There are a number of species of animals which have evolved to use parasitic methods to rear their young. You’re probably the most familiar with the cuckoo, which notoriously lays its eggs in the nests of other birds so that their chicks will overpower the mother bird’s own chicks and get the benefit of the mother bird’s feeding. There are also several varieties of wasp, including the aptly-named cuckoo wasp, which use similar methods.
This article at Nature News (the public website of the scientific journal Nature) tells us that a species of butterfly called the Alcon Blue also uses brood parasitism: its larvae (caterpillars) work their way into the nests of wood ants and through the use of a chemical they excrete mimic the smell of the ants’ own larvae. The ants are thus tricked into thinking the caterpillars are their own offspring and feed and care for them until they pupate. But what’s unique about this symbiotic relationship is that the ants keep evolving new chemical scents that let them distinguish between the ant and butterfly larvae. And, in response, the butterflies counter-evolve to keep up with the changes, resulting in a sort of escalating evolution. Evolutionary biologists call this co-evolution the “Red Queen Theory”.
Unless, of course, you’re a creationist like Mike Huckabee, and believe that there is no evidence for evolution.
