Sit yourself down comfortably while I tell you a bedtime story. It's the story of some little ants that lived in a garden. They scurried around doing ant things, as ant are wont to do, for a long time, not really bothering anyone much. One day some gardeners decided these ants were responsible for the damage to the trees. Maybe they were, maybe they weren't, but there was a simple solution. Get rid of the ants.
Getting rid of ants is not easy, but as every gardener knows, the best way is to get some nasty poison into the nest. So that was what they did. And they killed the Queen ant. The rest of the ants scurried about very confused for a while and the gardeners killed a few here and there and tried to get them under control, but after a while they more or less gave up with that, and dumped poison in random places instead.
Some other, bigger ants had been hanging around, causing a bit of a nuisance, but while the Queen was there they weren't too big a deal. And although they caused some problems, damaging the lawn a bit and biting the gardeners they were a bit scattered and not very well organized, and then the gardeners killed their Queen too.
Which was the perfect opportunity for the fire ants to move in. They came out of nowhere and swarmed across the lawn killing other ants and all the other insects too, as they went. Fearless and apparently crazy, with no sign of their Queen, they seemed to want nothing more than to take over the entire garden.
The gardeners realised they had a much bigger problem on their hands now, and began to wish they'd never interfered in the first place. If they'd left the original ants alone this would never have happened. Now all the ants were upset with the gardeners and biting them every chance they got.
Of course, something had to be done about the fire ants, but what?