Although research on modern plant-arthropod associations is one of thecornerstones of biodiversity studies, very little of that interest haspercolated down to the fossil record. Much of this neglect is attributable todismissal of Paleozoic plant-arthropod interactions as being dominated bydetritivory, with substantive herbivory not emerging until the Mesozoic. Recentexamination of associations from some of the earliest terrestrial communitiesindicates that herbivory probably extends to the Early Devonian, in the form ofspore feeding and piercing-and-sucking. External feeding on pinnule margins andthe intimate and intricate association of galling are documented from theMiddle and Late Pennsylvanian, respectively. During the Early Permian, therange of external foliage feeding extended to hole feeding and skeletonizationand was characterized by the preferential targeting of certain seed plants. Atthe close of the Paleozoic, surface fluid feeding was established, but there isinconclusive evidence for mutualistic relationships between insect pollinivoresand seed plants. These data are gleaned from the largely separate trace-fossilrecords of gut contents, coprolites, and plant damage and the body-fossilrecords of plant reproductive and vegetative structures, insect mouthparts, andovipositors. While these discoveries accentuate the potential for identifyingparticular associations, the greatest theoretical demand is to establish thespectrum and level of intensity for the emergence of insect herbivory in arange of environments during the Pennsylvanian and Permian.