Bugs, beetles and crickets

Read about this group on the north and south coastal invertebrates group page.

The blue ground beetle is Britain’s largest beetle. It likes mild conditions and is found in the south-west of England and south Wales in old, damp woodlands and wood pastures that have  a sparse shrub layer and lots of dead wood and slugs.

Adults and larvae both eat slugs, mainly the tree slug and the ash-black slug, which the adults hunt for on tree trunks at night. It’s thought they lay their eggs in the soil. They hibernate under bark or in dead wood on trunks, branches and stumps.

Over half of the blue ground beetle sites are in Devon. The largest is in the upper Dart valley and there are others in the upper Bovey valley and Dendles Wood, with smaller colonies known from Ivybridge, Houndstor Woods, Shaugh Priors and the Tavistock area.

One of the reasons blue ground beetles are so rare is because they can’t fly and so can’t move between fragmented habitatsThe natural environment in which an animal, plant or other organism lives. More. The woods they live in are unlikely to be at threat from loss, so a key issue is their condition, including loss of dead wood and invasive speciesA group of similar organisms that can breed and exchange genes. More such as rhododendron. Most of the beetle’s breeding sites are in favourable condition.

This nationally threatened beetle is only found in Sussex, Buckinghamshire, Cambridgeshire and Devon. It likes dry, species-rich grasslands on chalk or limestone soils.

All three of its sites in Devon are on the Torbay limestone grasslands, where it’s sometimes found under reptile mats. However, it’s thought one site has been lost to housing (where – check this) and the other two may be threatened. A key issue is lack of grazing as it’s hard to graze the urban Torbay sites. See Grasslands for more information. 

The apple lacebug feeds on the sap of apple trees in orchards and wild crab apple trees in open woodland, wood pasture and on outgrown hedgebanks. They particularly favour old trees in relatively open, unshaded situations with clean air that allows lichens to grow on their branches. Adults overwinter under the bark or in rotten wood and emerge in May to mate and lay their eggs on fresh leaves.

The apple lacebug population has contracted sharply across the UK. All recent records are from Devon and Cornwall and there are none from its former sites in southeast England.  There’s been no systematic survey for the apple lacebug and its only known sites in Devon are Ashclyst Forest CWSCounty Wildlife Site More, Compton Castle CWSCounty Wildlife Site More and Sydenham Damerel near Tavistock.

Read more on the Sidmouth to Dorset coastal wildbelt group page.

Read more on the Start Point to Bolt Tail invertebrates group page.

Read more on the sand dune invertebrates group page.

The scaly cricket lives on shingle beaches where it forages for food at night. It lays eggs in driftwood which hatch after around a year, generally in June.

It is classed as vulnerable to extinction and is only known from three sites in England and Wales: Chesil Fleet lagoon in Dorset, Branscombe beach in Devon and Marloes Sands in Pembrokeshire. The main issues for the scaly cricket are loss of habitat through winter storms, pollution and sea level rise. However the Branscombe population is monitored by the County Recorder and other volunteer experts every five years and a 2019 survey showed that the population is healthy. As the population is isolated potential genetic inbreeding is also thought to be an issue. Buglife therefore carried out an enhancement introduction programme in the mid 2010s.

No specific actions are currently needed for the scaly cricket other than to continue monitoring to ensure that there are no other issues such as habitat disturbance or removal of driftwood.