Universal "Death Stench" Repels Bugs of All Types

Hugh Pickens writes "Wired reports that scientists have discovered that insects from cockroaches to caterpillars all emit the same stinky blend of fatty acids when they die and that the death mix may represent a universal, ancient warning signal to avoid their dead or injured. 'Recognizing and avoiding the dead could reduce the chances of catching the disease,' says Biologist David Rollo of McMaster University 'or allow you to get away with just enough exposure to activate your immunity.' Researchers isolated unsaturated fatty acids containing oleic and linoleic acids from the corpses of dead cockroaches and found that their concoction repelled not just cockroaches, but ants and caterpillars. 'It was amazing to find that the cockroaches avoided places treated with these extracts like the plague,' says Rollo. Even crustaceans like woodlice and pillbugs, which diverged from insects 400 million years ago, were repelled leading scientists to think the death mix represents a universal warning signal. Scientists hope the right concoction of death smells might protect crops. Thankfully, human noses can't detect the fatty acid extracts. 'I've tried smelling papers treated with them and don't smell anything strong and certainly not repellent,' writes Rollo in an e-mail. 'Not like the rotting of corpses that occurs later and is detectable from great distances.'"

Sharks, too

[Das Auge]

The same thing works on sharks. I watched a Discovery show where they got the sharks into a feeding frenzy, dropped some of the repellent (dead shark material) into the water, and all of the sharks took off in seconds.

Thinking about it, I doubt very much that humans millennia ago smelled dead human and though, "Hey, I wonder what killed him. I'm going to go see."

Bring out your dead !

[Fred_A]

Your anecdote does nothing to invalidate the article's data.

It makes sense for any animal to avoid a site where its own are dead.

It's the same category of reflex that makes us want to throw up when someone pukes (being social animals we often eat together), that makes us universally find some smells offensive (pretty much always originally attached to something potentially toxic), etc.

Re:This is nonsense

[eldavojohn]

Maybe for some bugs, but for those nasty caca roches, I get a bowl, wipe the top 4 inches around inside with vegtable oil then put whatever inside... coffee grounds, bananas... whatever... There are tons of dead ones in there but that doesn't stop more from coming. Also, cockroaches are cannibals.

Well, to be fair, your observations are from cockroaches that have lived in close quarters with humans and not those in nature. Notice that in the article, it's only Wired who suggests this would protect you from an infestation. The scientists say this may protect crops--which are in a more natural setting. And I think you would see a much higher success rate on cockroaches or wood beetles that live in the wild versus those in your home. Many animals behave very differently in their natural environment.

Whatever the case, I'm really excited to see fatty acid extracts used instead of chemical compounds on the food that I eat. Especially for people that have small gardens of tomatoes and vegetables. I'd personally pay a small premium on my produce for crops grown and repelling insects with this technology.

Crops

[Stile 65]

How are they going to use this for protecting crops? If ants are repelled, wasps and bees will be, too, and there goes your pollination.

Re:This is nonsense

[nameer]

But fatty acid extracts are chemical compounds. And lets be clear, if they figure this out to the point that it works reliably, the next step is bring in the chemists and chemical engineers to figure out how to scale this up to industrial proportions. That will mean building the compounds in bulk, not extracting them from cockroaches. Which to be fair, is better for the roaches.

Especially good, because..

[Anonymous Coward]

An obvious reason why pest traps may be less effective is if the dead pests emit a smell that makes others stay away.

If you spread this smell around, it will make pests stay away - but if it comes a point they develop "immunity" to it, it will also greatly increase the effectiveness of pest traps.

Re:Prolly not going to work.

[Anonymous Coward]

It's called Evolution if there is any kind of advantage (Which outweighs any disadvantages)
Sort of. Any advantage that outweighs a disadvantage and allows for more procreation stands a chance. The procreation bit is key.

Re:This is nonsense

[quadrox]

you are completely wrong. Go read dawkins books, e.g. the blind watchmaker.

Re:Sharks, too

[Nadaka]

Not really. It takes a lot of practice to overcome revulsion of the dead. There is nothing that smells quite as bad like a dead person, even a fresh one has a smell that will tie your stomach in a knot. My fiance is a mortician and it took her quite some time to get over the smell. It still creeps me out when I end up having to wait on her at the funeral home.

Re:This is nonsense

[Jeffrey_Walsh VA]

Roaches have lived among humans for long enough that their natural eviroment is our home.

Re:This is nonsense

[Nerdposeur]

It also seems to not jive with the currently understood mechanics of evolution. DETECTING such a stench would lead to a survival advantage, but actually emitting it is something done after death - so there is no natural selection at work to lead to the unification of a "death scent" to evolve towards.

I don't know any more than you do, but here's a possible scenario: when bugs died, they emitted a slight odor as an accidental part of the decomposition process. Insect X is born with a gene that makes him dislike that odor, so he and his offspring avoid diseased corpses and are slightly less likely to die. But it's not foolproof, because the odor is slight.

Later, one of those insects develops a "be extra stinky when you die" gene. Maybe it means he has more of a certain chemical in his exoskeleton, which bacteria like. It doesn't really help him survive, but it doesn't hurt him either. He has some offspring, and later dies. All his offspring avoid his corpse like crazy, and start doing the same for each other's corpses. Now that whole population is less likely than before to catch disease, and that particular gene keeps getting passed on.

Think of the gene itself as an organism, with the actual insect being just a host. Would those organisms help either other reproduce? I think so.

Re:Bad plan, darlings.

[Novae D'Arx]

You know, this actually might work out: 1) Use the repellent for X seasons, until no longer effective due to the bugs losing their fear of dead bugs. 2) Spread a known (bug-only!) disease the next Y seasons, until no longer effective due to the bugs regaining their fear of dead bugs. 3) See 1) Actually, the same would theoretically work with antibiotics - have the FDA remove all, say, penicillin-based antibiotics from the market (except special cases, like where someone is allergic to every other antibiotic, or the only thing a specific bacteria is susceptible to is penicillin-based drugs) for a few years. Studies show that bacteria quickly lose resistance to antibiotics (at least in the lab) when no longer routinely exposed - it takes more energy to produce the resistant proteins/plasmids, and the resistant bacteria are quickly outcompeted. Cycle in/out 1-2 major groups like this every few years, and the "superbugs" that have people so freaked out will be susceptible again. There, I solved that problem - 1 billion dollars, please. I'll take local checks. Really, it's simple. Use evolutionary genetic patterns to our advantage - it's like hacking for the biosphere! ...Cue: "what could possibly go wrong" here...

Re:This is nonsense

[Anonymous Coward]

Even if it did work, if you spray it on plants and it repels the all bugs (including bees) how on earth will any of it be pollinated?

Re:This is nonsense

[Ajaxamander]

But fatty acid extracts are chemical compounds.

Please tell this to as many people as possible... substitute "wood" "air" "table salt" and "sugar" as needed. I'm getting really tired of this anti-"chemicals" attitude that's sneaking into everyone's mindset.

Re:This is nonsense

[Jah-Wren Ryel]

I like the cut of your jib, sir!

Re:Bring out your dead !

[Alcoholist]

Here's what I do for ants, works better than any of those nerve agent poisons. Plain old diatomaceous earth (diatomite, silica powder, kisselgur, etc...) Some farmers use it to protect grain and stuff, but it works on ants and other crawly pests too. You put it in places where ants like to run around, like say, the base of a door, along a foundation or on top of an anthill. It kills some of them, injures others but they seem to hate it so much eventually the colony gives up and moves away from your house.