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Chicken odour repels malaria mosquitoes, research in Ethiopia finds (bbc.co.uk)
101 points by hanoz on July 21, 2016 | hide | past | web | favorite | 34 comments

As I understand it, the issue is that, while it might repel them to begin with, mosquitos evolve quite rapidly, and sooner or later they will learn to ignore the repellent, and it will be ineffective. There are tons of substances that mosquitos and insects find repelling. We have mapped the receptor in mosquitos which, when activated, make them shy away from a substance. But if it doesn't kill the mosquitos, or damage them, they will eventually learn that it's unharmful, and it will no longer be effective.



While looking for a different paper, which shows that mosquitos can adapt to certain repellents, I discovered that the paper from above has been retracted: http://www.nature.com/nature/journal/vaop/ncurrent/full/natu...

I will post a link to the other paper if I find it.

Here's the paper.

Aedes aegypti Mosquitoes Exhibit Decreased Repellency by DEET following Previous Exposure: http://journals.plos.org/plosone/article?id=10.1371/journal....

Not if they can live their lives as usual everywhere else, then the evolutionary pressure to adapt is low. Assuming you spray only houses.

> But if it doesn't kill the mosquitos, or damage them, they will eventually learn that it's unharmful, and it will no longer be effective.

If a repellent stimulus no longer harms them, that doesn't automatically mean there's any strong advantage to not being repelled anymore.

(And I would avoid uses phrases like "learn" to describe this behavior. A population of mosquitoes may evolve to no longer be repelled by chicken smells, but that doesn't mean they're remotely aware of it.)

I assume this works because the mosquitoes don't want to get eaten. Unless this somehow causes chickens to evolve to no longer eat mosquitoes, it seems unlikely this effect would diminish over time.

chicken actually eating, ie. killing mosquitoes, suggests similar technical solution - like miniature anti-aircraft weapon consisting of small laser and either camera or radar (like Google's recently demonstrated 60GHz penny sized one) which one would hang over the bed. By focusing laser right at the position of the mosquito it can be pretty safe for humans around. Can be a tool against flies too.

Sooner or later, sure. But mosquito coils use the same compounds since at least 100 years and still are pretty effective.

Poppycock. It is widely known that miasmas such as chicken odour are the source of disease, not a cure. In fact even the name "malaria" means "bad air" for this reason.

""" For when the morning breezes blow toward the town at sunrise, if they bring with them mist from marshes and, mingled with the mist, the poisonous breath of creatures of the marshes to be wafted into the bodies of the inhabitants, they will make the site unhealthy. """


Oh, this also explains something else!

If the Earth's surface was curved, clearly all the miasmas would just roll downhill away from us and we wouldn't have any disease. Therefore, the Earth is flat. I love how science explains everything!

Nonsense! Anyone knows that the miasmas are best dispersed with two good fires, and the constant use of tobacco smoking! Even the very small children should they be able, must smoke. Why in Oxford all students must, on pains of a good thrashing.

I actually really love miasma theory- as fundamentally incorrect as it is, it gets a lot right.

That and Lamarckian evolution. They're actually pretty good examples of early science--they fit a lot of the facts as they were known at the time.

Is this meant to be satire?

Bill Gates fights against malaria (http://www.gatesfoundation.org/What-We-Do/Global-Health/Mala...), then he says that he would raise chickens (https://www.gatesnotes.com/Development/Why-I-Would-Raise-Chi...)...he knew!

... that chickens are the only medicine strong enough to save humanity

Are chickens a significant predator of mosquitoes or mosquito larvae? That would make a lot of sense. Or maybe some other bird that chickens happen to have a smell in common with.

> the compounds from the smell of the chicken can be extracted and could work as a repellent

Might actually work as long as only a statistically insignificant minority of ppl is using it. After that point, it's Darwin all over again.

DEET has been in use as an insect repellent since 1946. Insensitive mutant insects are known but in most cases it's still effective. The more distinct mechanisms of action we have available the less likely insensitivity will become a problem, so it's worth identifying the active compound in chicken odor.

Only if "not being repelled by chicken smells" conferred a large enough selective advantage over "being repelled by chicken smells". Mosquitoes have plenty of other animals to bite besides humans, so it's not immediately apparent that it would change selection pressures at all, much less to the degree needed to push the population genotype in one direction or the other.

The most dangerous malaria mosquito, Anopheles gambiae, does selectively target humans. See:


We just need to breed a bunch if genetically modified chickens that produce L-lactic then, and we'll be set (if we use chicken odor as a repellant).

You might be right. But if we got mosquito bites low enough for even a short time it might bring the maleria infection rate to below one and wipe it out.

Missing a comma perhaps? I first misread it as chicken odor prevented researchers from doing their job since it smelled so bad.

With all due respect to the 'use the existing headline' convention, a minor edit to this Yoda-style instance would dramatically decrease misunderstanding of the article topic.

(While I enjoy hearing British English most of the time this commaless reversing tends to drive me a little nuts.)

A better title would be "repels malaria mosquitoes".

Every once in a while somebody aces the ever-popular genre of title complaint by suggesting a better one. Thanks!

The rest of you may have a comma as well. :)

Mosquitoes would only avoid something if being near it made them less likely to reproduce successfully. Seeing that, we've decided to surround ourselves with those things.

This concerns me a little.

Chickens are not known for their predation of humans...

That's what the chickens want you to think

I don't see why it should, symbiosis is a widely spread phenomenon. We've already done it with domestic animals for example (cats against mice/rats).

I'm pretty sure if there were a negative effect of chickens on our reproductive rate, we would have discovered it any time in the last couple thousand years living in proximity to chickens.

That said, they do stink. I don't blame the mosquitoes at all.

You mean chickens might make it harder for humans to reproduce?

Yes, if it was a 4 foot man eating chicken[1]

1. https://www.youtube.com/watch?v=yxFlX1BudYw

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