Pheromone contents and physiological conditions of adult bean bugs, Riptortus pedestris (Heteroptera: Alydidae), attracted to conspecific males during nondiapause and diapause periods in fields

Abstract

The contents of five pheromone components and the physiological conditions of wild male and female Riptortus pedestris attracted to bait males during non-diapause (from early July to early September) and diapause (from mid-September to mid-October) periods in the field were examined. Although tetradecyl isobutyrate (14:iBu), an essential pheromone component, was detected in males attracting conspecific individuals, this component was not detected in almost all males attracted to bait males. This indicated that the attracted males are not attractive to conspecific individuals unlike bait males. During non-diapause, (E)-2-hexenyl (E)-2-hexenoate and (E)-2-hexenyl (Z)-3-hexenoate, which are synergistic components of the pheromone, were detected in most males. On the other hand, these components were not detected in most of the males during diapause, indicating that the function of these two components in the attractiveness of males might be related with the sexual communication mechanism. (E)-2-hexenyl hexanoate was detected in almost all males and females attracted to bait males. The physiological conditions were similar between adults attracted to bait males during non-diapause and diapause. Most of the attracted adults had little or no food in their stomachs. This suggested that male-attracted adults of R. pedestris are starved and are searching for suitable host plants.