Original article The complex Robertsonian system of Dichroplus pratensis (Melanoplinae, Acrididae). I. Geographic distribution of fusion polymorphisms

Summary- A chromosomal survey was performed in Argentine natural populations of the South-American melanopline grasshopper Dichroplus pratensis Bruner (Acrididae). The cytogenetic study of samples from different populations revealed the existence of at least 7 distinct Robertsonian translocations which involve the 6 L (large) autosomes of the 2n = 20 (Q)/19 (d) all-telocentric standard karyotype. Some of the fusions thus share monobrachial homologies. The Robertsonian variation found in D Pratensis is discussed in relation to a model of chromosomal evolution for the species in which the changes in recombination patterns produced by the fusions are central. centric fusion / polymorphism / polytypism / grasshopper Résumé — Le système robertsonien complexe de Dichroplus pratensis (Melanoplinés, Acrididés). I. Distribution géographique des polymorphismes de fusion. Une enquête chromosomique a été réalisée sur des populations naturelles de sauterelles mélanoplines * Member of the Carrera del Investigador Cientifico y Tecnolôgico (CONICET) * * Correspondence and reprints sud-américaines Dichroplus pratensis Bruner (Acrididés). L’étude cytogénétique d’échan