Molecular Markers for Analyses of Genetic Diversity within the Anastrepha fraterculus Complex with Emphasis on Argentine Populations.

Simple Summary: The South American fruit fly Anastrepha fraterculus (Wiedmann) is found from northern Mexico to northern Argentina, where it causes damage to many different wild and cultivated fruits. It is a not a single species, but a complex of practically identical species. Eight morphological types (morphotypes) have been identified. To facilitate the identification of the species, alternative, non-morphological methods, such as those based on genome sequences, are necessary. The sterile insect technique is an efficient method used to combat these pests, which involves the release of many sterile male insects into the wild. Mass-reared sterile field-released males mate with females, which lay inviable eggs, thereby reducing the population. This approach is only successful when the released males are sexually compatible with the females of the target population. Hence, accurate identification is necessary for its success. We evaluated the use of the internal transcribed spacer 2 (ITS2) sequence for discriminating members of the A. fraterculus cryptic species complex and a related species, Anastrepha schultzi Blanchard. The ITS2 sequence successfully discriminated between different morphotypes and provides a basis for the development of keys for discrimination of the species within the complex. ITS2 also represents an important marker for the poorly studied species A. schultzi. The South American fruit fly Anastrepha fraterculus (Wiedmann) has a vast range extending from northern Mexico, through Central America, to South America where it is an extremely polyphagous pest of wild and cultivated fruits. It is a complex of cryptic species currently composed of eight recognised morphotypes: "Mexican", "Venezuelan", "Andean", "Peruvian", "Ecuadorian", and the three Brazilian morphotypes "Brazilian-1", "Brazilian-2", and "Brazilian-3". Molecular markers that can identify the member species of the complex are crucial for the implementation of effective pest control measures, such as the sterile insect technique. The object of this study was to evaluate the use of the internal transcribed spacer 2 (ITS2) sequence for discriminating several members of the A. fraterculus cryptic species complex (Mexican, Peruvian, and Brazilian-1) and a related species, Anastrepha schultzi Blanchard. The analysis highlighted significant genetic differentiation between the evaluated morphotypes, allowed their discrimination within the A. fraterculus cryptic species complex, and provided new insights into their genetic relationships. The ITS2 marker provides a basis for the development of taxonomic keys for the discrimination of the cryptic taxa within the A. fraterculus cryptic species complex. ITS2 also represents an important marker for the poorly studied species A. schultzi. [ABSTRACT FROM AUTHOR]