The Secret World of Moths

Remember this post?  I snapped this photo of a large sphinx moth on the sill of my boss’s office window and posted it to Bug Guide, thinking someone there would know what species it was.  I was expecting that a moth enthusiast would get back to me saying it was such-and-such a common species, and I’d update my original post with the ID and think no more of it.

I was not expecting what happened next.  Warning: extreme moth-nerdiness is about to ensue, so if you’re allergic, feel free to scroll down to the final paragraph.

*begin extreme moth-nerdiness*

Anyway, sure enough within ten minutes someone replied with the suggestion that Achemon Sphinx looked like a close match, and I thought the matter was settled.  However, then more people showed up with more possibilites.  Pandorus Sphinx?  Satellite Sphinx?  They all looked the same to me!

And then the photo ended up getting passed on to some bona fide moth experts: a guy named Bill Oehlke who apparently runs a mail-order moth egg business out of Prince Edward Island (who knew people order moth eggs through the mail?) sent it to a guy named Jim Tuttle, who is the coordinator and editor of the “season summary” (a database of people’s moth and butterfly sightings) of the Lepidopterists’ Society and who literally wrote the book on this family of moths.

Turns out my moth was an Intermediate Sphinx, Eumorpha intermedia, a species that didn’t even have an entry on Bug Guide.  No entry in Bug Guide???  And check out the USGS’s official range map for this species:

Note that there is absolutely no blue anywhere in south Georgia.  I had the first record of an Intermediate Sphinx moth for anywhere in this part of the state.  Crazy!  I asked one of the moth experts if this species is considered rare, looking at its sparse distribution, and he said it’s probably not so much rare as it is under-reported.  It looks very similar to the aforementioned Satellite Sphinx, and when you add to that the facts that these are cryptic, nocturnal species and that there aren’t a whole lot of sphinx moth experts running around looking for them, we just don’t know that much about their range or abundance.

So how did those guys know that this wasn’t a Satellite Sphinx, anyway?  Apparently Intermediate Sphinxes have a scalloped subterminal line, while the subterminal line of Satellite Sphinxes is merely wavy.  I’m not one hundred percent sure what the “subterminal line” is (and Google failed to provide me with a definition) but after comparing photos of the two species I’m going to hazard a guess that they’re talking about these markings:

If you ask me, this all begs the question of how anyone decided that the Intermediate Sphinx is a separate species in the first place.  Here is the paper from 1980 detailing just that.  According to the author, Intermediate Sphinxes differ from Pandorus and Satellite Sphinxes in “size, color, maculation, and genital characteristics.”  What the heck is maculation, anyway?  (The pattern of markings.  I looked it up.)  And without DNA testing, is anyone really sure whether or not they all interbreed?  Search me.

So anyway, my moth sighting is being included in the season summary of the Lepidopterists’ Society, Mr. Oehlke is using my photos on his website, and Bug Guide has a shiny new entry for Intermediate Sphinxes based on my photo.  And me a rank amateur at both photography and lepidoptery.  Wow.

*end extreme moth-nerdiness*

I guess the take-home message from all this is how amazingly little we know about the fauna even of an area as well-populated as coastal Georgia.  We humans sometimes like to think we have everything all figured out, and it’s worthwhile to take a step back and remind ourselves of this.  No one knows precisely what moth species are and aren’t found right here on Jekyll Island!  Forget the depths of the Amazon, someone could launch a research expedition into the forest across the street and probably add something significant to our understanding of the natural world.  To me, that is awe-inspiring.

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14 thoughts on “The Secret World of Moths”

  1. What a cool story . . . I love this post!

    I’m currently at a conference in Chicago about 21st Century Education, and while I don’t fully buy into the enthusiasm for infusing technology in the classroom (more time in the real world and less in the virtual, please), I can get excited about the ways technology can be effectively leveraged for real-world purposes. Yours is a perfect example.

    1. As an educator whose “classroom” consists of beaches, forests and salt marshes, you know I agree about the importance of getting students outside into the real world. However, there’s no doubt that the internet can be an amazing tool if used properly. If I hadn’t known about the Bug Guide site, the creature in this photo probably would never have been identified beyond being a nice-looking sphinx moth. (At most I might have paged through a moth field guide, if I could find one, and called it an Achemon or Pandorus Sphinx.) Instead, posting it online not only led me to the correct ID, but enabled information about this insect’s presence here to get to people who study this sort of thing. How cool is that?

  2. Impressive find, though a little part of me can’t help being jealous… In the UK there has been such a long history of amateur and professional naturalists that you begin to feel that every plant and animal has been described in a field guide, from butterflies to bot flies, sea birds to sea slugs, trees to tardigrades… (you get the idea). Thankfully, global warming and lax import laws are bringing a steady stream of exotic new plants and animals to our shores for the delight of the alert naturalist. Personally I’m keeping my eyes open for the giant predatory flatworms that landed on our southern shores….

  3. Great find Rebecca. Hope it feels as good as it should!
    We had a similar experience in finding a Western Grebe on Lake Oconee last year. Still awaiting the formal official verification but it still is a thrilling experience.

  4. I just found this exact moth on my kitchen window screen this morning. I’ve never seen anything like it. So, I went looking on the internet until I found this one. We live in North East OHIO!! I’ve been to Jekyll Island but that was 11 years ago. How cool.

    1. Monica, I’ve sent you an email with a more lengthy answer, but I would guess your moth was one of the other members of the genus. My understanding is that this species is only found in the South.

  5. Exciting find! And yes, those are the subterminal lines – if you think of a moth’s wing as basically a triangle, the leading edge is the costa, trailing edge is the dorsum, and the ‘wingtip’ is the termen, hence lines immediately inboard of the termen are subterminal – the lower one here is the one splitting the two species.

    The great thing about wildlife is that there’s always more to discover – even here in Britain, where we have the best-studied flora and fauna in the world, people discover new species in new places on a regular basis!

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