ScienceAsia 22 (1996): 097-104 |doi: 10.2306/scienceasia1513-1874.1996.22.097

METAPHASE KARYOTYPES OF FRUIT FLIES OF THAILAND II. FIVE SPECIES IN FOUR SUB GENERA OF Bactrocera

VISUT BAIMAI^a, WACHAREEPORN TRINACHARTVANIT^a, SAEN TIGVATTANANONT^b AND PAUL J. GROTE^a,c

ABSTRACT: Five species of fruit flies of the genus Bactrocera (Diptera, T ephritidae) collected from natural populations at different localities in Thailand were examined cytologically. They showed distinctive metaphase karyotypes with respect to the amount and distribution of constitutive heterochromatin in centromeric regions of autosomes and sex chromosomes. Bactrocera (Hemigymnodacus) diversa, B. (Bactrocera) latifrons and B. (Asiadacus) modica,. three distinct species belonging to different subgenera, clearly exhibited different pericentric heterochromatin in all autosome pairs. The large metacentric X chromosome and conspicuous blocks of heterochromatin of B. (B.) latifrons makes it distinctive from B. (A.) modica and B. (H.) diversa. Further, B. (Z.) rubella and B. (Z.) scutellaris belong to the same subgenus Zeugodacus, but they have different metaphase karyotypes based on the amount of centromeric heterochromatin in all autosomes. The X and Y chromosomes of B. scutellaris are much longer than those of B. rubella due to accumulation of large quantities of heterochromatin. Such cytological differences among these distinct species are very useful as diagnostic characters in cytotaxonomic studies and may provide information concerning chromosomal evolution of these important pests in Thailand.

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a Department of Biology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
b Department of Plant Production Technology, Faculty of Agricultural Technology, King Mongkut Institute of Technology, Lat Krabang, Bangkok 10520, Thailand.
c Present address: School of Biology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.

Received May 2, 1996