Invertebrates
Oil Beetle
Meloe proscarabaeus · also called black oil beetle
On a sunny bank in early spring, a blue-black oil beetle trundles through the grass, its swollen body heavy with eggs.
Overview
The oil beetle, Meloe proscarabaeus, is a plump, flightless beetle of flower-rich grassland and sunny banks in Europe and parts of Asia. Its blistering oil, hitchhiking larvae, and dependence on wild bees make it one of the most remarkable and most threatened beetles of European meadows.
A beetle that sends its young by bee
The oil beetle’s larvae cannot find food by themselves, so they rely on catching a ride on a solitary bee, a risky strategy that depends on there being plenty of bees.
Status
Not Evaluated, but declining with bees and flower-rich grassland.
Oil Beetle: common questions
Why is it called the oil beetle?
When disturbed, it oozes drops of oily, orange fluid from its leg joints, which contain cantharidin, a chemical that blisters skin.
How do oil beetle larvae find food?
They climb onto flowers, cling to a visiting solitary bee, are carried to its nest, and then eat the bee's egg and its stored pollen and nectar.
Why is the oil beetle declining?
It has declined with the loss of flower-rich grassland and the solitary bees on which its larvae depend.
Can an oil beetle fly?
No, it has short wing cases and cannot fly, and moves by walking.