Du Xiaoliang, Yue Chao, Hua Baozhen
Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, Yangling, Shaanxi 712100, China.
J Morphol. 2009 Aug;270(8):984-95. doi: 10.1002/jmor.10736.
The Mecoptera are thought to be one of the most primitive groups in the Holometabola, but their embryology is rarely studied. By means of scanning electron microscopy, we studied the external features of the embryo of the scorpionfly Panorpa emarginata in middle and late development. The embryo remains in the superficial position until hatching. Embryonic development can be divided into 10 stages along with the first-instar larva. The external features are described from the germ band to the first-instar larva, with special reference to the components and segmentation of the head, the segmentation of abdomen and the formation of abdominal prolegs. Our results confirm that the head consists of an anterior-most acron and six trunk segments: the labral, antennal, intercalary, mandibular, maxillary, and labial segments. The labrum is confirmed to derive from the paired appendages. Our observations also provide additional direct evidence that the abdominal prolegs are not serially homologous with the thoracic legs. The presence of the eleventh abdominal segment is clarified.
长翅目昆虫被认为是全变态类中最原始的类群之一，但其胚胎学研究很少。通过扫描电子显微镜，我们研究了凹缘蝎蛉胚胎发育中后期的外部特征。胚胎在孵化前一直处于体表位置。胚胎发育可与一龄幼虫一起分为10个阶段。从胚带到一龄幼虫描述了外部特征，特别提及了头部的组成和分节、腹部的分节以及腹足的形成。我们的结果证实，头部由最前端的原头节和六个躯干节组成：上唇节、触角节、间节、上颚节、下颚节和唇节。上唇被证实源自成对的附肢。我们的观察还提供了额外的直接证据，表明腹足与胸足并非连续同源。明确了第十一腹节的存在。
