Neil Aldridge / Stingless bee (Trigona sp.) returns to nest entrance as others rest, Danum Valley, Sabah, Borneo, Malaysia.

Solvin Zankl / Two-coloured mason bee (Osmia bicolor) female covering nest with twigs and grass for camouflage, Witzenhausen, Germany, May.

Solvin Zankl / Two-coloured mason bee (Osmia bicolor) female covering nest inside snail shell with twigs and grass for camouflage, Witzenhausen, Germany, May.

Solvin Zankl / Two-coloured mason-bee (Osmia bicolor) female repositioning empty snail shell where she has her nest, Witzenhausen, Germany, May.

Solvin Zankl / Two-coloured mason bee (Osmia bicolor) female provisioning nest inside a snail shell with pollen and nectar, Witzenhausen, Germany, May.

Kim Taylor / Female Leaf-cutting bee (Megachile species) arriving at her nest carrying a section of maple leaf, Surrey, UK, March.

Nick Upton / Female Red mason bees (Osmia rufa) collecting mud from the margins of a garden pond for sealing their brood cells in an insect hotel, Wiltshire, UK, May.

Nick Upton / Female Red mason bee (Osmia rufa) collecting mud from the margins of a garden pond for sealing her brood cells in an insect hotel, Wiltshire, UK, May.

Brian Bevan / Pantaloon bee (Dasypoda hirtipes) digging nesting burrow, Bedfordshire, UK, September.

David Perpinan / Cuckoo bee (Melecta albifrons) taking pollen from a nest of a Solitary bee (Anthophora romandii), Barcelona, Spain, May. Controlled conditions.

David Perpinan / Cuckoo bee (Melecta albifrons) leaving nest entrance of Solitary bee (Anthophora romandii) and flying away, Barcelona, Spain, April.

David Perpinan / Female Solitary bee (Anthophora fulvitarsis) flying into nest entrance, Barcelona, Spain, April.