Abstract
The effects of photoperiod and temperature on developmental and larval diapause of Dacne picta (Coleoptera: Erotylidae) were observed by rearing beetles on dried basidiocarps of shiitake mushroom, Lentinula edodes, under various environmental conditions in the laboratory. The theoretical lower thermal threshold and thermal constant for egg, larva and pupa were 12.0°C and 47.7 day-degrees, 7.3°C and 456.1 day-degrees and 5.9°C and 139.1 day-degrees, respectively. Diapause was induced in the 4th larval stadium under shorter daylength than 14 h and 13 h at 20°C and 25°C, respectively, and averted at a photoperiod ≥13.25 h at 20°C. The heat requirement indicated that the beetle may complete three generations per year in Tsuchiura, Japan (36°05′N, 140°10′E).
