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