Geographic distribution of sex chromosomes polymorphism in Anastrepha fraterculus sp. 1 from Argentina

GIARDINI, MARÍA CECILIA; NIEVES, MARIELA; SCANNAPIECO, ALEJANDRA CARLA; CONTE, CLAUDIA ALEJANDRA; MILLA, FABIÁN HORACIO; SCHAPOVALOFF, MARIA ELENA; FRISSOLO, MARIA SOLEDAD; REMIS, MARÍA ISABEL; CLADERA, JORGE LUIS; LANZAVECCHIA, SILVIA BEATRIZ

Bogotá

Congreso; Congreso Americano de Mosca de la Fruta; 2020

Anastrepha fraterculus is recognized as a quarantine pest in several American countries. It has been reported as a complex of cryptic species with at least eight morphotypes described. Only one entity of this complex, formerly named Anastrepha fraterculus sp. 1 is present in Argentina. Previous cytogenetic works performed on this morphotype described the presence of sex chromosome variation identified by chromosomal size and staining patterns. This works aimed at describing the current geographic distribution of sex chromosomes in A. fraterculus sp 1 wild populations from main fruit-producing regions of Argentina and improving the cytological characterization of laboratory strains of this morphotype. We analyzed mitotic metaphases of individuals from wild populations of Northwest (Tucumán and La Rioja), Northeast (Entre Ríos and Misiones) and Central (Buenos Aires) regions of the country and also from four laboratory strains.In wild samples, we observed a high frequency of X1X1 (0.94) and X1Y5 (0.93) sex chromosome karyotypes, whereas, X1X2 and X1Y6 were exclusively found at a low frequency in Buenos Aires (0.07; 0.13, respectively), Entre Ríos (0.16; 0.14, respectively) and Tucumán (0.03; 0.04, respectively). X2X2 and X2Y5 karyomorphs were not found in wild populations, whereas were detected at low frequency in laboratory strains. No differences were found among A. fraterculus wild populations in either karyotypic or chromosomal frequencies, however, significant correlation was observed between Y5 chromosomal frequency and latitude. Our cytogenetic study contributes with valuable knowledge to understand possible routes of invasion and dispersion of this pest in Argentina and allows to rise some hypothesis regarding the potential source of origin of the chromosome size polymorphism evidenced in this morphotype. In addition, our results set the bases for further studies of other morphotypes in support to the resolution of cryptic species in A. fraterculus complex.