Observations on the egg ultrastructure of some rhaphidophoridae (Orthoptera) of the mediterranean area

Abstract

The scanning electron microscope study of the eggs of seven species of cave Orthoptera belonging to the family Rhaphidophoridae has shown a series of characters useful for taxonomic purposes. The eggs studied belong to four species of the genus Troglophilus, one of the genus Tachycines and three of the genus Dolichopoda. All the studied species show cylindrical eggs with an external surface formed by polygonal fields delimited by emerging ridges of different size. Aeropyles are widespread on the egg surface and cross the chorionic layers by means of little canals. In each genus, the micropylar areas are located in the equatorial zone of the eggs and are of typical «rosette» shape. However the numbers of this structure vary significantly among the different species. Furthermore, micropylar canals and the inner layer of the chorion show different patterns in the three studied genera. These results are discussed on the basis of present knowledge of the phylogenetic relationships and the biogeography of these cave crickets. © 1994 Taylor & Francis Group, LLC.