Some species of ants, notably stinkin' fire ants are attracted to electric fields. Here's an old article where experiments confirmed they liked them:

http://findarticles.com/p/articles/m...136/ai_8243169

It acts like some sort of drug, and they will forego food and water and normal colony activies, starving to death just to get their electric fix. What they like is relatively strong electric fields, and that means regions of high voltage gradients, such as the tight space between contacts in switches and relays. Once they discover such a zone, they apparently mark it and bring all their buddies who swarm all over it. It can be a PITA to keep them away once they learned of a particular location.

Anyway, I bring this up because just a few hours ago, I went to the bathroom and discovered I had no water pressure. I'm in the country on a well, and just as I suspected, fire ants had gummed up the contacts in the pressure switch.

The well is on a "general services" pole service next to the well house. Besides the pressure switch inside the well house, they were all over the main box and the meter box above it. It was ridiculous. I had to open everything up and spray ant killer, and then clean the contacts on the pressure switch. Luckily the contacts on the pressure switches are exposed where you can get to them, unlike some relays and switches which can't be opened, requiring the whole thing to be replaced.

Now, what I'm going to have to do is go down there every few days and respray with ant killer or they'll gunk it up again now they learned where it is.

This has happened with that well several times over the years ever since the fire ants invaded locally. Several years ago they got into a wall switch box out in my little gargage (out bulding). I had to replace the switch several times as I fought to keep them from coming back.

And finally, I've read that they're having problems with another "foreign" ant species called "crazy ants" (tiny little buggers that run around helter-skelter, rather than in the orderly fashion of most ants) in Texas. These things really love electrical and *electronic* equipment, even getting inside personal computers and other electronic boxes and just making a mess.

-Richard

I was reading some more, and apparently there's some controversy over whether or not the ants are actually attracted to electric fields. One theory is that a foraging worker randomly enters electrical equipment and manages to get shocked. When he does, he tries to sting what hurt him and releases "alarm" phermones. These chemicals call the other ants to deal with the threat.

I don't know if this has been resolved yet or not.


-Richard

The Caribbean crazy ant (for Paratrechina pubens). However, here in Texas, more specifically in the Houston area, the common name often referenced is the crazy rasberry ant (for Paratrechina sp. nr. pubens). thread, anent NASA

The things I get interested in sometimes .... The question of whether fire ants (Solenopsis invicta, sometimes called RIFA = red imported fire ant) are attracted to electric fields seems to be yes, they are.

Research on this was done by a MacKay and Vinson (and others), whose papers seem to be the most cited. I can't find the papers online myself, only references to them. They looked at fire ants as well as some native ant species.

There is some confusion. One of their papers was cited as showing *no attraction* to electric fields (by a Wiki article), when in fact that very paper found they were attracted. The trouble is the wording. They found no attraction to magnetic fields or "electromagnetic fields", but did to electric fields. By EM field, what is meant is generally RF or other time-varying propagating fields, not static or slowly time-varying fields. That's bad terminology, IMO, but it is used a lot.

Anyway, they set up colonies around some copper point electrodes, then turned on the voltage. When the voltage difference, AC or DC, reached
50V, the ants began to swarm over the electrodes, ignoring their normal duties. They ruled out a number of competing hypotheses, such as they were attracted to ozone (due to arcing during switching), 60Hz vibration (in iron cores), and some others. It seemed to be frequency independent, although they did find that ants retured to normal behavior after switching it off more quickly after exposure to DC fields than AC fields.

AC drives 'em wild. I'm recalling some more electrical infestations of fire ants I've had over the years. One was in an outside contactor enclosure controlling a 3-phase motor. I'd put a standard stop/start pushbutton assembly in the enclosure. One fine day I went to turn it on and nothing happened. Then I quickly jerked my hand back as I noticed fire ants started swarming out of the cracks (fast reflexes are a must when dealing with fire ants. ) You have to kill 'em before you can get in there to repair things.

Anyway, the hadn't infested the main contactor, just the little contacts in the pushbutton assembly. This was an industrial grade switch which could be taken apart, which I did. The contacts were completely gummed up with dead ant residue. The little buggers got up in there, and electrocuted themselves in the short air gap of those contacts, kept coming, and just messed it up. It took a wire brush and carburetor cleaner to clean it up.

And that agrees that they like electric fields. The field will be relatively higher between close contacts and sharp contacts and that's where they get. The main contactor contacts were much farther apart, double contacts per pole actually (armature basically pushes a little bar that makes contact between two points per pole), so the local field wouldn't be as strong there.

And that's where they were in the well pump pressure switch, swarming all over the close contacts, gumming them up.

-Richard

It's probably a good thing their carcasses don't conduct electricity or your situation may have been worse. I've seen what squirrels and raccoons can do to power substations but I've never heard of ants shorting out an electrical system. Those residential "bug zappers" pretty much depend on it the fact they can't.

The pheromone explanation seems more plausible to me than attraction to electrical fields.

I'm failing to understand the explananation differentiating eletric field from electromagnetic field. Especially when you are talking about 60hz AC. RF frequencies are going to be practically nonexistant and well below the 50 volt threshold which the research claims "attracts" the ants.

I am very familiar with conventional motor control and in residential applications such as you are describing, they would be across-the-line contactors. It is possible a variable speed drive may produce RF frequencies but they are not typically used in residential applications because of cost.

Do the ants swarm radio towers or high tension lines?

Yes, it's bad terminology. In my usage, an electric or magnetic field is a subset of the more general electromagnetic field. But that's the way its used sometimes.

Here's an article which refers to MacKay and Vinson, from 1997:

http://findarticles.com/p/articles/m...09/ai_n8760991

And yes, the contactor I mentioned above is a NEMA size 1, across the line (with electronic overload relay) controlling a 3HP 208V motor.

I'm going to ask some linemen I know if they've had any problems with fire ants in pad mounts. I seem to recall mention of fire ants getting in pad mounts, but I can't remember for sure.

-Richard

Oh yeah, they like padmounts:

http://www.wildlifeoutages.com/insects.html

Googling "fire ants padmount" will turn up a bunch.


-Richard

Based on the excerpt of the paper I would think warm, dry environments are favorable to the ants, but showing a preference to the high voltage side of transformers is ... well ... strange. And apparently they do short-out equipment!

Sounds like more research is needed and if you hear any more I would be interested if you posted it - but in the meantime - keep them critters south of the Mason-Dixon line, please.

Oh, and one more thing. As soon as possible, check all your grounds and make sure they're good. If the ants conduct, a pile of them could conduct 208 VAC out to the side of a motor housing or a switch box. It will knock you or someone else for a loop if you're not careful.

I wouldn't wish fire ants on my worst enemy. You want to watch where you step very carefully. Actually, they might just make it up north. Years ago, when they first started invading the United States (IIRC, they came in on South American cargo ship at a port in Alabama), they didn't think they'd make it up too far north because the winters would be too cold. But they did.

And various states and localities started fire ant "eradication" programs. That was soon changed to "control". Now it's just "management". Gosh time is flying, they've been firmly established here for at least 15 years.

They are very aggresive -- just poke a mound and millions swarm out in full attack mode. And what they do is swarm all over a victim before they bite. They'll be all over you before you know it, and then the leaders send out a little chemical signal to attack and they all sting at once. Each sting raises up a little pustule that burns like, well, fire.

Me, I've never been swarmed, but I've come close, and have been stung by a few of them at once. It ain't pleasant. A small percentage of the population is allergic (I think its possible to become progessively sensitized ot it, but I'm not sure) to the venom and they have killed people. I think I remember a local women dying after she got swarmed just a year or two ago.

Last year, I tried a new anti-fire ant product, a growth regulator hormone in a typical "grits" bait that worked pretty good. I just applied some last month around the yard. And yep, I'll be putting some around the well house as well.

The buggers are so clever that getting a poison in the colony to kill the queen is very difficult. She has a long chain of food tasters. Their sense of "smell" is to a dog as a dog is to us and they can detect certain chemicals in low concentrations. The workers bring food in and it goes through a chain of feeding to various larval stages inside the colony and the workers themselves before it finally gets to the queen. If anything happens to them, they know who ate what and throw out everybody who touched the suspected food source.

So to get a poison in, it's got to be undetectable to the ant and slow enough to get to the queen before they notice anything is wrong. And then even then, they multiply so prolifically it's a losing battle.

The growth regulator approach messes up the life cycle, preventing the larva from maturing at the right time, and it seems to do fairly well. Other research is looking at bringing in some of the fire ant's natural South American enemies (but taking care not to create a monster with that). Let's see, Clemson has being doing some research on some fly that lays eggs in the workers......

-Richard

And if you think fire ants are bad, there's another South American species that we hope never gets here. It's called a "bullet ant". They call it that not because it resembles a bullet, but because a single sting feels like getting shot by a bullet.

The locals use it in some "manhood initiation" ritual. A boy who wishes to be considered a man must stick his hand into a "glove" full of them and endure the stinging for several minutes. Me, I'd remain a boy, I think.

-Richard

In my experience, they don't conduct enough at low voltages to do any damage. They do conduct enough to eletrocute themselves, and presumably enough to shock a person -- all it takes is a few mA, even less with some people to feel it. I'm certain that dead fire ant goo would conduct enough to shock you, especially is still moist. The problem is they get in between contacts and prevent them from conducting. That goo is also corrosive. That may be responsible for any real shorting out incidents more than anything else (and the general public uses "short" to mean "it don't work", as you know I'm sure. )

High voltage would be another story though. "Rubber tires" insulate at low voltages (by low voltage, I mean less than 600V which is the standard for "low voltage" in power terms, but really 1kV is the cut off -- if an insulator is good for a volt, it's usually good for a kV --- but don't bet your life on it, though, and always respect insulation voltage ratings. How long something will withstand a kV is another question) They don't do so good at 7200V, as a lineman once showed me. They had a little mishap and he showed me the arc marks on the truck tires. Hissed and popped liked crazy, he said.

-Richard

What about putting poisoned bait near there? That might work longer term.

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Or sealing the thing so they can't get in...

You're right, publius, re progressive sensitivity. My first few stings after being torn from my roots in CT and displaced to SC were painful but soon healed. The last sting caused my right hand to swell to about 50% larger than normal.

The only place in the South I'd like to return to is the mountains of Tennessee/North Carolina. The house my fiancée and I had up there saw snow 4 months out of the year and no fire ants.

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To me only one word describes a lineman - Crazy! But I respect them immensely. One guy I know describes working on a 138KV line in the rain while "blue devils", their words, danced up their arms. They would cringe not knowing if the devils were going to arc over on to their faces or necks. They clamp their buckets to the line to put everything at the same potential. I suppose under the right circumstances, dirt, mud, who knows, you could arc across the tires. Me, the hair rises on the back of my neck just walking into a 138KV substation, but more deaths and injuries occur at lower voltages. Somehow they don't 'seem' as dangerous so electricians may get careless.


As for your ants, Delvo's suggestion is good. Fill the openings with duct seal and put gaskets on your NEMA 1 enclosures. Maybe it will help keep them out. Hopefully nothing needs ventilated - except the motors.

If the building has a foundation, spray the skirt where the wood meets the cement with resmethrin or bifenthrin or hornet kiiller (piperonyl butoxide)...they won't cross that line for a long time. Ants must drink, if you salt their water supply...sinks, tubs, they disappear quickly too.

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Hornet related story.
At one point in time, I had strung wire around the top rail of our horse paddocks and attached a standard "electric fence" device to them. There was, unknown to us, a hornet nest/hive in the ground at the far edge of the property, and the fence and wire was just above it.

I had first noticed something weird when I had wandered towards that back corner, and saw a mound of dead hornets on the ground. Up on the wire was a very angry swarm of hornets furiously attacking the wire. The electrified wire is, of course, insulated from metal pole, but the hornets were swarming around the base of the conductor and completing the circuit between the wire and the fence. Every 10-20 seconds, it would arc, killing a handful of hornets, which dropped to the ground.

I can only surmise that some improbable event caused the hornets to mass on the conductor, starting the first kill. Pheromones, or some other hornet-related trigger, caused the rest to go into full defense mode.

The end result was many hours of entertainment with friends and family. Of course, the nest/hive was soon depleted.