Monthly Mystery #20: Mudball on a String

Two weeks ago, as I began exploring the first of seven properties where I am conducting natural resource inventories this year for the Maine Coast Heritage Trust, I noticed a little ball of mud hanging from a goldenrod leaf. I was intrigued, but resisted the temptation to investigate it: I had lots of ground to cover, and I didn’t want to get distracted by minutia before I had accomplished anything. After I encountered a third one, however, I gave in and took some photos, then collected it.

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The only one of these I remember seeing before was the one pictured on page 45 of Tracks & Sign of Insects…, which Noah photographed as we were wandering along a river in Pennsylvania. The paragraph accompanying that photo discusses how McCook (1884)* referred to the spider that makes this egg sac as Micaria limnicunae, and how it is unclear to what species that name refers. Platnick and Shadab (1988)**, in revising the genus Micaria (Gnaphosidae), listed this as an uncertain name:

The name M. limnicunae was applied only to egg sacs and spiderlings from Illinois, and no specimens identified by McCook can now be located in the collections of the Philadelphia Academy of Natural Sciences (Dr. James Newlin, in litt.); as Banks (1893) indicated, McCook’s description is “worthless.”

The spider may not even be a Micaria; McCook himself thought it might actually belong to the genus Herpyllus, which includes the eastern parson spider (H. ecclesiasticus):

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Unfortunately, as far as I can tell, every known gnaphosid (ground spider) egg sac is an unadorned, disk-shaped object. Possibly some spiderlings will emerge from the egg sac I collected and shed some light on this mystery, but so far I have never succeeded in raising any kind of spider from egg to adult.

Here’s another observation that may or may not be relevant: Two years ago I collected this sand-covered egg sac, which was one of many found under some snake boards (big pieces of plywood lying on the ground) on Nantucket:

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Some spiderlings emerged, but none lived to be more than about 1.5 mm long.

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I would have had no clue what to call them, but Mandy Howe recognized them as liocranid sac spiders, probably in the genus Agroeca. Fortunately, Andrew McKenna-Foster has done extensive spider surveys on the island, and he told me that Agroeca is the only liocranid he has caught there. He has identified two species, A. pratensis and A. ornata; the former seems to be more common there.

It is well known that some European Agroeca species construct pendulous, dirt- or mud-covered egg sacs, but I haven’t found any references to American species doing this. Is McCook’s description of Micaria limnicunae so “worthless” that it might actually refer to an Agroeca? I haven’t checked, and I don’t know enough about spider identification to be able to judge, but I would be interested to hear an arachnologist’s take on this.

* McCook, H. C.  1884. A spider that makes a spherical mud-daub cocoon. Proceedings of the Academy of Natural Sciences of Philadelphia 36:151-153.

** Platnick, N. I. and M. U. Shadab. 1988. A revision of the American spiders of the genus Micaria (Araneae, Gnaphosidae). American Museum Novitates 2916:1-64.

 

 

 

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Another Mystery Solved, Sort Of

At the beginning of this month, I reported having found these tied leaves on smooth aster (Symphyotrichum laeve) plants in my backyard.

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On May 27, I had put three samples in jars on my desk to see what might emerge.  On June 9, this caterpillar appeared in one of the jars, apparently because the leaves had deteriorated to the point where they were no longer edible. I put it in a clean jar with a fresh sprig from the same host plant.

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On June 23, I returned home from a week in Maine to find this dead ichneumon wasp in one of the other two jars. I suspect, based on its color pattern, that it is something in the subfamily Pimplinae*.

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Meanwhile, the caterpillar had pupated between a leaf and the side of the jar, without so much as a nibble on the replacement leaves. On June 27, as I was heading out the door for the weekend, I happened to notice a moth fluttering around in that jar. I quickly took a few photos of it and then stuck it in the fridge until I got home this evening. After a few minutes browsing through superfamily Gelechioidea on BugGuide.net, and then a few Google searches for “orange palps,” I arrived at a definite match: Dichomeris ochripalpella (Gelechiidae), whose known hosts include heart-leaved aster (Symphyotrichum cordifolium), hoary aster (Machaeranthera canescens), and Canada goldenrod (Solidago canadesis). Having identified it to species and having determined that I hadn’t discovered anything new, I was able to spare the life of a beautiful moth and have a chance to get some photos of it on its host plant in my yard instead of on a plain white background.

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Apparently I never took a photo of the pupa before the moth emerged, but here’s what it looked like after it was thrust from the silken chamber between the leaf and the glass so that the moth could come out.

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The only problem with all this is that the identity of the Iowa goldenrod leaftier pictured here remains a mystery.  I had wondered when I first found the leaf ties in my backyard whether the two were really the same, since in the Iowa examples there was a silk-lined tube that ran through the whole series of leaves, and this didn’t seem to be the case with the ones in my backyard. Once I saw what the Massachusetts larva looked like, I knew I had something completely different. So I’ll have to keep watching for those goldenrod tubes… it may be that they can only be found in the fall.

* I suspected wrong. Bob Carlson informed me that the wasp belongs to the subfamily Campopleginae, noting that “the only campoplegine that has been reared from this host is Meloboris marginata (Provancher), but this is definitely not that and appears to be Campoplex or Sinophorus.”

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Another Mystery Host Plant

Last week Owen Lonsdale gave me a first batch of identifications from the big box of agromyzid fly specimens I sent him a few months ago. Unfortunately, of the ten species represented, he was only able to put species names on three (of these, it appears that one is a new host record, one a new state record, and one a new US record). Four were only identifiable to genus because the specimens were all females. The remaining three were new species.

Two of the three new ones are from New England, and their host plants are species I know well. The third emerged last spring from leaf mines I collected in Iowa the previous September. The host plant was growing in a small patch at the base of a bur oak in the middle of a huge lawn in a park. There were only basal leaves (no flowers or fruits to help identify it).

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At the time I had the impression that it was a waterleaf (Hydrophyllum), but on looking at the photos later, I was pretty sure it wasn’t. This shot of the leaf mine gives a better view of the leaf margin and vestiture.

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When I asked John Pearson, who had initially agreed with my thought that it was a waterleaf, to take another look, he suggested that it was a buttercup, and maybe early buttercup (Ranunculus fascicularis). That looks like a plausible match to me, but I’d like to be as sure as possible before I go reporting that as the host plant of this new species. So if anyone out there has other suggestions, or has experience with R. fascicularis and can confirm John’s suggestion, please let me know.

The fly itself, incidentally, looks like this:

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Externally, it looks awfully similar to many other Phytomyza species. The identification is all about the male genitalia–which Owen says place it in the Phytomyza aquilegiae group. This group is associated with the buttercup family (Ranunculaceae), so John’s suggestion is certainly on the right track.

Not all of the new species that have been emerging from my collected leaf mines are so cryptic. I brought these moths to Dave Wagner a few months ago, and upon taking one quick look, he said he thought they represented a new genus. He saved one for DNA analysis and sent the rest off to Don Davis at the Smithsonian, to join the hundreds of other unnamed gracillariid species awaiting description.

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Microhabitats

It was a nice surprise yesterday morning, when I stepped out into my front yard, to see the first wild turkeys since my neighbor shot the beautiful tom that was displaying there earlier this spring. And it was great to see a small black bear wander by the edge of the yard a few moments later. But I was especially excited when I stepped into the vegetable garden and spotted this little hole:

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Ever since we cut up staghorn sumac stems from the edge of the yard to use as stakes in the garden, I’d been wondering when the small carpenter bees (Apidae: Ceratina) would show up to nest in them. Unlike their cousins, the large carpenter bees (Xylocopa), instead of boring into wood, they excavate the soft pith in the centers of stems to construct their nest chambers.

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It was difficult to get a very good look into this hole, which was only 2.5 mm across, but this shot clearly shows a shiny metallic bee butt and the tips of some wings.

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Here is a better look at a small carpenter bee I found in one of the only patches of violet wood sorrel (Oxalis violacea) in Massachusetts:

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It’s amazing how quickly animals show up to occupy whatever little niches we create for them. At the beginning of May, we hurriedly put up this little birdhouse on one of the garden fence posts, right after a pair of bluebirds stopped by to explore.

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The bluebirds showed up the next day and spent a good while contemplating the house, but then took off and never returned. However, within a week some tree swallows showed up, and the’ve been nesting there ever since.

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(I took that picture of another swallow several years ago, but you get the idea.)

If you look closely at the first photo, you’ll see that the sumac stake with the bee hole in it has some buds that are starting to open up. Some of the taller stakes by the birdhouse have fully opened leaves. It will be interesting to see how long that lasts.

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Mullein Weevils

As anticipated, Julia and I have been filling our front yard with fruit trees and a vegetable garden, and letting most of the remaining lawn grow into a meadow–not out of laziness but from a desire to turn this sterile mini-landscape into habitat for something. Already, the monotonous carpet of green has given way to an ever-shifting array of flowers, attracting multitudes of nectar- and pollen-seeking bees, flies, and butterflies. The taller plants provide cover for toads and all sorts of insects and spiders, as well as perches for damselflies and dragonflies like this calico pennant (Libellulidae: Celithemis elisa) that showed up yesterday.

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Every additional species of plant that is allowed to grow, whether a native wildflower or a European “weed,” further increases the diversity of our yard by providing food for its own suite of host-specific insects. For the most part, the native plants do a better job of this, but even this meadow dominated by European plants is a tremendous improvement over closely cut grass.

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In the above photo, the yellow flowers are common cinquefoil (Potentilla simplex). I collected some cinquefoil leaf mines here when we first came to look at the house last May, and the adult agromyzid flies emerged four months later, after we had moved in. The white flowers are lesser stitchwort (Stellaria graminea), the presumed host of this chickweed geometer. The big rosette in the middle of the photo is common mullein (Verbascum thapsus), and it’s just beginning to send up what will be a tall stalk covered with yellow flowers. When I peeked down into the center of the rosette yesterday, I found it covered with little brown weevils.

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I’m a sucker for weevils in general, but I thought these furry ones were particularly adorable.

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Can you spot the female in this pile?

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I had never seen these weevils before, but I had a hunch they were connected with something I saw while walking along a trail in Vermont in early August, 2005. A downy woodpecker was pecking open the seed pods on a mullein stalk, and whatever it was finding in there was exciting enough that it let me get within a few feet of it as I watched it forage. Every stalk nearby had similar ragged feeding holes opened up in many of the pods.

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After the woodpecker had left, I opened up one of the intact pods and found a weevil pupa inside.

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I later learned that the larvae of Rhinusa tetra (Curculionidae; formerly Gymnetron tetrum) develop inside the seed pods of common mullein and pupate there when they have finished feeding. A quick check of online photos of this species seems to confirm that this is the weevil currently congregating on the mullein in my yard. I looked at the other mullein rosettes there, and a few others I came across at work today, and every one of them was similarly covered with these weevils.

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Monthly Mystery #19: Aster Leaf Tubes

As I mentioned here, I normally can’t be bothered with leafrollers, leaftiers, etc.  Not so much because the thousands of leafminers (not to mention gallmakers) in North America are enough to keep me busy for a while as because what I’m most interested in is learning to identify insects by the signs they leave behind.  Leafminers leave such characteristic patterns, and are mostly so host-specific, that they can be identified by the combination of the mine characteristics and the host plant once someone has gone to the trouble of rearing the adult insects.  The leafrollers, -tiers, and -folders, on the other hand, often do not manipulate leaves in a particularly distinctive way, and some of them are extreme generalists, feeding on all sorts of unrelated plants.  So I don’t pay much attention to them until I encounter a recognizable pattern recurring on a particular type of plant.

A year and a half ago in Iowa’s Loess Hills, Julia and I noticed some tied leaves on tall goldenrod (Solidago altissima) that piqued my interest.  On each affected plant, a series of adjacent leaves were tied together and tucked into one another so that they formed a silk-lined tube.

DSC_9980This top view shows the entrance to the tube:

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Opening up one of these leaf shelters, we found this larva:

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Despite this being a low-resolution and slightly out-of-focus photo, it was sufficient for Terry Harrison to identify it on BugGuide as something in the family Tortricidae. This family is often referred to as the “leafroller moths,” and the larvae of many of the species do roll leaves, but other species do many other things (including mine leaves, form stem galls, feed in flowers, and so on), and many other kinds of moth larvae roll leaves.

I declined to collect any of those larvae, but last week in my backyard I found something similar on smooth aster (Symphyotrichum laeve).

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This could well be the same thing as the goldenrod one, even if it is a fairly host-specific moth.  Many insects seem content to feed on both goldenrods and asters, which belong to the same tribe (Astereae).  I found similar leaf tubes the other day on heart-leaved aster (Symphyotrichum cordifolium) in a friend’s driveway.

I now have three of these smooth aster tubes in jars on my desk, so perhaps I’ll be able to post an update eventually with the solution to this mystery.  Incidentally, I’m pretty sure I have last month’s mystery solved, but I’ll wait a bit to see if I get adult moths before posting a follow-up.

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Neighbors

Here’s a view of a bald-faced hornet I don’t get to see very often:IMG_9205 IMG_9205-001

I took these photos a few minutes ago through the sliding glass door that leads from our kitchen to our deck.

When we moved in last August, this was on the deck:

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I like bald-faced hornets as much as the next guy, but I’m sort of hoping they’ll choose a new location this year.

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