Pal Hermansen / Hoverfly in flight, backlight, Norway, September.

Nick Garbutt / Yacare Caiman (Caiman yacare) gaping to regulate its body temperature, with attendant hoverflies, the Paraguay River, Taiama Reserve, western Pantanal, Brazil, South America.

Andy Sands / Hunting Wasp (Ectemnius cavifrons) female carrying paralysed hoverfly in flight toward tunnel entrance in rotten log. Hertfordshire, England, UK, July.

Stephen Dalton / Hoverfly (Eristalis tenax) taking off from Snapdragon flower, UK

Kim Taylor / Male hoverfly hovering {Eristalis sp.} Europe.

David Kjaer / Hoverfly at flower, England

Heather Angel / Marmalade hoverflies (Episyrphus balteatus), two feeding on pollen of Dwarf formosa lily (Lilium formosanum var. pricei). Surrey, England, UK. July.

Nick Upton / Slow motion clip of Marmalade hoverflies (Episyrphus balteatus) feeding from a Greater knapweed (Centaurea scabiosa) flower, before taking off, Wiltshire, England, UK, July.

Nick Upton / Gatekeeper (Pyronia tithonus) and Small heath (Coenonympha pamphilus) butterflies and Hoverflies (Eristalis sp.) nectaring on Wild marjoram (Origanum vulgare) flowers, Wiltshire, England, UK, August.

Stephen Dalton / Marmalade hoverflies (Episyrphus balteatus) feeding on fallen lily pollen, England, UK. August.

David Woodfall / Male and female Hoverflies (Syphrus) on Pink Cosmos flower, sownto attract bees and other insects. Outside Wales Environment Centre, Bangor, Gwynedd, North Wales

Bernard Castelein / Hoverflies (Helophilus pendulus) mating, Brasschaat, Belgium, May.