Exuvia(e).

My wife and I always enjoy Bill Danielson’s weekly nature columns in our local paper, the Hampshire Gazette; he usually writes about birds, but this week it was an oddly specialized topic and an unusual word I didn’t remember encountering before:

The word was “exuvia” and those of us that heard it were overcome with a mixture of surprise, confusion and skepticism. The person who dished up this scientific morsel was Brian Adams, professor emeritus of environmental science at Greenfield Community College. The setting for such an utterance was a radio studio at WHMP in Northampton, where I was sitting for an interview with Brian, Bill Newman and Buz Eisenberg on their wonderful “Talk-the-Talk” program on July 23.

Our conversation was centered around a photograph in last week’s paper that featured a fragrant water lily with a spreadwing damselfly clinging to one of the petals on the left-hand side of the photo. I then called everyone’s attention to a yellow “smudge” on the inside surface of the very same petal that was supporting the damselfly. This, I explained, was the shed skin of a damselfly nymph that had crawled out of the water, freed itself from its shell and abandoned it in order to start its adult life. Everyone was looking at the photo and then we heard “exuvia” in our earphones. It was Brian who had offered up the term out of nowhere.

As luck would have it, we were right at the point in our segment where it was time for a commercial break. The microphones went dead and every cellphone and computer in the studio was immediately activated for our combined mission to fact-check this spontaneous utterance. Was Brian a genius, or a complete lunatic? In seconds, the answer to our question was settled: Genius! Bill Newman read the search results and the studio (and the first moments of the second half of our segment) erupted with exuberant, triumphant and congratulatory laughter.

Here is what our search found: “In biology, exuviae (singular: exuvia) refers to the shed exoskeleton or outer covering of an arthropod (like insects, crustaceans, and spiders) after molting. Essentially, it’s the ‘skin’ they leave behind after growing.” Examples of this structure included cicadas and dragonflies. Jackpot! I went on to explain that the photo of the water lily was meant to show the flower, rather than the insects, but it was true that I could have zoomed in on the exuvia to reveal its details. Sometimes, a single photo has so much going on that you need to make a choice. […]

So what we see in today’s photo is the exuvia of a large species of dragonfly. The nymph that may have lived underwater for a couple of years had finally reached a point where it was time to crawl up out of the water, break out of its skin one more time, and take its adult form. It is not clear in this particular photo where the exact location of the split on the nymph’s dorsal surface might be, but the presence of those white “strings” gives a hint. These white structures are called “tracheae”: which are “the internal air tubes that insects use for respiration, essentially their ‘lungs.’” Imagine pulling off your socks and having them turn inside out and you have the right idea.

The photo that showed the details of the exuvia did not show you what the plant itself looked like, so I decided to create a composite image that combined the details of two different photographs. The insert shows the blossoms of the flowering rush (Butomus Umbellatus) that the dragonfly nymph had chosen to climb. I didn’t have room for the plant’s leaves, nor for the shape of the “umbell” formed by the plant’s many flowers, but I think the detail of a single flower was the most interesting. The plant was about 4 feet tall and growing in shallow water. I took these photos on July 25, 2011, and have only just now found an opportunity to use them in tandem.

Naturally, I looked it up in the OED, where it’s under the plural exuviae, “Cast skins, shells, or coverings of animals; any parts of animals which are shed or cast off, whether recent or fossil” (entry from 1894; first cite 1670: “They [insects] divested the habit they had..and appeared with their exuviæ or cast coats under their feet,” R. Boyle, Contin. New Exper. iv, in Works III. 378). This note was added in 1997:

Also in singular in the form exuvium (the reconstructed Latin feminine singular exuvia being reinterpreted as neuter plural), and in plural as exuvia.

Wiktionary has it s.v. exuvia and says:

Back-formation from the plurale tantum exuviae (“the skin of an animal sloughed off”), from exuō (“to take off”). See also exuvium.

And under exuvium we find:

Perhaps from Latin exuvium, or perhaps an independent back-formation from exuvia, under the impression that exuvia is the plural of a Latin second-declension neuter noun exuvium, whereas exuvia is in reality the regularised first-declension singular of Latin exuviae.

Incidentally, today marks the twenty-third anniversary of Languagehat; as always, I am endlessly grateful to all those who frequent these environs and provide the information, jokes, and camaraderie that make it worth keeping the thing going.

Comments

  1. cuchuflete says

    Happy anniversary to Mr. Hat and all the Hattery!

    And thanks to all of you for the ongoing education, the chortles, and
    the occasional guffaw.

  2. 23!
    the most significant anniversary of them all for discordians and other connoisseurs of synchronicity!

    biz hundert-dray-un-tsvantsik!

  3. Hail Eris!

  4. Happy blogiversary!

    In addition to the improper capitalization, the quoted article is missing crucial information. What species of spreadiwng was it???

    I admit I’ve been confused about the spelling and number of “exuvia”.

  5. I am sure I learned exuviae from Dido’s dying words (Aeneid 4.651-662; Josquin’s setting).

  6. J.W. Brewer says

    i assume Discordians everywhere plus fellow travellers noted that “Eris” was the perhaps hubristic name of the Australian spacecraft that just failed to be launched successfully.

  7. cuchuflete says

    As the Southwestern Cicada Choir sang,

    All my exuviae live in Texas

    Some took exception to the refrain.

    I’m just a shell of the man
    I used to be…(banjo break)

  8. Trond Engen says

    Exuverant greetings on the day!

    In other news: Storing in starling – teaching a bird the sound sequence of a 176 kB png image of a bird. (This obviously calls for an amendment to RFC 1149.)

  9. I knew induviae, but not exuviae. Maybe it’s something about my personality?

    Happy Hat Day!

  10. David Marjanović says

    It’s not the skin, BTW (in arthropods, nematodes and other ecdysozoans); it’s the exoskeleton that lies on top of the skin. Snakes shed the actual epidermis (after growing a new one under it).

  11. I’ve heard exuvia before. In fact, I’ve got three monarch chrysalises on the porch, and soon they’ll be exuviae. A neighbor pulls caterpillars from her milkweed and raises them, and was worried about ones that might eclose while they’re on vacation. We have a native-plant garden, partly to provide habitat for butterflies, but my tendency, when not asked by a well-meaning friend, is to let nature take its course once we’ve provided the habitat.

    Anyway, it seemed an odd reaction — “I’ve never heard of that, so I’m going to fact check the scientist who said it.” In particular, if you studied damselflies, you’d surely have heard the word, and if you didn’t, why would you second-guess someone who was in a position to know? My guess is no one was skeptical, nor fact-checking. They were actually looking up exactly what it meant, and the outburst was more appreciation than congrats that he was right.

    Congrats, Hat! And thank you!

  12. My guess is no one was skeptical, nor fact-checking. They were actually looking up exactly what it meant, and the outburst was more appreciation than congrats that he was right.

    Yes, I’m sure that’s it; Danielson is a schoolteacher and goes for a lively style.

  13. May there be many more birthdays of disobscurification.

  14. Happy anniversary!

  15. Lars Mathiesen (he/him/his) says

    So TIL that besides L ūtor there was also a non-deponent from a different PIE root. But participles ūsus and ūtus are not safe from conflation.

  16. No, there was exuo but no *uo.

  17. thank you for all the hattery, we do appreciate it..

    oddly I knew exuvia, fly fishing gives me an excuse for some light amateur entomology, damselflies are one of my favorites. The nymphs swimming to shore to hatch are the wiggliest things in nature..

  18. Lars Mathiesen (he/him/his) says

    Yeah, I should have put a star on *uō. Accident of non-attestation, or was it actually not a part of the active vocabulary of Republican Latin?

  19. In Russian there are definitely prefixed verbs that don’t exist as simplexes.

  20. David Marjanović says

    Likewise in German: vergessen “forget”, no direct cognate of “get”; gewinnen “win, gain”…

  21. Lars Mathiesen (he/him/his) says

    Danish has those too, like fornemme, but in general atonic verb prefixes are found in loans from MLG into ON which did away with those (including *ga- < *kom-) at an earlier stage. But nema _is_ attested in ON, and nemen in MLG.

    (The vanished prefixes were conventionally replaced by the preposition of or umb, meaningless in context:

    sjaldan liggjandi ulfr
    lær of getr
    né sofandi maðr sigr

    My best guess is that it was bi-getr at some stage).

    So even when *uō isn’t attested in Golden Age Latin, it might be in Plautus or some other preserved OL text. But de Vaan only has it as the base of prefixed verbs, so I guess not.

  22. I learned the word “exuvia” from the title of a song and album by the excellent Italian rapper Caparezza, whose lyrics are full of that kind of thing.

    Happy anniversary! Next prime number to aim for is of course 29.

  23. Trond Engen says

    “I’m in my prime. You didn’t ask which prime.”

  24. I’m goin’ for it!

  25. Trond Engen says

    Of course, the average distance between your primes just keeps increasing.

  26. David Marjanović says

    News magazine article about Austrian politician: Der vierte Frühling des Josef Cap – the 4th spring of his life/career.

  27. In Danielson’s latest column he provides some more esoteric vocabulary:

    Before I go any further you need to understand that I will be using extremely plain language for this column. The world of insects in general, and of the dragonflies in particular, is loaded with such highly technical language that it can become a distraction from the telling of a story. As an example, here are a few anatomical terms used to describe the heads of dragonflies: prothorax, occipital spine, occiput, ocelli, vertex, fons, postclypeus, anteclepeus, and labrum. That is quite enough of that!

    So what we see in today’s photo is a pair of Scarlet Bluets (Enallagma pictum) in a position known as “tandem linkage.” This particular posture is a requirement of the anatomy of dragonflies and the nature of their habitats. All species of Odonata have abdomens with 10 segments. The family we know as dragonflies are heavier and chunkier, while the family we know as damselflies (seen here) are much lighter and more slender. Both sexes have genital openings underneath their abdomens at the position of the ninth segment, which presents a major challenge. How do the members of a mating pair get everything lined up properly?

    Well, the excruciatingly subtle differences in the exact geometry of the heads of each species come into play here. At the end of the 10th (and final) segment of the abdomen, males have special claspers that can lock onto the heads of the females of their species. But before locking together in tandem, the males will transfer sperm into a “secondary genitalia” at the base of their third abdominal segments.

    The male will lock onto a female and then he will support her entire body weight while she curls her abdomen under his, so that the genital opening on her ninth segment connects with the male’s secondary genitalia and the sperm can be transferred to her.

    The pair of bluets in this photo has probably just initiated their tandem linkage. The landscape location where this occurs is charmingly known as “the rendezvous,” and for the bluets this means over the water of a pond where lily pads can be found. The bend in the female’s abdomen shows the segmentation I’ve been talking about and you should be able to imagine her reaching under the male.

    You can also imagine her using this flexible abdomen to deposit eggs in the water. Once the eggs are released, they typically float to the bottom and begin to develop. In smaller species that live in warmer, southern areas of North America, this might only require a few weeks. Larger species that live in colder, northern areas might require several years. In this “nymph” form, the insects are fully aquatic and they breathe with gills that are present inside their abdomens, or hanging off their rear ends. In the case of the former, water is pulled in and out of the abdomen in the same way that a bellows will move air. This also gives the nymphs the ability to suddenly expel all of the water at once, leading to a burst of “jet” propulsion; a handy way to escape from predators.

    One thing that is nice to know is the fact that both the nymphs and the adults are pure carnivores. The adults prey on other flying insects, while the nymphs generally stick to aquatic insects. That being said, the largest nymphs of some of the largest species might also grab small fish, tadpoles and even newts; basically, anything they can eat. After enough time has passed to allow the nymph grow to full size the nymph will then find its way out of the water and shed its skin one final time. This brings us to the exuvia that was featured in last week’s column, so I won’t go down that road any further this week.

    One last thing before I sign off – the name “bluet.” In my library I have a wonderful field guide: “Dragonflies and Damselflies of the East,” by Dennis Paulson. In this guide there are 36 species of damselflies that are called “American bluets” because most of them are blue. Some are miniscule, while others are described as being medium sized, but all of them are very slender and delicate in their appearance. In most species, the males are some shade of blue ranging from a dark, primary blue all the way to a light, powder blue. But, of course, there are always exceptions and the scarlet bluet is an example. The male is red and the female is orange. Only when they are in tandem can one be reasonably sure that they are members of the same species.

  28. Once the eggs are released, they typically float to the bottom …

    “float” huh? I thought that could only mean upwards — or at least not downwards. ‘settle’?

  29. Interesting — now that you point it out, that usage is odd, but I didn’t even notice it when I read it myself.

  30. i don’t particularly like “a secondary genitalia”.

    Damselflies in copula (“in cop” or “in whieel”, I’m told). I’ve gotten surprisingly little enthusiasm about my suggestion to make that picture, or one like it, into a T-shirt that says “I [heart] damselflies.”

    As a fellow odonate enthusiast said to me, “I tried to identify a damselfly, but I blew it.”

    By the way, in case any American or Canadian here is such an enthusiast, I strongly second the recommendation for Paulson’s guides.

  31. For some decades, “float up” and “float down” have been practically equally common in books, not that that settles what anyone should like.

  32. make that picture, or one like it, into a T-shirt that says “I [heart] damselflies.”

    well, i want one! and i feel i speak for at least three other people i know.

  33. For some decades, “float up” and “float down” have been practically equally common in books

    Well, that would explain why it didn’t strike me as odd.

  34. Keith Ivey says

    It seems a little odd when pointed out, I guess, but how is it any more contradictory than “fly down” or “climb down”?

  35. Because there’s nothing in the least contradictory about those; people and other creatures fly and climb both up and down. “Float,” on the other hand, does seem to carry an inherent bias against downward motion. At least to me, and presumably AntC.

  36. well, i want one! and i feel i speak for at least three other people i know.

    The hard part for me would be getting rid of the background so you’d just have the damselflies. I suppose that these days, with the right software, you just tell it, “Get rid of the background.”

  37. For a moment I read “damselfies”. Quick, ™ it!

  38. I once had an editor who objected to “[he] lands in the water.”

  39. Heh. I can actually see that as a sort-of-legitimate peeve!

  40. David Marjanović says

    German has actually created a verb wassern for this, and it has seen some real use – but few people would notice anything about auf dem Wasser landen.

  41. Reminds me of how Russian coined прилуниться “land (on the moon)” because one obviously only can приземлиться (the usual word for “land”) on Earth (земля).
    (And it’s a pity that “to moon” already has an established meaning in English.)

  42. French has amerrir, alunir, and amarsir, but the last two are condemned by the Académie.

  43. but the last two are condemned by the Académie.

    Bien sur!

  44. Trond Engen says

    I have probably told before about the time we flew to Paris and I had promised to text our host when we arrived at CDG. As soon as we were landed, I turned on my phone and thumbed in my best French “Nous sommes enterrés”.

  45. I hope he got over his shock 🙂

  46. but the last two [alunir and amarsir] are condemned by the Académie

    Interesting! The RAE has no objection to alunizar or amerizar

  47. Trond Engen says

    Hans: I hope he got over his shock

    It was my sister’s mother-in-law. When we arrived an hour or two later, she was very amused. As I recall, she had forwarded the message to my sister, who could explain what I probably meant.

  48. The RAE has no objection to alunizar or amerizar

    The RAE dictionary also includes amartizar (land on Mars).

    Several other Romance languages have verbs parallel to alunir for landing on the Moon, but Romanian prefers aseleniza for some reason.

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