嘴壶夜蛾的形态、生活史及昼夜节律

嘴壶夜蛾Oraesia emarginata (Fabricius)是危害水果果实的重要害虫之一， 其成虫和幼虫取食不同的寄主植物， 可以作为理想的嗅觉研究模式昆虫。为了全面地了解嘴壶夜蛾的形态特性和生物学特性， 本实验通过室内饲喂和红外摄像机观察， 对嘴壶夜蛾各虫态的外部形态、 发育以及昼夜活动节律进行了系统研究。结果表明： 嘴壶夜蛾的各龄幼虫可以通过体色， 体表色斑的类型、 位置和数量， 以及腹足的数量进行区别。通过蛹的生殖孔和成虫触角能够很好地区别雌雄。在室内饲养条件下， 嘴壶夜蛾的寿命为53.18±1.70 d， 存活率为63.62%±2.15%， 其中幼虫的发育历期最长， 存活率最低， 卵的发育历期最短， 存活率最高， 雄成虫的存活时间显著长于雌成虫（P=0.008）。6龄幼虫的发育历期（5.29±0.15 d）显著长于其余各龄幼虫（P<0.001）。同一龄发育中期幼虫的体长和体重显著大于将蜕皮幼虫和刚蜕皮幼虫（P≤0.037）； 第2-6龄刚蜕皮幼虫的体重和体长与前一龄发育中期幼虫之间没有显著差异（P≥0.106）。幼虫在光期的孵化、 蜕皮和化蛹比例高于暗期， 而成虫在暗期的飞行、 产卵比例高于光期， 成虫的飞行随着暗期时间的增加而逐渐变少， 光期成虫的飞行主要在开灯之后1 h。成虫交配集中在暗期的第3-5 小时。本研究结果有助于制定有效的嘴壶夜蛾防治措施， 而且为嘴壶夜蛾作为嗅觉研究模式奠定基础。

Morphology,life history and circadian rhythm of the fruit-piercing moth,Oraesia emarginata (Lepidoptera: Noctuidae)

The fruit piercing moth, Oraesia emarginata (Fabricius), is an important pest for fruits and can be used as model insect for olfactory study, because its larvae and adults feed on different host type. In order to understand the morphological and biological characteristics of O. emarginata, its external morphological characters, developmental duration and the circadian rhythm of different developmental stages were studied through artificially feeding in the controlled conditions and monitoring with infrared camera. The results showed that different larval instars could be differentiated by body color, the color, location and number of spots in the body, and the number of abdominal feet. The genital pore in the pupae, and moth antennae could be used for sex identification. The life time of O. emarginata was 53.18±1.70 d and the survival rate was 63.62%±2.15% under laboratory conditions. Compared with other stages, larva had the longest developmental duration and lowest survival rate while the egg had the shortest developmental duration and highest survival rate. Male moths lived significantly longer than female moths (P=0.008). The developmental duration of the 6th instar larva (5.29±0.15 d) was significantly longer than that of other larval instars (P<0.001). The body length and body weight of larvae in the middle time of an instar were significantly larger than those before ecdysis and after ecdysis for the same instar (P≤0.037). There were no significant differences in the body length and body weight between the larvae after ecdysis of a later instar and the larvae in the middle time of the former instar (P≥0.106). The proportions of hatching, ecdysis and pupation of larvae during light period were higher than those during dark period. However, the rates of moths in flight and oviposition under dark condition were higher than those under light condition. The flight frequency of moths decreased when the dark time prolonged and the moths in flight during light period were mostly found in the first hour of light period. The moth copulation was only found at 3-5 h after dark. These results will not only help to design more efficient pest control methods, but also provide knowledge for using the insect as a model for olfactory study.