ACTIVE from about now and into high summer, oil beetles are quite rare nationally but less rare in the west country.

They are up to 3cm long, have a glossy sheen with something of the manner of wearing a tail coat.

The violet oil beetle (Meloe violaceus) and the black oil beetle (Meloe proscarabaeus);are most likely to be spotted. The violet oil beetle has a distinct curve at the bottom of the thorax while the black oil beetle does not.

Oil beetles are so named because they squirt cantharidin, a stinky yellow oily substance from the joints in their leg joints when attacked. Pick one up and you'll get this all over your fingers. It's better to look than to touch.

Oil beetles are parasites of solitary mining bees. Female oil beetles dig nest burrows in the ground where they lay hundreds of eggs. When the larvae hatched, they climb on to flowers and lie in wait for a solitary miner bee to land on the flowers.

The larvae have hooked feet with which they grip onto an unsuspecting bee while she collects nectar ready to feed her larvae once they hatch from eggs. The bee carries the stowaway oil beetle larva back to her nest. The oil beetle larva moves into the nest and eats the bee’s eggs and the store of pollen and nectar. The larva stays in the bee’s nest until it is ready to emerge as an adult oil beetle.

You'll find oil beetles in areas of beaten earth into which they burrow. For this reason you're likely to see one on a well trodden path in woodland margins or in fields or gardens.

I'm Helen Shalders, if you'd like to join in with activities and courses I run look for Wayfarers Outdoors on Facebook and Instagram.

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