06 Mar Have you seen a Black Oil Beetle?

 

Across South Devon, the fields are starting to erupt with vibrant wildflowers, bees are buzzing and butterflies are fluttering once again – sure signs that spring is on the way!

 

 

But, if you happen to glance down at your feet whilst out along the coast, you may have spotted another clue that winter is behind us.

 

Drawn out by the warmer weather, Black Oil Beetles are emerging – they are iconic residents of the South Devon Coast. Thanks to it’s fascinating life-cycle, its presence signifies not only the changing of the seasons, but tells us a lot about the health of it’s habitat.

 

 

Let us know if you see any Black Oil Beetles this Spring by sending us your records. By submitting a photo along with the location of your sighting, you can help us learn more about these amazing insects and where they live, so we can protect them. Learn how to spot a Black Oil Beetle and read about their incredible life-cycle below!

 

 

C. John Walters

 

 

 

 

How to spot a Black Oil Beetle:

 

 

 

Black Oil Beetles can be seen between mid-February and late May ambling along areas of bare earth, such as the coast path. They are active during the daytime, and their distinctive large, black, glossy bodies, long fat abdomens and stunted wing-cases make them an exciting find!

 

 

There are four species of oil beetle found in South Devon – the Black Oil Beetle (Meloe proscarabaeus),   Violet Oil Beetle (Meloe violaceus),  Short-necked Oil beetle (Meloe brevicollis) and the Mediterranean Oil Beetle (Meloe mediterraneus) – so here are some key features to tell it apart:

 

 

 

Things to look for:

 

 

 

 

You can also download an identification guide from Buglife where you can find out more about these brilliant beetles. 

 

 

 

 

 

Recording your findings:

 

 

If you spot one, snap a photo, make a note of your location, and upload your sighting to iRecord. To submit records using iRecord, you will need to create an account and join the ‘Life on the Edge’ activity. Instructions for joining an activity can be found here.

 

 

 

 

An Unusual Life Cycle:

 

 

 

Oil beetles, so called because they secrete a foul oil from their joints to deter predators, have one of the most extraordinary life cycles of any British insect.

 

On warm Spring days, adult oil beetles emerge, feed, and search for a mate. Once mated, the female oil beetle will lay hundreds of eggs in a nest burrow, dug into bare soil. Later in the year, the eggs will hatch and the oil beetle larvae will emerge with a mission: to seek out and scape a nearby flower.

 

Upon completing their epic ascent, the larvae lie in wait for a visit from an unsuspecting solitary bee. When one arrives, the larvae cling on tightly using specially adapted hook-like feet in hopes of hitching a ride back to the bee’s nest, where it will grow into an adult beetle.

 

Once in the bee’s nest, the larva disembarks and sets about eating the bee’s eggs, larvae and ‘bee bread’, a mixture of compacted pollen and nectar.  The larva develops within the bee burrow until the following year, when it will emerge as an adult oil beetle ready to mate and start the whole cycle again. 

 

This is a high-risk strategy for the beetle. If it boards the wrong pollinator, it may never reach the solitary bee’s nest. Furthermore, the Solitary Mining Bees aren’t so easily fooled! If one becomes aware of the young larvae, she’ll do everything she can to dislodge it before returning to her nest. With such tremendous odds stacked against them, it’s no wonder a female oil beetle will lay up to 40,000 eggs in her lifetime.

 

 

Habitat and Conservation:

 

Black Oil Beetles can be found on wildflower-rich grasslands and heathland.  Their habit of seeking out bare compacted earth in which to dig nest burrows means that they are frequently seen on the coast path.    

 

The reliance of oil beetles on the health of wild bee populations means that, with the decline in our bee populations, the oil beetles are suffering too.  The Black Oil Beetle is one of the target species for Life on the Edge, along with the Short-necked Oil Beetle and the Mediterranean Oil Beetle.  Life on the Edge is restoring wildflower-rich grassland along the South Devon coast, filling it with spring colour, buzzing bees, ambling oil beetles, and other wildlife. 

 

 

Please keep a look out for oil beetles this spring when walking and enjoying the South Devon Coast Path; and if you see any, please let us know.  Your sightings will help us to better understand the health of our oil beetle populations. 

 

 

Use the iRecord app and its “Life on the Edge – South Devon” activity. Here you can submit a record with a photograph from your phone which will directly contribute to this species’ conservation.