June wildlife - Oil beetles

An oil beetle at Lanhydrock, Cornwall

An organically managed parkland, a good proportion of semi-natural ancient woodland and individual trees of up to 700 years old make Lanhydrock a real haven for bugs. The ancient trees with all their associated dead wood and decay are just like high-rise flats for thousands of creepy crawlies, whilst large lumps of dead timber lying on the ground are ideal cul-de-sacs.

Many of the beetles and bugs living here are extremely tiny and rarely ever noticed but we do have some quite large and spectacular ones to find as well.

The oil beetle

The oil beetle is one of the largest beetles in the UK and can be found wandering around some of our woodland paths and adjoining flower-rich parkland during spring and early summer. They get their name from a toxic oily substance they secrete from their leg joints to put off would-be predators.

They also have a fascinating, if rather gruesome, life-cycle. The female will dig a hole in the ground and lay up to 1,000 eggs. These hatch into small three-legged things called tringulins, which crawl up onto nearby plants and then attach themselves to mining bees. They then get taken back to the bees’ nest, where they feed on the bee eggs, before pupating and appearing as an adult oil beetle.

An oil beetle at Lanhydrock
Oil beetle in the undergrowth at Lanhydrock, Cornwall
An oil beetle at Lanhydrock

Due to a reduction of flower-rich meadows over the past century, four out of eight oil beetle species have now become extinct and even the remaining four are quite scarce. Thankfully the positive conservation management at Lanhydrock ensure we remain a beetle hotspot.


Where to look

See what beetles you can find out on the estate. Looking under a piece of wood on the ground is a good place to start, but remember to put everything back as you found it. It is the bugs’ home, after all.