Mimicry and mutualism in carnivorous pitcher plants (Sarraceniaceae, Nepenthaceae, Cephalotaceae, Bromeliaceae)

The carnivorous pitcher plants of the Sarraceniaceae, Nepenthaceae and Cephalotaceae seem to have developed attraction and rewarding systems which resemble those of many flowers. Contrary to a previous view, Batcsian mimicry does not appear to apply to pitcher traps because: (a) there is no evidence of insects visiting traps by mistake, (b) no model is known for any one of the traps, (c) the duration of the trap activity and the structure of the plant community are not compatible with a deceptive mimetic status, (d) nectar which is a real reward is provided to visiting insects by the pitcher plants. It is suggested that these plants perform mutual rather than deceptive relations with the insect communities in their habitats. Insects benefit from nectar which is provided by pitchers and which serves for their nutrition in habitats where sources of floral nectar might be either uncommon or absent. At the same time the insects pay the plants in a small portion of their community which is 'sacrificed' as prey and consumed by the plants, which grow in nutrient deficient soils.