The Chromosomes of the Carambola Fruit Fly Bactrocera carambolae (Diptera: Tephritidae): Metaphase Karyotype and Polytene Genome

Abstract

The carambola fruit fly Bactrocera carambolae Drew & Hancock (Diptera: Tephritidae) is a sibling member of the Bactrocera dorsalis complex group. This species can cause serious financial damage in fruits and vegetables in Malaysia. The mitotic metaphase chromosomes from larval neural ganglia and polytene genome from larval salivary gland cells of this species are presented for the first time. Mitotic chromosomes consist of one pair sex chromosomes (XY/XX) and five pairs of autosomes. Morphometric characteristics of chromosomes, i.e. number, centromeric index, morphology, relative length and arm ratio are examined. In polytene genome, five banded chromosomes are found which composed of a linear series of alternating bands and interbands. The banding pattern is distinctive for each chromosome. No polytenized sex chromosomes are observed, indicating that five polytene chromosomes are corresponding to five mitotic autosomes. This investigation shows that B. carambolae has cytological material that may be very useful for studying comprehensive genetic organization of the pest’s natural populations and contributing towards its control.