First cytogenetic study of Coleorrhyncha: Meiotic complement of Xenophyes cascus (Hemiptera: Peloridiidae)

Abstract

Cytogenetic information on the hemipteran suborder Coleorrhyncha is here provided for the first time. The New Zealand peloridiid species, Xenophyes cascus Bergroth, 1924 (Hemiptera: Coleorrhyncha: Peloridiidae), was found to display testes with a single follicle each, holokinetic chromosomes (like other Hemiptera), a karyotype of 2n = 26 + X(0) and a single chiasma per bivalent in male meiosis. Comparative analysis of sex chromosome systems in all four hemipteran suborders (Sternorrhyncha, Auchenorrhyncha, Heteroptera and Coleorrhyncha) allowed inference that an X(0) sex determining system was ancestral within the Hemiptera, whilst the XY-system was most likely a derived condition within the Heteroptera.

Keywords

• hemiptera
• coleorrhyncha
• peloridiidae
• xenophyes cascus
• meiotic complement
• holokinetic chromosomes
• male reproductive system