Question

What is the nature of substance secreted an ant bite

Answer 1

it is formic acid formed by ants

Answer 2

Formic acid is an irritating chemical present in the sprayed venom of some antspecies and in the secretion released from some stinging nettles. It's dangerous at high concentrations, but at low concentrations it's very useful. Humans use formic acid as a food preservative, since it's an antibacterial substance.