willow ghost moth

This morning, while doing some yard work, I noticed this moderately large moth clutching a leaf in the garden. I thought, “I should go and get my camera,” but was soon distracted by my work. I noticed it again a little later in the morning, and realized I’d forgotten all about the moth. I finally did go to the house to get my gear and shot several photos. When I first noticed the moth, it was obscured by vegetation, and I thought it might be a False Crocus Geometer (Xanthotype urticaria) moth, which I often see around the farm. Later, after I saw that it was actually fairly large, I thought it might be an Io moth (Automeris Io). After I got my camera and shot a few photos, I gently pushed one of its front wings out to the side to see what the hind wings looked like. It turned out that they were a pale yellowish white, and nothing like the Io moth’s spectacular eyed wings. This moth was less boldly marked, but still very lovely.

This evening, I downloaded the photos from my camera and hit the books to see if I could find an ID. It didn’t take long and the results were a bit of a surprise. It seems that this is a very uncommon species – at least, here in Canada. After looking at the few photos I could find online, I’ve concluded that it’s a Willow Ghost Moth (Sthenopis thule) – Hodges #0021. So far, the only records I’ve seen are for a couple of moths found in Quebec. I’ve emailed a couple of lepidopterists to find out if there are any records in Ontario.

As yet, I haven’t been able to find too much info on this moth in my field guides or online. About all I can tell you is that the larva of this moth is a borer of willow roots. It’s a member of the small Family Hepialidae, which go by the common name of Ghost Moths or Swifts. I also found a brief reference to mating behaviour in a paper contained in Journal of The Lepidopterists’ Society (1999-53(3) 127:

Members of the genus Sthenopis are unusual in that males possess long-range sex attractants, whereas this strategy is usually characteristic of female Lepidoptera (Mallet 1984, Wagner & Rosovsky 1991). Two types of courtship behaviour have been observed in Sthenopis: Males of S. thule and S. argenteomaculatus form mating swarms (leks) which females enter to mate (Winn 1909, Covell 1981), and male S. auratus are sessile and call for females, fanning their wings over the scent tufts (McCabe & Wagner 1989). These two mating strategies may be density-dependent, with male lekking behaviour occurring at higher densities (Wagner & Rosovksy 1991).

Anyhow, that was my excitement for today. I’ve got something else of interest on the go, but I won’t write about it for a couple of more days (suspense!).

In other notes, Don is taking this week off work, so my posts may be more sporadic than usual for the next few days. We had actually planned to go to either Nova Scotia, or the north shore of Lake Superior for a couple of weeks. However, it seems that his workplace will fall down without him, so he has to take a week here and a week there instead, which pretty much washed up any chance of going away. I guess the one good thing that can be said about the change in plans is that, if we had left on our planned vacation, I would have missed seeing this wonderful moth.

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12 Responses to “willow ghost moth”

  1. John Says:

    Bev, it is a beauty, indeed. It’s exciting to learn that you may be one of the few people in Canada to see the Willow Ghost Moth, at least in a natural environment! It amazes me that you’re able to find information about these creatures…I wouldn’t have the vaguest idea about where to look. Sorry to hear you won’t make a Nova Scotia trip (nor will we, it appears, I am afraid), but I hope you and Don are able to get some time to relax and enjoy yourselves. I’m looking forward to your unveiling the suspenseful matter…don’t make me wait too long!

  2. robin andrea Says:

    What a very cool find, Bev. I’m glad it showed itself again, and you got the camera. You must have quite a calm presence. I’m amazed that you were able to touch this beautiful moth.

    Hope you and Don have a wonderful week off together.

  3. Wayne Says:

    Very striking moth, Bev, and bravo on the difficult id. Interesting about the male lekking behavior – I add a new work to my vocabulary! It sounds like related species have versions of the male pheromone secretions – I wonder if related genera do too?

    Suspense is good.

  4. bev Says:

    John – It’s always neat to find something new here at the farm, especially when it’s an uncommon species. That seems a good indication that we must be doing something right as far as creating good habitat for species diversity. When IDing moths, there are a number of places that I usually look. I’m getting pretty quick at finding the info now — it’s one of those “experiece” things. (-:
    As for the “suspense” piece, I hope it won’t be too disappointing. It’s one of those quirky subjects that may not seem as exciting to others as it is to me!

    robin – I’m so glad that I got to photograph and ID this moth and didn’t just ignore it thinking it was something common. It’s always nice to add to the collective knowledge of a species and its range. The moth was actually remarkably docile – it seems happy so long as it has a leaf to cling to, and didn’t mind having its forewing moved a little to reveal the hindwing. As for our week off – thanks! Although we won’t be traveling far, we will probably still have a good time. While it’s nice to go away somewhere special, that can also be a bit tiring. Luckily, we live in an area with so many nice places to hike or canoe, that it’s no hardship to stick around home.

    Wayne – I’d heard the term “lekking” used in connection with birds and fish, but never with insects, so it was a new one for me too! As for the male pheromones, I don’t really know how common this is among moths. I’ve only ever heard of males being attracted to females and not the other way around, so this is quite interesting.

  5. Cathy Says:

    Well. So the fellas get to wear the perfume. Nature is so fascinating. This is a very pretty moth and what a thrill to find a rarity. Like Robin Andrea – I’m so intrigued by your ability to get up close and actually touch creatures.

    I photographed a moth yesterday on an old granite stone tower here on Cape Cod. I went to What’s That Bug and also several websites and had no luck with the ID.
    Just for fun – I’m going to reduce it and send it your way. PLEASE! Don’t fret over it. If the ID pops into your head I’d love to hear it – otherwise ignore this not very attractive rock clinger. (Your moth is much prettier)

    Hope you and Don have a very pleasant week just ‘being’ in your own splendid back yard.

  6. bev Says:

    Cathy – Many moths don’t actually mind being held on you hand so long as you let them move to it on their own. A lot of moths will crawl foreward on their own, so it’s just a matter of offering them your hand to move onto. If they are already clinging to something, you can usually gentlly nudge their front wings out to the side to reveal the hind wings. On certain moths, the hind wing patterns are just as important as the front wings for figuring out an ID.
    I received the moth that you emailed last night. At first glance it doesn’t look familiar to me. It certainly has unusual markings — very distinctive, in fact. It does remind me a bit of a couple of the Morrisonia moths (Woodgrain moths) – you can see some examples in the top couple of lines on this page on the Moth Photographers Group site. I’m going to keep this moth in mind while I do my usual IDs of other moths (I usually have a bunch in mind as I flip through books and website), and I may come across it. However, what you might do, and which would be interesting to me as well, is to submit the image to the Moth Photographers Group to see if anyone can come up with an ID. They usually like the moth image to be cropped square, and at least 300 x 300 pixels or a little larger (not huge though), and with the head pointed toward the top of the image. The instructions for submitting an image are at the link I’ve just supplied. If you do that and get a response (I’m quite certain that you will), be sure to let me know the species.

  7. Cathy Says:

    Bev! That’s a great site you linked me to. Look at plate 8834. Eureka! Sure looks like my moth. Remember that I said it probably didn’t have anything colorful hidden beneath those dull wings. Wrong. If my ID is correct, then – it’s the Sweetheart Underwing. How sweet is that? I’ll also submit this if I can get my hubby to help with the specs. I’m thinking we’re pretty close here :0)

    Scrolling around I found your nice picture of the Spotted Grass moth on the ‘Walk Through the Major Families of Moth’ page. Cool. I then did a ‘find on this page’ survey of further pages. You’ve got some real dazzlers featured there. Way cool :0)

    Thanks for the help, Bev – this is fun.

  8. bev Says:

    Cathy – I looked at that moth and I think it’s close, but having looked around a bit more, I have a feeling it may be a closely related one. Take a look at the Ultronia Underwing (Catocala ultronia) – Hodges 8857. In particular, look at the one on the very bottom right by James Vargo. It has those same dark patches on the “inside edges” of the forewings, the smooth dove gray on the forewings, and that brown and black area along the forewing tips. Thta one seems like it might be a closer match. And yes, isn’t that a great website? Bob Patterson did a great job of getting the site up and running and continues to be very involved. It’s a super resource. I have a few moths on there — I can’t really remember how many, but it’s nice to occasionally run into one of my photos as I peruse through the pages trying to ID new moths.
    And yes, it’s sometimes amazing to find beautiful hind wings revealed beneath dull forewings. The Catocala moths are some of the most spectacular of these species.
    Sounds like you could get hooked on this “moth thing”. If you do, you’ll be in good company with a lot of other moth people. (-:

  9. DougT Says:

    Bev, your moth is so cool that it isn’t even listed in Covell’s Field Guide to the Moths of Eastern North America, though he does list S. argentomaculatus. Great photos. A bunch of Drosphila exhibit lekking behavior. This is the first I’ve heard of it in a lep.

  10. bev Says:

    Doug – I know! I was very surprised when I checked Covell and didn’t find the moth there! Fortunately, there’s a photo of a specimen in “Le Guide des Papillons du Quebec” by Louis Handfield — I guess because there have been a few specimens found in the Montreal area. In my net searching, I did find mention of a specimen having been found in Vermont. I emailed Don Lafonataine at Agriculture Canada and he replied that the species is quite rare, but that that may partly because it isn’t attracted to lights, so is missed by those who survey moths. Anyhow, I think it’s neat to have found it here at the farm, right in the wild plants in our garden. To me, such sightings confirm that we’re on the right track as providing habitat that encourages biodiversity. Pretty cool! (-:

  11. Layla Says:

    That is so beautiful, thank you so much for sharing! I’ve never even heard of this moth. It reminds me of a giant fuzzy lemon. Best wishes,

    Layla :)

  12. bev Says:

    Layla – Thanks! Yes, it’s such a neat colour, isn’t it? I love the furry legs on some of these big moths.