Fine scale analysis of the spatial structure of an Argentinian population of Anastrepha fraterculus using molecular (SSR) and morphometric markers

DAMIÁN FREILIJ; PAULA GÓMEZ CENDRA; JUAN CÉSAR VILARDI; LAURA INÉS FERREYRA

Bogotá

Congreso; 10 Congreso Americano de moscas de la fruta; 2020

Grupo de Trabajo en Moscas de la Fruta del Hemisferio Occidental

An efficient integrated management program may be improved using information of genetic structure, population dynamics, and adaptive landscape of the target species. In the present study phenotypic, genotypic and environmental data were combined, within the frame of a landscape genetics analysis, to uncover the spatial population genetic structure (SGS) of an Anastrepha fraterculus population. Eight SSR loci and six morphometric traits were analyzed in 105 adults emerged from 35 fruits of 7 guava trees. The sampling site is located at San Pablo, Tucumán, Argentina, where guava trees grow without any horticultural care. The orchard is mostly linear and distance between neighbor trees would be shorter than the dispersal capacity of adult flies. The distribution of molecular and morphometric variances was evaluated respectively by AMOVA and multivariate generalized linear analysis, considering the hierarchical levels: tree / fruit / individual. Genetic variability and population structure were analyzed with the package hierfstat of R. Spatial autocorrelation (SA) of molecular and morphometric data was analyzed at global and local scale with the package EcoGenetics. Finally, geographic, molecular and morphometric information was combined in an integrative landscape analysis conducted with the package Geneland. The loci analyzed were very variable an average of 12 alleles per locus and HE= 0.72. Homozygote excess was observed in the whole population (FIS= 0.11) and genetic differentiation among fruits was low (FST= 0.024). The eight SSR loci allow to identify each sampled individual by its multilocus genotype. The highest proportion of molecular variance occurred within individuals, followed by the variance among individuals within fruits. The variation between trees, although small, was significant. For morphological traits the highest proportion of morphometric variance was found at the tree level, and the lowest among individuals within fruit. SA analysis failed to show any significant association between neither genetic nor morphometric differentiation with geographical distance. Geneland analysis identified 3 clusters with a low level of admixture. One cluster involves all individuals emerged from the trees in the middle of the sampling site. The other two clusters correspond to individuals retrieved from trees at opposite edges of the sampled area. Taken as a whole the analyses conducted showed significant differentiation among flies emerged from different trees. There is a cryptic structure revealed by the identification of at least 3 clusters spatially separated. Most individuals obtained from fruits of the same tree belong to the same cluster. This might be related to local environmental conditions affecting female choice of egg laying site.