Common knotweed, Polygonum aviculare L. (Polygonaceae), a summer annual occurring in agricultural and urban settings in the Sacramento Valley, was attended by numerous predatory and parasitic insects, many of which fed on the exposed floral nectar. Representatives of 36 insect taxa were observed feeding at the flowers; 29 of these groups contain entomophagous species. Other entomophagous insects were associated with a honeydew-producing, host-specific aphid, Aphis avicularis Hille Ris Lambers. Among predators frequently observed feeding at the flowers were bigeyed bugs, Geocoris spp.
