Anastrepha Fraterculus (Wiedemann)

Anastrepha fraterculus was described in the genus Dacus by Wiedemann (1830), based on specimens from Brasil. This species is of great economic importance because of the wide variety of plants which it attacks and its extensive distribution. In most of South America it probably is the most important species of Anastrepha. Despite its importance it has no accepted common name. It has been called the South American fruit fly, but this is an inappropriate name since the species, as currently understood, occurs also throughout most of Central America northward to southern Texas. There is increasing evidence that what has been considered for many years to be a species which varies widely throughout its range is a species complex which represents 2 or more species and possibly several biological rates, the Brasilian population being the true A. fraterculus described by Wiedemann. Alan Stone (1942) believed A. fraterculus to be a highly variable species ranging from Texas to central South America, and he identified specimens from peach and guava as A. fraterculus. However, he further stated that populations occurring from Texas to Argentina eventually may be found to represent a complex of species rather than a single one. Baker (Baker et al., 1944) considered the Mexican form distinct from A. fraterculus, noting differences between Brasilian and Mexican forms. He observed that the Brasilian A. fraterculus possesses wing markings that differ from those of the Mexican form. The inverted V is separated from the main pattern, the wing thus resembling that of Anastrepha distincta Greene. The Mexican form has the inverted V connected with the main pattern, the wing thus resembling that of Anastrepha obliqua (MacQuart). However, occasional specimens occur in South America in which the inverted V is connected, and some specimens have been found in Mexico, usually males, in which the connection fades out. The ovipositors, too, differ slightly. Baker (1944) noted that those of the Mexican specimens vary very slightly from one host to another but that those from all hosts appear more tapered at the tip than do those of A. fraterculus from Brasil, and the opening seems slightly farther from the distal extremity. In South America A. fraterculus attacks various fruits including peach, Citrus, guava, Spondias, and Eugenia. The Mexican “A. fraterculus” has been reared from peach, guava, and rose apple. What appears to be the same thing or very similar, was reared from tropical almond, but only in the city of Veracruz. Tropical almond is not recorded as a host of A. fraterculus in South America. It may be that the Veracruz population associated with tropical almonds is more closely related to the typical A. obliqua of the West Indies. Larvae of the Veracruz population attacking tropical almond possess spiracular processes which resemble those of larvae of A. obliqua from Puerto Rico. Populations of Mexican “A. fraterculus” in northern Mexico occur commonly in the vicinity of Citrus, but no infestation in sour orange or other Citrus has been found in that region. Baker (Baker et al., 1944) noted that attempts to rear the Veracruz form which attacks tropical almond from Spondias were unsuccessful, although Spondias is one of the common hosts of A. fraterculus in South America. Dr. R.H. Foote (pers. comm.) recently stated that he believes there are at least 4 biologically distinct populations included in the A. fraterculus complex. There are several other species of Anastrepha which closely resemble the A. fraterculus complex, so that there is great difficulty in determining specific limits. Further biological and taxonomic studies, sampling populations throughout the range of this complex and in association with various fruit hosts, are needed to resolve these questions. Evidently all forms of this complex attack economically important plants.