Evolving spots, again and again

i-991d06462ff65d834c815f9662268805-flyspots.jpg
a–c, The wing spots on male flies of the Drosophila genus. Drosophila tristis (a) and D. elegans (b) have wing spots that have arisen during convergent evolution. Drosophila gunungcola (c) instead evolved from a spotted ancestor. d, Males wave their wings to display the spots during elaborate courtship dances.

It’s all about style. When you’re out and about looking for mates, what tends to draw the eye first are general signals—health and vigor, symmetry, absence of blemishes or injuries, that sort of thing—but then we also look for that special something, that je ne sais quoi, that dash of character and fashionable uniqueness. In humans, we see the pursuit of that elusive element in shifting fashions: hairstyles, clothing, and makeup change season by season in our efforts to stand out and catch the eye in subtle ways that do not distract from the more important signals of beauty and health.

Flies do the same thing, exhibiting genetic traits that draw the attention of the opposite sex, and while nowhere near as flighty as the foibles of human fashion, they do exhibit considerable variability. Changes in body pigmentation, courtship rituals, and pheromones are all affected by sexual selection, but one odd feature in particular is the presence of spots on the wing. Flies flash and vibrate their wings at prospective mates, so the presence or absence of wing spots can be a distinctive species-specific element in their evolution. One curious thing is that wing spots seem to be easy to lose and gain in a fly lineage, and species independently generate very similar pigment spots. What is it about these patterns that makes them simultaneously labile and frequently re-expressed?

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Let’s all be strident

Salman Rushdie was in Minneapolis last night—I wish I could have been there, but that 3 hour drive can’t be taken lightly—and it sounds like he was in excellent form:

When asked the question, “Who gets to tell our stories, and who decides who gets to tell them?” Rushdie replied, “Well, you’re talking about religion, aren’t you? Religion is some people deciding to tell stories for the rest of us, to us.”

When asked what spiritual practice he used in his writing, if any: “I have no spiritual practice. The word spirituality should be banned from the English language for at least 50 years… Talk about a word that has lost its meaning! You can’t walk your dog without doing it in a ‘spiritual ‘manner, you can’t cook without talking about spirituality!”

Bravo!

Sex and guns!

In the discussion about the Minnesota GOP platform, this comment from Molly made me think about what it would be like if Republicans were consistent in their attitudes towards sex and guns.

If Republicans taught gun safety like they do sex education, they would:

  • allow everyone to own a gun (even more, they’d require it: gunlessness is an abomination), but they’d insist that kids could never, ever take them out of their holster, sheath or gun rack
  • it would be illegal to expose your weapon or even talk about it
  • exposing a gun on TV would outrage viewers, who would deluge the network with complaining phone calls
  • blanks, trigger locks, and even safeties would be forbidden
  • there would be accidental discharges every night in every teenager’s home, but no one would ever talk about it
  • it would be a shameful sin to go off by yourself and practice shooting at targets
  • the only acceptable use would be to kill something, although it would be OK to miss if you were sincerely trying to kill something
  • most hunters would be desperately hoping to miss every time they went hunting, and would try to contrive situations in which they could fire their guns without actually hitting anything

It seems like a useful analogy to me. If it’s common sense gun ownership to know how to clean and maintain the thing, to practice sensible gun safety rules, and to treat it as a responsibility that demands knowledge and care and good understanding of its operation, why not expect the same of people who own a penis or vagina? There’s nothing about knowing how something works that is antithetical to the idea that one should refrain from using it for its intended purpose, whether that is killing something or getting it pregnant, and in fact, we know that understanding in detail how something works is the best way to prevent it from going off inadvertently.

As it is, they’re in a situation where they are tacitly favoring accidental, unplanned accidents over the possibility that kids will intentionally practice safe operation of their equipment.

Carnivalia, and an open thread

A few carnival announcements:

The next Tangled Bank will be held next Wednesday at The Inoculated Mind (yes, it’s back up!). Send your submissions to karl AT inoculatedmind DOT com with “Tangled Bank Submission” in the subject line, or send it to me or host@tangledbank.net.

As always, carnival barking threads are also open threads—talk about what you will.

Mollusc vs. Annelid

We had some rain overnight, and this morning the sidewalk on my way to work was swarming with earthworms and slugs. The slugs here in Minnesota are tiny little pathetic things, unlike the lovely behemoths I grew up with in Washington state, but they’re still cool to see. Anyway, Afarensis led me to this short photoessay about what happens when a hungry slug meets a worm. I am not surprised at all: I’ve seen a few cannibalistic slug feeding frenzies in my time. They’re like the slo-mo sharks of the damp undergrowth.

Yet another timeline

The true history of the world is told in the movies, so obviously what we need is a compilation of movie events to see what was really going on. It’s a work in progress, so there are a few gaps—the period between 1 zillion BC and 65,000,000 BC is a bit sparse on information—but more recent events are better covered. For instance, the year of my birth was quite busy:

1957 New Zealand – Lionel Pritchard and his girlfriend Paquita battle a horde of zombies (Braindead)
Camp Crystal Lake, New Jersey – Jason Voorhees drowns (Friday the 13th)
Michael Myers born (Hallowe’en)
Lana Turner meets Johnny Stompanato (L.A. Confidential, 1997)
The Iron Giant
October Sky

Zombies, supernatural mass murderers, and giant robots…oh, yeah, I remember that. The late 1950s were rife with alien invasions and mutant monsters, too. Lana Turner is a little out of place, until you realize it’s also the year my wife was born.

(via Eclecticism)