Carnivorous Plant Has Bodyguard Ants

The carnivorous pitcher plant Nepenthes bicalcarata isn't that terrifying of a deathtrap: its pitcher leaf isn't slippery and it doesn't have the corrosive slime that kill its victims quickly.
But it does have something that makes up for all those weaknesses: vicious bodyguard ants!

The carnivorous plant has swollen tendrils at the base of each pitcher that serve as homes for the insects, and a food source in the form of nectar secreted on the pitcher rims.
In return, the ants apparently provide a host of services for the pitcher plants. They clean the pitcher mouth to keep it slippery enough to help catch prey. They attack weevils that would otherwise munch on the plant. They cart off the remains of large prey from the pitchers that would otherwise rot. They lie in ambush under pitcher rims and systematically attack any of the plant's prey that attempt to escape the traps. And their droppings fertilize the plants.

More