Evolutionary ecology of carnivorous plants

Nicholas J. Gotelli Dept of Biology, University of Vermont, Burlington, VT 05405, USA. Carnivorous plants have fascinated evolutionary ecologists, botanists and horticulturists for centuries. Early investigators were reluctant to accept that plants could consume insects and other small invertebrates1; Darwin2 provided the first detailed experimental evidence for carnivory in several genera. Since then, approximately 600 species of carnivorous plants have been identified in six angiosperm subclasses, including both monocotyledons and eudicotyledons3,4. Twentiethcentury botanists focused on describing the anatomical specializations and physiological mechanisms associated with botanical carnivory1,5 and identifying commonalities among the carnivorous plants. In the mid-1980s, Givnish6 proposed a general cost–benefit model to explain the restriction of most carnivorous plants to well-lit, nutrient-poor, waterlogged habitats. Although common ecological factors have led to some evolutionary convergence, focus on ecological similarities has obscured important evolutionary differences. Recent research on carnivorous plants has highlighted these differences, which illustrate the richness of ecological and evolutionary questions that can be approached with these plants. New research on carnivorous plant phylogeny informs interpretations of cost–benefit analyses for the evolution of carnivory in plants, use of captured prey, tradeoffs between attracting pollinators versus prey, and overall ecological effects of the carnivorous syndrome1. Recent studies also have successfully modeled the demography of some carnivorous plant populations, elucidating how changes in fitness affect population dynamics. As with other groups of plants, such as mangroves7 and alpine plants8 that exhibit broad evolutionary convergence because of strong selection in stressful habitats, detailed investigations of carnivorous plants at multiple biological scales can illustrate clearly the importance of ecological processes in determining evolutionary patterns.