Most organisms compete for resources, and this competition can affect the distribution and abundance of species as well as their evolution. Ecologists usually assume that species in a community evolve to be more different from one another in order to reduce competition. A more recent view is quite the opposite, suggesting that species will converge in the types of resources they use, becoming more similar and equal competitors. These views have been difficult to test because of the time required for species to evolve and the complicated experimental design needed to follow the simultaneous evolution of many competitors. In this project, multispecies evolution will be followed using the organisms found in the water-filled leaves of pitcher plants to determine if these contrasting views of community evolution are realistic. These leaves capture insects, which are eaten by bacteria, which are in turn consumed by protozoa, which are themselves eaten by mosquito larvae. There are several species of protozoa, which have been shown to evolve to become better competitors as the resource availability decreases in a leaf. The evolution of several species of protozoa will be followed by sampling communities from leaves of different ages, allowing increasing amounts of time for evolution to proceed. The protozoa will be tested for their competitive ability, as well as their ability to withstand predation, to quantify multispecies evolution through time in this natural community.
The small community of bacteria, protozoa, and insects found in pitcher plant leaves is also ideal for teaching K-12 students about ecosystems. A program will be continued that brings pitcher plants, microscopes, and other equipment into public school classrooms (primarily 8th and 9th grades). The focus is studying ecosystems at different scales: the local long-leaf pine forest, bogs, pitcher plants, and, at the smallest scale, ecosystems within pitcher plant leaves. Students suck the water out from leaves and study the invertebrate community, then discuss ecosystem dynamics and scale. At the University level, 2-4 undergraduate and 2 graduate students will be involved in this research. All will receive some training in basic lab and field methods, as well as data management and analysis. All undergraduates in this research will enroll in a one-credit research and reading course that will be taught in the summer of 2008 to provide a further introduction to scientific research.
