Abstract
Many insects can reach the diapausing stage with sufficient time to accumulate more metabolites in virtue of photoperiodic regulation. The present study investigated the effects of photoperiod on the larval development, pupal diapause induction and accumulation of metabolites under conditions of 25°C combined with long days (16L : 8D and 14L : 10D) and short days (12L : 12D, 10L : 14D and 8L : 16D) in the swallowtail, Sericinus montelus. All pupae entered diapause under short days but developed without diapause under long days. The average developmental periods of larvae (less than 19 days) under long days were shorter than those (greater than 20 days) under short days. Dry-weights of feculae in the larval stage under short days were significantly greater than those under long days. Average weights of pupae obtained under short days were significantly greater than those under long days in terms of fresh and dry weight. However, the water content of pupae showed a reverse tendency. Average contents of lipids of pupae obtained under short days were significantly higher than those obtained under long days except for the female obtained under 8L : 16D. Carbohydrate analysis revealed similar results except for the male obtained under 8L:16D. No significant differences were found in the analysis of proteic substances. We concluded that photoperiods associated with diapause induction caused more accumulation of metabolites during the prediapause period in this species.
