Jan Hamrsky / Water spider (Argyroneta aquatica) detail of air bubble around its abdomen, Europe, July, controlled conditions

Jan Hamrsky / Water spider (Argyroneta aquatica) refilling its air supply, Europe, July, controlled conditions

Jan Hamrsky / Water spider (Argyroneta aquatica) with air bubble, Europe, July, controlled conditions

Bernard Castelein / Nursery web spider (Pisaura mirabilis) with spiderlings, Brasschaat, Belgium, July

Bernard Castelein / Crab spider (Misumena vatia) on Herb Robert (Geranium robertianus) Brasschaat, Belgium, May

Bernard Castelein / Crab spider (Misumena vatia) on Herb Robert (Geranium robertianus) Brasschaat, Belgium, May

Theo Bosboom / Raft Spider (Dolomedes sp) and algae in a hot spring, Landmannalaugar, Iceland, July

Theo Bosboom / Water mite larvae (Arrenurus) a parasite on a Common blue damselfly (Enallagma cyathigerum), Hondeven, the Netherlands, July

Wild Wonders of Europe / Giesbers / Round-headed rampion (Phyteuma orbiculare) flower with small mite on it, Liechtenstein, June 2009