Tui De Roy / Volcan Alcedo giant tortoises (Chelonoidis nigra vandenburghi) group wallowing in a muddy pool, possibly for thermoregulation or to deter parasites, with sulphur fumaroles from Alcedo Volcano, Isabel...

Tui De Roy / Volcan Alcedo giant tortoises (Chelonoidis nigra vandenburghi) wallowing in a muddy pool, possibly for thermoregulation or to deter parasites, with sulphur fumaroles, Alcedo Volcano, Isabela Island,...

Philippe Clement / Orange-barred Sulphur butterfly {Phoebis philea} on leaf, Costa Rica.

Pete Oxford / Giant sulphur butterflies (Phoebis sp.) at salt lick. Madre de Dios river, Amazonia, Peru, Southern Africa

Christian Ziegler / Left to right, from top: Blue Helicopter Damselfly (Megaloprepus coerulatus), Mydas Fly (Mydidae), Saw-nosed Planthopper (Cathedra serrata), Metalmark (Lymnas pixe), Grasshopper (Proscopia panamensis)...

Adrian Davies / Straight-lined sulphur butterfly (Phoebis trite) male, in visible light, top, and reflected Ultraviolet light, bottom. Pinned specimen.

Claudio Contreras / Large orange sulphur butterfly (Phoebis agarithe) on leaf. Tamaulipas state, Mexico.

Lynn M. Stone / Cloudless sulphur butterfly (Phoebis sennae) nectaring on Zinnia. Connecticut, USA. August.