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One-Way Ant Hill Fence   (+2)  [vote for, against]
A one-way fence for placing around an ant hill

The purpose of this fence is to allow ants to leave a colony, but not allow them to return. Allowing them out, but not in, seems a better alternative than trying to keep them inside, because they would probably dig their way out as part of an instinctive defensive measure. Ants trying to return to the nest though, would probably not be in defensive mode and therefore wouldn't try to dig their way past the fence. Keeping ants away from a nest would starve out the colony.
The fence would be in the form of a hollow plastic ring, having a triangular cross-section, but without a base (to make manufacture easier). Its inner wall would slope gently outward (30 to 45 degrees) and its outer wall would be vertical, or perhaps slope outward to produce an overhang. The important thing about the outer wall, is that it must be too steep and slippery for ants to climb up. It would be from one to four inches high and have three or more one-inch spikes to hold it in place.
When applied, the ants would sense the vibrations and pour out of the nest (and the fence) to defend it, producing an initial rapid reduction in population. After the ants had calmed down, the remaining ants would gradually leave to gather food, never to return.

Added Dec 3, 2011:
Make sure they have food available in large enough particles that the added weight is too much for them to keep their grip while climbing up the outer side of the fence. There should be enough smaller particles of the same food mixed in so that some of the ants can get back to the nest and maintain an active trail.
-- Alvin, Dec 02 2011

Ant Lion http://youtu.be/EnVO8mXPAzg
We used to play with these when I was a kid. Fed them ants until they couldn't eat any more. [Klaatu, Dec 02 2011]

Insect-a-Slip Insect Barrier — Fluon http://www.bioquip....oduct.asp?pid=2871A
It might not be perfect, but many ant keeepers swear by it. [Alvin, Dec 03 2011]

Lobster trap technology http://images.searc...&.crumb=qPfvPW7nTl.
One-way valve designed to control the flow of living creatures [ye_river_xiv, Dec 04 2011]

Diatomaceous Earth for killing ants. http://www.vegetabl...on-toxic-ant-killer
[AusCan531, May 26 2015]

vegetable oil https://www.youtube...watch?v=REQ2Oa1ldbE
[pashute, May 26 2015]

Ants can’t stick to Teflon https://www.popsci....ant-stick-to-teflon
[AusCan531, Apr 07 2019]

why not a mini ant tread mill that moves faster than ants... once they leave they could never go fast enough to get back in.
-- metarinka, Dec 02 2011


This will work, except for the ants part.

Having kept several thousand head of ant, I have devoted several tens of hours to devising a means of keeping the ants in while the lid of the antarium is off.

The starting point is vertical glass walls, which of course are no barrier to any self-respecting ant.

I then bought some Teflon solution and applied it in a neat band around the top. At this, the ants merely laughed.

Then some super-hydrophobic glass treatment from the lab. Even tiny water droplets just slide off this surface. The ants, however, took it in their stride.

Eventually, I implemented a mini electric fence (two parallel strips of adhesive copper foil, with about 12V across them). The ants did not laugh at this; they merely waited a few days until the copper had tarnished a little.

So, good luck making a too-slippery-to-climb ant- wall.
-- MaxwellBuchanan, Dec 02 2011


If you were farming ants why would you not extract their danger indicating pheromone and apply this to the glass?
-- rcarty, Dec 02 2011


I'm trying to picture [MaxwellBuchanan]'s ant ranching cowboy clothes...a thread ant lasso and tiny ant spurs? Would the effect be anticlimactic?
-- normzone, Dec 02 2011


//If you were farming ants// not so much farming as not-farming.

//I'm trying to picture [MaxwellBuchanan]'s ant ranching cowboy clothes.// [norm], [norm], [norm]. It would be better for everyone if you didn't.

//Would the effect be anticlimactic?// As far as I'm aware, I've had no impact on global warming.
-- MaxwellBuchanan, Dec 02 2011


I didn't realize ants could crawl up such slick surfaces. What some species will avoid though, are cleansers like Old Dutch cleanser, Comet and Ajax. If there was a way to keep a ledge around the fence covered with cleanser, maybe that would keep them out.

I've only tested Old Dutch cleanser, but others report success with other cleansers. One person claimed that they like the stuff though.
-- Alvin, Dec 02 2011


Yes, a moat is the classic antiant device.

Perhaps a ramp that the ants can fall off of, depositing them on the far side of the moat?

[mb] gold foil would have worked better than copper.
-- pocmloc, Dec 02 2011


Mother nature provides a moat of her own. <link>
-- Klaatu, Dec 02 2011


Why wouldn't the ants caught outside just tunnel back in?
-- Alterother, Dec 03 2011


Alterother,
//Why wouldn't the ants caught outside just tunnel back in?//
I doubt ants would have the sense to notice that their attempts at reentry by crawling were futile.
-- Alvin, Dec 03 2011


it's sort of a divide a conquer idea ...[+] but only because this is half bakery. If it was full bakery I'd expect the "one way" bit addressed better.
-- ixnaum, Dec 03 2011


//Why wouldn't the ants caught outside just tunnel back in?//

Because the moat is ringed with magnifying glasses, so the ants are fried in the sun.
-- Klaatu, Dec 03 2011


Hmmm... this sounds like a job for the Bugrowave...
-- Alterother, Dec 03 2011


Notice the solution for climbable surfaces added to the article.

Also, here's one way to produce an ant barrier:
Compress a mixture of a substance like talcum powder along with a binder into a solid mass. The grains should be bound so weakly that they pull apart under the weight of an ant. The binder should be petroleum based for use in wet conditions. Getting just the right bond strength is the tricky part.
This material could be used in layers thick enough that the ants would take a long time to wear through it.
-- Alvin, Dec 04 2011


The weight of an ant is so small, that the material has to be right on the edge of instability. Best way to keep it that way might be a simple berm of granular material, without binder, which would continually adjust itself (via self-similar micro-avalanches) so that it was always precisely at its angle of repose.

Problem is, sand granules are obviously too big for this; sufficiently small granules, on the other hand, might blow away in trivial air currents. It's an empirical question.

Another approach: a solution of nitrogen triiodide and sucrose painted onto the surface, and allowed to dry.

But [pocmloc]'s gold foil suggestion seems the most promising.
-- mouseposture, Dec 04 2011


//But [pocmloc]'s gold foil suggestion//

After the failure of the copper foil, I did set up a new electric fence consisting of two parallel copper rods which I gold-plated. It worked for a while, but eventually even gold gets a layer of crud on it (or maybe my plating wasn't very good).
-- MaxwellBuchanan, Dec 04 2011


What about a foam or aerogel into which the ant sank untill just sufficient had been compressed beneath it to support its weight. It would then only be able to flounder around, without gaining enough purchase to climb out.
-- mouseposture, Dec 04 2011


I can't help thinking that it would be kinder to just use a flamethrower.
-- MaxwellBuchanan, Dec 04 2011


Isolate the substance secreted by the inner walls of a pitcher plant and use that.
-- 2 fries shy of a happy meal, Dec 04 2011


Might I suggest a more dome-shaped design, with many lobster-trap-entrance shaped cones going out of it?

Most living organisms seem to have difficulty traveling both ways through cone-shaped openings made out of stretchy material or individual sticks. They can usually enter from the base and leave from a hole in the apex, but a suitably sized hole in the apex will often prevent travel from outside the apex down to the base.

I suspect some sort of silicon mold might be able to produce the desired product with openings in a suitable size. Finding ALL the possible entrances to the ant hill could become an issue though.
-- ye_river_xiv, Dec 04 2011


This principle has been used to remove bee colonies from inaccessible spaces, such as wall cavities. The non-return system was a cone of fine wire mesh with a small exit hole for the bees. The goal was not to destroy the colony, but to help relocate it into an artificial hive.
-- spidermother, Dec 06 2011


//I have devoted several tens of hours to devising a means of keeping the ants in while the lid of the antarium is off.//

I've been worrying about [MaxB's] problem (It has been a quiet day at work and I've been fighting a months-long battle with ants at home and in the office). I think an antarium could be lidless if one rigged a series of downward facing air nozzles around the perimeter. An aquarium's bubbler with a perimeter ring of perforated hose would do the trick. A laminar flow device would be ideal.

A further enhancement would be to have the air nozzles shut off when your alarm clock sounds in the morning causing one to leap out of bed to reset the blessed thing before the @##$%-ing ants escape.
-- AusCan531, Mar 18 2013


What was wrong with the old-fashioned method of using a perimeter ring of borax (boric acid) to contain an ant colony and/or prohibit ants from entering your home?
-- jurist, Mar 18 2013


Too simple for the halfbakery.

I'd propose using a double-walled approach, with an inner ant-containing tank magnetically levitated inside the outer tank, with more than an ants' worth of clearance between the two at all points.
-- Wrongfellow, Mar 18 2013


// Having kept several thousand head of ant, I have devoted several tens of hours to devising a means of keeping the ants in while the lid of the antarium is off.

I've been lying awake at nights worrying about this problem [Max] (its more interesting than my many other problems apparently.) And think I have come up with a solution. I've been battling ants in the office kitchen for several years now and have declared complete, total and utter victory on many, many occasions so have become something of an expert in ant personnel warfare.

One of the keys to defeating a foe is to surreptitiously observe them and learn their ways. This is what I was doing when I made a critical observation after moving the refrigerator to plug up their tiny ingress point in the baseboard. Ants don't like dust! Specifically they don't like the household dust found under fridges, beds etc which is the precursor ingredient for dust bunnies (or dust buffaloes in my case). Its fineness and fuzziness is apparently unpleasant, or perhaps even dangerous, to the otherwise persistent little blighters who go to great pains to avoid the stuff.

If you still have your antarium, procure some double- sided tape and apply one side to the accumulation of dust fuzz under one of your fridges (summarily firing the staff in that wing as a warning to others) then you can apply this miniature kraal (anti ant crawl kraal?) around to top perimeter of your ant ranch enclosure. Please make this your top priority then report back to the Halfbakery for a debrief ASAP.

If that doesn't work I suggest diatomaceous earth as that is fatal to them although it might be a tad trickier to affix in place.
-- AusCan531, May 24 2015


Sadly the antarium is no more.

Howevertheless, I am intrigued by your statement that diatomaceous earth is fatal to ants. Have you a reference?
-- MaxwellBuchanan, May 25 2015


Diatomaceous Earth is basically the 'ant powder' you buy from the hardware store. Lasts MUCH longer than those surface spray-on insect killers (lasts longer in potency - not how long the ants stay dead as that's pretty much consistent). [LINK]
-- AusCan531, May 26 2015


oil does the trick. youtube for it...
-- pashute, May 26 2015


What's wrong with just keeping an aardvark?
-- xenzag, May 26 2015


hmm, figure out how fast ants climb a glass wall, look up how long ants live, make wall tall enough so that no ant could expect to make it up in a single lifetime.

This is also a metaphor for human space travel.
-- bs0u0155, May 26 2015


//What's wrong with just keeping an aardvark?//

You have no idea how flatulent aardvarks can be, or how destructive they can be with their digging. In the end we had to let all ours go. The neighbouring golf course has now banned me for life.
-- MaxwellBuchanan, May 26 2015


Coming back to the ant problem - I feel almost somewhat sure that it should be solvable with topology.

What's needed is a surface curved in such a way that any path will eventually lead you back the way you came**. Most ants* are notoriously averse to jumping.

(*Before you point out that the Galapagos Palm Ant can jump up to 2 metres vertically or 3 metres horizontally, let me mention that the Galapagos Palm Ant can jump up to 2 metres vertically or 3 metres horizontally.)

(**I know this to be possible, because that is how Milton Keynes is designed.)
-- MaxwellBuchanan, May 26 2015


Continuing our conversation from Dec 2011, [MaxwellBuchanan] apparently even ants can’t climb spray on Teflon [link]
-- AusCan531, Apr 07 2019


A small no-entry sign in Antish on the outside of the colony?

Nb a certain orange-faced person is cribbing all ideas on this site. Remember to speak loudly and slowly when you say "of course the best way to make a barrier is red mercury' etc.
-- not_morrison_rm, Apr 07 2019


Is moat on a vertical wall possible? If the rim had small holes that contained water that, because cohesion and adhesion, doesn't flow. An ant trying to step past the holes would trigger a drip and be washed back in a torn bubble of water.
-- wjt, Apr 08 2019


Well, water is magnetic just about, so could be done...but ants have water in them, so they might enjoy standing on a vertical moat.
-- not_morrison_rm, Apr 08 2019


Just put a normal horizontal moat around the top.

// This principle [of cone-shaped one-way passages for animals] has been used to remove bee colonies from inaccessible spaces, such as wall cavities. The non-return system was a cone of fine wire mesh with a small exit hole for the bees. The goal was not to destroy the colony, but to help relocate it into an artificial hive. //

How did they get the queen to move?
-- notexactly, Apr 09 2019


//Just put a normal horizontal moat around the top// Nice, an ant infinity pooling.
-- wjt, Apr 10 2019



random, halfbakery