Honest Liars

A yellow and black band on an insect is a sentence addressed to birds. Its meaning is roughly: swallow me and regret it. Because a young bird has to learn that lesson the hard way, on a real mouthful, the warning works only if it is usually true.

Which is what makes the hoverfly interesting. It has no sting and nothing unpleasant to offer, yet it wears the wasp's colours and is left alone. It profits from a reputation it never earned and pays nothing for the lesson that protects it. The arrangement is parasitic on honesty.

It is also self-limiting. The mimic's safety rests on the odds a predator faces, and as harmless copies grow common relative to genuine wasps, more encounters end pleasantly and the band loses its force. Deceit of this kind cannot spread far without destroying the credit it draws on, which makes it rare in nature: a cheat that must stay rare to keep cheating.

The other strategy is stranger. Several species that are all genuinely unpleasant sometimes converge on one shared pattern, so a bird's single bad experience teaches it to avoid them all. Nobody is lying, and each species is spared its share of the tuition. Here the resemblance is not theft but a bill split between honest neighbours.