昆虫学报 ›› 2020, Vol. 63 ›› Issue (12): 1441-1451.doi: 10.16380/j.kcxb.2020.12.002

• 研究论文 • 上一篇    下一篇

蒙古寒蝉末龄若虫与成虫复眼的形态、组织结构和超微结构

兰英, 魏琮*   

  1. (西北农林科技大学植物保护学院, 植保资源与病虫害治理教育部重点实验室, 陕西杨凌 712100)
  • 出版日期:2020-12-20 发布日期:2021-01-14

Morphology, histology and ultrastructure of the compound eyes of the last instar nymphs and adults of Meimuna mongolica(Hemiptera: Cicadidae)

LAN Ying, WEI Cong*    

  1. (Key Laboratory of Plant Protection Resources and Pest Management of the Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China)
  • Online:2020-12-20 Published:2021-01-14

摘要: 【目的】本研究旨在明确蒙古寒蝉Meimuna mongolica末龄(5龄)若虫与成虫复眼的差异,探讨蝉总科昆虫在若虫与成虫生态位发生改变的过程中复眼的形态结构及功能变化。【方法】采用光学显微镜、扫描电子显微镜和透射电子显微镜技术,详细观察和比较研究了蒙古寒蝉末龄若虫和成虫复眼的一般形态、组织结构和超微结构。【结果】蒙古寒蝉的复眼为并列像眼。出土羽化前其末龄若虫复眼的颜色逐渐由白色变为红色至深褐色,成虫复眼则为浅褐色。末龄若虫复眼表面具有毛形感器、锥形感器和刺形感器,成虫复眼表面无感器。末龄若虫白色复眼的表面为完整的角膜,未分化形成小眼面;末龄若虫红色和深褐色复眼则由许多五边形或六边形小眼组成,排列不甚规则;成虫复眼均由排列整齐的等边六边形小眼组成。末龄若虫白色复眼内部由大量细胞团构成,未分化形成小眼结构;在末龄若虫深褐色复眼中,小眼次级色素细胞的细胞核集中分布在视杆和晶锥之间;在成虫复眼中,小眼次级色素细胞的细胞核分布在晶锥近心端周围。末龄若虫深褐色复眼中的初级色素细胞和小网膜细胞内的色素颗粒分布较均匀,而成虫复眼小网膜细胞内的色素颗粒都分布在视杆周围。【结论】蒙古寒蝉不同发育阶段的末龄若虫与成虫的复眼在小眼发育程度、色素颗粒分布及表面感器有无等方面存在显著差异,红色复眼期是末龄若虫复眼的主要发育阶段。研究结果说明,蒙古寒蝉及其他具有同样生活习性与发育过程的蝉总科若虫的复眼在末龄的早期阶段及更早的低龄若虫阶段不具备视觉功能,但具有感受外界机械压力或其他环境刺激的功能。这应是该总科昆虫从若虫发育为成虫过程中对生态位显著改变(若虫长期在地下漆黑环境营固定生活,成虫则在地上生活)的一种适应。本研究获得的蒙古寒蝉末龄若虫和成虫复眼的形态、超微结构和功能方面的信息,为昆虫复眼的发育及其功能变化与生境的相关性研究提供了重要信息,也为深入探讨蝉总科与半翅目其他相关类群的系统演化提供了功能形态学方面的新信息。

关键词: 半翅目, 头喙亚目, 蝉科, 视觉器官, 发育, 形态, 超微结构

Abstract: 【Aim】 This study aims to clarify the differences in the compound eyes of the last instar (5th instar) nymphs and adults of the cicada Meimuna mongolica, so as to ascertain the changes in the morphological structure and functions of compound eyes of nymphs and adults of Cicadidae in the process of ecological niche shift. 【Methods】 The compound eyes of the last instar nymphs and adults of M. mongolicawere observed and compared at the morphological, histological and ultrastructural levels using light microscopy, scanning electron microscopy and transmission electron microscopy. 【Results】 The compound eyes of M. mongolica are of apposition type. The color of the compound eyes of the last instar nymphs change from white to red and dark brown gradually before adult emergence, whereas the compound eyes of the adults are light brown. Sensilla basiconica, sensilla trichoid and sensilla chaetica were observed on the surface of the compound eyes of the last instar nymphs, but no sensillum was found on the surface of the compound eyes of adults. The surface of the white compound eyes of the last instar nymphs has a complete cornea, and no ommatidial facet was observed. The red and dark brown compound eyes of the last instar nymphs are composed of many irregular, hexagonal or pentagonal ommatidia, whereas the compound eyes of adults are composed of equilateral hexagonal ommatidia. The white compound eyes of the last instar nymphs are composed of a large amount of clustered cells, and no ommatidium was observed. In each ommatidium of the dark brown compound eyes of the last instar nymphs, the nuclei of secondary pigment cells are distributed between the rhabdom and the crystalline cone. In the compound eyes of adults, the nuclei of secondary pigment cells are distributed around the proximal center of crystalline cone. In the dark brown compound eyes of the last instar nymphs, the pigment granules of the primary pigment cells and retinula cells are evenly distributed, whereas those in the compound eyes of adults are mainly distributed around the rhabdoms.【Conclusion】 The compound eyes of the last instar nymphs and adults of M. mongolica show significant differences in the development of ommatidia, the distribution of pigment cells, and the presence or absence of sensilla. The major developmental period of compound eyes of cicadas is during the last instar nymphal stage when the compound eyes are red in color. The results suggest that the compound eyes of cicada nymphs during the earlier developmental stage of the last instar as well as the earlier instars do not have visual ability, but can function to sense mechanical pressure or other environmental signals underground. This should be an adaptation to the niche shift during the ontogeny of cicadas which live underground for a very long time in the nymphal stage and have a short adult lifespan above ground. The findings of morphological, ultrastructural and functional characteristics of compound eyes of the last instar nymphs and adults of this species improve our understanding of the changes in the development and function of compound eyes of insects and their association with habitats, and provide new information for further exploring the phylogenetic relationship between Cicadoidea and allies in Hemiptera.

Key words: Hemiptera, Auchenorrhyncha, Cicadidae, visual organ, development, morphology, ultrastructure