美国白蛾成虫复眼的外部形态及显微结构观察

External Morphology and Microstructure of the Compound Eye of Hyphantria cunea ( Lepidoptera: Arctiidae)

利用扫描电镜和石蜡切片技术观察研究美国白蛾成虫复眼外部形态、显微结构及其在不同光照强度下的变化。结果表明:1)该蛾复眼半球形,成倒"八"字形排列,雌、雄蛾复眼的小眼数量分别约为2700和2900个;2)小眼主要由屈光器、小网膜细胞柱、视杆和基膜组成,其中屈光器、小网膜细胞柱周围环绕着初级虹膜色素细胞和6个次级虹膜色素细胞,同时基膜处也有基膜色素颗粒分布,且气管密集;3)明适应时,大部分次级虹膜色素颗粒向近心端移动,均匀分散在晶锥远端至视杆远端的小眼之间;暗适应时,次级虹膜色素颗粒逐渐向晶锥远心端方向集中,最后分布在各晶锥周围;4)在相同明、暗环境中,雌、雄成虫复眼的显微结构差异不明显。美国白蛾为具有重叠像眼的夜行性昆虫,其复眼主要通过色素颗粒位移等调节入光量,以便适应外界不同光环境的变化。

The external morphology of the compound eye of Hyphantria cunea,and the microstructure and its changes under different light intensity were observed by using a scanning electron microscopy and an optics microscope. The result showed that the compound eyes were hemispherical,and formed an upended typeface of the Chinese figure ＂eight＂on the head. Male and female eyes have approximately 2 900 and 2 700 ommatidia. Each ommatidium was composed of dioptric apparatus,retinula cell column,the rhabdom and basement membrane. The dioptric apparatus and retinula cell column were surrounded by primary iris pigment cells and six secondary iris pigment cells,and pigment granules and a reflecting tracheal sheath were found in the basement membrane. Moreover,in light adaptation,most of pigment granules of secondary iris pigment cells gradually invaded the clear-zone from the cone region and evenly distributed in the whole region between the cones and the clear-zone. When the eye was in dark adaptation,the pigment granules of secondary iris pigment cells withdrew back to the cones and distributed around the crystalline cone. However,the microstructures of male and female compound eyes were not different under the same light- or dark-adaptation. In conclusion,the compound eye of H. cunea belonged to a refracting superposition eye. In light- or dark-adaptation,it could adapt to the change of ambience light intensity by controlling the longitudinal movement of pigment granules.