Grey-backed Mining Bee, Heesch, Netherlands

One of the largest mining bees. Relatively uncommon in the Netherlands, here found at a crucial stage in the lifecycle. This is the pollen-loaded female digging a nest. They are very powerful diggers and undithered when in dig mode. The nest will be as deep as 25-50 cm. When finished, she'll knead the pollen into a ball and lay an egg on top of it. She'll then soon die. Her potential offspring is far from safe, several species of parasitic wasp will attempt to lay their earlier-hatching eggs on top of this bee's egg.

One such parasite is the Greater bee fly that will actually "bomb" the nest. Flying lowly over the nest opening, they then drop their egg into it.