Duncan Murrell / Common Southeast Asia tree frog (Polypedates leucomystax), Puerto Princesa Subterranean River National Park, Palawan, the Philippines.

Duncan Murrell / Tree with large buttress roots in a swamp, Puerto Princesa Subterranean River National Park, UNESCO World Heritage Site, Palawan, the Philipines.

Vincent Grafhorst / River in sandstone cave, Sof Omar Cave, Ethiopia

Vincent Grafhorst / River in sandstone cave, Sof Omar Cave, Ethiopia

Vincent Grafhorst / River in sandstone cave, Sof Omar Cave, Ethiopia

Doug Wechsler / Eastern subterranean termite (Reticulitermes flavipes) soldier and worker, Fort Washington State Park; Philadelphia, Pennsylvania, USA. April.

John Abbott / Subterranean termite (Reticulitermes flavipes) reproductive alate in flight, Bastrop County, Texas, USA. Controlled conditions. March

Ingo Arndt / Edible Snail (Helix pomatia) laying eggs, Germany

John Abbott / Formosan subterranean termite (Coptotermes formosanus) Texas, USA, June.

John Abbott / Formosan subterranean termite (Coptotermes formosanus) Texas, USA, June.

Doug Wechsler / Eastern subterranean termite (Reticulitermes flavipes) worker, larvae and eggs in rotten log, French Creek State Park, Pennsylvania, USA, August.

Vincent Grafhorst / Stalagmites and stalactites in cave chamber, Gcwihaba Caves, Botswana