Egg envelope synthesis and chorion modification after oviposition in the dragonfly Libellula depressa (Odonata, Libellulidae)

Abstract Libellula depressa (Odonata, Libellulidae) is an exophytic dragonfly ovidepositing eggs in clutches on the surface of floating plants and algae. The present work investigates, at ultrastructural level, the gradual differentiation of the egg envelopes and the chorionic changes after egg depo...

Full description

Saved in:
Bibliographic Details
Published in:Tissue & cell 2008-10, Vol.40 (5), p.317-324
Main Authors: Gaino, E, Piersanti, S, Rebora, M
Format: Article
Language:English
Subjects:
Advanced Basic Science
Animals
Aquatic insects
Chorion - growth & development
Chorion - ultrastructure
Endochorion
Exochorion
Female
Insecta
Jelly-layer
Libellula depressa
Libellulidae
Morphology
Odonata
Oviposition
Ovum - ultrastructure
Vitelline envelope
Vitelline Membrane - growth & development
Vitelline Membrane - ultrastructure
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Abstract Libellula depressa (Odonata, Libellulidae) is an exophytic dragonfly ovidepositing eggs in clutches on the surface of floating plants and algae. The present work investigates, at ultrastructural level, the gradual differentiation of the egg envelopes and the chorionic changes after egg deposition in water. The ovary of the mature female of L. depressa is composed of numerous strings of panoistic ovarioles, where the eggshell formation takes place gradually throughout the activity of the follicle cells. The present data show that the egg envelopes are constituted of a very thick electrondense vitelline envelope, a thin endochorion and an extremely thick exochorion composed of a fibrillar matrix resting on a thin electrondense layer. After deposition in water, L. depressa eggs, initially white and almost transparent, gradually become brown spots in a semitransparent jelly coat, rich of incorporated debris. The jelly coat enveloping the eggs of L. depressa derives exclusively from the exochorion, constituted of a fibrillar matrix, which swell at contact with water. The jelly-like coat performs an adhesive function and presumably a protective role during egg segmentation and ensuing larval hatching.
ISSN:0040-8166
1532-3072
DOI:10.1016/j.tice.2008.02.005