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Human activities such as fossil fuel burning and deforestation have contributed significantly to the increasing levels of CO2 in the atmosphere since the industrial revolution. Under the IPCC A1FI emission scenario, we are expected to reach levels as high as 1000 ppm by the end of the century. On average, C3 plants experience a 27% increase in carbon to nitrogen (C:N) ratio under elevated CO2. As a result, C3 plants typically exhibit an increase in carbon-based secondary compounds. Carnivorous plants are a rare type of C3 plant that has adapted to survive in low nutrient soils. The insectivorous pitcher plant Sarracenia purpurea, is a special kind of C3 plant that captures prey to obtain nutrients and provides an aquatic habitat for mosquito and midge larvae. This study focuses on the potential effects of elevated CO2 on pitcher plant nectar composition, prey capture, and inquiline communities. We modified a technique using filter paper wicks to sample the nectar content of 24 pitchers in Mud Lake Bog, Pellston, Michigan. After our final nectar collection, we removed the fluid from each pitcher with a turkey baster augmented by syringe injection. We first counted and removed any inquilines from the pitchers and placed them separately in a petri dish, then we identified each prey head capsule using a dissecting microscope, then counted, weighed, and dried all contents for total prey biomass. Finally, we removed the lips from the 24 pitchers for C:N analysis. We used our results to address the following questions: 1) Do carbon-based sugars in nectar affect the total biomass of prey captured and/or the specific types captured by a pitcher?, 2) Do sugars in nectar affect the number of inquilines and/or the specific types of inquilines within a pitcher?, and 3) Is pitcher C:N correlated with sugar content of nectar? Our data suggest that prey biomass, prey types especially mosquitoes and ants, inquiline abundance and C:N are positively correlated with the amount of nectar present on the lip of the pitcher. We therefore infer that future increases in C:N due to future increases in atmospheric CO2 will have positive effects on pitcher plants and the insect communities they support.
Courtney, Deirdre, "Potential Effects of Elevated CO2 on Pitcher Plant Nectar Composition, Prey Capture, and Inquiline Communities" (2014). Honors Theses. 2524.
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