It begins its life by hitching a ride on a bee, looks like it’s wearing a tiny waistcoat and squirts out yellow oil from its legs when threatened.
The Short-necked Oil Beetle is one of the UK’s rarest inhabitants and has so-far only been found in a handful of far-flung locations on Scottish islands.
Now a hunt has been launched to establish how many of the bugs are out there in the wild, in a bid to stop it slipping into extinction.
Conservation charity Buglife has launched a ‘citizen science’ project to try and track down the elusive critter, with people asked to record any sightings.
Oil Beetles has only been found on the Isles of Coll and Islay in the Inner Hebrides, as well as Uist and Barra on the Outer Hebrides.
The insect gains its name from its habit of exuding a yellowish oily substance from its leg joints when disturbed, while their carapaces resemble a ‘waistcoat’ — in reality short wing cases that do not fully cover the creature’s abdomen.
They are large, shiny black beetles, often with a slight blue or green tinge to their colouring and can be seen in wildflower-rich grasslands, heathland, and coastal areas from March to June. They are often seen crossing footpaths due to the availability of compact bare ground in which they can burrow.
The bugs have an unusual life cycle, intricately linked to that of solitary bees. After hatching, oil beetle larvae (known as triungulins) make their way onto a flower head where they lie in wait for a solitary bee.
READ MORE: How to learn to love the ugly bugs in your garden
Using specialised hooks on their feet, they attach themselves to the back of a visiting female bee and when the bee returns to its underground nest, the triungulin disembarks and continues its development underground, eating through the bee’s stores of pollen and nectar.
The following year, it emerges as an adult Oil Beetle ready to start the life cycle all over again.
Populations have declined due to the loss of flower-rich habitats owing to changes in countryside management.
Beetle larvae
As Oil Beetles are nest parasites of solitary bees, declines in populations of wild bees has worsened their fortunes further as they depend on them for survival.
READ MORE: The critters we need to watch out for as we ease into autumn
The search is part of the Species on the Edge programme launch within the Outer Hebrides, and Buglife is running a free oil beetle workshop at North Uist Agricultural Showground on Thursday 25 April.
Sally Morris, Buglife Conservation Officer explains “We need help to find other populations of these amazing beetles. Until early 2021, it was thought Short-necked Oil Beetles were only found on a single island in the Inner Hebrides, and now two more populations have been discovered – why not more?
“Have you ever seen a shiny black beetle that may be an oil beetle? Please send us a photo and help us to learn more about the state of oil beetles within Scotland.”
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