Jasmina Ludoški

Wing Geometric Morphometric Inferences on Species Delimitation and Intraspecific Divergent Units in the Merodon ruficornis Group (Diptera, Syrphidae) from the Balkan Peninsula

A study of the Merodon taxa on the Balkan Peninsula, a region with a number of Pleistocene refugia, provides a useful framework for examining evolutionary processes and detecting hidden biodiversity. The phenotypic diversity of 22 samples of the Merodon ruficornis group on the Balkan Peninsula was examined using landmark-based geometric morphometrics. The boundaries of the species M. ruficornis, M. trebevicensis, M. auripes, M. armipes, and M. loewi were well defined based on wing shape and size. Canonical variate analysis showed that wing shape possessed sufficient differences to discriminate the species with a successful classification rate of 75–92% for males and 82–100% for females. The observed interspecific differentiation is generally in agreement with a previous study of the M. ruficornis group using a traditional morphological approach and molecular markers (allozyme loci, COI mtDNA). The spatial variability between conspecific populations and interpopulation variation were assessed based on both wing shape and size for male specimens. Phenotypically divergent units were delineated within previously defined species of the M. ruficornis group, indicating the possible presence of evolutionary independent units within the taxa analysed.

Phenotypic evidence for hidden biodiversity in the Merodon aureus group (Diptera, Syrphidae) on the Balkan Peninsula: conservation implication

Cryptic species and phenotypic divergent units provided useful information about hidden biodiversity in the Merodon genus (Diptera, Syrphidae) on the Balkan Peninsula. Discrimination three cryptic species within both the M. aureus (M. aureus A, M. aureus B and M. aureus C) and M. cinereus (M. cinereus A, M. cinereus B and M. cinereus C) complexes was done by study of subtle wing variation (wing size and shape) using a geometric morphometric approach. Observed interspecific differentiation is generally in agreement with a previous study using molecular markers (allozyme loci, COI mtDNA). A considerable evolutionary and phenotypic intraspecies diversity of the M. aureus A, M. aureus B, M. aureus C, M. cinereus A, M. cinereus B, M. cinereus C and M. funestus species from the Balkan Peninsula has important implications for diagnosing biodiversity, including endemic and cryptic species. Observed phenotypic divergent units within the species might be considered as an evolutionary potential of the M. aureus group and used for defining conservation priorities. This study has contributed to the recognition of the value of wing traits in order to decipher the hidden diversity and evolutionary diversification.

Phenotypic variation of the housefly, Musca domestica : amounts and patterns of wing shape asymmetry in wild populations and laboratory colonies

Musca domestica L. (Diptera: Muscidae) is a vector of a range variety of pathogens infecting humans and animals. During a year, housefly experiences serial population bottlenecks resulted in reduction of genetic diversity. Population structure has also been subjected to different selection regimes created by insect control programs and pest management. Both environmental and genetic disturbances can affect developmental stability, which is often reflected in morphological traits as asymmetry. Since developmental stability is of great adaptive importance, the aim of this study was to examine fluctuating asymmetry (FA), as a measure of developmental instability, in both wild populations and laboratory colonies of M. domestica. The amount and pattern of wing shape FA was compared among samples within each of two groups (laboratory and wild) and between groups. Firstly, the amount of FA does not differ significantly among samples within the group and neither does it differ between groups. Regarding the mean shape of FA, contrary to non-significant difference within the wild population group and among some colonies, the significant difference between groups was found. These results suggest that the laboratory colonies and wild samples differ in buffering mechanisms to perturbations during development. Hence, inbreeding and stochastic processes, mechanisms dominating in the laboratory-bred samples contributed to significant changes in FA of wing shape. Secondly, general patterns of left-right displacements of landmarks across both studied sample groups are consistent. Observed consistent direction of FA implies high degrees of wing integration. Thus, our findings shed light on developmental buffering processes important for population persistence in the environmental change and genetic stress influence on M. domestica.

Estimating genetic and phenotypic diversity in a northern hoverfly reveals lack of heterozygosity correlated with significant fluctuating asymmetry of wing traits

The genetic structure and phenotypic diversity of a population of Cheilosia naruska Haarto and Kerppola, 2007 (Diptera, Syrphidae) from Lapland, Finland, was examined through allozyme electrophoresis and wing morphometrics. The morphological identification of the species was verified molecularly using partial sequences of mitochondrial COI and the nuclear ribosomal ITS2 genes comparing with corresponding sequences of a paratype of the taxon. Based on protein electrophoresis, out of 12 analyzed allozyme loci, only one locus (Me) was found to be polymorphic. The low genetic variability was further evidenced by the absence of heterozygote genotypes. Fluctuating asymmetry was used as a measure of developmental stability. For this we used different wing traits that were estimated using both wing landmark positions and metric traits. Procrustes ANOVA and Canonical variate analysis revealed asymmetry in wing metric and wing shape and size, and within each sex considered separately. Principal component analysis revealed similar multivariate patterns of landmark covariation between within-individual variability (fluctuating asymmetry) and variation among individuals. Finally, the observed association between lack of heterozygosity and high level of asymmetry is discussed in light of conservation.

Phenotypic Diversity and Landscape Genetics of Eristalis tenax in a Spatially Heterogeneous Environment, Durmitor Mountain (Montenegro)

The study of the spatial distribution of phenotypic and genetic diversity of pollinators has conservation implications since pollination is a key ecosystem function and a basis for the maintenance of biodiversity. The impact of landscape heterogeneity on the population structure of the important hoverfly pollinator, Eristalis tenax (Diptera, Syrphidae), was investigated. Allele frequencies at allozyme loci, wing traits (size and shape) and abdominal colour pattern were compared using samples from eight locations in the Durmitor National Park, Montenegro. These locations covered a broad range of altitudes and vegetation structures, from deciduous and coniferous forests to alpine meadows. From the conservation point of view, we investigated to what extent the localities in the Durmitor mountain range are connected. Results indicated a lack of population structure in the study area. A genetic clustering analyses based on Bayesian model revealed no resolution among samples, coinciding with FST estimates. Weak genetic differentiation was accompanied by wing size and shape similarity. In addition, there was an overlap between the levels of abdominal colour variation among samples supporting the negative association between gene flow and phenotypic divergence in E. tenax. We conclude that the surrounding landscape is of no relevance to the species movement capabilities. The availability of many sites for E. tenax and its strong dispersal capacity might make the study region a more or less continuous habitat for this species. Thus, our results may contribute to understanding the potential extent to which E. tenax can facilitate gene flow among isolated plant populations on Mt. Durmitor.

Genetic and phenotypic variation in central and northern European populations of Aedes (Aedimorphus) vexans (Meigen, 1830) (Diptera, Culicidae).

ABSTRACT: The floodwater mosquito Aedes vexans can be a massive nuisance in the flood plain areas of mainland Europe, and is the vector of Tahyna virus and a potential vector of Dirofilaria immitis. This epidemiologically important species forms three subspecies worldwide, of which Aedes vexans arabiensis has a wide distribution in Europe and Africa. We quantified the genetic and phenotypic variation in Ae. vexans arabiensis in populations from Sweden (northern Europe), Hungary, and Serbia (central Europe). A landscape genetics approach (FST, STRUCTURE, BAPS, GENELAND) revealed significant differentiation between northern and southern populations. Similar to genetic data, wing geometric morphometrics revealed two different clusters, one made by Swedish populations, while another included Hungarian and Serbian populations. Moreover, integrated genetic and morphometric data from the spatial analysis suggested groupings of populations into three clusters, one of which was from Swedish and Hungarian populations. Data on spatial analysis regarding an intermediate status of the Hungarian population was supported by observed Isolation-by-Distance patterns. Furthermore, a low proportion of interpopulation vs intrapopulation variance revealed by AMOVA and low-to-moderate FST values on a broader geographical scale indicate a continuous between-population exchange of individuals, including considerable gene flow on the regional scale, are likely to be responsible for the maintenance of the observed population similarity in Aе. vexans. We discussed data considering population structure in the light of vector control strategies of the mosquito from public health importance.

Shift in Phenotypic Variation Coupled With Rapid Loss of Genetic Diversity in Captive Populations of Eristalis tenax (Diptera: Syrphidae): Consequences for Rearing and Potential Commercial Use

ABSTRACT Because of its importance as a pollinator and its potential economic usefulness for the biodegradation of organic animal waste, the genetic and phenotypic diversity of the drone fly, Eristalis tenax L. (Diptera: Syrphidae), was studied in both wild and captive populations from southeastern Europe. Wild specimens from a natural protected habitat (with low human impact), field crop habitat (semisynanthropic condition), and intensive pig farming habitat (synanthropic condition) were compared with a laboratory colony reared on artificial media. An integrative approach was applied based on allozyme loci, cytochrome c oxidase I mitochondrial DNA, wing traits (size and shape), and abdominal color patterns. Our results indicate that the fourth and eighth generations of the laboratory colony show a severe lack of genetic diversity compared with natural populations. Reduced genetic diversity in subsequent generations (F4 and F8) of the laboratory colony was found to be linked with phenotypic divergence. Loss of genetic variability associated with phenotypic differentiation in laboratory samples suggests a founder effect, followed by stochastic genetic processes and inbreeding. Hence, our results have implications for captive bred Eristalis flies, which have been used in crop pollination and biodegradation of organic waste under synanthropic conditions.

Integrative approach revealed contrasting pattern of spatial structuring within urban and rural biotypes of Culex pipiens

Population structure of pests is an important issue when designing management strategies to optimize control measures. In this study, we investigated a spatial pattern of genetic and phenotypic variation within seven urban and within six rural populations of Culex pipiens from Vojvodina Province (Serbia) incorporating landscape genetic methods (using allozyme data) and wing size and shape (using geometric morphometric approach). Comparing rural samples, no strong genetic groupings of individuals were detected. Nevertheless, traditional approaches where individuals are pre‐assigned to populations, including F statistics and amova (analysis of molecular variance), revealed low, but significant genetic differentiation among samples. Similarly, phenotypic data (wing size and shape) indicated some level of heterogeneity among rural samples. Contrary to genetic homogeneity found within rural biotype, the individual‐based structuring characterized urban biotype. Geneland revealed the presence of two genetic clusters within urban group which is in concordance with FST and amova results. These results showed that sample from Novi Sad (NS) is a distinct genetic unit, which has been likely resulted in intensive insecticide use over several decades. Furthermore, phenotypic differentiation supported the existence of spatial structuring. Therefore, complementary use of molecular markers and phenotypic traits may be a powerful tool for revealing hidden spatial diversity within Cx. pipiens.

Lead-Induced Variation in Wing Size and Shape in Populations of Drosophila subobscura

ABSTRACT The aim of the current study was to analyze the direction and range of changes in wing size and shape in both sexes of Drosophila subobscura (Collin, 1936) flies that originated from two natural populations with different evolutionary history (sampled from ecologically distinct habitats) maintained during seven generations in laboratory conditions on different lead (Pb) concentrations. The results showed significant wing size variability differences across seven generations of rearing on lead for both populations. Wing size is negatively correlated with lead level, in contrast with wing shape in which significant variation was observed in just one of the populations. According to our results, wing size seems to be more affected by lead pollution in both tested populations compared with wing shape. Our data suggest that presence of lead in higher concentration over extended period of time may reduce the stability of wing morphology and consequently reduce the fitness of exposed individuals. Therefore, specific stress that persists over multiple generations could increase the probabilities for extinction of populations composed of sensitive individuals.