Ana Legrand, Ph.D.

My current research efforts focus on the influence of plant morphological variation on the control of pea aphid by its complex of predators and parasitoids. I am taking advantage of pea lines that possess single gene mutations that drastically alter the shape of leaves and stipules. By using near-isogenic lines I can control, as much as possible, other non-morphological factors such as phytochemicals and surface waxes. I have shown that changes in plant morphology did not influence the performance of the pea aphid. Subsequent research tested the hypothesis that predator efficacy should decrease as plant complexity increased. For experiments, we used near-isogenic pea lines that could be ranked from low to high complexity. Indeed, we obtained support for our hypothesis but it appears that predators have an idiosyncratic response to plant complexity. While foraging by ladybird beetleadults and larvae (Coccinella septempunctata) is hampered by increases in plant complexity, lacewing larvae (Chrysoperla rufilabris) are less affected.

In addition to exploring the effect on plant complexity, I have also studied how two other plant morphological traits influence the foraging success of coccinellid and chrysopid predators. For example, we found that the reduced stipule trait enhances predation on pea aphids and this is a trait that could be easily incorporated into pea cultivars with, presumably, no agronomic disadvantages. I hope to continue field investigations on the advantages of this morphological character. Currently, we are working on the influence of plant complexity on the intraguild interactions of pea aphid predators and parasitoids