Sharing the Fruit Trees

Periodically I am asked how to get rid of some bug or another. If I am giving a public talk, I want to reply, “have you not been paying attention to anything I’ve said for the past hour?” If the question comes in the form of a comment on this blog, I have to wonder what possessed the person, rather than asking any of the innumerable extension entomologists or pest control specialists out there, to instead ask the author of a website dedicated to celebrating the natural history of insects—it says “Bringing glory to Earth’s small and neglected creatures” right there at the top, for crying out loud.

For future reference, here is the sum total of my experience dealing with insect pests: When Japanese beetles are abundant in my yard, I walk around with a bowl of water (with a drop of soap added to break up the surface tension), knock them into it, and give them to my chickens. When cabbage white caterpillars are abundant on the broccoli or some other Brassica, I pluck them off and give them to the chickens. When the Pegomya leaf-mining flies show up on the spinach or chard, I try to eat the leaves before the eggs hatch or the larvae get too big; if I miss some, those leaves go to the chickens. That’s pretty much it.

Today I was delighted to find larvae of the beetle Baliosus nervosus mining the leaves of our cherry, plum, and medlar trees—all of these were previously undocumented hosts for this species, and the beetles confined their damage to less than one leaf per tree. I was mildly concerned when I saw this mass of tiny caterpillars on one of the plum trees:


I believe these are young larvae of Schizura concinna (Notodontidae), which I found four years ago on the neighboring cherry tree:


August 16, 2015


August 22, 2015

The next year I found some nearly mature ones busily defoliating our young persimmon tree:


September 4, 2016

These caterpillars are hungry and numerous, so they’re not the best thing to have on a fruit tree, but I don’t hold anything against them. Today, as before, I plucked the leaf they were on and moved them to a wild black cherry tree at the edge of the yard, which they can munch to their hearts’ content as far as I’m concerned. There, they were greeted by another caterpillar…


…which appears to be Acronicta radcliffei (Noctuidae). Also on that black cherry tree was this Callosamia promethea caterpillar:


(It was actually hanging head-down, but I rotated this photo 90 degrees to better fit the format of the blog.) Bigger (than 1 cm) moths are not my forte, and I confess to having initially mistaken this for a young cercopia. While I was out documenting the charismatic megafauna on my fruit trees, I figured I might as well get a shot of this caterpillar I’d spotted earlier in the day on the medlar:


This is another notodontid, Schizura unicornis, and it is quite dead—perched atop a logpile of cocoons spun by the microgastrine braconid wasp larvae that until recently were feeding inside it. Look closely and you’ll see that the side of its abdomen is riddled with their exit holes.

It’s just as well that the things I wanted to photograph today were on the large side, because this morning I sent my beloved MP-E 65mm macro lens off to the Canon Factory Service Center to be repaired. This was actually my second MP-E 65, which I’d bought as a backup when the first one developed the same problem, but apparently I’d never gotten around to sending the first one off to be repaired, so I actually sent both lenses off today. Hopefully I don’t come across anything tiny that needs photographing in the next couple of weeks, because I don’t think a third $1000 lens is in the cards for me.

One of the last things I was able to photograph before my backup macro lens gave up the ghost was this 1-mm entedonine eulophid wasp, which coincidentally also came from a caterpillar on a rosaceous fruit tree:


On Saturday afternoon, on my way home from teaching a week-long course on leafminers at the Eagle Hill Institute in Maine, I stopped at Mt. Wachusett in eastern Massachusetts to lead an insect walk at a BioBlitz event. The walk ended in an old orchard, where we found several species of leafminers on the apple trees, including underside tentiform mines like this one…


…made by a species of Phyllonorycter, likely blancardella. I collected a few mines to try and rear adult moths, and on Tuesday the wasp emerged from one of them. Yesterday after I had photographed the wasp, I located the mine that had an exit hole and opened it up to see what other evidence the wasp had left behind. I discovered that rather than being a primary parasitoid of the moth larva, this wasp had emerged from the cocoon of a microgastrine braconid wasp (in the genus Pholetesor, I believe), the larva of which was what had actually done in the leafminer.

Here’s a view of the braconid cocoon inside the Phyllonorycter leaf mine, with the eulophid’s exit hole toward the left end:


Had the braconid not been parasitized by the eulophid, here’s what would have emerged from that cocoon:


And had the moth larva not been parasitized by the braconid, here’s what would have emerged from the leaf mine:




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Complete leafminer guide now available!

This weekend I finished the first edition of my Leafminers of North America e-book—1857 pages long (plus a 54-page table of contents, 20-page glossary, and 68-page bibliography), and illustrated with thousands of color photographs. To purchase it or learn more about it, you can click this image of the cover.

Although the book is a “complete” guide in terms of including all previously published information about North American leaf mines—heavily supplemented with previously unpublished observations—I have, as expected, continued to find new things to add on an almost daily basis. Just last week, my third paper with Owen Lonsdale was accepted for publication; it will describe another ten new species of agromyzid flies. And just yesterday, I went on a successful mission to collect more larvae of this Calycomyza species, which appears only in early June, has only been found at a single location, and is so far known only from unidentifiable females (but almost certainly represents another new species):


As a bonus, on my way to look for that species, I discovered two new larval hosts for the adorable Orchestes pallicornis (Curculionidae).


So I already have plans to complete an updated second edition of Leafminers of North America by the end of 2020. My current thought is that I will release the first installment in January, so that I’ll have time to finish up a number of papers as well as get started on a brand new project: a hostplant-based guide to North American sawfly larvae (only 37 of which are leafminers, out of about 1000 species).


I will of course be posting more about that project as it gets underway. In the meantime, anyone who has purchased the full first edition of Leafminers of North America before the end of July 2019 (when I will be teaching my week-long leafminer course at the Eagle Hill Institute in Maine) will receive a free subscription to the second edition.

And for those who just want to contribute to my ongoing efforts to uncover natural history mysteries and share my findings with the world, there is always the “Make a Donation” button at the top of the right sidebar. If everyone reading this chipped in the same amount I do every year to keep this blog ad-free ($30), I could do this full-time! Thank you for reading, whether or not you are able to make a financial contribution.

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More charismatic megafauna

Although this blog is mostly devoted to tiny, obscure insects, once in a while I encounter something big and conspicuous that seems worth sharing. And so today I find myself writing a second consecutive post without any leafminers in it—though it was in search of an elusive leafminer of false hellebore (Veratrum viride) that I wandered over to the edge of a small brook this morning. There, perched atop a skunk cabbage (Symplocarpus foetidus) leaf, I spotted this dragonfly naiad:


After checking that it wasn’t just an empty skin, I decided to hang around for a minute and see if the adult started to emerge. Sure enough, one minute later I saw something bulging from the middle of its thorax.


Although my camera battery was nearly dead when I arrived, it managed to hang on throughout the ensuing spectacle, so you can now witness it in a fraction of the time, and with none of the accompanying mosquitoes.


Fifty-one minutes had now gone by. During that time, I was keeping an eye on its neighbor, who looked like this when I arrived:


Thirty-seven minutes in:


At forty-five minutes, its wings suddenly popped open:


And five minutes later, it flew away, leaving its exuviae still clinging to the leaf:


I didn’t feel the need to hang around for another hour to see the first one through to this point. Not far away, I found another that was still perched atop its exuviae but had finished getting “colored in”:


Today was evidently the day for these to emerge; there were numerous others along a short stretch of the brook. Here’s one more:


I’m not sure exactly what these are, beyond “some kind of clubtail” (Gomphidae). I think identifying these to species often requires a close look at the tip of the abdomen, and this may or may not cut it:


Edit: Ben Coulter and Dave Small concur that these are Southern Pygmy Clubtails (Lanthus vernalis).

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Another denizen of my lawn

I often write about the diversity of invertebrates that dwell in our unkempt yard, from the leafminers that colonized the first wildflower that popped up in the middle of it to the three dozen species that emerged from a shovelful of sod last spring. But we’ve also tallied 126 species of birds, mammals, reptiles, and amphibians in our yard and adjacent woods since we’ve lived here. One that has figured prominently in recent weeks is this porcupine:


Last fall I often heard it mumbling contentedly to itself as it grazed in the lawn outside my office window, but this was generally at dusk and it wasn’t usually around when Julia and I were outside. Over the winter we could regularly see it up in its favorite hemlock tree at the edge of our backyard, slowly dismantling it, and only sneaking into our yard at night to prune our raspberry canes. But lately it has been waddling through our yard on a daily basis, munching on the vegetation, completely unconcerned about our presence. It spends as little time as possible standing up, instead flopping down with its face buried in whatever it’s eating.


The other day we watched it for a while as it slowly worked its way toward the strawberry patch where we were sitting, and when it started to munch on a strawberry plant, Julia actually pushed its face away and it didn’t feel like that was anything worth raising its quills about. It just turned slightly and went back to munching on dandelion leaves.

So yesterday morning when I headed out the front door to do some yard work and saw the porcupine there, I decided it was time for a little photo session.


I’m sorry to say that what looks like its left eye in the above photo is actually a bloated tick. There’s one below its right eye too:


We don’t have any deer ticks in our yard, but for a few weeks in the spring there is a fair amount of dog ticks. They’re easy to spot when they venture onto our pant legs, and we hand-feed them all to our chickens.

In the next few shots the porcupine is enjoying some dandelion greens, which seem to be among its favorite menu items from our yard.


After the first few photos, which were taken with my 105mm macro lens (the one that happened to be on my camera when I grabbed it), I switched to the 18-55mm so I could get closer to the porcupine and not have so much grass in the way. In the next few shots it lumbered within about a foot of my face, and I had to keep backing up.


It contemplated this white violet for a moment, but ultimately decided to spare it.


It seems to prefer eating forbs, but I got one photo that clearly shows it biting off a blade of grass:


I think it’s pretty adorable when it uses its front paws to hold the plant it’s munching on.


This last couple of shots was taken as it began to waddle back down to the woods, pausing to bite the head off a dandelion along the way.


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Life in a Pinch of Duckweed

Five years ago, in June 2014, I was conducting a natural resource inventory for the Maine Coast Heritage Trust on a property in Perry, Maine (just across Passamaquoddy Bay from New Brunswick), when I came across this interesting little wetland:


The low area surrounded by a fringe of speckled alders (Alnus incana) consisted of an unstable Sphagnum mat covered with buckbean (Menyanthes trifoliata) and hoary sedge (Carex canescens).


Buckbean isn’t a plant I see very often, and I think this was the first time I got to see its frilly white flowers.


Part of my job was to make a map of the natural communities on the property, fitting all of the vegetation types I found into Maine’s natural community classification*. This wetland turned out to be a pretty good match for what they called the “Low Sedge – Buckbean Fen Lawn.” This is an uncommon community, and I never saw anything else like it in my three years of conducting inventories for MCHT, so when I returned at the end of August I made a point of revisiting the wetland to get a complete list of the plant species there. I even took a pinch of duckweed to key it out under my microscope back at home—if I hadn’t been paying special attention to this little wetland, I probably would have just scribbled down “Lemna sp.,” if I had even noticed the duckweed.

It turned out to be good old Lemna minor, the common duckweed. As I was examining the sample under magnification a few days later to make this determination, I was excited to discover that there were fly larvae feeding inside the tiny thalli (leaves, more or less). One is visible near the middle of this photo:


A closer look:


Other thalli contained puparia:


Surprisingly, there are several different insects that feed inside duckweeds, the smallest vascular plants. One of them is a shore fly (Ephydridae) named Lemnaphila scotlandae, after Minnie B. Scotland, who discovered it in the course of studying insects associated with duckweed in Ithaca, NY, throughout the 1930s**. The only other miner Scotland studied was a weevil, Tanysphyrus lemnae, but two other shore flies have also been found mining duckweeds in North America: Hydrellia personata, another apparent duckweed specialist, and H. griseola, which mostly mines in grasses but sometimes turns up in other plants.

The puparia I found were about 1.75 to 2 mm long, much too large for Lemnaphila scotlandae (~1.3 mm) and much too small for Hydrellia griseola (over 2.5 mm). They were within the right range for H. personata, but that species had only been found from Iowa to the West Coast. So I kept an eye on my vial of duckweed to see what would emerge.

In this photo taken a few days later, you can see a fully-formed fly almost ready to pop out of its puparium:


Between September 5 and October 2, nine of these little shore flies appeared:


Here I encountered an all too familiar problem: the insects I had reared belonged to a group that no one in North America studies. I sent them off to Canada with a batch of agromyzid flies, and Owen Lonsdale kindly attempted to run them through the most recent key to North American shore flies (published in 1971), but he didn’t reach a satisfying conclusion. So he passed them along to Tadeusz (Tadek) Zatwarnicki in Poland, who identified them as Hydrellia albilabris, a species known from many European countries but never found elsewhere until now. Whether H. albilabris is a recent arrival in Maine or has been a Holarctic species all along is anybody’s guess; there just hasn’t been much attention paid to these little flies.

Our paper documenting this discovery was just published today***. Why this took five years is another story, and not one that’s necessarily worth telling. So many bugs, so little time!

* Gawler, Susan and Andrew Cutko. 2010. Natural Landscapes of Maine: A Guide to Natural Communities and Ecosystems. Maine Natural Areas Program, Augusta, Maine.

** Scotland, Minnie B. 1940. Review and summary of studies of insects associated with Lemna minor. Journal of the New York Entomological Society 48(4): 319–333.

*** Eiseman, Charles S. and Tadeusz Zatwarnicki. 2019. First Nearctic record of Hydrellia albilabris (Meigen) (Diptera: Ephydridae), a leafminer of duckweed (Araceae: Lemnoideae), with comments on related species. Proceedings of the Entomological Society of Washington 121(2): 160–167.


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Spring Beauty Visitors

Narrow-leaved spring beauty (Claytonia virginica) is a rare species where I live, listed as Endangered by the Massachusetts Natural Heritage & Endangered Species Program. So it was a treat to spend the past week in Ohio, where in some places it is difficult to take a step in the woods without stepping on one. On Monday, when it was too nice out to try to do anything productive, I decided to take a closer look at the spring beauties and see what bugs were attracted to them.

At first I wasn’t seeing anything, but when I slowed down and looked more closely, I saw that there were tiny (~1 mm) midges (Chironomidae: Orthocladiinae) all over them.


However, although that last one happened to be climbing around on a stamen, I didn’t see any evidence that they were interested in pollen or nectar, and for all I know I would have seen just as many midges if I had focused on any other plant or object on the forest floor.

Similarly, these spiderlings probably didn’t care what kind of plant they were spinning their communal web on, although they may well have ended up ensnaring some insects that were attracted to the spring beauties.


I’m glad I stopped to check them out, though, because they appear to be baby purseweb spiders (Atypidae). These are tarantula relatives that construct tubes of silk, which generally extend from their burrows in the ground up the bases of trees or other vegetation. The spider waits for an insect to crawl onto or land on the surface of the tube, then runs up, bites through the tube, and pulls its prey inside. Based on this paperSphodros niger is the only species occurring in (or anywhere near) Ohio. That species typically makes tubes that lie flat on the ground and are often entirely concealed by leaf litter, so it is by no means easy to find.


The first insects I actually saw drinking nectar from the spring beauties were little 3-mm false honey ants (Prenolepis imparis).


There were also a few much larger (~6.5 mm) ants, Formica subsericea.


Finally, I started seeing some bees. Most were zipping around unpredictably and not staying on one flower long enough for me to even attempt to photograph them. The first to cooperate was this ~5-mm sweat bee (Halictidae: Lasioglossum (Dialictus)):


Among the bees that eluded me was a bright, iridescent green sweat bee. And then, the stars of the show arrived: mining bees (Andrenidae: Andrena), fuzzy and coated with pollen. All of the insects pictured above looked awfully clean and presumably weren’t doing much in the way of pollination, but these mining bees were another story.


I posted these photos to, hoping John Ascher would confirm my assumption that these bees were Andrena erigeniae, a species that (despite being named for Erigenia bulbosa, harbinger of spring) is a specialist pollinator (oligolege) of spring beauties. Although it may visit other flowers for nectar, it only collects pollen of spring beauties when provisioning its nests. For reasons I don’t have time to investigate, Dr. Ascher identified the photos above only to the genus Andrena, but he identified the one below—the very last one I took on my spring beauty excursion—as A. erigeniae. It certainly is the one with its legs most impressively loaded with pollen.


In just a few weeks, the spring beauties will all disappear into the ground until next spring, and Andrena erigeniae will along with it.

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A wasp has its day

If you’ve followed this blog for any length of time, you know that a lot of my attempts to rear insect larvae to adults end up producing parasitoid wasps. You have probably also heard me lament from time to time how hard it is to get a specialist to examine these wasps and tell me what they arenot because no one is interested, but because there are so many wasps in the world, and so few people that study them, that those who do are perpetually overwhelmed and need to focus on whatever little slice of the unending diversity they’ve chosen to focus on at the moment if they’re ever going to get anything done. I guess that goes for pretty much all entomologists, actually.

So it was a happy day in May 2016 when Dave Wagner directed Scott Shaw and Eduardo Shimbori to me for specimens they might use in their revision of the New World braconid wasps of the tribe Adeliini. These wasps specialize in parasitizing the larvae of tiny leaf-mining moths in the family Nepticulidae. The wasp larva waits until its host has finished feeding and spun its cocoon before finally devouring it; some time later, the adult wasp chews its way out of the moth cocoon. Although there are a few records of these wasps from other hosts, they seem to all be bogus records resulting from nepticulid larvae wandering into the leaf mines of other insects before spinning their cocoons.

I sent Scott and Eduardo the few Adelius specimens I had in my possession, and José Fernández-Triana kindly located some others that I knew were among the heaps of braconids I had deposited in the Canadian National Collection, and he passed them along. When Eduardo sent me the newly published paper* yesterday, I learned that the latter specimens were the most interesting ones: they constituted the entire type series of a new species, Adelius floridensis Shimbori & Shaw.

I reared the wasps from leaf mines of Fomoria hypericella that Julia and I collected on two different species of St. Johnswort at St. Sebastian River Preserve State Park in Florida back in March 2013. Here’s a larva of F. hypericella munching away in a leaf of roundpond St. Johnswort (Hypericum cistifolium):


The finished mine of this species is more blotchy. Unlike virtually all other nepticulids, Fomoria hypericella spins its cocoon within the mine rather then popping out of the leaf and wandering for a bit before getting ready to pupate. The cocoon is visible in the lower right corner of the photo below (there is also a mine of another larva just getting started in the upper left corner):


Before spinning its cocoon, the larva cuts a crescent-shaped exit slit in the leaf, just as larvae of other nepticulids do before exiting. This gives the pupa a place to pop out when the adult (which has no chewing mouthparts) is ready to emerge.


The 2-mm adult moth may not have an exciting wing pattern, but you have to love the flashy orange pompom on its head.


The wasp, Adelius floridensis, is a zippy little thing, just over 1.5 mm long (not counting the antennae), but I was able to get a few decent shots of one as it ran around:


This female’s ovipositor is visible in the second photowell suited to poking through the leaf epidermis to insert its egg in a nepticulid larva.

There are now 19 described species of Adelius in the Americas (up from three), with just five of these known from the US and Canada. The other one I’ve met is A. coloradensis, which is widespread in the western US and seems to have an affinity for Stigmella species mining leaves of buckthorns (Rhamnaceae).


This particular one was reared from an as yet unnamed species of Stigmella that mines leaves of cascara buckthorn (Frangula purshiana). Here are three of the moth cocoons, two with moth pupal exuviae poking out and one with an exit hole chewed by the wasp:


Besides Adelius floridensis, the other newly described North American species is A. canadensis, which is known from just two specimens caught in fir-pine-aspen forest in Alberta in 1988. Adelius nigripectus is known from Indiana and Kansas and has been reared from an unidentified poplar leafminer. The final species, A. fasciipennis, was reared from Zimmermannia phleophaga in 1913. The moth was described at the same time and hasn’t been seen since. Its larvae mined in the inner bark of American chestnut and the species is believed to have gone extinct (perhaps along with its parasitoid) after the chestnut blight made larger chestnut trees scarce. It would be a tricky moth to find if it is still around though; there is no external evidence of the mine until the larva chews a tiny exit hole in the bark and drops to the ground. This was reported to happen between April and June, so if there are American chestnuts near you, it’s worth keeping an eye out, starting right about now!

* Shimbori, Eduardo M., Marco A. Bortoni, Scott R. Shaw, Carolina Da S. Souza-Gessner, Paula De C. M. Cerântola, and Angélica M. Penteado-Dias. 2019. Revision of the New World genera Adelius Haliday and Paradelius de Saeger (Hymenoptera: Braconidae: Cheloninae: Adeliini). Zootaxa 4571(2): 151–200.

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