黑带食蚜蝇Episyrphus balteatus De Geer的复眼结构及其调光机制

Structure and its light tuned mechanism of the compound eye of the hoverfly, Episyrphus balteatus De Geer(Diptera: Syrphidae)

【目的】观察研究黑带食蚜蝇Episyrphus balteatus De Geer成虫复眼形态、小眼结构和不同光暗条件对小眼结构的影响,以明确其光视觉的结构基础和调光机制。【方法】利用组织切片法和扫描电镜等技术。【结果】1.复眼位于头部两侧,正面观呈半球形,占据除额颜外大部分头部。雄虫与雌虫单个复眼分别有约7 180个、7 230个小眼。各小眼面呈整齐排列的规则六边形。2.小眼由角膜及伪晶锥组成的屈光器、不同水平面分布的8个小网膜细胞及其特化形成的离散型视杆、屏蔽色素细胞和基膜等组成。小眼自远端至近端由主色素细胞和12个附属色素细胞围绕。3.随光暗条件的改变小眼内的附属色素细胞色素和基细胞细胞核沿小眼纵轴移动。光适应时,附属色素细胞色素颗粒沿小眼纵轴均匀分布,基细胞细胞核位于基膜上方。暗适应时,附属色素细胞色素颗粒向伪晶锥近端压缩,基细胞细胞核亦向远端移动,到达视杆中段。【结论】黑带食蚜蝇复眼精密的小眼排列形式和内部结构均显示了其强大的生理功能;屏蔽色素颗粒的移动是其复眼适应外界光环境变化的重要机制。本试验为进一步探究黑带食蚜蝇视觉结构和光调节机制,以及与其飞行行为间的关系提供了一定的理论基础。

[Objectives] To investigate the microstructure and its light tuned mechanism of the compound eye of the hoverfly, Episyrphus balteatus De Geer（Diptera Syrphidae）. [Methods] The compound eye of E. balteatus were investigated using scanning electron microscopy（SEM） and histological methods. [Results] 1. The compound eye is located on the lateral sides of the head, is hemispheric in front view, and covers most of the head. Each compound eye consists of about 7 180 facets in males, and 7 230 facets in females. The facets are regularly hexagonal in shape and are tightly arranged in rows.2. Each ommatidium consists of a dioptric apparatus, 8 retinula cells and an open rhabdom, a basement membrane. The ommatidium is surrounded by several primary pigment cells and 12 accessory pigment cells from its distal to proximal end. 3. When adapted to light, pigment particles in accessory pigment cells were distributed uniformly in the ommatidium and the basement cell nucleus lay just above the basement. However, when adapted to darkness, the pigments are contracted to the proximal ends of the pseudocone and the basement cell nucleus moved distally, reaching the middle of the rhabdom. [Conclusion] The result provide a basic foundation for understanding the structure and light regulating mechanism of the visual system of Episyrphus balteatus, and its relationship with flight behavior.