FIRST MOLECULAR CONFIRMATION OF BACTROCERA SCUTELLATA AND PHYLOGENETIC ASSESSMENT OF MAJOR FRUIT FLY SPECIES IN BANGLADESH

ABSTRACT Fruit flies of the genus Bactrocera (Diptera: Tephritidae) are among the most destructive insect pests of fruits and vegetables in tropical and subtropical regions, causing significant economic losses in Bangladesh. Accurate identification of these species remains challenging because of their morphological similarity and the presence of cryptic taxa, while molecular data from Bangladesh are still limited. To fill this gap, extensive field surveys and laboratory analyses were conducted to determine the species composition, host associations, and infestation patterns of fruit flies across major agroecological regions of Bangladesh. Adult flies were collected using pheromone traps and reared from infested fruits and vegetables. Morphological identification followed standard taxonomic keys, and molecular confirmation was performed through cytochrome oxidase subunit I (COI) gene sequencing. Morphological observations revealed Bactrocera cucurbitae (melon f ly) and B. dorsalis (oriental fruit fly) as the predominant species in all surveyed sites. COI sequencing of 27 specimens resolved four major clades: B. dorsalis, B. tau (pumpkin fruit fly), B. cucurbitae, and B. scutellate (striped fruit fly), with B. scutellata representing the first confirmed record in Bangladesh. A sample initially identified morphologically as Ceratitis capitata was molecularly confirmed as B. tau, highlighting the limitations of morphology-based identification. These results reaffirm the dominance of B. dorsalis and B. cucurbitae in Bangladeshi fruit and vegetable ecosystems and highlight the value of integrating molecular diagnostics with traditional taxonomy. The findings provide crucial baseline information for species-specific, sustainable fruit fly management and strengthen the molecular framework for future tephritid research in Bangladesh. 

Keywords: Fruit fly, Bactrocera spp., molecular identification, DNA barcoding