From 2008 to 2009, we investigated the effects of photoperiod and temperature on the development of a noctuid moth, Asota ficus, under laboratory conditions, and its seasonal occurrence in Osaka Prefecture, central Japan, near its current northern distribution limit. At 20℃, most individuals reared under a photoperiod of 10L-14D, 11L-13D or 12L-12D entered diapause in the pupal stage, whereas those under 13L-11D, 14L-10D or 16L-8D developed into adults without any arrest of development. Individuals at 25℃ did not enter pupal diapause irrespective of photoperiod. The critical photoperiod for diapause induction at 20℃ was about 12.5h. Diapause intensity varied among photoperiodic regimes, and the time required for adult emergence after chilling of diapausing pupae was longer in individuals reared under 12L-12D than under 10L-14D. Most females had mature eggs 5 days after adult emergence irrespective of photoperiod and temperature. Under quasi-natural conditions, individuals pupating between October and December emerged as adults in the first half of May next year. In the field, egg and/or larval masses were found from May to November except in August.
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