Enchanter’s Nightshade Bugs

I should probably begin this post by introducing you to the featured plant, with which I think few people are familiar, despite its being right up there with bastard toadflax and mad-dog skullcap among the plants with the best common names.  The plant is enchanter’s nightshade (Circaea canadensis, a.k.a. C. lutetiana), and is actually in the evening primrose family (Onagraceae), having nothing to do with true nightshades (Solanaceae) such as tomatoes, potatoes, and eggplants.  It’s such a common and unassuming plant that apparently I’ve never bothered to get a decent photo of it, but its flowers are similar to those of its close relative, dwarf enchanter’s nightshade (C. alpina):

IMG_5723

If you look closely at the lower left flower, you can see a fuzzy green fruit beginning to form beneath it.  The barely presentable photo below shows a C. canadensis plant with more mature fruits.  You may recognize them as the little green burs you sometimes have to pluck from your dog (or perhaps your hairy legs).

colrain july 25 064

Below this flowering raceme are a few pairs of opposite, long-petioled leaves.  In the example below, two new branches are starting because some browsing mammal has munched off the raceme.

DSC_2352

In the lower left of this photo is a leaf mine.  I am pretty much perpetually scanning plants for leaf mines at this point, but I was paying special attention to enchanter’s nightshade this year because of some perplexing leaf mines that had been posted to BugGuide in 2011, from which the larvae had been pushing out all their excrement from little holes at the edges.  The only known leafminer in enchanter’s nightshade is Mompha terminella (a moth), but in the example shown at the top of this page, there is plenty of excrement in the mine.  I had brought the photos to the attention of Terry Harrison, whose website that is and who happens to be working on a revision of the genus Mompha.  He agreed that this insect was definitely not Mompha terminella.

Flipping over the above leaf, I found little squiggles of excrement on the underside, confirming my suspicion that I had found the mystery miner.

DSC_2353

I collected several leaves containing these larvae, and within a few days noticed that the larvae had stopped carefully disposing of their waste.  Some moved to fresh leaves, never returning to their earlier habit of pushing the excrement out.  I repeated this observation with mines collected from two or three different locations.  Eventually the larvae spun cocoons, and adult moths began to emerge:

IMG_3787

They sure looked like Mompha terminella to me, and Terry confirmed this.  Apparently he had never found the mines in an early enough stage to observe this behavior, and for whatever reason Annette Braun neglected to mention this unusual detail when she described the species’ life cycle in 1915.  She only wrote that “the earliest mine is a narrow, threadlike, sometimes spiral, tract, which abruptly enlarges into a small blotch.  Several successive blotches are formed, the last occupying almost half of one of the larger leaves.”

Of course, moths were not all that emerged in the vials containing these leaf mines.  One parasitoid emerged, a braconid wasp in the subfamily Microgastrinae:

IMG_5650

To my surprise, this leafhopper also emerged:

IMG_4439

Scouring the leaves, I was able to find its nymphal exuviae:

IMG_4440

Perhaps I shouldn’t have been surprised to find a leafhopper in the vial.  Looking at the leaves in my first photo above, they are conspicuously speckled with pale spots from leafhoppers sucking their juices (also visible in these two close-ups).  And in my photo of the underside of the mine, you can even see the leafhopper as a nymph, near the lower right corner!

I posted this leafhopper on BugGuide recently, and Chris Mallory quickly suggested it was Erythroneura (Erasmoneura) atra.  Looking at the existing photos on BugGuide, I saw Andy Hamilton’s comment here, thanking Claude Pilon for the new host record: enchanter’s nightshade.  Claude and I both found these leafhoppers this summer, and evidently their host plant was previously unknown.  I also gather from the comments here that this species was not even known to occur in notheastern North America until some time in the past two years when Tom Murray gave Andy a specimen from Massachusetts. There is so much to be learned from just choosing a plant and taking a close look at what’s eating it.

The only other insect I can remember seeing feeding on enchanter’s nightshade is a dumpy-looking little weevil named Dietzella zimmermanni.

IMG_0398 IMG_0372

D. zimmermanni is associated with various plants in the evening primrose family, and the one in the photos above was actually on prairie sundrops (Oenothera pilosella) in the garden.  The pair below were in fact munching holes in enchanter’s nightshade leaves.

DSC_4950

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.
This entry was posted in Uncategorized and tagged , , , , , , , , , , , , , , , , , , , , , , , , , , . Bookmark the permalink.

12 Responses to Enchanter’s Nightshade Bugs

  1. maryann says:

    Charley I’m really taken by the number of little moths that have appeared on this blog, that look like they have winter overcoats on. the wisps at the ends of the wings and the very visible scales might just be artifacts that result from the magnification. However, artifacts or not, there they are. It suggests to me layers of ‘stuff’ that protect the creature from the night chills. Am I being fanciful or this this a justified observation?

  2. maryann says:

    Another observation–following this post of bugs on the lowly nightshade. Do you see as many bugs on non-native plants?–do you see any, apart from the usual introduced suspects?

    • As I pointed out toward the end of my article that was modified for publication in Wild Ones, non-native plants tend to host far fewer insect herbivores, which is a big reason for their success. Sometimes if the plant has native relatives in the same genus, native insects can adapt, as I observed here, but I generally still see much less insect feeding on non-native plants even in these cases. I’m planning on discussing this topic more in posts next year when I write about my battles with non-native shrubs and vines around my yard.

  3. Sue Cloutier says:

    A great study. Thank you!

  4. MJ says:

    Charley!
    Dumpy-looking?
    Hardly!

  5. Ms. Carol Gracie says:

    What a fascinating post! I’ve always been drawn to that plant because of it’s intriguing name and interesting 2-petaled flowers. I even had it on the long list for my next book on summer flowers. It didn’t make the cut only because I didn’t feel that I had enough to write about it to fill a chapter. I now see that I wasn’t being observant enough.

    A photo of enchanter’s nightshade, showing the hooked hairs that cling to my bootlaces, is attached (I reduced the size and resolution to ensure that it could travel as an attachment). It was named such because it was believed to be the plant used by Circe to enchant Odysseus and his men. The genus Circaea is found in Greece.

    I forward your blogs to several friends, some of whom are now regular readers. The photos are great. Keep up the good work.

    Carol Gracie

  6. Brian O'Brien says:

    Fascinating post, and I, too have a fondness for the weevil – endearing in its odd, weevil-y way. I am also a fan of plants that have great common and botanical names, and Enchanter’s Nightshade is definitely one of those (along with the genus being named for Circe). I have some mad dog skullcap photos that I’ll have to upload to Flickr. Meanwhile, here’s a link for some of my photos of Enchanter’s Nightshade: http://www.flickr.com/search/?w=81566369@N00&q=Circaea
    Looking back at the photos, there looks to be evidence of leaf miners – I’ll be looking more closely in the upcoming season.

    You also mentioned Bastard Toadflax, another great name: http://www.flickr.com/photos/81566369@N00/5820505030/in/photolist-9SkBn1

    Yet another great name is False Mermaidweed (Floerkea proserpinacoides). I’m hoping to search that one out this coming spring.

  7. Iris Clearwater says:

    Love your post, and your photos Charley! Thank you. You are introducing me to a new world in a wonderful way. Happy Solstice!

  8. Pam Polloni says:

    My front yard is covered by a layer of Enchanter’s Nightshade acquired from NEWFS. I’ll be examining for those leaf-miners in 2014! Thanks to Iris for alerting me and to Charley for the post!

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s