二化螟水稻、茭白种群幼虫口器和触角及其感器扫描电镜观察

Mouthparts and Antenna and Their Associated Sensilla of Rice and Water-oat Populations of the Striped Rice Borer(Chilo suppressalis)

【目的】为明确二化螟不同寄主种群幼虫口器和触角及其感器,对上述结构的超微形态进行了观察。【方法】选择二化螟水稻、茭白种群幼虫口器和触角及其感器为研究材料,利用扫描电子显微镜进行观察。【结果】表明,二化螟两种群梗节具2个刺形感器、3个锥形感器;上唇具6对刺形感器;上颚切齿叶具7个端齿,基外侧具2个刺形感器;轴节和茎节各具1个刺形感器;外颚叶具3个锥形感器、2个刺形感器和2个栓锥感器;下颚须侧缘具1个指形感器;下唇须端部有1个刺形感器。两种群间鞭节和下颚须感器数目存在差异:茭白种群鞭节具1个栓锥感器和2个锥形感器,水稻种群则具1个栓锥感器和1个锥形感器;茭白种群下颚须具5个锥形感器和3个柱形感器,而水稻种群具4个锥形感器和4个柱形感器。在感器长度上,茭白种群部分龄期幼虫的部分刺形感器(分布于梗节、轴节、茎节)、锥形感器(分布于梗节、下颚须、外颚叶)、栓锥感器(分布于鞭节、外颚叶)显著长于水稻种群的相应感器。茭白种群(1~5龄)的部分柱形感器(分布于下颚须)、3~5龄幼虫部分刺形感器(分布于外颚叶)显著短于水稻种群的相应感器。

【Objective】In order to explore the ultramorphology in antennae and mouthparts and associated sensilla(especially the types,number and distribution)in different populations of Chilo suppressalis Walker,the two organs and their sensilla at different developmental stages were investigated.【Method】The antennae and mouthparts and associated sensilla of rice and water-oat populations of C.suppressalis were used as materials.We observed the organs with a scanning electron microscopy.【Result】The antennae,mouthparts and their associated sensilla varied with larval stage within populations.The two populations of C.suppressalis possessed the following characters:the pedicel was typically equipped with three sensilla basiconica and two sensilla chaetica;six pairs of sensilla chaetica were found on the labrum;the mandible bore seven incisor cusps distally,and carried two sensilla chaetica basally on its outer face;the cardo andstipes each possessed a sensillum chaeticum distally;three sensilla basiconica,two sensilla chaetica and two sensillastyloconica were observed on the galea;a sensillum digitiformium laterally was found on each maxillary palpus;andsensillum chaeticum were observed on the distal of each labial palpus.Difference in sensillum number of flagellum andmaxillary palpus between the two populations were as follows:flagellum of the water-oat population was equipped with asensillum styloconicum and two sensilla basiconica,while the rice population possessed a sensillum styloconicum and asensilla basiconica;maxillary palpus of the former was equipped with rive sensilla basiconica and three cylindricalsensilla,whereas four sensilla basiconica and four cylindrical sensilla were carried in the latter.Some sensilla chaetica(located at the pedicel,cardo,stipes),sensilla basiconica(distributed at the pedicel,maxillary palpus and galea),sensillasty loconica(distributed at the flagellum and galea)of water-oat population were significantly longer than those of the rice population;whereas some cylindrical sensilla(located at the maxillary palpus)of1st-to5th-instar larvae,and sensilla chaetica(distributed at the galea)of3rd-to5th-instar larvae were significantly shorter than those of the rice population.