One of the UK’s rarest oil beetles found in Wales

The short-necked oil beetle has been rediscovered in Pembrokeshire.

Short-necked oil beetle. © Annie Haycock

It hasn’t been seen anywhere in Wales for more than 70 years, but the short-necked oil beetle (Meloe brevicollis) has now been recorded in Pembrokeshire.

Advertisement

Though the species was once widespread in Britain, it suffered a severe decline in the 20th century – there were no sightings at all in the UK between 1948 and 2006.

Apart from Pembrokeshire, the species is known to exist in just a handful of locations across the UK: the island of Coll in the Inner Hebrides and single locations on the Salisbury Plain and in south Devon. There has also previously been an unconfirmed sighting in Dorset.

As nest parasites of solitary bees, oil beetles have highly specialised life-cycles, making them vulnerable to environmental change.

They dig burrows in the ground, into which they lay hundreds of eggs. Once hatched, the louse-like larvae, known as triungulins, climb onto flowers and lie in wait for a suitable host bee.

When a bee visits the flower, the triungulin attaches itself to the hairs on the bee’s back, and is then carried to the bee’s nest.

Once inside the nest, the beetle larva feeds on the bee’s store of pollen and nectar until it is ready to emerge as an adult.

The adults are active from late March to June and are found in wildflower-rich cliff-top grasslands, heathlands and machair dunes.

These oil beetles are known to use the hairy-saddled colletes bee as its host on Coll and at its single Irish site, but any other host bee species remain unknown.

Short-necked oil beetles can be identified by their rectangular-shaped thorax, their short and straight antennae (which are slightly thickened at the tips) and their shiny blue-black colour.

Though the more common and widespread black oil beetle and violet oil beetle look similar, these species have a thorax that is squarer in shape.

At just 24mm in length, the short-necked oil beetle can easily be missed or overlooked. Conservation charity Buglife is therefore asking people to keep an eye out for the species and report any potential sightings to them.


Advertisement

Main image: Short-necked oil beetle. © Annie Haycock