Queen’s executioner beetle Megapenthes lugens, Windsor Forest and Great Park SSSI, Berkshire A large, nocturnal beetle that is thought to feed on the larvae of other beetles as well as flowers, it makes a distinctive clicking sound as it escapes from predators. Grows to about 3cm long and lives on the decaying trunks of beech and elm trees. It pupates in the autumn before overwintering as an adult inside its pupal case. Now so rare that it can only be found at this site in the UK

Photograph: Frank Blackburn/Corbis