FORAGING BEHAVIOR OF LACEWING LARVAE (NEUROPTERA, CHRYSOPIDAE) ON PLANTS WITH DIVERGENT ARCHITECTURES

We investigated the effects of plant architecture on predator-prey int eractions by quantifying the behavior of green lacewing larvae on pere nnial grasses with divergent leaf architectures. Crested wheatgrass pr oduces flat, broad leaves similar to those of,wheat, whereas Indian ri cegrass bears linear leaves that are tightly rolled inward. In the abs ence of prey, lacewing time budgets and residence times were similar o n the two grasses, although predators tended to search longer on crest ed wheatgrass, On plants infested with the Russian wheat aphid, lacewi ng larvae dislodged, contacted, and captured significantly more aphids on Indian ricegrass than on crested wheatgrass. Comparisons between a phid-free and aphid-infested plants suggest that differences in plant architecture modified prey accessibility rather than predator movement . Aphids on seedlings and mature plants of crested wheatgrass frequent ly occurred in concealed locations, such as in the rolls of immature l eaves or in the blade-sheath junctions of mature leaves; aphids on Ind ian ricegrass were more likely to feed in exposed locations. Our focal -animal observations were consistent with results from population-leve l experiments and suggest that short-term, behavioral studies may help predict the effectiveness of predators at larger spatial and temporal scales.