swamp rosemallow seeds, we got to meet those too. Here’s a portion of a seed capsule with at least two beetles visible:

After spending its whole larval life eating out the inside of a single seed, and pupating in the resulting chamber, the adult weevil emerges by chewing a neat circular lid at one end of the seed.

This is one of three Althaeus species in the US north of Mexico, all of which develop inside mallow seeds; I’m not sure exactly which one. They belong to the subfamily Bruchinae (Chrysomelidae), which are known as “bean weevils,” but that name doesn’t work for them since they don’t feed on beans (not to mention that they aren’t really weevils). Kelly calls them “Gonzos,” which seems reasonable to me.

* Davis, Donald R. and Mignon M. Davis. 2017. First report of the genus Telamoptilia from the western hemisphere with descriptions of two new species (Gracillariidae). Journal of the Lepidopterists’ Society 71(4)261-273.

Ten Years Later

Since we have ten fingers and ten toes, I suppose it’s worth mentioning that it was ten years ago today that Tracks & Sign of Insects and Other Invertebrates was first published. People are often surprised when I tell them that Noah and I didn’t know much about the subject matter when we started writing it, and that it didn’t take years and years to finish. We set out to write it precisely because we didn’t know: we wanted a book that would solve those nagging natural history mysteries, like what are those shiny red discs we always find on the undersides of rocks, and what makes those feathery patterns in the algal film on birch bark, and what’s the deal with the flattened, dead flies we keep seeing stuck to the undersides of leaves?

Mark Elbroch had suggested we give ourselves a year to put this book together, but given the vastness of the topic and how little we knew about it, I decided on a year and a half. In the fall of 2007 I began scouring the literature in earnest; throughout 2008 we took thousands of photos, traveling throughout the US to photograph things that couldn’t be found at home in New England; and the next winter was spent compiling and writing. I ended up getting a one-month extension on the deadline for submitting the manuscript—I think from March 1 to April 1, 2009—and even so, I remember we were still working on finishing the introduction the day before the new deadline (including Noah running out into the woods behind his house to take the pictures of white pine trees that appear on pages vi and ix).

It was a good thing we had a firm deadline, because we could easily have spent the rest of our lives adding and revising. As it was, I did keep slipping new tidbits in for a while longer until the editor cut me off. I still remember the last thing I tried to slip in that didn’t make the cut; it was my discovery that a beetle named Chalepus walshii was responsible for those distinctive white rectangles I kept seeing on Canada bluejoint and other marsh grasses while conducting botanical fieldwork:

The answers to other riddles have remained elusive. In May 2011, I wrote here about a Bucculatrix cocoon Noah and I found in Tennessee that was curiously marked with little figure-eights.

As you can read in that post, I speculated that these markings might have been the work of a parasitoid wasp. This seems far-fetched to me, but I still don’t have a better explanation. Annette Braun never mentioned any such markings in her 1963 revision of the genus Bucculatrix, and I have never found another cocoon like this among the hundreds or thousands of Bucculatrix cocoons I’ve encountered over the past decade.

Or rather, I had never until October 10 of last year, when I went for a run down the road from my house and stopped to inspect a heart-leaved aster (Symphyotrichum cordifolium). John van der Linden had told me about a fly he found in Iowa that sneakily mines the petioles of heart-leaved asters, hardly leaving any discernible evidence besides its puparium; I wanted to see if I could find it in Massachusetts and rear adults to learn its identity. Curled in one of the petioles of the aster I stopped to examine was a Bucculatrix cocoon covered with little “8”s.

Were these “8”s inscribed in the surface or just a result of the Bucculatrix larva using two different colors of silk to spin its cocoon? I couldn’t tell for sure—the latter seemed almost plausible with this new cocoon, but looking back at the one from Tennessee, the “8”s are just too rounded and irregular; I think it has to have been done from outside. Naturally I collected the cocoon to see what would emerge.

Two weeks later I was doing some fieldwork in Northampton and I spotted two more cocoons decorated with little “8”s, this time attached to pine needles.

The same sprig of pine needles also had a similar cocoon without the “8”s:

Both the aster and the pine were directly below red oak trees, and I believe oak was the actual larval host of the Bucculatrix larvae that spun these cocoons. Many species of Bucculatrix start out life mining in oak leaves, then complete their development feeding on the surface of these leaves. When mature, they drop down on strands of silk and may wander some distance before finding a suitable place to spin a cocoon. There is a Bucculatrix cocoon just outside my second-floor bathroom window, 100 feet from any tree. Maybe it’s one of the aster-feeding species and didn’t have to walk that far, or maybe it blew there on a very windy day. The point is, one shouldn’t assume that the plant a cocoon is found on is the caterpillar’s actual food plant; my hope would be that the moth that emerges from the cocoon would be a species whose larval host is already known. If the “8”s indicate parasitism, though, this will make it very tricky to learn the moth’s exact identity—unless a moth emerges from that one unmarked cocoon and can be assumed to be the same species as the others.

Well, a few days ago this wingless wasp emerged from the cocoon on the aster petiole:

I believe it is an ichneumonid in the genus Gelis. Whereas many parasitoid wasps that emerge from their hosts’ cocoons arise from eggs that are laid when the host is still a larva or even an egg, Gelis species oviposit in their hosts’ cocoons. So I suppose if it’s really a wasp scribbling little “8”s on these Bucculatrix cocoons, Gelis would be a good candidate for the culprit. If the two cocoons on the pine needles have the same fate, that will be good supporting evidence. I’m still open to other explanations, but have none to offer at the moment.

This is the (now somewhat moldy) cocoon with the exit hole chewed by the emerging adult wasp. The “8”s are fainter now but still discernible.

Introducing Grapholita thermopsidis

Almost every year since we bought our house, Julia and I have spent a few weeks on a road trip in search of exciting new leafminers. At this point we’ve visited nearly every US state and two Canadian provinces. This year, we’re looking forward to sticking around the homestead for the entire growing season for a change, but our past collecting trips continue to bear fruit. Today, for instance, a moth species we discovered in Colorado five years ago finally has a name.

In July 2015, our travels were centered around a visit to our friends in Colorado, Sally Waterhouse and Denny Radabaugh, who were Julia’s biology professors in college and who officiated at our wedding. This was the trip on which we found the rose leaf-mining sawfly Fenusa julia. Exactly one week earlier, we were poking around Sally and Denny’s yard and checking out the unusual (to us) plants in it when we spotted some mines on Thermopsis (Fabaceae), a plant known as goldenbanner or false lupine.

From above, the mines were visible as only slight discoloration, and they were only conspicuous because of the way they caused the leaflets to buckle.

The mines were perfectly distinct when viewed from below.

“Underside tentiform mines” like these are characteristic of certain moths in the family Gracillariidae, and on a legume like Thermopsis the expected genus would be Macrosaccus. However, upon collecting some of these mines, it soon became apparent that the larvae inside were expelling their frass:

A few gracillariids expel frass from their mines, but none of these are species that make tentiform mines, so this was something weird. At this point my leafminer book manuscript was far enough along that I knew the only documented leafminer on Thermopsis was Parectopa thermopsella (Gracillariidae), described in 1875 by V. T. Chambers, who collected the species in Colorado. No specimens of Parectopa thermopsella are known, but there is nothing in Chambers’ description of the leaf mine or the adult that indicates how it would be distinguished from the moth now known as Micrurapteryx occulta, which Annette Braun described in 1922 as Parectopa occulta and mines leaves of a variety of legumes. We found mines of “Parectopa thermopsella” during that trip to Colorado. They are flat, upper-surface mines, with a more or less lobed or “digitate” shape. Each lobe represents a different feeding excursion; in between bouts of feeding, the larva returns to a point along the midrib where it expels its frass through a hole in the lower epidermis.

In the lower-surface view above, you can see the initial linear track the larva makes on the lower leaf surface before switching to the upper surface to make a blotch mine. Unfortunately we were unable to rear any adults of “Parectopa thermopsella,” but they would look something like this Micrurapteryx we reared from a similar mine on Astragalus during the same trip to Colorado:

Anyway, ten days after we collected the mystery mines on Thermopsis, some larvae had abandoned their mines and were continuing to feed on the leaves externally, within shelters made by rolling or tying the leaves with silk.

A few days after that, parasitoid wasps started emerging from some of the mines. These little ~1 mm beauties are a female and male Zagrammosoma mirum (Eulophidae):

There were also a few braconid wasps, a little shy of 3 mm long:

So far, what José Fernández-Triana has been able to tell me about them is that they are in the genus Dolichogenidea. Their DNA barcode matches that of some specimens from Canada, but the species has not yet been identified (if it in fact has a name).

Fortunately, some of the moth larvae escaped parasitism and pupated in early August.

It was clear by now that this moth was not a gracillariid at all, but I wasn’t quite sure what it was. It wasn’t until the following spring that the adults finally emerged:

I knew they belonged to the family Tortricidae, which are commonly known as the “leafroller moths.” I sent them to Jason Dombroskie at Cornell University, who confirmed his impression from my photos that they belonged to the genus Grapholita.  He suspected they represented an undescribed species, but he didn’t have time to investigate further.

Last year, when I heard that moth aficionado Kyhl Austin had become Jason’s grad student and was focusing on Tortricidae, I seized the opportunity to ask Kyhl if he could take a look at these specimens. He was happy to, and within a few weeks he had confirmed that they belonged to a new species and described them in intricate detail. He also dissected and identified all of the other tortricids I’d sent to Cornell, several of which had not been reared before or were not known to start out life as leafminers. Today our paper* was published, in which the new species is named Grapholita thermopsidis and the natural history of six other leaf-mining tortricids is discussed.

At ~5 mm long (wingspan ~1 cm), this is the largest insect species I’ve had the pleasure of naming. It is the third moth species I’ve coauthored, and it occurs to me that each moth has taken five years after its initial discovery to actually get described (although with Marmara viburnella  what took so long was successfully rearing adults, and the species description was published the following year). Many more new moths await, so hopefully I can pick up the pace a bit!

* Eiseman, Charles S., Kyhl A. Austin, Julia A. Blyth, and Tracy S. Feldman. 2020. New records of leaf-mining Tortricidae (Lepidoptera) in North America, with the description of a new species of Grapholita. Zootaxa 4748(3): 514–530.