Comments on: If you see a glowing millipede, best not to bite it

By: Nancy

Nancy — Sat, 02 Jun 2012 01:01:34 +0000

Saw one near south lake tahoe last night…

By: Christina

Christina — Wed, 05 Oct 2011 04:04:35 +0000

One thing that confuses me about aposematism is why it isn’t vulnerable to cheaters. There are mimics, certainly, take advantage of other species’ learned aversion to the actually toxic animals, but why doesn’t this happen intra-species? It seems to me that a mutation that knocked out the toxin would be adaptive – such an organism would be spared the cost of producing the toxin while displaying the “I’m toxic” signals and avoiding being eaten. So, why doesn’t non-toxicity spread, especially once would-be predators have evolved innate avoidance? Or *does* that happen, making aposematism an evolutionarily short-term phenomenon? I.e., toxin evolves, warning displays evolve, and then non-toxicity spreads, initially benefiting from innate avoidance until the predators lose that innate avoidance, possibly starting the cycle over again?

By: Paul M.

Paul M. — Fri, 30 Sep 2011 16:29:18 +0000

@Russ, Chris Yes aposematism is strange, and at first counterintuitive. But totally makes sense after some thought. Aposematism is a biological phenomenon where a feature (appearance, sound, smell) deters predators because it denotes something noxious, or unpleasant. E.B. Poulton coined the word in the book “The Colours of Animals” in 1890. Any signal can be aposematic, and it doesn’t have to be garish, or even conspicuous. Although often times in nature aposematic signals are conspicuous. There’s empirical evidence that demonstrates conspicuous aposematic signals work better because they are more quickly learned, easier to remember, and so different looking as to reduce errors in discrimination against edible prey. Anyways, learning (at some point in establishing avoidance) is a big component of aposematism. Predators, over time, learn that some appearance denotes something unpleasant. And learning a signal that is associated with something unpleasant is very rapid. In some instances, after some time, avoidance becomes fixed, this is referred to as innate avoidance. (It’s believed that humans have an innate, or unlearned avoidance to snakes, as a result of an ancient evolutionary association with them.)

By: Chris M.

Chris M. — Wed, 28 Sep 2011 01:35:03 +0000

@Russ, it’s usually targeting a learned response, as far as I can tell; a predator will try one of them, maybe two, and then won’t go near them again. It’s a bit of a medium-term strategy; doesn’t rely on the predators evolving an aversion, but does need a few to take one for the team. These are high enough density that it apparently makes sense!

By: Mephane

Mephane — Tue, 27 Sep 2011 08:05:01 +0000

Woah, these are real. I must have seen some of these in my childhood, I vividly remember small things with that very color, moving quickly out of sight, but at one point I concluded it might just have been a trick on the eye or the mind.

By: ElOceanografo

ElOceanografo — Tue, 27 Sep 2011 05:50:20 +0000

I wonder if the “burglar alarm hypothesis” might be an alternate explanation. It’s thought that some plankton and fish light up when attacked to bring attention to their attackers, putting them at higher risk of getting eaten.

By: Paul Orwin

Paul Orwin — Tue, 27 Sep 2011 02:29:23 +0000

I haven’t read the paper (and I hate when people write that, but I just saw the article), but GFP is a fluorescent protein, while luminescence is a different phenomenon. Luminescence is a chemical reaction that releases photons, while fluorescence is the absorption of light at a specific higher energy (sometimes more than one) and the release of light at a specific lower energy (longer wavelength). The proteins that do these two different things are not related to one another structurally, AFAIK. I could be wrong, tho

By: ChasCPeterson

ChasCPeterson — Tue, 27 Sep 2011 01:07:12 +0000

So cool. Chalk up another for the hypothetico-deductive method.

By: Ed Yong

Ed Yong — Mon, 26 Sep 2011 22:54:49 +0000

Daniel – paper says that it works through a similar mechanism but the structure is unknown.

By: Daniel

Daniel — Mon, 26 Sep 2011 22:52:29 +0000

But the millipedes’ protein is structurally very similar to GFP, according to Marek.