Ultrastructure of the eggs of Culicoides molestus (Diptera: Ceratopogonidae)

The eggs of Culicoides molestus (Skuse) are described and illustrated by scanning and transmission electron microscopy. Eggs are elongate with a slight dorsoventral curvature. No outer chorionic tubercles are present. Aeropyles are present in large numbers at the anterior end and in lower numbers at the posterior end and lateral regions. The chorion has 5 layers. An outer, rough, proteinaceous layer covers a smoother inner surface, which in turn encloses a layer of columns and meshwork that appears capable of containing air. These columns are underlain by an additional 2 layers. The aeropylar region, in combination with the chorionic meshwork, appears to provide a plastron that may aid in the survival and development of inundated eggs.