东亚飞蝗胚胎体节的形成过程

Segmentation process during embryogenesis in Locusta migratoria manilensis (Orthoptera:Acrididae)

体节形成是昆虫胚胎发育过程中的关键问题。东亚飞蝗Locusta migratoria manilensis(Meyen)是一种重要的农业害虫,其体节形成的时序过程尚无详细报道。本研究采用免疫组化和品红染色方法研究了室内人工饲养东亚飞蝗的体节形成过程。结果表明:完成受精后,细胞核开始分裂并向卵表面迁移。细胞核到达卵表面的时间有差异,卵后端的表面最先出现细胞核。卵后端腹面的细胞分裂旺盛,在此处形成胚盘。胚盘分化成原头和原躯干2个部分,随后形成前头部、颌部、胸部和腹部等区域。到产卵后50 h,胸部区域首先开始分节,向前依次形成颌部和前头部体节,一次形成1个或几个体节,向后依次形成腹部体节,一次形成1个腹节。所有体节在44 h内形成,包括3个前头部体节,3个颌部体节,3个胸节和10个腹节。研究结果进一步证实东亚飞蝗是以胸部为中心进行体节形成的,属于典型的短胚带昆虫;不同蝗虫的胚胎发育速率不一样,但体节形成模式完全一致,形成体节所需要的相对时间也一样。

Segmentation is critical to insect embryogenesis,yet little is known about this process in Locusta migratoria manilensis（Meyen） which is an important pest.In this study,the spatio-temporal process of segmentation in L.migratoria manilensis was observed by using immunohistochemical and fuchsin staining methods.The results showed that the zygote nucleus quickly divided and migrated to the egg periphery after fertilization,and then the nuclei were condensing at the posterior end of the egg where a circular blastodisc formed.The blastodisc subsequently differentiated into head lobe and posterior germband.With elongation of the germband,the first segment was observed at thoracic region at about 50 h after egg laid,and then other segments,including 3 head segments,3 gnathal segments,3 thoracic segments,and 10 abdominal segments, gradually formed in a sequential pattern within 44 h.The thoracic and gnathal regions were added one or more segments at a time,while only one segment at a time was formed for the abdomen.Our results further confirmed that L.migratoria manilensis is a classic short germband insect with the anterior thoracic region as the morphological differentiation center.Meanwhile,the developmental rates of embryo vary among different locust species,while the segmentation patterns and the relative time required for segmentation are identical.