Miotic Karyotypes of Four Species of Fruit Flies (Bactrocera) in Thailand

Abstract

Giemsa and Hoechst 33258 stained mitotic chromosomes of four species of fruit flies belonging to the genus Bactrocera, namely B. dorsalis, B. tau, B. cucurbitae and B. correcta, were studied. The metaphase karyotype (2n = 12) of these species consists of one pair of heteromorphic sex chromosomes and five pairs of autosomes of different size and shape. In all the species examined, the X chromosome is metacentric while the Y is a small submetacentric which normally appears as a dot in general preparations. The autosomes of B.dorsalis, B. tau and B.cucurbitae are characterized by distinct H-bands in the centromeric regions of all the autosomes. Only in B.cucubitae and intercalary heterochromatin in chromosome 3 was observed. Bactrocera correcta differs from other by having extensive blocks of pericentric heterochromatin in all the autosomes and relatively small metacentric X chromosome.