Waggle dana. The behaviour pattern by which bees convey information on the location of pollen supplies.

Wallace’s line. An imaginary line that runs between the Indonesian islands of Bali and Lombok and represents the separation of the Australian and Oriental faunas. It was proposed by the naturalist A.R. Wallace (1823-1913) who had noted that the mammals in South-east Asia are different from and more advanced than their Australian counterparts. He suggested this because the Australian continent had split away from Asia before the better adapted placental mammals evolved in Asia. Hence the isolated Australian marsupials and monotremes were able to thrive while those in Asia were driven to extinction by competition from placental mammals.

Warfarin. 3-(alpha-acetonylbenzyl)-4-hydroxycoumarin: a synthetic anticoagulant used both therapeutically in clinical medicine and, in lethal doses, as a rodenticide.

Warning Coloration. (aposematic coloration). The conspicuous markings of an animal that make it easily recognizable and warn would be predators that it is a poisonous, foultasting, or dangerous species. For example, the yellow and black stripped abdomen of the wasp warns of its sting. See also mimicry.