不同种群密度地区长足大竹象生殖系统的超微结构研究

Ultrastructure of Reproductive System of Cyrtotrachelus buqueti in Different Population Densities

长足大竹象Cyrtotrachelus buqueti是竹林的毁灭性害虫,但四川省乐山市和贵州省赤水市相距不足300 km,其种群密度却相差48倍。生殖是维持昆虫种群密度的关键环节之一。本文应用形态解剖及扫描电镜技术,系统比较了乐山、赤水两地长足大竹象成虫生殖系统的形态特征和超微结构差异,旨在探究两地种群差异的原因。结果显示,成虫生殖系统形态结构、外生殖器超微结构未观察到显著差异;赤水地区雌虫卵黄颗粒表面粗糙有镂空,直径显著小于乐山地区,雄虫睾丸内壁粗糙有褶皱,精细胞直径极显著小于乐山地区,每万立方微米内精细胞的数量超过乐山地区2倍。精细胞和卵细胞结构、大小的变化可能是两地长足大竹象种群数量差异显著的直接原因。本文结果对研究长足大竹象种群变化、种群发生等具有现实参考价值。

Cyrtotrachelus buqueti is a destructive insect for bamboos.Leshan city of Sichuan province is less than 300 km away from Chishui city of Guizhou province.However,the population density of C.buqueti is 48 times difference between the two cities.Reproduction is one of the key links in maintaining insect population density.In this study,the morphological characteristics and ultrastructure of the reproductive system of C.buqueti in Leshan and Chishui were systematically studied by using morphological anatomy and scanning electron microscopy to explore the differences of population reproductive system.The results showed that there was no significant difference in the morphological structure of the adult reproductive system,neither in the ultrastructure of their external genitalia.In Chishui,the egg surface of the females was rough and hollow,and the diameter was significantly smaller than that of Leshan.The inner wall of Chishui males’testicles was wrinkled and rough.The sperm cell diameter was significantly smaller than that of Leshan,and the number of sperm cells per 10 000μm 3 was more than twice that of Leshan.The structure and size variation of sperm cells and egg cells may be the direct cause of the decrease of population density of C.buqueti in Chishui.The results will provide a practical reference for further analysis of the population changes of C.buqueti.