Violet Dor beetle ( Geotrupes mutator)

Violet Dor beetle (Geotrupes mutator)

Over 600 invertebrate species have now been recorded at Knepp.

Removing pesticides and avermectins, and leaving deadwood on the land, has triggered a rise in notable beetles: the first record in Sussex for 50 years of the violet dor beetle (Geotrupes mutator - a type of dung beetle); the rare click beetle (Calambus bipustulatus) whose larvae live in the soft, rotting stumps of old oaks; and the steely blue beetle (Korynetes caeruleus), which feeds on the larvae of wood-boring insects.

Mayflies and dragonflies throng the messy, vegetative margins of our lakes and ponds now rejuvenated by clean water. Banded and beautiful demoiselles, particularly sensitive to pollution, flit in hundreds over the streams and the surface of the river Adur.

Rarer species like the scarce chaser, a blue-eyed dragonfly found only in six places in Britain, have appeared out of nowhere. 18 were counted here in a single day.

Butterflies are rising in number and variety. The first survey of the North and Middle Blocks in 2005 recorded 13 different species; by 2014 we had 23. Surveys of the Southern Block, begun in 2012, increased the tally of butterfly species for the whole of Knepp to 34.

Some of them are new arrivals, like the marbled white (first recorded here in 2005), the small heath (another species deceptively tagged to a particular habitat) and the dark green fritillary (first recorded here in 2015). And some – like green-veined whites, Essex skippers and, of course, purple emperors – have exploded in numbers. In 2015 Neil Hulme of Butterfly Conservation counted 790 small skippers – a spectacular increase from the 62 he counted the previous year which was, in itself, a great year for butterflies.