This article is reposted from the old Wordpress incarnation of Not Exactly Rocket Science.
An ant nest is sheltered, well defended and stocked with food, but one that takes time to build and protect. That's why some species of ants don't bother to do it themselves - they just squat in the nests of others.
These ants are 'social parasites' - they don't feed off their hosts' tissues, but instead steal their food, sleep in their homes and use their resources. They're like six-legged cuckoos
An ant colony is too dangerous a target to victimise lightly and the social parasites use several tricks to stop their hosts from ripping them apart. Some escape reprisal by chemically camouflaging themselves, either by mimicking their hosts' odour, or by acquiring it through contact.
This specialised strategy ties the parasite's fates into those of its host. Both are caught in an evolutionary arms race, ...
