Do plants forage? The resources that plants consume come from various sources: water and nutrients from the soil, nitrogen and phosphorous from microbial symbionts, light from the solar radiation and, in the case of carnivorous plants, nutrients from animal prey. And, in the heterogeneous world in which plants live, phenotypic plasticity comes in handy: stems elongate in response to shade from neighbors and defenses are induced following herbivory. Recently, biologists have developed conceptual models and experiments that show the use, by plants, of phenotypic plasticity, and yes, even optimal foraging, in terms of ramet-level specialization, for maximal resource acquisition. In a new paper, Ellison and Gotelli [1xNitrogen availability alters the expression of carnivory in the northern pitcher plant, Sarracenia purpurea. Ellison, A.M. and Gotelli, N.J. Proc. Natl. Acad. Sci. U. S. A. 2002; 99: 4409–4412Crossref | PubMed | Scopus (72)See all References][1] show a similar pattern for a carnivorous plant, extending our knowledge of phenotypic plasticity in plant-resource acquisition.The northern pitcher plant Sarracenia purpurea inhabits open areas in bogs and fens; such nutrient-poor sites are thought to favor carnivory in plants. The high carbon:nitrogen (C:N) ratio of such sites is purported to allow for the investment of excess C in prey-capturing (i.e. N-capturing) organs. Over three years of field experiments, Ellison and Gotelli show that additions of N to natural plant populations in New England led to a reduction in prey-capturing pitchers (modified leaves) and an increase in phyllodia, or leaves that are specialized for C capture. Indeed, at increasing N levels, not only did the capacity for carnivory decrease, but the maximum photosynthesis rates also increased linearly. Results were consistent when nutrients were added to individual plants, whole plots, and when the authors surveyed the natural correlation between nitrate levels and indices of pitcher size across 26 bogs. The concordance of manipulative experiments with the observed geographical pattern is a satisfying indication that the environment is a key player in the distribution of phenotypic variation in resource acquisition.These results are similar to recent demonstrations of resource quality affecting the relative consumption of different trophic levels in omnivorous animals. But, other than the fantastic natural history, what is the real advance here? First, the strong influence of the biotic and abiotic environment on apparently adaptive phenotypes, even in organisms that appear to live in homogeneous environments, reinforces the view of economy in nature and the importance of phenotypic plasticity. Second, the results are consistent with Givnish et al.'s C–N-based hypothesis for the origin of botanical carnivory. Carnivorous plants are not only found primarily in sunny, moist and nutrient-poor sites, but carnivory is also reduced when these conditions are ameliorated. This phenotypic reallocation can occur within a single growing season, consistent with thinking of the plants as foragers. Finally, from the perspective of global change, Ellison and Gotelli propose that the pitcher:phyllode ratio could be a useful indicator of local rates of N deposition. This study therefore represents an important contribution linking theory, description and experiment, and potential application.