Ant lion pupal sac by Michael Kirby
Lurking in the sand are creatures which have been described as ‘demons in the dust’. They are the larvae of a member of the lacewing family that prey on small invertebrates which stray into their traps.
The ant-lion detects the movement of woodlice, ants and other prey using tiny hairs on their body and either wait for them to fall to the bottom of the trap or flick up sand to knock them down. These unlucky creatures are grabbed in the larva’s powerful pincers and the juices sucked out of their bodies via a tube. The traps, often all that is seen of the ant-lion, are conical pits which it forms by flicking sand outwards with its head. They are found in colonies in loose, dry sand at the base of small south facing sandy cliffs protected by overhanging vegetation or on the root-plates of fallen trees. The larvae take two years to mature in the ground where they pupate and emerge in late summer as winged adults which, in their brief lives, mate and lay eggs in the sand. They are sometimes attracted to moth traps.
The Suffolk Sandlings is the only confirmed breeding area in Britain for this unusual creature. It has now been found on a number of Sandlings heaths and in local gardens, with new sites being added all the time as interest in and knowledge of this species increases. Populations are monitored by counting the number of pits.
Ant-lion can be found on the following Trust reserves - Sutton and Hollesley Heaths, Blaxhall Common and Sizewell Belts. Habitat management to encourage this species includes maintaining open eroding sandy cliffs with some protection from trampling. At Sizewell Belts we had a problem with rabbits digging up the ant-lion habitat sites so the wardens there have given them a bit of a helping hand. Sand has been piled on to concrete against a south facing barn wall which has an overhang. The concrete prevents the rabbits burrowing, and last summer we had over 1000 ant-lion pits so they obviously love their new home!
Ant-lions are one of many specialist heathland species benefiting from the large-scale heathland restoration undertaken by the Trust over the past 25 years. They depend on the open heathland that is created by clearing trees and scrub and maintained by pony and sheep grazing. The Sandlings Living Landscape vision aims to increase the amount of heathland within the Sandlings and link heathland areas creating more habitat for species like the ant-lion which are not found anywhere else.