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.

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

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

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.

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...

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

Alex Mustard / Red eye medusa (Polyorchis penicillatus) with hitchhiking amphipods (Hyperia medusarum). Browning Pass, Vancouver Island, British Columbia, Canada. North East Pacific Ocean.

Ole Jorgen Liodden / Meadow pipit (Anthus pratensis) feeding young Eurasian cuckoo (Cuculus canorus), Valdres, Norway, July.

MYN / Gil Wizen / Human botfly (Dermatobia hominis), adult and larva. Cayo District, Belize. Composite image. Meetyourneighbours.net project

Alex Mustard,Alex Mustard / Red eye medusa (Polyorchis penicillatus) with its feeding tentacles extended to catch planktonic prey. Note that the bell of the jelly has hitchhiking amphipods (Hyperia medusarum). Browning Pass, Van...

Juergen Freund / Spectacled flying fox (Pteropus conspicillatus) casualty of paralytic tick (Ixodes holocyclus) bite being cared for on site of colony by Jenny Mclean, North Queensland, Australia, November 2012

Daniel Heuclin / Mosquito (Anopheles gambiae) feeding on human in controlled conditions. The body is becoming engorged with blood. Malaria vector. Africa, June. Engorging sequence 2 of 3. Model released

Alex Hyde / Cleg fly / Horsefly (Haematopota pluvialis) sucking blood from human.

Doug Perrine / Salmon shark (Lamna ditropis) female with mating scars and copepod parasites trailing from fins, Port Fidalgo, Prince William Sound, Alaska, USA. Digital composite

Stephen Dalton / Mosquito (Culicidae) female feeding on human blood, controlled conditions

SINCLAIR STAMMERS / Photomicrograph of fully embryonated (Neoascaris / Toxocara vitulorum) eggs containin larvae immediately prior to hatching. Parasitic nematodes which normally infect cattle, collected from Egyptian ca...

Wild Wonders of Europe / Benvie / Broomrape (Cistanche phelypaea) in flower, killing its host Glasswort (Salicornia sp) Huelva, Andalucia, Spain, April 2009

Martin Dohrn / Mosquito gorged with human blood {Culex pipiens} UK

John Cancalosi / Reed warbler's nest with eggs and European cuckoo chick just hatched, UK

Ingo Arndt / Rafflesia (Rafflesia arnoldii) flower, is the largest flower in the world, fresh open first day, highlands, Malaysian Peninsula

Scott Leslie / Limpkin (Aramus guarauna) amid curtain of Spanish Moss (Tillandsia usneoides), Florida

Richard Du Toit / Burchell's Zebra (Equus burchellii) reacting to parasitic Bot Fly (Oestridae) trying to lay eggs on it, KwaZulu-Natal, South Africa

Piotr Naskrecki / Yellow Fever Mosquito (Aedes aegypti) female feeding on human blood, Gorongosa National Park, Mozambique

D. Parer & E. Parer-Cook / Galapagos Land Iguana (Conolophus subcristatus) with a Small Ground-Finch (Geospiza fuliginosa) on its head removing parasites, Galapagos Islands, Ecuador

Nick Upton / Red poplar leaf beetle (Chrysomela populi) with parasitic mites (Linobia coccinellae) attached, crawling along Willow (Salix sp.) sapling , Kenfig National Nature Reserve, Glamorgan, Wales, UK, July.

John Abbott / Ant (Formicidae) infected with Cordyceps fungus, Cayo District, Belize.

John Abbott / Ant (Formicidae) infected with Cordyceps fungus, Cayo District, Belize.

John Abbott / Ant (Formicidae) infected with Cordyceps fungus, Cayo District, Belize.

John Abbott / Ant (Formicidae) infected with Cordyceps fungus, Cayo District, Belize.

Linda Pitkin / Female flower of Butterbur (Petasites hybridus), Surrey, England. March.

Linda Pitkin / Female flower of Butterbur (Petasites hybridus), Surrey, England. March.

Linda Pitkin / Common toothwort (Lathraea squamaria) in flower, under trees, Surrey, England. April. © Linda Pitkin LP0559

David Fleetham / Female Sea urchin crab (Echinoecus pentagonus) living in the rectum of the Common banded urchin, (Echinothrix calamaris), Hawaii, Pacific Ocean.

Chris Mattison / Ichneumon wasp (Dolichomitus sp.), Monmouthshire, Wales, UK. September.

Chris Mattison / Tachinid fly (probably Tachina fera) feeding on Ivy (Hedera sp.) flowers, Wales, UK. October.

Chris Mattison / Ichneumon wasp (Dolichomitus sp.) resting on a tree branch, Monmouthshire, Wales, UK. September.

Ashley Cooper / Dodder (Cuscuta epithymum) a parasitic, climbing plant growing on gorse, Cape Cornwall, UK. September.