Synaptinemal complexes in the achiasmatic spermatogenesis of Bolbe nigra Giglio-Tos (Mantoidea)

In chiasmatic meiosis of mosquitoes, ascomycetes and lilies the synaptinemal complex (SC) disassociates from the bivalent before metaphase I. Conversely, in the achiasmatic meiosis of Bolbe nigra, the SC remains associated with the bivalent during first metaphase. Light microscopy reveals mid-bodies between disjoining half-bivalents during early first anaphase in Bolbe. Optically controlled serial sections for electron microscopy show that the mid-bodies seen in light micrographs and synaptinemal complexes seen in electron micrographs are the same structure. Electron micrographs indicate that the SC breaks transversely at a point corresponding to the chromosomal kinetochore during anaphase I as the chromatin and the SC begin to separate. During telophase I, SC remnants are at the poles with the chromosomes or between poles. Presently, the evidence is inadequate to state whether the SC serves alternately or simultaneously as a biological contrivance for conjunction and crossing-over or singly as a device for one of these phenomena.Supported by a University of Melbourne Research Fellowship.