Carnivorous plants occupy nutrient-poor environments and have evolved a number of mechanisms to attract, trap, and digest insect prey to supplement nutrient uptake from the soil. However, most carnivorous plants depend on insects for pollination. Because studies of the cues used to attract prey and pollinators are still in their infancy, it is unknown whether different cues are used for pollinators and prey. We examined volatiles emitted from the pitcher plant, Sarracenia alata, in a bog in west central Louisiana. We collected volatile samples from (1) capturing pitchers, (2) non-capturing pitchers, (3) flowers accessible to pollinators, and (4) flowers from which pollinators had been excluded. Volatiles were analyzed by gas chromatography-mass spectrometry. We hypothesized that pitchers and flowers would have distinct volatile signatures. We further hypothesized that capturing and non-capturing pitchers would exhibit differences in volatile signatures.
Results/Conclusions
Floral volatiles were dominated by terpenoids common to floral scent such as b-myrcene, limonene, trans- and cis-ocimene, among others. Preliminary analyses indicate that there are no qualitative differences between flowers open to pollinators and those from which pollinators had been excluded, but there were differences in relative concentrations of compounds. Although some compounds were found in both flowers and pitchers, the overall volatile signature of flowers and pitchers differed. Differences between flowers and pitchers in volatile signatures may lead to differences in attraction of pollinators and prey. We observed differences in volatiles between capturing and non-capturing pitchers. Changes in volatile emissions in capturing pitchers may be associated with changes in prey capture from leaf visitors early in the growing season to carrion feeders later.