If “cyanide two-ways” sounds like an unappetising dish, you’d do well to stay clear of the bird’s-foot trefoil. This common plant flowers throughout Europe, Asia and Africa, and its leaves are loaded with cyanide. The plants are also often crawling with the caterpillars of the burnet moth, which also contain a toxic dose of cyanide

The poisons in the insect are chemically identical to those of the plant, and they are produced in exactly the same way. But both species evolved their cyanide-making abilities separately, by tweaking a very similar trinity of genes. This discovery, from Niels Bjerg Jensen at the University of Copenhagen, is one of the finest examples of convergent evolution – the process where two species