Fruit flies (Diptera: Tephritidae) represent, in our opinion, one of the best study systems any researcher can find. These insects are well suited for interspecific comparisons, field and laboratory studies, and studies under seminatural conditions. Since adults of many species are relatively easy to obtain, there is no difficulty in quantifying their behavior and performing long-term studies on marked individuals. In addition, some species in the subfamilies Dacinae and Trypetinae are notorious pests. This combination of features has motivated entomologists worldwide to study this group for more than a century. Species such as

Rhagoletis pomonella


R. cerasi


Ceratitis capitata


Bactrocera dorsalis


, B. oleae


, B. cucurbitae


), B. tryoni


, Anastrepha ludens


, A. obliqua

(Macquart), and

A. suspensa

(Loew) have been the subject of important studies on basic biology, ecology, evolution of animal-plant interactions, sexual selection, and speciation (work reviewed by Baker et al. 1944; Christenson and Foote 1960; Bateman 1972; Bush 1974; Bateman et al. 1976; Boller and Prokopy 1976; Boller and Chambers 1977b; Burk 1981; Prokopy 1977; 1980; 1982; Zwölfer 1983; 1988; Freidberg 1984a; Fletcher 1987; Drew 1987; Aluja 1994; Headrick and Goeden 1998; also see reviews in this volume by Aluja et al., Chapter 15; Drew and Romig, Chapter 21; Eberhard, Chapter 18; Headrick and Goeden, Chapter 25; Prokopy and Papaj, Chapter 10; and Yuval and Hendrichs, Chapter 17).