Insects - Beetles

A rove beetle Actocharis readingii - Red listed and nationally rare

This small staphylinid beetle lives under stones between the tide lines on sandy shores. It has recently been discovered in south-west Wales but is otherwise known only from the Channel Islands (1 hectad), Cornwall (2 hectads) and Devon (8 hectads). Devon is, as far as is known, the British Isles stronghold. However, it is probably under-recorded reflecting its obscure habitat. Last recorded in 2017, the status of the beetle in Devon is uncertain, and further survey and monitoring are required.

Image above by John Walters
Blue ground beetle Carabus intricatus - Near threatened and nationally rare

This large dark blue beetle is restricted to some ten sites, all either on Dartmoor in Devon or on Bodmin Moor in Cornwall, except for one recently discovered in in south Wales. It inhabits deciduous woodlands with high humidity and much moss. The adult beetles feed on slugs and hibernate under moss-laden dead bark. Ad hoc monitoring is carried out by Buglife, John Walters and others: the Dartmoor populations appear stable. It would be placed at risk by changes in management of the moorland edge woodlands where it occurs if the ecological requirements of the beetle were not taken into account. It may become the subject of Ph.D. research from Exeter University.
Beach Comber Beetle Eurynebria complanata - Endangered and nationally rare

This beetle occurs on the strandlines of beaches backed by sand dunes. Here it shelters, forages and lays its eggs under woody and especially large pieces of plastic debris. It occurs, or occurred, on Saunton Sands (Braunton Burrows) but was last recorded there in 2002 and may now be extinct in Devon and as a result in England. However, its ecology is poorly understood and the beetle may reappear - further searching is required. The remaining British stronghold is in South Wales, although it is apparently declining here and is now limited to seven localities. Once the reasons for its loss have been examined, the beetle could be a good candidate for reintroduction to Saunton Sands from South Wales. Beach cleaning and the removal or burning of driftwood are likely to have major implications for the species.

Map to show the Devon distribution of this species

A rove beetle Gabrius astutoides - Red listed and nationally rare

This rove beetle of river and stream shingles is known mainly from Devon (eight hectads, five since 1980), with fewer records in Cornwall and one in south Wales. The most recent record is from Gara Mill in 2014. The beetle is likely to be at risk from riverine shingle extraction, watercourse engineering works and any decline in water quality.

Map to show the Devon distribution of this species

Gravel water beetle Hydrochus nitidicollis - Vulnerable and nationally rare

The water beetle is known only from Cornwall and South Devon. It is typically found in pockets of still water among coarse gravel in shingle beds at the edges of rivers and open water. It has been found during surveys of the River Bovey and River Teign, including within several sites in Dartmoor National Park. However, it has been recorded from just two hectads in Devon since 1980 and some sites have apparently been lost. Regulation of river systems, such as deepening or straightening, will be detrimental. However, overall, the narrow distribution of the beetle in England indicates a strong dependency on a warm Atlantic climate rather than on a particular management practice or habitat.

Map to show the Devon distribution of this species

Image above by John Walters
Mediterranean oil beetle Meloe mediterraneus - Vulnerable and nationally rare

Thought extinct in the UK, this species was rediscovered in Britain in 2012, in Devon, after a gap of nearly 100 years. It is now known from five coastal sites in south Devon and East Sussex. This beetle is a cuckoo parasite in the nests of solitary bees. Its larvae emerge in June and wait on flowers to hitch a lift back to a suitable host bee nest. Once inside they feed on the pollen supply collected by the bee for her own larvae. The adults emerge in late September and are active throughout the winter, but only at night. John Walters monitors the beetle on an ad hoc basis, and records continue to be received by Buglife through the Oil Beetle Hunt. In 2019 John found good numbers at Prawle Point (e.g. 29 in one hour). The key Devon population on National Trust land at Bolberry needs monitoring, in part to check that path resurfacing work has not damaged the population there. Light to moderate rough grazing is thought necessary to maintain the sward in suitable condition for the oil beetle: heavy grazing has the potential to be damaging by removing the flowers on which the host bees are dependent.

Further information can be found here

Map to show the Devon distribution of this species

Image above by Buglife

Lundy cabbage flea beetle Psylliodes luridipennis - Critically endangered and endemic

The world distribution of this beetle is limited to Lundy island. Here it is found along the south east coast. It inhabits sea cliffs, granite outcrops and cliff grassland. Both larvae and adults feed solely on Lundy Cabbage, also a Devon Special Species and endemic to the island. Lundy Cabbage is threatened by grazing (rabbits and possibly goats, sheep and deer), tourist pressure (e.g. trampling and erosion), and invasive rhododendron. Recent clearance of rhododendron has resulted in an increase in the number of Lundy Cabbage plants, with over 50,000 in 2018. It is not known whether this has resulted in an increase in numbers of the flea beetle, although likely so.
Map to show the Devon distribution of this species

Further sources of information:

UK Beetle Recording

The Devonshire Association – Entomology Section