Fig. 2. Nocturnal bees and wasps. (A) The Central American sweat bee Megalopta genalis (Halictidae), whose sensitive apposition eyes allow them to forage at night by visually learning landmarks along the foraging route and around the nest entrance. Reproduced with the kind permission of the photographer, Dr Michael Pfaff. (B,C) The pale-yellow coloured Central American paper wasp Apoica pallens (Vespidae), which congregates on the outside of the nest (B) to create a distinctive pale object that may be visible to returning foragers at night. Photographs in B and C were reproduced with the kind permission of the photographer, Gillian Little, and Daniel Marlos from `What's That Bug?', a website devoted to popular entomology (www.whatsthatbug.com).