Lucas Bustamante / Amazonian millipede with parasites. Sumaco National Park, Napo, Ecuador

Guy Edwardes / Red-billed oxpecker (Buphagus erythrorhynchus) feeding on Impala (Aepyceros melampus), Savuti, Botswana.

Lucas Bustamante / Brush footed butterfly (Lycorea sp.) caterpillar with parasitic wasp cocoons on silk threads, Yasuni National Park, Orellana, Ecuador.

Alan Murphy/ BIA / Northern Caracara (Caracara cheriway) chasing sub-adult with prey, Texas

Theo Bosboom / Water mite larvae (Arrenurus) parasitizing Common blue damselfly (Ennalagma cyathigerum), Hondeven, the Netherlands, July.

Tony Wu / Humpback whale (Megaptera novaeangliae) adult female at rest. The tubercles on the whale's head are clearly visible, as are the barnacles (Coronula diadema), whale lice (Cyamus boopis), and hairs on t...

Jordi Chias / Giant Manta (Manta birostris) with Remoras (Remora brachyptera) attached to both wings, offshore Santa Maria Island, Azores, Atlantic Ocean

Jordi Chias / Mobula / Chilean devil ray (Mobula tarapacana) with remora (Remora brachyptera) and Amberjacks (Serila dumerilli) Santa Maria Island, Azores, Atlantic Ocean

Bence Mate / Great reed warbler (Acrocephalus arundinaceus) feeding Cuckoo chick (Cuculus canorus) Pusztaszer, Kiskunsagi National Park, Hungary, June.

Solvin Zankl / Gall wasp (Cynips quercusfolii) emerging from the oak gall. Germany, October.

Alex Hyde / Parasitic fungus (Cordyceps militaris) fruiting body. This entomopathogenic fungus grows from an underground insect pupa or larva. Sherwood Forest National Nature Reserve. Nottinghamshire, UK. October...

Juergen Freund / Paralytic tick (Ixodes holocyclus) with engorged body on human hand, this species affects many species, Spectacled flying fox (Pteropus conspicillatus) among them and infects them with a toxin that ca...