Jan Hamrsky / Diving beetle larva (Hyphydrus ovatus), Europe, June. Controlled conditions.

Jan Hamrsky / Diving beetle (Haliplus ruficollis), Europe, June. Controlled conditions.

Jan Hamrsky / Diving beetle (Colymbetes fuscus) close up head portrait. Europe, June. Controlled conditions.

Jan Hamrsky / Great diving beetle (Dytiscus marginalis) portrait, Europe, September, controlled conditions

Jan Hamrsky / Diving Beetle (Rhantus suturalis). Czech Republic. Controlled conditions.

Jan Hamrsky / Great Diving Beetle (Dytiscus marginalis) larva feeding on small fish. Czech Republic. Controlled conditions.

Stephen Dalton / Great Silver Water / Diving Beetle (Hydrophilus piceus) male. Sussex, UK, March.

Michael Durham / Diving Beetle (Cybister fimbriolatus) jumping into water, photographed with a high-speed camera, central Texas

Kim Taylor / Water beetles (Dytiscus marginalis) and (Acilius sulcatus) clustered around an air bubble trapped beneath the ice of a frozen pond, digitally enhanced, Surrey, England

Jane Burton / Great Diving Beetle {Dytiscus marginalis} female taking air at water surface, Surrey, England.

Jan Hamrsky / Diving beetle larva (Platambus maculatus), Europe, February, controlled conditions

Jussi Murtosaari / Red-footed falcon (Falco vespertinus), juvenile catching a diving beetle, Finland, September

Will Watson / Head on view of Diving beetle (Cybister lateralimarginalis) resting among Bladderwort (Utricularia sp.) captive conditons, Belgium.

Will Watson / Diving beetle (Graphoderus cinereus) among Bladderwort (Utricularia sp.), captive, Belgium

Robert Thompson / Great diving beetle (Dytiscus marginalis) larva, Montiaghs Moss NNR, County Antrim, Northern Ireland, UK.

Will Watson / Diving Beetle (Rhantus exsoletus), Moccas Park National Nature Reserve, Herefordshire, England.

Will Watson / Diving bettle (Agaubus bipustulatus) taking air, Captive, Carmarthenshire, Wales, UK. July.

Will Watson / Diving Beetle (Colymbetes fuscus) resting on submerged log, captive, Herefordshire, England.

Will Watson / Diving beetle (Graphoderus cinereus) with Ciliates, Moccas Park, National Nature Reserve, Herefordshire, England, UK. Vulnerable species.

Will Watson / Diving beetle (Graphoderus cinereus) with Ciliates, Moccas Park, National Nature Reserve, Herefordshire, England, UK, June. Vulnerable.

Will Watson / Mud dweller beetle (Ilybius ater) at rest on Hornwort (Ceratophyllum demersum), Carmarthenshire, Wales. Captive.

John Abbott / Predacious diving beetle (Cybister fimbriolatus) swimming Williamson County, Texas, USA Controlled conditions. October

John Abbott / Predaceous diving beetle (Thermonectus basillaris), Tuscaloosa County, Alabama, USA Controlled conditions. July

Jan Hamrsky / Diving beetle (Haliplus ruficollis), Europe, June. Controlled conditions.

Jan Hamrsky / Diving beetle (Platambus maculatus), Europe, August. Controlled conditions.

Jan Hamrsky / Diving beetle (Colymbetes fuscus), Europe, June. Controlled conditions.

Jan Hamrsky / Diving beetle larva (Cybister lateralimarginalis), Europe, May. Controlled conditions.

Jan Hamrsky / Diving beetle larva (Cybister lateralimarginalis), Europe, May. Controlled conditions.

Jan Hamrsky / Diving beetle (Cybister lateralimarginalis), Europe, May. Controlled conditions.

Jan Hamrsky / Diving beetle (Cybister lateralimarginalis), Europe, May. Controlled conditions.

Jan Hamrsky / Great silver water beetle (Hydrophilus piceus) female, Europe, May. Controlled conditions.

Jan Hamrsky / Great silver water beetle (Hydrophilus piceus) female, refilling its air store at water surface, Europe, May. Controlled conditions.

Jan Hamrsky / Great silver water beetle (Hydrophilus piceus) female, refilling its air store at water surface, Europe, May. Controlled conditions.

Jan Hamrsky / Great silver water beetle (Hydrophilus piceus) female, Europe, May. Controlled conditions.

Will Watson / Black belly diving beetle (Dytiscus semmisulcatus), Cheshire, England, UK, July. Captive.

Will Watson / Lesser silver diving beetle (Hydrochara caraboides), captive, Cheshire, England, UK, July.

Will Watson / Lesser silver diving beetle (Hydrochara caraboides), captive, Cheshire, England, UK, July.

Will Watson / Lesser silver diving beetle (Hydrochara caraboides), captive, Cheshire, England, UK, July.

MYN / Niall Benvie / Great diving beetle (Dytiscus marginalis) Burgundy, France. April.

MYN / Niall Benvie / Great diving beetle (Dytiscus marginalis) Burgundy, France. April.

MYN / Niall Benvie / Great diving beetle (Dytiscus marginalis) underwater, Burgundy, France. April.

MYN / Niall Benvie / Great diving beetle (Dytiscus marginalis) underwater, Burgundy, France. April.

MYN / Niall Benvie / Great diving beetle (Dytiscus marginalis) Burgundy, France. April.

MYN / Paul van Hoof / Great diving beetle (Dytiscus marginalis) larva, June, The Netherlands, Meetyourneighbours.net project

Will Watson / Water beetle (Rhantus suturalis) Shropshire, England. Captive. May 2014.

Jussi Murtosaari / Great diving beetle (Dytiscus marginalis) diving in aquarium, Kumlinge, Ahvenanmaa / Aland Islands Archipelago, Finland. November

Jussi Murtosaari / Great diving beetle (Dytiscus marginalis) in aquarium, Kumlinge, Ahvenanmaa / Aland Islands Archipelago, Finland. November

Jussi Murtosaari / Great diving beetle (Dytiscus marginalis) Photographed in aquarium, Kumlinge, Ahvenanmaa / Aland Islands Archipelago, Finland. November

Jan Hamrsky / Diving beetle (Graphoderus bilineatus) larva, head detail. Europe, June, controlled conditions.

Jan Hamrsky / Diving beetle (Graphoderus bilineatus) larva breathing at surface, Europe, June, controlled conditions.

Jan Hamrsky / Diving beetle (Graphoderus bilineatus) larva breathing at surface, Europe, June, controlled conditions.

Jan Hamrsky / Water beetle (Laccophilus sp) taking air at the surface, January, Europe, controlled conditions.

MYN / Niall Benvie / Field studio composite of amphibians, fish, and aquatic invertebrates from Preporche, Burgundy, France, April. meetyourneighbours.net project

MYN / Krista Schlyer / Diving beetle (Dytiscidae sp.) larva, Lily Lake, Estes Park, Colorado, USA. August. Meetyourneighbours.net project.

Ann & Steve Toon / British diving beetles (Dytiscus sp.), museum specimens, Tyne and Wear Archives and Museums

Will Watson / Female Great diving beetle (Dytiscus circumflexus) at surface to breath, UK, captive.

Will Watson / Female Great diving beetle (Dytiscus circumflexus) view of underside with cloacal sperm plug from previous mating, UK, captive.

Will Watson / Male Great Diving Beetle (Dytiscus marginalis) taking in air, captive, Essex, England.

Will Watson / Female Great diving beetle (Dytiscus circumflexus), resting on Hornwort, captive, UK.

Will Watson / Female Great diving beetle (Dytiscus circumflexus), resting on Hornwort, UK, captive.

Will Watson / Female Black Belly (Dytiscus semisulcatus) at surface for air, Llyn Heilyn, Radnorshire, Wales.

Jan Hamrsky / Lesser diving beetles (Acilius sulcatus) mating pair, Europe, May, controlled conditions

Jan Hamrsky / Lesser diving beetles (Acilius sulcatus) mating pair, Europe, May, controlled conditions

Jan Hamrsky / Lesser diving beetles (Acilius sulcatus) mating pair, Europe, May, controlled conditions

Jan Hamrsky / Lesser diving beetle (Acilius sulcatus) male, Europe, May, controlled conditions

Jan Hamrsky / Lesser diving beetle (Acilius sulcatus) refilling its air supply by the surface, male, Europe, May, controlled conditions

Jan Hamrsky / Diving beetle (Agabus sturmii) refilling its air supply by the surface, Europe, May, controlled conditions

Jan Hamrsky / Diving beetle (Agabus sturmii) Europe, May, controlled conditions

Jan Hamrsky / Diving beetle (Haliplus ruficollis) crawling in freshwater Bryozoan colony (Plumatella fruticosa) Europe, August, controlled conditions

Jan Hamrsky / Diving beetles (Graphoderus bilineatus) female (right) and male (left) Europe, August, controlled conditions

Jan Hamrsky / Diving beetle (Graphoderus bilineatus) male, Europe, August, controlled conditions

Jan Hamrsky / Diving beetles (Graphoderus bilineatus) female (left) and male (right) Europe, August, controlled conditions

Jan Hamrsky / Diving beetle (Graphoderus bilineatus) refilling the air supply by the surface, female, Europe, August, controlled conditions

Jan Hamrsky / Diving beetle (Graphoderus bilineatus) refilling the air supply by the surface, male, Europe, August, controlled conditions

Jan Hamrsky / Diving beetle (Graphoderus bilineatus) cleaning its antennae, female, Europe, August, controlled conditions

Jan Hamrsky / Diving beetle larva (Graphoderus bilineatus) Europe, June, controlled conditions

Jan Hamrsky / Great diving beetle larva (Dytiscus marginalis) head detail, Europe, June, controlled conditions

Jan Hamrsky / Great diving beetle larva (Dytiscus marginalis) with dragonfly nymph prey, Europe, June, controlled conditions

Jan Hamrsky / Great diving beetle larva (Dytiscus marginalis) with dragonfly nymph prey, Europe, June, controlled conditions

Jan Hamrsky / Great diving beetle larva (Dytiscus marginalis) breathing by the water surface, Europe, June, controlled conditions

David Pattyn / Little Grebe (Tachybaptus ruficollis) female feeding a Great diving beetle (Dytiscus marginalis) to one of its chicks age 10 days, The Netherlands, June.

Wild Wonders of Europe / Lundgren / Water beetle (Dytiscidae) swimming just under the surface at night, Danube Delta, Romania, June.

Wild Wonders of Europe / Lundgren / Water beetle nymph (Dytiscidae) attacking a large dragonfly nymph, Danube Delta, Romania, June. Ph

Wild Wonders of Europe / Lundgren / Water beetle (Dytiscidae) nymph, Danube Delta, Romania, June.

Jussi Murtosaari / Horned Grebe (Podiceps auritus) with diving beetle prey, southern Finland, May.

Michael Quinton / Diving Beetle (Dytiscidae) larva with caddis fly larva prey, Alaska

Michael Quinton / Diving Beetle (Dytiscidae) larva, Alaska

Michael Quinton / Diving Beetle (Dytiscidae) larva with mosquito larva prey, Alaska

Jan Hamrsky / Great diving beetle (Dytiscus marginalis) female, Europe, September, controlled conditions

Jan Hamrsky / Great diving beetle (Dytiscus marginalis) hiding in freshwater red algae (Batrachospermum moniliforme) Europe, September, controlled conditions

Jan Hamrsky / Great diving beetle (Dytiscus marginalis) female, Europe, September, controlled conditions

Jan Hamrsky / Great diving beetle (Dytiscus marginalis) hind oar-like leg detail, Europe, September, controlled conditions

Jan Hamrsky / Great diving beetle (Dytiscus marginalis) refilling its air supply under the wing cases, Europe, September, controlled conditions

Jan Hamrsky / Great diving beetle (Dytiscus marginalis) female, Europe, September, controlled conditions

Jan Hamrsky / Great diving beetle (Dytiscus marginalis) refilling its air supply under the wing cases, Europe, September, controlled conditions

Jan Hamrsky / Great diving beetle (Dytiscus marginalis) refilling its air supply under the wing cases, Europe, September, controlled conditions