Abstract
To understand the significance of the cross-attraction of Piezodorus hybneri to Riptortus pedestris pheromone, we investigated the physiological conditions of P. hybneri attracted to the synthetic pheromone of R. pedestris. More than 95% of P. hybneri females caught during the non-diapause period (from August to September) had already been mated. The adults were also attracted by the pheromone in late autumn, when they are likely to be in reproductive diapause. Fat-body development and the appearance of the stomach of the attracted adults varied from season to season, and no clear tendency was found. The function of R. pedestris pheromone for conspecifics has been demonstrated to be communication for food searching. Considering this function in R. pedestris and that nymphs and diapausing adults of P. hybneri are also attracted by the pheromone, P. hybneri possibly utilizes the R. pedestris pheromone for host searching (as a kairomone), rather than for mate finding.
