Our study was designed to assess the consequences of plant-toplant information exchange for herbivory rates and plant fitness in a realistic plant community. The results from our field study contrast sharply with previous experiments in which damage to neighboring plants consistently led to reduced susceptibility to herbivores and greater plant fitness. Instead, we found that the effects of damage to a neighbor in the field depended on the plant species and the relatedness of the neighbor. In striking contrast to previous studies, damage to neighbors decreased various measures of receiver fitness in all three plant species in the field, and in A. mollis, receivers experienced more damage and delayed phenology when neighbors were experimentally damaged. They tended to parallel patterns observed in the field. The similarity between the palatability assays and the field damage observations persisted despite differences in root contact and duration of exposure to emitter volatiles between field receiver plants versus bioassay receiver plants. For example, in S. arvensis, damage to the emitter plant increased the leaf tissue that Spodoptera caterpillars consumed on bioassay receivers that were placed in the field for only two days and increased the likelihood that Spodoptera caterpillars would initiate feeding. The only case in which damage to an emitter plant resulted in evidence for induced resistance in a receiver plant was in laboratory feeding trials in which S. arvensis receivers were challenged by a specialist herbivore. In this case, damage to a related emitter plant decreased the leaf tissue that Pieris caterpillars consumed, but had no effect on Pieris weight gain. The effects of damage-induced plant cues on neighboring plants were often highly dependent on whether the emitter and receiver plants were genetically related to one another. For example, damage to a neighbor resulted in higher natural levels of herbivory to A. mollis, but this trend was only apparent when neighboring plants were close relatives. Likewise, in all three plant species, damage to a neighbor reduced the receiver’s lifetime seed production only when that neighbor was a close relative. Finally, in lab feeding trials with the specialist herbivore Pieris, damage to a neighboring plant decreased Pieris feeding only when the neighbor was related to the focal plant. As these examples suggest, we found that the consequences of having a wounded neighbor were generally stronger when the neighboring plant was a close relative. Our results strongly TH-302 918633-87-1 suggest that the genetic relationships among neighbors within a plant population are an important component of plant-herbivore interactions, and that genetic relatedness influences the transfer of information between plants. The complex, often indirect ecological interactions that occur in natural settings may explain why the effects of neighbor-wounding we observed did not conform to simpler expectations. The emerging pattern from previous studies is that herbivore damage to an emitter plant elicits.