I've heard ants are attracted to electricity, but never seen any evidence until today. I started my tender vegetable seedlings inside my spare room a couple of months ago. Once they had germinated, I set them up under lights plugged into a timer. Today, I moved the plants outside for a bit, hardening them off in preparation for setting out after Memorial Day.
Since the lights were no longer needed, I started breaking everything down to store for another year. When I unplugged the timer from the wall plug, tiny little piss-ants came just pouring out of it. I ran to get that timer outside, ants swarming over my hand (and biting, too! nasty little creatures!). I set it out in the middle of the yard on an upturned bucket, and went back in to take a second look at the outlet. There were a few ants wandering around the plug, but it looked like the majority of them had been inside the timer. When Aries got home from work, he took the outlet faceplate off and pulled the outlets out of the junction box a bit (he's a facilities engineer at work, so knows about safely working around electricity).
That wall is an outside cinder block wall, so there are hollow spaces inside, built on a cement slab floor. Checking with a flashlight, he could see some more ants at the back of the box, using the wiring for a highway, probably coming up inside the wall from the dirt outside through a crack in the mortar. We vacuumed up all we could see (but they didn't seem to have come inside beyond the plug and the timer connected to it), and then he sprinkled a bit of boric acid inside the box. He left everything apart so we can check it again tomorrow.
Outside, the timer rattled inside when I shook it, and the ants still kept pouring out. Knocking it against my hand over the white bottom of the bucket, I shook out a bunch of pale little ant eggs. They'd turned that timer into a nursery! I shook it and rapped it until it seems like it's empty, but it's going to stay outside for a while anyway. Yuck! I'm just amazed that the timer kept turning - it kept perfect time. (Note: Aries took the timer apart and cleaned it out completely - now I can put it away without getting the shudders.)