David Attenborough's Life Stories - Large Blue

Series of talks by Sir David Attenborough on the natural histories of creatures and plants from around the world. The Large Blue butterfly died out in Britain in 1979, but why? Investigations pointed to a complex life cycle linked to a single species of ant. With this knowledge the Large Blue was re-introduced into the British countryside, but there is a sinister twist in the tale, in the form of a parasitic wasp.