Brett Westwood encounters the large blue butterfly on the Somerset Downs, which was reintroduced 25 years ago after being declared extinct in 1979. It has become established there with the help of scientists who have unravelled its bizarre, carnivorous life cycle. The large blue's caterpillar spends most of its life in the nests of ants who milk it for its sweet honeydew, but as Brett discovers, the ants get more than they bargained for. Show less