ULTRASTRUCTURE OF THE EGGSHELL OF AESHNA-JUNCEA (L) (ODONATA, AESHNIDAE)

Authors
Citation
G. Sahlen, ULTRASTRUCTURE OF THE EGGSHELL OF AESHNA-JUNCEA (L) (ODONATA, AESHNIDAE), International journal of insect morphology & embryology, 23(4), 1994, pp. 345-354
Citations number
25
Categorie Soggetti
Entomology
ISSN journal
00207322
Volume
23
Issue
4
Year of publication
1994
Pages
345 - 354
Database
ISI
SICI code
0020-7322(1994)23:4<345:UOTEOA>2.0.ZU;2-I
Abstract
The eggshell of Aeshna juncea L. (Odonata : Aeshnidae) is described us ing scanning and transmission electron microscopy. The vitelline envel ope is homogenous. The endochorion is many-layered, the thickness of t he sub-layers increasing from the inside and out. About 50 or more thi n strata are arranged in a crystalline-like fashion, 0.17 mum thick, f acing the vitelline envelope. This structure corresponds to the innerm ost chorionic layer (ICL) reported from Drosophila melanogaster. About 70 thin, bilaminar crystalline-like strata associated with a more ele ctron-dense material, appear between the endochorionic sub-layers near the anterior end of the egg. The electron-dense exochorion is perfora ted with thin canals opening in small pores on the surface. The filame ntous pre-chorion substance forming the exochorion, previously reporte d from Aeshna, is believed to form a paracrystalline region with a sph erulite-like configuration comprising the inner half of the layer. At the anterior end of the egg, the endo- and the exochorion are anchored to each other in a regular manner. The micropylar chutes are 5 mum wi de. Corresponding passages in the vitelline envelope are believed to c lose after fertilization. A standardized nomenclature for endophytic d ragonfly eggs is proposed.