‘Alien’ predator threatens butterfly

One of Britain’s favourite butterflies may be being killed by a parasite that behaves like the monster from the movie Alien, experts say. The small tortoiseshell, right, has suffered a dramatic decline in recent years and it is thought that a tiny parasitic fly, Sturmia bella, is the cause. The butterfly caterpillars eat the fly’s eggs, found on nettles, which then hatch, killing the host. The charity Butterfly Conservation and Oxford University’s zoology department are conducting research to find out if the fly is to blame.

http://www.timesonline.co.uk/tol/news/environment/article3642889.ece