Roland Seitre / Harlequin Poison Dart Frog (Dendrobates histrionicus) in defensive posture, native to South America

Paul Hobson / Harlequin Ladybird (Harmonia axyridis) melanic form, on turning leaf. Sheffield, October.

Chris Shields / Illustration of Kidney-spot ladybird / Harlequin beetle (Chilocorus renipustulatus).

Chris Shields / Illustration of Harlequin ladybird (Harmonia axyridis), four colour variants.

Steve Knell / Harlequin duck (Histrionicus histrionicus) portrait of male stood motionless on exposed rock, in river, Iceland, May

Steve Knell / Harlequin ducks (Histrionicus histrionicus) male chasing female on riverbank, Iceland, May

Steve Knell / Harlequin duck (Histrionicus histrionicus) male standing in rapids, Iceland, May

Tim Laman / Harlequin Tree Frog (Rhacophorus pardalis) in the air with webbed feet spread to glide, Danum Valley Conservation Area, Sabah, Borneo, Malaysia

Stephen Dalton / Harlequin beetle (Acrocinus longimanus) close up, portrait

Stephen Dalton / Harlequin beetle (Acrocinus longimanus) in flight, Venezuela, South America.

Gerrit Vyn / Two pairs of Harlequin Ducks (Histrionicus histrionicus) in flight. Ocean County, New Jersey, USA, January.

Stephen Dalton / Green mosaic / Rancho grande harlequin frog (Atelopus cruciger) walking along tree trunk, Henri Pittier NP, Venezuela, South America, Critically endangered, thought extinct until a gravid female was f...