Supernumerary segments in five species of grasshoppers (Orthoptera: Acridoidea)

✍ Scribed by J. P. M. Camacho; J. Cabrero

• Book ID: 104634976
• Publisher: Springer Netherlands
• Year: 1982
• Tongue: English
• Weight: 761 KB
• Volume: 59
• Category: Article
• ISSN: 0016-6707
• DOI: 10.1007/bf00133294

✦ Synopsis

Supernumerary segments have been observed in five species of grasshoppers: Calliptamus barbarus, Oedipodafuscocincta, Acrotylus insubricus, Omocestus raymondiand Chorthippus ariasi. In four cases they are located in the S-chromosomes, but in A. insubricus they are carried by the megameric pair (M,). In C. barbtirus and 0. fuscocincta we have observed non-homologous association during diplotene between the extra segments and the X-chromosome.

The supernumerary segments of these two species are distally located. However, in anaphase-I the unequal bivalents divide reductionally in 30% and 20% of the cells, respectively. Finally, the supernumerary segments of C. barbarus do not produce any effect on mean chiasma frequency, but they decrease significantly the between-cell variance of chiasmata in males carrying them.