POST-REDUCTIONAL MEIOSIS IN AESHNA (AESHNIDAE, ODONATA)

In many groups of insects with holokinetic chromosomes the meiotic process is, without doubt, either pre-reductional or post-reductional. In Odonata, however, the mode of orientation (axial or equatorial) and type of meiosis (pre- or post-reductional) of bivalents is still controversial. A careful analysis of the meiotic behaviour of autosomal and sexual bivalents and univalents in Aeshna confusa, A. bonariensis, and A. cornigera, a planaltica demonstrates that, in these species, autosomal bivalents divide post-reductionally. Bibliographic evidence also supports this type of meiosis in other species of Odonata, suggesting that it is characteristic of the order.