Genetic and Cytogenetic Analysis of the Walnut-Husk Fly (Diptera: Tephritidae)

Abstract

Genetic and cytogenetic information is an essential basis for understanding the biology of insect pests, as well as for designing modern control strategies. The walnut husk fly, Rhagoletis completa (Cresson) (Diptera: Tephritidae), is an important pest of walnuts (Juglans spp.) in North America and has invaded Europe in the early 1990s. Studies on the genetics and cytogenetics of R. completa are scarce. The mitotic karyotype and detailed photographic maps of the salivary gland polytene chromosomes of this pest species are presented here. The mitotic metaphase complement consists of six pairs of chromosomes, the sex chromosomes being very small and similar in size, The analysis of the salivary gland polytene complement shows a total number of five long chromosomes (10 polytene arms) that correspond to the five autosomes of the mitotic nuclei and a heterochromatic mass corresponding to the sex chromosomes. The banding pattern as well as the most characteristic features and prominent landmarks of each polytene chromosome are presented and discussed.