Big bug

I was thrilled to spot this massive oil beetle lumbering across the lane close to home. There's something  a tad steam punk about the way its liquorice black, swollen abdomen resembles moulded leather armour  and at over 3 cms. long it really can't be mistaken for any other sort of beetle. Its life cycle is even more extraordinary that its appearance. The female beetle lays a mass of eggs in an earth burrow. The larvae that emerge are tiny, louse-like creatures. They lie in wait on flower heads (typically celandines) for solitary bees to visit. Using clawed feet each larva aims to hitch a lift on a bee's back and once  in the bee's nest eats the egg along with the food collected by the bee for its own offspring,   much as a young cuckoo supplants a baby bird and benefits from the parents' nurture. The larval oil beetle then develops within the bee burrow and emerges as an adult the following year.
The presence of oil beetles is a reason to rejoice since it signifies the wildflower rich habitat required by solitary bees. As we all know this kind of traditional natural flora is in  sharp decline owing to modern farming methods and countryside loss.  However those of us who have gardens can all help. Dispense with notions of order, pristine lawns and trays of hardy annuals from the garden centre - instead allow the so-called weeds like nettles, daisies, docks and dandelions to flourish and watch the bees, beetles and butterflies multiply and thrive. And if you find an oil beetle* trundling across your path leave it to pursue its unorthodox lifestyle and rejoice.


*So called because in defensive mode it exudes an irritant liquid from its leg joints. For this reason aka blister beetles.

http://www.bbc.com/earth/story/20150506-the-life-cycle-of-oil-beetles
https://www.buglife.org.uk/sites/default/files/Oil%20Beetle%20management%20web.pdf (includes picture of the larvae)