Mycroscopy and egg morphology of Mayflies

10 páginas, 5 figuras.The chorionic structures of mayfly eggs can be categorized into three main classes (micropyles, attachment structures and chorionic sculpturing), according to their physiological function. Each class of structure shows a great variability as regards morphology, arrangement and distribution on the eggshell, and the combination of these features is the result of very particular chorionic patterns. The study of chorionic variability in both patterns and structures is very interesting for systematic purposes, because these features may be specific at different taxonomic levels. In addition, eggshell morphology allows us to identify female imagoes at species level when they lack valid taxonomic features, since eggs are completely formed in mature female nymphs. Light microscopy has already showed the great variability of the chorion structures in mayfly eggs and even allowed their classification. At present, this classification continues to be used as the basic reference in the morphological description of mayfly eggs, although it can only be done with SEM. Our morphological study on mayfly eggs, with both microscopy techniques, has allowed us to appreciate the beauty and complexity of the eggshell in this group of insects, as well as to describe new structures and to re-describe several aspects of chorion structures already known.The work was partially supported by RETROCALMED project (CGL2006-11339/BOS).Peer reviewe

Egg morphology update based on new chorionic data of Potamanthus luteus (Linneo), Ephemera danica Müller and Oligoneuriella rhenana (Imhoff) (Insecta, Ephemeroptera) obtained by scanning electron microscopy (SEM)

15 páginas, 4 figurasThe chorionic patterns of Ephemeroptera eggs are very diverse and these have often been used for taxonomic and systematic purposes. In a great number of species, including Potamanthus luteus, Ephemera danica and Oligoneuriella rhenana, these egg features have been studied using light microscopy. However, current trends in egg morphology studies use scanning electron microscopy (SEM), so that the eggs of these species need to be re-described in order to establish morphological comparisons. The general chorionic features which have already been described in these three species are confirmed in our SEM study, although a more detailed description of both the architecture and arrangement of these can now be offered. In addition, this study has allowed us to note new morphological data, such as the chorionic reticulation in P. luteus and the complex extrachorion-adhesive layer in E. danica; classification of the lateral attachment structure in P. luteus and O. rhenana has been changed; and the variability of the polar cap observed in P. luteus underlines the care that must to be taken when selecting chorionic structures for taxonomic purposes.Peer reviewe

New application of air-dry techniques for studying Ephemeroptera and Plecoptera eggs by Scanning Electron Microscopy

8 páginas, 6 figuras.Hexamethyldisilizane (HMDS) and tetramethylsilane are organic compounds that are volatile at ambient temperature and which can therefore be used for air-drying biological samples for SEM studies. The techniques using these compounds provide results that are comparable with those obtained by critical point drying, but which involve a very simple process that saves time and money. Both techniques were applied to SEM studies of Ephemeroptera and Plecoptera eggs in order to assess their suitability as alternative methods to critical point drying for these kinds of biological material. The results show no morphological differences between eggs HMDS air-dried and critical point-dried.Peer reviewe

Contribution to the egg morphology of the Spanish stoneflies (Plecoptera). An overview in the Segura river basin (S.E. of Spain)

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Biodiversitat de Plecòptersi Efemeròpters al Parc Nacional d’Aigüestortes i Estany de Sant Maurici

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