The onset and termination of reproductive seasons in insects are determined by various environmental factors under natural conditions. These factors will be reviewed in seed-feeding heteropterans that have winter adult diapause in Japan. Most species use photoperiod to time the induction of adult diapause and therefore the termination of reproduction in autumn. In some species, however, temperature or the quality of food are also used as seasonal cues. For initiation of reproduction in spring, a temperature increase above the lower thermal threshold for postdiapause development is essential. The appearance of host plant seeds primarily determines the onset of reproduction in Dybowskyia reticulata, and the photoperiod plays a definitive role in Cletus punctiger. However, the proximate factors that determine the onset of reproduction in spring have not been examined as intensively as those for the termination of reproduction in autumn.
2004 by the Japanese Society of Applied Entomology and Zoology