2001 年 36 巻 1 号 p. 53-58
At 20°C, only 0–19% of newly emerged females of Argopistes coccinelliformis laid eggs under short-day conditions (LD 13.5 : 10.5, 13 : 11 and 12 : 12), but all females laid eggs within 30 days after emergence under long-day conditions (LD 14.5 : 9.5 and 15 : 9). The critical photoperiod was between LD 13.5 : 10.5 and 14 : 10. At 25°C, 27–39% of females laid eggs within 60 days after emergence even under short-day conditions (LD 12.5 : 11.5 and 12 : 12). All females laid eggs under long-day conditions (LD 14.5 : 9.5 and 15 : 9), but the preoviposition periods were longer than those at 20°C. The critical photoperiod was between LD 14 : 10 and 14.5 : 9.5 when it was estimated on the 20th day from emergence and between LD 12.5 : 11.5 and 13 : 11 when it was estimated on the 60th day. At 28°C, 41–73% of females laid eggs within 60 days after emergence under short-day conditions (LD 13 : 11, 12.5 : 11.5 and 12 : 12), but 14–33% of females did not lay eggs, even under long-day conditions. The critical photoperiod could not be determined. From the past and the present data, I concluded that A. coccinelliformis might produce 4 generations per year around Tokyo, central Japan, if new sprouts of host plants are available beyond the spring. The best season for trimming host plants would be late autumn–early winter to control the flea beetle population.
