Advertising in biology

Advertising in biology means the use of displays by organisms such as animals and plants to signal their presence for some evolutionary reason. Such signalling may be honest, used to attract other organisms, as when flowers use bright colours, patterns, and scent to attract pollinators such as bees; or, again honestly, to warn off other organisms, as when distasteful animals use warning coloration to prevent attacks from potential predators. Such honest advertising benefits both the sender and the receiver. Other organisms may advertise dishonestly; in Batesian mimicry, edible animals more or less accurately mimic distasteful animals to reduce their own risk of being attacked by predators. Insect-pollinated flowers use bright colours, patterns, rewards of nectar and pollen, and scent to attract pollinators such as bees. Some also use drugs such as caffeine to encourage bees to return more often. Advertising is influenced by sexual selection: in dioecious plants like sallow, the male flowers are brighter yellow (the colour of their pollen) and have more scent than female flowers. Honey bees are more attracted by the brighter male flowers, but not by their scent. Many flowers that are adapted for pollination by birds produce copious quantities of nectar and advertise this with their red coloration. Insects see red less well than other colours, and the plant needs to devote its energy to attracting birds that can act as pollinators rather than insects that cannot. In fact, the Canary Island endemic Echium wildpretii has two subspecies, a red-flowering one on Teneriffe which is mainly pollinated by birds, and a pink-flowered one on Las Palmas which is pollinated by insects. Advertising takes a variety of forms in animals. Breeding adults often display to attract a mate. Breeding males of sexually dimorphic birds, such as peacocks, birds of paradise and bower birds, have elaborate plumage, song, and behaviour. These evolved through sexual selection by females.