"From genes to butterfly scale & color diversity"

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rjlittlefield
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"From genes to butterfly scale & color diversity"

Post by rjlittlefield »

Today I attended the following live webinar, part of the seminar series from the McGuire Center at the Florida Museum of Natural History:
March 16, 12 p.m.
Thomas C. Emmel Seminar Series presents: Expanding Horizons in Lepidoptera Research
Speaker: Arnaud Martin
Institution: George Washington University, Washington D.C., USA
Title: From genes to butterfly scale & color diversity (currently indexed as "The genetic basis of color patterning in butterfly wings")
I subsequently wrote email to the presenters that this "was probably the most information and insight that I've gotten in any one hour for the past 5 years. Please pass along my compliments to all involved."

You can probably guess that I highly recommend this presentation to other people.

If you're interested in anything to do with butterfly scales, including how they work, how they form, how this can be investigated with CRISPR knock-outs, and so on and so on, then I guarantee there'll be something in here for you.

Example: Some but not all yellow butterflies in the genus Colias are iridescent in UV, a property granted by Morpho-like nanostructures on the scales. Presence/absence of UV iridescence is controlled by a single recessive gene on the sex-determining chromosome. Between two closely related "incipient" species, C. eurytheme and C. philodice, the females of C. eurytheme use UV iridescence in the males for mate selection, which, combined with the recessive nature of the controlling gene, allows them to avoid mating with philodice or even hybrid males, and that's a Good Thing because any female offspring who get a philodice sex chromosome end up sterile.

Direct link to the recording: HERE
Link to the collection of recordings: https://www.floridamuseum.ufl.edu/nhdept/seminars/

--Rik

One caveat: the speaker's language is excellent English, but he has a significant French accent and he uses a lot of technical terms and scientific names that may be unfamiliar. To hear it all correctly may take several tries. There is a transcript but it is so riddled with automatic transcription errors that I find it more derailing than helpful. I recommend to read the slides, listen to the audio, and ignore the transcript.

* Start at 00:35:43 for a wonderful example of "derailing".

Lou Jost
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Re: "From genes to butterfly scale & color diversity"

Post by Lou Jost »

Thanks for letting us know about this. It was fascinating (and the automatic transcript was always entertaining to say the least). I'm about halfway through it.

MarkSturtevant
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Re: "From genes to butterfly scale & color diversity"

Post by MarkSturtevant »

That is really interesting. I have semi-followed research on butterfly wing pattern formation as time allows, and it has become an amazing story.
You may enjoy this video on the same subject, aimed at a more general audience, with the same French researcher. It includes time lapse development of the wings and it is very cool (Scroll down): https://entomologytoday.org/2020/01/09/ ... evolution/

Did you know that caterpillars have little wings inside them?

Genes controlling wing color patterns are well known to control other aspects of development. The one mentioned here was "Wnt" and it is also involved in development of body segments. Another not mentioned here but is central to the eye-spots seen in wings, is a gene called Distalless. It is also used for development of legs.
Both genes are important to development in all animals, including humans.
Mark Sturtevant
Dept. of Still Waters

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Re: "From genes to butterfly scale & color diversity"

Post by rjlittlefield »

MarkSturtevant wrote:
Thu Mar 18, 2021 10:57 pm
https://entomologytoday.org/2020/01/09/ ... evolution/

Did you know that caterpillars have little wings inside them?
The video on that web page is very cool. I was familiar with the concept of an "imaginal disc", but I have to confess that I was not expecting to see such well defined wing structures inside a Painted Lady larva (5:25 in the video). In retrospect, maybe I should not have been surprised, because I am well aware that when the still-soft pupa emerges from the last instar caterpillar skin, its wing cases are already large enough to form the expanded pads that are so prominent in the hardened pupa. But I was surprised, anyway.

--Rik

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Re: "From genes to butterfly scale & color diversity"

Post by MarkSturtevant »

In what I describe as my 'former life' doing research on insect development, I became exceedingly familiar with the imaginal discs of flies, especially those of the fruit fly Drosophila melanogaster. But along the way I looked into wing development in honey bees, beetles, and many other kinds of insects. But butterfly and moth wing discs became a favorite b/c they really do look like little wings, tucked inside the caterpillar.
If you look at a caterpillar, one thing you can see is that they have obvious spiracle openings on their first thoracic segment. The next two thoracic segments don't have spiracles, and then the spiracles start up again on each segment in the abdomen. Where the spiracle openings are missing on the two thoracic segments, there you will find the imaginal discs for the front and hind wings.
Mark Sturtevant
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Lou Jost
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Re: "From genes to butterfly scale & color diversity"

Post by Lou Jost »

Mark, that's a fascinating detail!

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