Comparative morphology of the eggs in some Panorpidae (Mecoptera) and their systematic implication

Abstract

The egg ultrastructure of 12 species in three genera of Panorpidae: Panorpa Linnaeus, Neopanorpa Weele and Sinopanorpa Cai & Hua, was examined using scanning electron microscopy. This is the first time the egg characters have been studied in detail for this family. The results show that egg morphology can be utilised for panorpid taxonomy both at the generic and specific levels. In the species investigated, the egg chorion is covered with a network of extrachorion. Several micropyles were visible on the anterior pole of the eggs after the extrachorion was removed. Neopanorpa eggs differ from the other two genera by neighbouring ridges of exochorion, which are separate and independent. The eggs of Sinopanorpa and Panorpa have only one fused ridge between every two adjoining polygonal cells. The eggs of Sinopanorpa have a network of ridges with even top edges, the granules within the cells being small and uniform. However, the eggs in the nine species of Panorpa are very diverse in morphology, reaffirming the heterogeneity and paraphyly of Panorpa, which may need further systematic analyses.