Seasonal changes in alary dimorphism of a water strider, Gerris paludum insularis (Motschulsky)

摘要: Abstract The water strider, Gerris paludum insularis (Motschulsky) shows trivoltinism in Kochi, Japan. first generation of offspring growing May and June show a higher proportion brachypterous adults than the other generations. In second August Deptember more macropterous appear A long-day photoperiod (14.5 h light-9.5 dark) during whole nymphal stage causes to be short-day 12 or 9.5 light each day. Only under (12 light), is significant effect temperature observed: high (30 ± 2°C) induces low (20 2°C).