Field of Science

Holometabolous When?

A few days ago, I asked you to guess the problem with this T-shirt (from here):
'Holometaboly' refers to the life-cycle found in insects belonging to the clade Holometabola (i.e. flies, moths, wasps, beetles, etc.), where the larval stage is significantly different in appearance to the adult stage, and the body undergoes significant reconstruction during an intervening, quiescent pupal stage. Some of you may be aware that thrips are not members of the clade Holometabola, being instead more closely related to the Hemiptera, the sucking bugs. Nevertheless, thrips can indeed be described as holometabolous, as they have evolved a pupal stage in their life cycle independently of the holometabolans. So my problem with the slogan 'Holometabolous before it was cool' is not with the use of the word 'holometabolous'.

It's with the word 'before'. The earliest known crown-group thrips, and thus the earliest known thrips that we can be reasonably certain was holometabolous (absent actual fossilised thrips pupae) is Liassothrips crassipes from the Late Jurassic (Shmakov 2008). In contrast, the earliest known crown-group holometabolans are stem-beetles and stem-neuropterans from the Early Permian, a good hundred million years or so before (Grimaldi & Engel 2005). Even if we open the gates to potential stem-group thrips (which may or may not have been holometabolous), that doesn't take us back any further than a potential tie with the Holometabola.

Liassothrips crassipes, from Schmakov (2008). Scale bar equals 1 mm.


So while thrips may be holometabolous, the possibility that they were so 'before it was cool' is fairly remote. Thrips are much more likely to have been late-comers to the holometaboly game.

REFERENCES

Grimaldi, D., & M. S. Engel. 2005. Evolution of the Insects. Cambridge University Press.

Shmakov, A. S. 2008. The Jurassic thrips Liassothrips crassipes (Martynov, 1927) and its taxonomic position in the order Thysanoptera (Insecta). Paleontological Journal 42 (1): 47-52.

8 comments:

  1. That actually fits well, because most hipsters weren't actually "doing it before it was cool" either.

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  2. I confess I've never seen a hipster undergo holometaboly either before or after it got cool. Thinking about it, I haven't even noticed holometaboly being cool. [/completely missing the point]

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  3. Perhaps 'cool' refers to a period of glaciation rather than the vernacular usage following the 1957 work of Miles Davis? If that is the case the Late Jurassic is way before cool.

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  4. The glasses on the thrips are still upside down. We don't need paleoentomology to know that!

    I didn't know thrips had a pupal stage. It only took me 40 years to find out.... Who knows what I'll learn in the next 40? :-)

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  5. You could argue about whether the glasses are upside down. Thrips have the head oriented so that the mouthparts extend back, underneath the thorax. So the glasses are upside if they're supposed to be oriented to the antennae, but right way up if they're supposed to be oriented to the mouthparts. This sort of confusion is doubtless why thrips don't normally wear glasses.

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  6. So there was a missing link we call Bigfoot? Are we sure it is not still found in North America?

    I don't remember Miles Davis mentioning the birthday of the Cool but presumably it was before Pope:

    1741 Pope et al. Art of Sinking 226 in Pope Wks. II, To treat..of the Emollients and Opiats of Poesy, of the Cool, and the manner of producing it. ( oed.com , ta)

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  7. So are you saying that Pope was cool before it was cool?

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  8. I see the author's point, but perhaps he misses part of the humor? That is a "Thripster" T-shirt.
    It's a little less catchy to sat "Mothster," "Beetlester" "Flyster," etc.
    Remember, hipsters define their own "cool" and take pride in the obscure. (They saw your favorite band performing in a garage behind a coffee shop YEARS before anyone heard them on the radio, etc.) Perhaps, they even delight in being misunderstood. I think the thripster t-shirt is Badass. Too bad I don't look good in black.
    On another note, I love evolutionary biology, and as an entomologist, appreciate having learned something new about thrips since I identify them every day.

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