The effect of trap colour and trap-flower distance on prey and pollinator capture in carnivorous Drosera species

1. The functional features of carnivorous plants’ traps have been mostly interpreted as adaptations to capture prey. Carnivorous plants that feed on insects, however, run the risk that increasing trapping effectiveness might in turn reduce reproductive success through capture of pollinators. Such a pollinator–prey conflict might play an important role in the evolution of trap features. In carnivorous plants with sticky leaves (e.g. Drosera, Pinguicula), both spatial distance between traps and flowers and their visual signals (e.g. colour, display size) likely play a role in attracting prey but it has also been suggested that they affect the risk of potential pollinators landing on a trap. It has been reported, for example, that red pigmentation in carnivorous plants may lure insect prey to traps. This idea remains controversial, however, because colour vision of most insects does not extend very far into the red part of the spectrum. 2. We tested an alternative hypothesis, namely that r...