Photoperiodism and seasonal adaptations in some seed-sucking bugs (Heteroptera) in central Japan

Photoperiodic responses and their adaptive significance were examined in Riptortus clavatus (Heteroptera: Alydidae), Plautia crossota stali, Dolycoris baccarum, Aelia fieberi, Nezara viridula, Nezara antennata, Graphosoma rubrolineatum, Dybowskyia reticulata, and Eurydema rugosum (Heteroptera: Pentatomidae) in the Kyoto-Osaka area, central Japan. All of these species overwinter as adults in diapause. Although they have similar feeding habits, their photoperiodic responses were quite different. Riptortus clavatus, P. c. stali, D. baccarum and N. viridula showed long-day photoperiodic responses with critical daylengths between 13 and 14 h, and were assumed to have three generations per year. The photoperiodic responses of the other five species were different both from those of the above species and from each other. These results suggested that A. fieberi and N. antennata produce two generations per year, and G. rubrolineatum, D. reticulata and E. rugosum have one or two generations per year. Nezara antennata showed a long-day-short-day photoperiodic response with summer adult diapause, which may avoid production of heat-susceptible nymphs in the hottest season. With the exception of N. antennata, the photoperiodic responses resulting in fewer generations were shown to be adaptations to dietary conditions in the field.