RESUMEN
The patterns and amount of variation in size, shape, and/or life history traits between females and males are fundamentally important to gain the comprehensive understanding of the evolution of phenotypic diversity. In addition, the covariation of phenotypic traits can significantly contribute to morphological diversification and sexual dimorphism (SD). Using linear and geometric morphometrics, 237 Eristalis tenax specimens sampled from five populations were, therefore, comparatively assessed for the variation in sexual size dimorphism (SSD), sexual shape dimorphism (SShD), and life history traits, as well as for trait covariation (ontogenetic and static allometry). Pupal body, adult wing, and body mass traits were analyzed. Female-biased SSD was observed for pupal length, width, and centroid size, adult wing centroid size, mass, wing loading, and wing area. Conversely, pupal length/width ratio, developmental time, and mass were not found to be sexually dimorphic. Next, wing SShD, but not pupal body SShD was revealed, while allometry was found to be an important "determinant of SD" at the adult stage, with only a minor impact at the pupal stage. By comparing the patterns of covariance (based on allometric slope and intercept) between respective body mass and morphometric traits of pupae and adults, greater variation in allometric slopes was found in adult traits, while static allometries of the two stages significantly differed, as well. Finally, the results indicate that changes in the allometric intercept could be an important source of intraspecific variation and SD in drone fly adults.
RESUMEN
With the advent of integrated pest management, the conservation of indigenous populations of natural enemies of pest species has become a relevant practice, necessitating the accurate identification of beneficial species and the inspection of evolutionary mechanisms affecting the long-time persistence of their populations. The long hoverfly, Sphaerophoria scripta, represents one of the most potent aphidophagous control agents due to a worldwide distribution and a favorable constellation of biological traits. Therefore, we assessed five European S. scripta populations by combining molecular (cytochrome c oxidase subunit I- COI, internal transcribed spacer 2- ITS2, and allozyme loci) and morphological (wing size and shape) characters. COI sequences retrieved in this study were conjointly analyzed with BOLD/GenBank sequences of the other Sphaerophoria species to evaluate whether COI possessed a sufficient diagnostic value as a DNA barcode marker to consistently delimit allospecific individuals. Additionally, the aforementioned characters were used to inspect the population structure of S. scripta in Europe using methods based on individual- and population-based genetic differences, as well as geometric morphometrics of wing traits. The results indicate numerous shared COI haplotypes among different Sphaerophoria species, thus disqualifying this marker from being an adequate barcoding region in this genus. Conversely, the analyses of population structuring revealed high population connectivity across Europe, therefore indicating strong tolerance of S. scripta to environmental heterogeneity. The results imply a multilocus approach as the next step in molecular identification of different Sphaerophoria species, while confirming the status of S. scripta as a powerful biocontrol agent of economically relevant aphid pests.
RESUMEN
Aedes (Stegomya) albopictus (Skuse 1984), the Asian tiger mosquito, represents the most invasive and one of the medically most important mosquito vectors. Although native to South East Asia, the species has recently spread globally, and was registered in the city of Novi Sad (Serbia, Central Balkans) in August 2018. We characterized the invasive population using phenotypic (wing size and shape) and molecular (nuclear, internal transcribed spacer 2- ITS2, and mitochondrial, cytochrome c oxidase subunit I- COI) markers. The results of phenotypic analyses indicated that the Serbian population could be differentiated from the native (Thailand) and invasive (Hawaii and Florida) populations due to restricted gene flow, founder effect, and supposed different strain origin. The Serbian population showed genetic homogeneity, indicative of a small founder number (bottleneck invasion model). Despite the incorporation of ITS2 GenBank sequences into the data set, neither spatial (Geneland) nor nonspatial (BAPS) genetic structuring analyses helped infer the Serbian population origin. However, the comparison of the retrieved COI haplotype with previously characterized mitogenomes indicated a temperate strain origin, capable of overwintering. Such findings suggest that the newly registered Ae. albopictus population could be able to establish itself since previous studies outlined Novi Sad as a suitable area.
