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