Genetical, Morphological, Behavioral, and Ecological Traits Support the Existence of Three Brazilian Species of the Anastrepha fraterculus Complex of Cryptic Species

Abstract

Within the Neotropical genusAnastrepha, the nominal speciesAnastrepha fraterculusis widely distributed from Mexico through northern Argentina. Currently it is believed to comprises a complex of at least eight cryptic species—known as theAnastrepha fraterculuscomplex (AF complex)—three of which occur in Brazil:A. sp.1 aff.fraterculus,A. sp.2 aff.fraterculus, andA. sp.3 aff.fraterculus. In this study, we present the results of a broad integrated analysis of multiple biological attributes in samples of the three species collected in sympatric areas. Analyses of the mitotic chromosomes confirm that all of them differ in sex chromosomes, and that the relative frequency of the distinct karyotypes is associated with variation in altitude. In these sympatric areas, a single female hybrid karyotype was detected within a significant sample of individuals. Population samples were analyzed for the ribosomal transcribed spacer ITS1, confirming that the three species have specific sequence types. Observations of reproductive behavior under laboratory conditions revealed thatA. sp.1 andA. sp.2 mate early in the morning, whileA. sp.3 mates in the middle of the day. A bimodal distribution of mating time was observed in the laboratory for hybrids, obtained betweenA. sp.1 andA. sp.3. In a mating choice experiment, most of the mating pairs were homospecific. In addition, through a list of the most frequent hosts associated with geographical occurrence, a bioclimatic model of their potential distribution was generated. The set of data allowed for the construction of explanatory hypothesis about the observed geographical pattern and the differential use of host fruits. Morphometric analyses of wings clearly demonstrated differences among the three species, for both males and females. Based on a wing image of theA. fraterculus(Wiedemann, 1830) type specimen, the morphometric analysis indicated that the type specimen would correspond to a male ofA. sp.2 aff.fraterculus. The information provided by this report is not only useful for taxonomic purposes, but also reveals aspects to be considered in any reconstruction of an evolutionary scenario of theAnastrepha fraterculuscomplex.