Department of Entomology, University of Manitoba, 12 Dafoe Road, Winnipeg, Manitoba, Canada R3T 2N2.
J Insect Sci. 2012;12:119. doi: 10.1673/031.012.11901.
The Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), is a serious insect pest of stored products, and its late-instar larvae diapause as pre-pupae. Diapause induction in P. interpunctella was investigated for four populations obtained from Modesto, California, U.S.A.; Vancouver, British Columbia, Canada; and two locations from Winnipeg, Manitoba, Canada. Insects were reared at 25° C and 16:8 L:D for 9 days. The larvae were then either continuously maintained under those conditions or transferred to 25° C 8:16 L:D, 20° C 16:8 L:D, or 20° C 8:16 L:D, and the percent diapause was recorded. In the experiment with four populations, the highest diapause frequency was observed at 20° C 8:16 L:D. The two Winnipeg populations had significantly higher frequency of diapause than the California populations, indicating the increased frequency of diapause in populations from higher latitudes. In a second experiment, the Vancouver population was selected for diapause. Larvae were reared at 25° C 16:8 L:D for 9 days, then placed at 20° C 8:16 L:D for the rest of their development, and percent diapause was determined. Eggs laid by moths that completed diapause in this first (parental) generation were used to obtain a second generation (F1), and the experiment was repeated as in the first generation. Selection increased the frequency of diapause to 91%, compared to 26% in the unselected population, after selecting over two generations. The narrow sense heritability of selection in P. interpunctella was 0.39 in the first selection, and 0.82 in the second. This study has shown that both low temperature and short photoperiod are required to induce diapause in North American populations of P. interpunctella, and that selection can increase diapause in a few generations.
印度谷螟，Plodia interpunctella（Hübner）（鳞翅目：Pyralidae），是一种严重的仓储害虫，其晚期幼虫以预蛹形式滞育。对来自美国加利福尼亚州莫德斯托、加拿大不列颠哥伦比亚省温哥华以及加拿大马尼托巴省温尼伯的四个种群的 P. interpunctella 滞育诱导进行了研究。昆虫在 25°C 和 16:8 L:D 下饲养 9 天。然后，将幼虫连续维持在这些条件下，或转移到 25°C 8:16 L:D、20°C 16:8 L:D 或 20°C 8:16 L:D，并记录滞育率。在四组种群的实验中，在 20°C 8:16 L:D 下观察到最高的滞育频率。两个温尼伯种群的滞育频率明显高于加利福尼亚种群，表明来自高纬度地区的种群滞育频率增加。在第二个实验中，选择温哥华种群进行滞育。幼虫在 25°C 16:8 L:D 下饲养 9 天，然后放置在 20°C 8:16 L:D 下完成发育，并确定滞育率。在第一代（亲代）中完成滞育的蛾子产下的卵用于获得第二代（F1），并重复第一代的实验。与未选择的种群相比，经过两代以上的选择，滞育频率增加到 91%，而未选择的种群的滞育频率为 26%。在 P. interpunctella 中，选择的狭义遗传力在第一代选择中为 0.39，在第二代选择中为 0.82。本研究表明，低温和短光照周期是诱导北美 P. interpunctella 种群滞育所必需的，并且选择可以在几代内增加滞育。
