Fog basking by the Namib Desert beetle, Onymacris unguicularis

Abstract

THE Namib Desert along the south-western coast of Africa supports a sand dune fauna without counterpart elsewhere in the world¹. The trophic base of the arthropod fauna is wind-blown detritus². Aperiodic advective fog collection from vegetation³ or detritus⁴ is a possible source of water for diverse Namib animals. For the specialised fauna living in vegetation-less dunes, fog collection from detritus⁴, disturbed sand projections⁵, directly from humid air⁶, or from water precipitated on the body^4,7, seem to be the only possible water uptake methods. Water uptake from saturated or subsaturated air, demonstrated for a few arthropod species⁶, is not a physiological capability of Namib tenebrionids already investigated^4,6,7.