Associative learning turns DEET from aversive to appetitive in Aedes aegypti

https://journals.biologists.com/jeb/article/229/10/jeb251935/371741/Associative-learning-switches-DEET-valence-from

by croes • 2 months ago

79 42 2 months ago

journals.biologists.com

gobdovan• 2 months ago

In plain English, they made mosquitos like repellent.

Y-bar• 2 months ago

Tldr: Repelln’t.

zeafoamrun• 2 months ago

Could this already be happening out in the wild?

cactusplant7374• 2 months ago

I use a lot of bug spray and I am still swarmed sometimes.

fooqux3• 2 months ago

As I understand it, DEET just prevents biting as they don't like the taste of it, and they taste with their feet. Thus, it doesn't do much to prevent initial attraction.

Edit: thought I'd include a link to a study about this as it's not well known. https://www.cell.com/current-biology/fulltext/S0960-9822(19)...

trhway2• 2 months ago

that explains. I was always wondering why in Siberia (where i worked for 2 summers back then at university times) coming out from house with freshly applied DEET you're getting covered with mosquitos - i was attributing that to the especial ferociousness of the mosquitos there - yet it sounds like the smell of DEET for them in those towns may have become like a BBQ smell for us :)

MiracleRabbit• 2 months ago

Freshly marinated in DEET

HPsquared• 2 months ago

A bit like how capsaicin was evolved to prevent things being eaten by mammals, but... Well.. humans came along and developed a taste for it.

"Evolution! Can you give me capsaicin, to deter mammals? I want birds to spread my seeds!"

https://youtu.be/1fW2uTRdUJU

tardedmeme• 2 months ago

They got the ultimate seed-spreading, since we farm them.

raverbashing• 2 months ago

So maybe the solution is to apply DEET to a bug zapper

neves• 2 months ago

It was fun, but not a bad idea. Are there mosquito mousetraps, or mosquitotraps?

adynaton• 2 months ago

Damn, were you working at Tselinoyarsk?

trhway2• 2 months ago

not, yet places where i worked - Purovsk, Krasnosel'kup - 35 years ago were already having the things of the future like android driven large trucks (dead-drunk drivers with only basic lizard brain instincts operational during deep night cargo ship operations) and self-driving tracked construction equipment like cranes, etc - as they would follow deep tracks (koleya) in the unpaved roads not being able to get out of those tracks on their own, so the driver would get out and walk in the forest gathering mushrooms, etc. while the equipment would drive itself along those deep tracks. And having a wall-to-wall fight with "vahtoviks" beats the fun of fighting monsters in any game :)

OutOfHere4• 2 months ago

I hope these mosquitoes were not released in the wild.

The simple answer would be to add a natural strongly repellent gentle oil to the DEET spray.

AyyEye• 2 months ago

At that point just skip the deet.

cbdevidal4• 2 months ago

Spray made from lemon eucalyptus works[1]. Not as well as DEET, but it works.

[1] https://www.consumerreports.org/health/insect-repellent/oil-...

cbdevidal4• 2 months ago

I don’t understand why sharing an objective study with good news would be downvoted, someone please explain?

I’m not saying you have to use it; it’s good news for people who have concerns about other chemicals. It works—less effectively, but it works.

“Repellants containing (..) oil of lemon eucalyptus have also been found to be effective.”[1]

[1] Iowa Department of Health, “Controlling Spread of West Nile Virus“ https://hhs.iowa.gov/health-prevention/providers-professiona...

YeGoblynQueenne2• 2 months ago

It works, as do other plants with strong, lemon-y smells (like citronella and geraniums) but the problem with those concoctions is that they don't last long. I've used them a lot in the past and at most they'll last an hour or so. Their problem as far as I can tell is that they evaporate quickly and once you can't smell them anymore nor can the mosquitoes, and you're fair game again.

DEET is so effective because its effects last a long time. In my experience it basically lasts until I wash or go for a swim, so for as long as it's on my skin. Granted, since I normally use it in the summer months when I'm likely to swim daily it doesn't last more than a day in practice, but that's already far longer than any of the plant-based ones I've tried.

Foobar8568• 2 months ago

A couple years back, I spray some DEET on my shoes, 5 seconds later, a tiger mosquito tried to bite me on that spot (and yes on the shoe itself, just insane to see it trying ).

They already loved that shit.

plmpsu• 2 months ago

Yeah, I would not be surprised if this learned behavior is passed on epigenetically. This is almost like gain of function research potentially.

alwa• 2 months ago

And remove the DEET from it, apparently… at least until it loses its appetitive charge.

Until, of course, they learn to like the replacement oil. At which point, break back out the DEET!

exabrial5• 2 months ago

There are no natural oils that have been proven to stay effective, or are effective as DEET.

Go ahead, hose yourself down with Lemon oil, citronella, oil, or lemon eucalyptus oil. They simply do not work.

OutOfHere4• 2 months ago

The parent comment was clearly not intended to replace DEET, only to add an oil that provides the missing repellent odor if this were to become a real issue. For all I care, the oil could intentionally be altogether useless for killing bugs. After all, even if DEET doesn't repel bugs, it still is intended to kill the bugs that intake it.

Also, the oils in question work reasonably for bug control, just for a lesser duration, requiring more routine reapplication. When you say they do not work, that's true only for the gap between how long the oils work versus how long ≥35% DEET works. And the concentration matters acutely for both.

GuB-42• 2 months ago

Maybe an effective answer would be to combine DEET with an insecticide.

Mosquitoes attracted to DEET will die because of the insecticide. Usually, for personal protection, we tend to prefer repellents, as we don't want to get bitten, killing the mosquito after the fact is not very useful. But here, the idea is to put some evolutionary pressure against mosquitoes not repelled by DEET.

There are also repellants other than DEET. Icaridin being the best alternative. It is almost as effective as DEET without many of its drawbacks. Some essential oils too, as you said, but I don't think any of them have the effectiveness of icaridin or DEET.

exabrial5• 2 months ago

The answer is just to use Picaridin instead of DEET, or perhaps a combination of both. Picaridin is sold as "Off - Clean Feel" or in Sawyer products in the USA.

The exact mechanism is not completely understood, but it's thought that DEET works because it interfere's with mosquitos ability to locate their prey. It is not thought to discourage bites as "they don't like the taste", just by interfering with sensing.

A newer repellent, Picaridin, not only interferes with locating prey, but actively deters mosquitos like pepper spray mace. It's an engineered molecule, derived from a compound called piperine, a substance found in black pepper plants.

Studies show that "Picaridin is as effective as DEET", but my personal experience is it is about twice as effective as DEET.

I spend an enormous amount of my free time outdoors and I can attest that Picaridin is far more effective than DEET for both mosquitos and ticks (we have two main species in the Kansas/Missouri/Arkansas region, others are present but less common).

As a personal data point, I had a friend trip on a hike this spring and fall into a grassy/bushy area. He did not put any repellent on. When we stood up, he was _covered_ in ticks. We got back to the truck and started peeling them off him, probably 15+ plus we flicked off or crushed. Unfortunately, we kept finding more, so we tried spraying Picaridin after the damn things hated that stuff so bad they jumped or fell off instantly.

You do not want to get Picaridin in your eyes or mouth, holy shit, that stuff is like bear mace. Also make sure you're downwind when you're spraying, your friends with appreciate that.

The other advantage of Picaridin is that it does not melt certain plastics. If you have life saving gear made of certain plastics, DEET can melt many times of plastics! (Notably some PVCs, polycarbonates, acrylics, acetates, and elastics).

random3• 2 months ago

That’s interesting! As I’m researching this (for my family) I have questions :) - have you tried entomol? How does it compare? - is it advisable with for young kids, if it’s irritant? - how long does it stay on? - what do you do when you get so many ticks on yourself? Watch if you get spots after 30 days?

Entomol is hydrogenated catmint oil

exabrial5• 2 months ago

Never tried Entomol. But I've found any of the essential oils simply don't work more than 10-20mins after application. I'd be very skeptical, but I'll try it if I can find an EPA/FDA approved spray.

Picaridin is safe for everyone, but follow all label instructions. Also use the 20% concentration. I find that 10%-15% is about as effective as DEET, 20% is about twice as effective (in my completely uncontrolled, unscientific, testing).

gucci-on-fleek• 2 months ago

is it advisable with for young kids

I can't comment on the safety factor, but to me it smells like cotton candy, so your kids will probably be more willing to put it on than DEET. (I don't know if this is how the chemical inherently smells or just the brand that I have though)

if it’s irritant?

You definitely don't want to get it in your eyes or mouth, but I have pretty sensitive skin and I've never felt anything when putting it on before, so it's not that irritating in my experience.

how long does it stay on?

I seem to remember that the bottle says 12 hours, which is a bit optimistic, but not too far off. I think that I've only ever needed to reapply it once, whereas I've sometimes had to reapply DEET multiple times in a day.

DannyBee2• 2 months ago

Picardin is based on the chemical that makes black pepper spicy, which is why it does that if you get it your eyes or mouth.

DEET is a toluene derivative which is why it is super effective at melting plastics and doesn’t evaporate quickly

It was actually discovered by massive brute force chemical search for repellants

pseudohadamard• 2 months ago

I've used picaridin and it seems to be minimally effective - the mosquitos won't land and bite, but they will whine endlessly in close proximity until their batteries run down.

fooqux3• 2 months ago

I couldn't tell from the paper, but perhaps I missed it. Is this learned behavior hereditary?

guiambros• 2 months ago

It doesn't seem the case; the study was made purely on behavioral conditioning. And mosquitoes don't live very long, so it's unlikely they'd learn this in practice, outside of a very controlled environment.

But there's a natural selective pressure, and it's plausible that mosquitoes would eventually evolve their sensors to become attracted to DEET, over multiple generations. And with each generation lasting only 20-30 days and a single female mosquito laying 300-500 eggs in total, they can evolve orders of magnitude faster than us.

YeGoblynQueenne2• 2 months ago

If all they wanted to achieve was attract mosquitoes they could have just hired me to stand there for a few minutes. Very reasonable rates, guaranteed mosquito attraction or your money back.

But if what they wanted to achieve was to show how to make DEET ineffective then I hope their entire research department is proscribed as the terrorist organisation it really is by every nation on Earth.

DannyBee2• 2 months ago

I always found DEET interesting because it is a toluene derivative, which is why it is remarkably effective at destroying plastics and such, in addition to being a repellant. Yet people spray it with abandon and then wonder what melted their watch or glasses or …

Associative learning turns DEET from aversive to appetitive in Aedes aegypti

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