美国白蛾幼虫消化道形态和超微结构观察

Morphological and ultrastructural characterization of the alimentary canal in larvae of Hyphantria cunea Drury

美国白蛾Hyphantria cunea Drury是我国重要的林业检疫性害虫之一,世界范围内寄主多达600余种,对我国林业生产和生态环境建设造成了巨大损失。明确美国白蛾幼虫消化道各部分的形态结构,可为进一步研究其幼虫的食性及消化机能奠定基础。利用光学显微镜、扫描电子显微镜与透射电子显微镜观察了美国白蛾6龄幼虫消化道形态及超微结构。美国白蛾幼虫的消化道由前肠、中肠、后肠组成。前肠是消化道最长的部分,占整个消化道的54.27%,包括咽、食道、嗉囊、前胃四部分;中肠较短,占整个消化道的21.28%,内部具围食膜;后肠由幽门、回肠、结肠和直肠组成,幽门由幽门锥和幽门瓣组成。马氏管共6条,丝腺2条。美国白蛾幼虫消化道总体结构与大部分鳞翅目消化道结构相似,但是其前肠在长度上发生了较大的变异,本文进一步讨论了美国白蛾幼虫消化道结构与其食性及耐饥饿能力等的相关性。

Hyphantria cunea Drury is one of the most important forest quarantine pests in China.It has a wide host plant range of more than 600 species in the world,and has caused huge damage to forestry and ecological environment.To clarify the morphological structure of the alimentary tract of H.cunea larvae,can help to explore the feeding habits and digestive physiology of H.cunea larvae.The morphology and ultrastructure of the alimentary tract of H.cunea 6 th instar larvae of were observed by optical microscopy,scanning electron microscopy and transmission electron microscopy.The alimentary tract of H.cunea larvae consists of the foregut,midgut and hindgut.The foregut is the longest part of the alimentary tract,which accounts 54.27%of the entire alimentary tract,includes the pharynx,oesophagus,crop and proventriculus.The midgut is relatively short,accounting for only 21.28%of the entire alimentary tract,with a peritrophic membrane inside;the hindgut consists of the pylorus,ileum,colon and rectum.The pylorus consists of the pyloric cone and the pyloric valve.There are 6 malpighian tubes and 2 silk glands.The alimentary tract of H.cunea larvae is similar to most of Lepidopteran alimentary tracts,except that the foregut has a large variation in length.The correlation between the alimentary tract structures of the H.cunea larvae and its self-defense mechanism,feeding habits and hunger tolerance is further discussed.