...Service personnel in Texas have reported that fully one third of all summer repairs stem from ants shorting out terminal blocks. They also have been found to have set up housekeeping in televisions, well pump controls, telephone junction pedestals, airport runway lights, utility watthour meters, electrical plugs and lamp sockets, computers, and transformers-where they prefer to nest on the high-voltage side. Why are imported red fire ants attracted to electric fields? No one is yet ready to offer a theory. But biologist Dr. William P. MacKay of the University of Texas at El Paso and entomologist Professor S. Bradleigh Vinson of Texas A&M have succeeded in eliminating a number of possible factors.
They have found fire ant behavior does not correlate with a-c frequencies, or with the presence of ozone, electromagnetic or magnetic fields. Nor is the type of insulation used on wiring a factor. In tests up to 140V a-c and 350V d-c, both attracted almost the same number of ants at the same voltage and distance. However, they did find that when electricity was turned off, ants attracted to d-c power dispersed more rapidly than those who had been experiencing the nirvana of an a-c source. While the Texas researchers still don't understand the reasons why the ants have a fatal attraction to electric fields, they have been able to devise successful control techniques. Based on their studies, they recommend using terminal cap protectors to prevent bridging, and denying entrance to the insects by enclosing mechanical relays in metal or plastic cases and sealing them, as well as all entrances to padmounted equipment, with epoxy cement. In laboratory tests, silicone rubber sealants and roofing cement proved ineffective."