不同虫龄桉蝙蛾幼虫下颚感器的扫描电镜观察

Scanning electron microscopic observation of maxillary sensilla of Endoclita signifer(Lepidoptera:Hepialidae)larvae at different instars

【目的】观察不同虫龄桉蝙蛾幼虫下颚感器的形态特征、分布、发育过程及数量,明确其幼虫下颚所具有的感器类型及其分布特点,为进一步研究桉蝙蛾幼虫口器上感器的生理功能与其取食行为的适应性奠定基础。【方法】以桉蝙蛾5龄、9龄和12龄幼虫为试验材料,将其头部切下,清洗、脱水、干燥制备成样品,利用扫描电镜观察不同虫龄桉蝙蛾幼虫下颚感器,并进行描述和统计分析。【结果】桉蝙蛾幼虫下颚由轴节、茎节、外颚叶和下颚须组成。轴节和茎节分别具有2对和1对刺形感器;外颚叶具有2对锥形感器、2对栓锥形感器和5对刺形感器,其中锥形感器和刺形感器均分为2个亚型;下颚须具有1对指形感器、1对柱形感器和3对锥形感器,其中锥形感器分为2个亚型。位于茎节和轴节的刺形感器(C)、外颚叶的锥形感器Ⅱ亚型(BⅡ)和下颚须的锥形感器Ⅰ亚型(BⅠ)的长度和宽度均随虫龄的增长呈显著性上升趋势,其余感器的长度和宽度差异不显著。【结论】在桉蝙蛾幼虫生长发育过程中,不同类型感器的数量和分布情况基本不变,但长度会随虫龄的增长而增加,宽度也会有小范围的增长。

【Objective】This study observed the morphological characteristics,distribution,development process and number of sensilla on maxillary of Endoclita signifer larvae at different instars and clarified the types and distribution characteristics of maxillary sensilla to lay a foundation for further research on physiological function of mouthparts of E.signifer larvae and their adaptability to feeding behaviors.【Method】E.signifer larvae at 5th,9th and 12th instars were selected,and their heads were cut off,washed,dehydrated and dried to prepare samples.The maxillary sensilla of E.signifer larvae at different instars were observed by scanning electron microscope,and the description and statistical analysis were carried out.【Result】The maxillary of E.signifer larvae was composed of cardo,stipes,maxillary galea and maxillary palp.The cardo and stipes of E.signifer larvae had two pairs of sensilla chaetica and one pair of sensillum chaeticum,respectively.The maxillary galea had two pairs of sensilla basiconica,two pairs of sensilla styloconica and five pairs of sensilla chaetica,of which the sensilla basiconica and sensilla chaetica were equally divided into two subtypes.The maxillary palp had one pair of sensillum digitiformium,one pair of sensillum cylindricum and three pairs of sensilla basiconica,of which the sensilla basiconica can be divided into two subtypes.The length and width of the sensilla chaetica located at the cardo and stipes,the sensilla basiconica typeⅡof maxillary galea and the sensilla basiconica typeⅠof maxillary palp increased significantly with the growth of instar,while those of other sensilla had no significant differences.【Conclusion】The number and distribution of different types of sensilla were basically unchanged in the process of growth and development,but the length and width increased with the growth of instar.