Estimación del flujo génico en insectos. El análisis de <i>Caledia captiva</i> . (Ortboptera: Acrididae)

Abstract

An indirect method was used for analyzing pattems and leyels of gene flow between two races of the Australian grasshopper Caledia captiva (Orthoptera: Acrididae). A site was chosen were two chromosomal races (Moreton and Torresian) of C. captiva meet and form an hybrid zone. Five of their enzyme systerns were analyzed and the allozyrnic disequilibria at the centre 01 the hybrid zone were calculated for estimating the dispersal rates. The estimates produce a dispersal rate in the order of93 (67-138) m (generation 1/2. This result evidences a rather restricted gene flow level, concordant with the narrow hybrid zone formed between the two races. Steep genetic clines that coincide with narrow hybrid zones are generally considered to have arisen either from a balance 01 selection gradients and gene flow, or from competitive effects. The existence of low genetic introgression levels in this species would appear to support the first possibility