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solving a buggy whodunit, with charley eiseman

ostrich fern with unfurled tipsI COULDN’T FAIL TO NOTICE the rolled-up balls at the tips of many ostrich ferns in the garden in June—which is how the plot of my latest backyard whodunit began. Step 2 after merely asking myself, “What’s that?” was asking Charley Eiseman, author of the field guide “Tracks and Sign of Insects.”

our ‘whodunit?’ conversation

CHARLEY KNOWS what motivates bugs—the “why’s” behind the actions they take, and how their life cycles go–or at least how to find out. I’d sent Charley home with some ostrich ferns from my garden last fall, when he’d visited, to plant in his, so magically he had seen the rolled-up tips last month, too.

Here’s how our conversation went—and led to my “raising” my first moth; to learning that putting 2 and 2 together doesn’t always add up; and that phrases like “good” and “bad” are tricky to use when it comes to insects:

June 26

Charley,

Ever since I met you, I can’t stop taking photos of disfigured stuff in the garden. Ostrich fern, in this case (see top photo).

I must get the right lens for small closeup stuff, but meantime…On BugGuide you answered a thread about fern galls…but probably this is not one like that.

M.

June 30

Margaret,

This morning I thought I’d try to raise some of the ostrich fern-rolling moths from the ferns you gave me last fall, but I opened the rolls up and they had all been vacated. Oh well. Next year…

C.

June 30

Charley,

I could try with my ferns—but what do I do?

M.

June 30

Margaret,

I would just break off the rolled portion and put it in a clean jar, maybe with a crumpled-up paper towel in case the larva wants to pupate in that. No need to poke holes in the lid.

C.

ferns in jar to hatch mothsJuly 1

Charley,

Stray thought department:

There are always a large number of silver-spotted skippers on the ostrich fern. Every year, all season long. They also like the big Aesculus next to the ferns when it blooms (below).

silver-spotted skipper in aesculusI know they are not meant to enjoy ferns as a food plant, but thought I would mention it as I have for many years wondered what they are doing on the fronds (and again: in the Aesculus blossoms, but those only come in July).

Probably no connection to our balled-up tips, but anyway…an observation. I think skippers cut leaves and flap them over to reproduce in, or so I have read in David Wagner’s caterpillar field guide.

Local Japanese beetles love the ostrich fern here in July, too, but as a food. But they aren’t the ones balling up the fern tips like that!

July 1

Margaret,

Yes, skippers cut leaves and flap them over…black locust, in the case of silver-spotted, if I remember right.  I’m not sure why they would be interested in ostrich fern. What are the ferns growing under? Could the skippers be sipping honeydew from aphids/scales/treehoppers?

Speaking of which, you might be interested in this post from a few years ago, on how hard it is to define “good” versus “bad” bugs.

July 1

Charley,

That post of yours is fascinating (and I am looking at scale insects and such through a different mental “filter” now as a result).

The ferns the skippers visit all the time are under a dwarf white pine that is (after 25 years) no longer dwarf. A big evergreen rhodie is behind that. I will go check the vicinity carefully by the light of day–when I go out to check my banana-baited woodchuck traps and hope for success with more of them, if not the seven cwazy wabbits who refuse to be caught.

M.

ostrich fern moth 1July 7

Charley,

My first hatchling ever (our ostrich fern inhabitant)!

At least i guess that’s what happened…nobody else so far, and i never opened any of the still-rolled balls of frond to see what else was going on.

How many would be in a single nest?

Can this be the guy? (I let it fly to take its picture.)

M.

July 7

Margaret,

Nice work!  Yeah, that’s the guy.  I was guessing a Herpetogramma, and that’s what it looks like. Maybe H. theseusalis?  My friend Eric raised that species on sensitive fern, and mentions at this link on BugGuide having found it on a number of other ferns.

There should be just one larva per roll.

C.

July 7

Charley,

I am so excited–now you really have me hooked.

How can it be that I have been outside for 30 years in a fairly intimate relationship with the plants and birds and frogs, and never tuned into all this?

I set him/her free of course, and hopefully the other four will soon follow if they hatch out.

Thanks for the inspiration, Charley.

By the way, this morning I awoke to at least 100 (not kidding) lesser maple spanworm moths on the side of my barn. Like insane. Here’s just a section of the side of the barn (and a photo of one of the moths a few feet away on a–you guessed it–maple leaf):

lesser maple spanworms on barnMaybe it is an annual convention! (On BugGuide they say, “May be locally abundant; numbers may vary considerably from year to year,” and I’d have to concur.)

lesser maple spanworm moth on acer pseudosieboldianumSee you soon. Can’t wait to continue my education.

M.

(More on Charley’s field guide “Tracks and Sign of Insects and Other Invertebrates” is at his Northern Naturalists website. You can visit his BugTracks blog anytime, where there is even a whole archive of “Unsolved Mysteries.”

  1. Lorie says:

    Absolutely wonderful reward for being observant. The monarchs finally found my dill…the caterpillars are chewing like crazy. Hours could be wasted watching the munching party.

  2. Kathy Sturr of the Violet Fern says:

    I MUST commit to more time in my garden and really SEE what is happening … fascinating. Thank you for this eye opener!

  3. Julie @ Southern Wild Design says:

    Hi Margaret!

    The addiction has begun! I raised butterflies commercially on my farm in Texas before transplanting to the Carolinas. Along with the butterflies, we hosted skads of children for school field trips teaching them about the butterfly lifecycle. Once inside the butterfly house, we pointed out eggs, caterpillars, and chrysalis to the kids. This was just enough to spark their interest and we hatched a load of nature detectives as a result. So much fun! Mother Nature is so very busy–particularly on a micro-level–so the closer you look, the more interesting it becomes!

    Happy sleuthing!
    Julie

    1. margaret says:

      I love it, Julie. “Nature detectives” is just right to describe the experience. Nice of you to say hello.

  4. My bug observation: My hollyhocks get get a yellow rust fungus on the undersides of the leaves which will spread and kill the leaf. But during the night pill bugs climb up the plants and eat the rust spots leaving a small hole where they have done there work. The leave survive with their sieve like appearance and the Hollyhocks keep on blooming.

  5. Dale Hoyt says:

    What a coincidence! I lead a weekly “Nature Ramble” at our local botanical garden and in early May we noticed fern balls at the ends of Christmas ferns. I solved our mystery of what they were but did not rear any moths. You can find my conclusion and how I arrived at it here.

    I’m located in Athens, GA, so the species that makes our fern balls may be different from yours. You can consult the references in the link listed above if you’re curious.

    1. margaret says:

      Hi, Dale. Love hearing that others are seeing them, too! Today in the woods I saw them on other species of ferns as well.

  6. Dahlink says:

    Just solved another garden mystery here. We have old-fashioned columbines in our garden and are accustomed to columbine leaf miners. This year, for the first time ever, something ate almost all the leaves down to the stems. At first I suspected bunnies, but now I think we had Columbine Sawflies in May. Anyone else have this problem?

  7. Paula Wolff says:

    I had a garage wall covered with lesser maple spanworm moths last summer–just didn’t know what they were. They covered the wall, especially at night near the light fixture, and I would see them still there in the morning. Thanks, Margaret, for identifying them for me!

  8. Vicky says:

    Glad you posted this. I have tassel ferns and this afternoon found a bunch of curled up leaf tips just like this. I opened one and it was filled with tiny red-brown eggs. Is this the same culprit?

    1. margaret says:

      Don’t know, Vicky. The way I found out was by “hatching” one tip of a frond (cutting and putting in a ventilated jar to see what happened).

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