小菜蛾幼虫、蛹和成虫的雌雄形态识别

摘要

Based on the morphological appearances and descriptions in literature, a simple and convenient method for identifying the sex of diamondback moth (DBM), Plutella xylostella (Linnaeus), was developed. The results showed that the sex of the first- and second-instar larvae was not easily distinguishable by naked eyes or optical microscopic observation. However, the male third- and fourth-instar larva showed a lighter colored fifth abdominal segment than that on the female counterparts. On the male pupae, a lump on each side of a short, longitudinal slip was visible near the gonopore on the 9-1 abdominal segment. The female pupae had a long, longitudinal slip between the genital pore on the 8th abdominal segment and the oviporus on the 9th segment. The adult males had characteristic brown wings with a wavy edge on the posterior margin and a yorked abdominal end. The female adults, on the other hand, were lighter in color and bigger on body size than the males, and had their abdominal ends appeared round in shape.%在形态观察基础上,结合相关文献,系统描述了小菜蛾幼虫、蛹和成虫的雌雄形态快速识别特征.结果表明,用肉眼和光学显微镜无法区分小菜蛾1龄和2龄幼虫的性别,但可以区分3龄和4龄幼虫的性别,主要特征是雄虫在第5腹节内有睾丸,背面呈浅黄色,与相邻体节形成明显区别.小菜蛾雄蛹第9腹节腹面有1个生殖孔,形成短纵裂缝且两边各有一瘤状突起,而雌蛹第8腹节腹面有1个生殖孔,第9腹节腹面有1个产卵孔,2孔之间连成长纵裂缝.雄蛾翅后缘从翅基到外缘呈三度曲波状的黄褐色带,腹部末端钳状,抱握器微张开;雌蛾体色较雄蛾淡,个体较雄蛾大,腹部末端圆筒形.