Structure and its light tuned mechanism of the compound eye of the hoverfly, Episyrphus balteatus De Geer (Diptera: Syrphidae)
Author of the article:ZHANG Sheng-Jie** FAN Fan LI Na YANG Xiao-Fan WEI Guo-Shu***
Author's Workplace：Institute of Plant Protection, Agricultural University of Hebei, Baoding, Hebei 071001
Key Words：Episyrphus balteatus, compound eye, microstructure, accessory pigment cells, light tuned mechanism
Abstract：[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.