Fruit flies of economic importance: karyotype studies on some Bactrocera spp

The true fruit flies (family Tephritidae) comprise over 4,000 species distributed over most of the world, and include several of the greatest potential threats to agriculture. The New World genus Anastrepha, the primarily African genus Ceratitis, and the genus Bactrocera contain most of the world's most serious fruit fly pests. Genus Bactrocera is known to be a major tropical fruit pest causing heavy losses in fruit and vegetable cultivation. Forty-three species have been described under the genus Bactrocera from Asia, Africa, and Australia. Amongst these, a small number of polyphagous pests have international significance including Bactrocera cucurbitae, Bactrocera dorsalis, Bactrocera papayae and Bactrocera carambolae. Because of their widespread agricultural impact and rapid range expansions, these fruit flies are the subject of quarantine and control efforts worldwide. The efforts for controlling of these pests are based mainly on chemical insecticides. The insecticides create widespread environmental pollution and leave pesticide residues in food and water, and this has implications for human welfare and health. However, there are some environment-friendly genetic control techniques, such as sterile insect technique (SIT), sterile male technique and other autocidal methods. Genetic and cytogenetic information is an essential basis for understanding the biology of insect pests, as well as for designing modern novel control strategies. In this study, the mitotic metaphase chromosomes from larval brain ganglia of these important pests species were observed and their standard karyotypes were presented. All of them have six pairs of mitotic chromosomes including a XY/XX sex chromosome pair. The significance of studying the mitotic metaphase characteristics of these species is obvious. They can be used as reference material for future studies dealing with the population structure of these pests and their control.