The shared organization of three optic lobe neuropils-the lamina, medulla, and lobula-linked by chiasmata has been used to support arguments that insects and malacostracans are sister groups. However, in certain insects, the lobula is accompanied by a tectum-like fourth neuropil, the lobula plate, characterized by wide-field tangential neurons and linked to the medulla by uncrossed axons. The i...

This review focuses on grasshoppers that are polymorphic for Robertsonian translocations because in these organisms the clarity of meiotic figures allows the study of both chiasma distribution and the orientation of trivalents and multivalents in metaphase I. Only five species of such grasshoppers were found in the literature, and all of them were from the New World: Oedaleonotus enigma (Scudde...

This study was carried out to investigate the effect of Ethanol extract of the seeds of Annona muricata on some meiotic parameters in the pest grasshopper Zonocerus variegatus. Adult grasshoppers were treated with 28μl of the Ethanol extract of sun dry seeds of Annona muricata and absolute ethanol (control) for 48 hours and all the parameters (chiasma frequency, formation of rod and ring shaped...