9801641 Barbosa and Legrand This research will determine how both direct and indirect effects of plant morphological complexity affect the efficiency of insect predation. Plant morphology can directly act on the predator by influencing its movement or indirectly by influencing its prey. The objective of this investigation is to test the hypothesis that plant morphological complexity will reduce the efficiency of predation by a beetle (Coccinella septempunctata), which is a predator of the pea aphid Acyrthosiphon pisum. The investigators propose to test the effect of plant morphological complexity by utilizing morphological mutant forms of the garden pea. Specifically, three forms have been selected based on their degree of complexity in edges and branching. The research has three objectives: 1) to determine the direct effects of plant morphological complexity on the aphid prey, 2) to determine the direct effects of plant complexity on the predatory search patterns, and 3) to determine the effects of plant morphological complexity when both predator and prey are present. This work will be done by making detailed observations on speed of movement of the predator on the different plants, location of search effort, time needed to find the prey and likelihood of leaving the plant. The results of this research will answer questions about the role of plant physical traits mediating tritrophic level interactions and the role of spatial structure heterogeneity in studies of predator-prey interactions.
