Male Large Blue Butterfly (Maculinea eutryphon / arion) collected in 1865. It is here surrounded by other extant UK blue butterfly species. The large Blue was first recorded as a British species in 1795 and went extinct in the UK in 1979. This was mainly due to over-collection and loss of habitat. The last locality being Dartmoor in Devon. The Large blue was reintroduced to the UK using a close relative from Sweden, M. arion. Numbers reached over 10, 000 flying by 2006. Larvae spend time underground as brood parasites on the grubs of the red ant, Myrmica sabuleti. Loss of these ants' habitat ultimately resulted in the extinction of this subspecies (partly because protected sites were left ungrazed, which did not favour this warmth-loving ant). Successful reintroduction has focused on the ants as well as the butterflies, and follows the observations of entomologist Jeremy Thomas.