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The arbovirus vectors Aedes aegypti (yellow fever mosquito) and Ae. albopictus (Asian tiger mosquito) are both common throughout the Indo-Pacific region, where 70% of global dengue transmission occurs. For Ae. aegypti all Indo-Pacific populations are invasive, having spread from an initial native range of Africa, while for Ae. albopictus the Indo-Pacific includes invasive populations and those from the native range: putatively, India to Japan to Southeast Asia. This study analyses the population genomics of 480 of these mosquitoes sampled from 27 locations in the Indo-Pacific. We investigated patterns of genome-wide genetic differentiation to compare pathways of invasion and ongoing gene flow in both species, and to compare invasive and native-range populations of Ae. albopictus. We also tested landscape genomic hypotheses that genetic differentiation would increase with geographical distance and be lower between locations with high connectivity to human transportation routes, the primary means of dispersal at these scales. We found that genetic distances were generally higher in Ae. aegypti, with Pacific populations the most highly differentiated. The most differentiated Ae. albopictus populations were in Vanuatu, Indonesia and Sri Lanka, the latter two representing potential native-range populations and potential cryptic subspeciation respectively. Genetic distances in Ae. aegypti increased with geographical distance, while in Ae. albopictus they decreased with higher connectivity to human transportation routes. Contrary to the situation in Ae. aegypti, we found evidence of long-distance Ae. albopictus colonisation events, including colonisation of Mauritius from East Asia and of Fiji from Southeast Asia. These direct genomic comparisons indicate likely differences in dispersal ecology in these species, despite their broadly sympatric distributions and similar use of human transport to disperse. Our findings will assist biosecurity operations to trace the source of invasive material and for biocontrol operations that benefit from matching genetic backgrounds of released and local populations., Author summary The mosquitoes Ae. aegypti and Ae. albopictus are highly invasive and transmit dengue and other arboviruses. This study investigates the genetics of these mosquitoes in the Indo-Pacific region, where 70% of global dengue transmission occurs and where both species have established widespread invasions by hitch-hiking on human transport vessels. We compared patterns of genetic differentiation to determine the pathways these species have taken while spreading through the Indo-Pacific, and to better understand how they disperse. We sequenced DNA from 480 mosquitoes sampled from 27 locations in the Indo-Pacific, and found many genetic differences between the two species. Populations of Ae. aegypti, which is not native to the region, tended to be genetically different from each other, and populations in the Pacific Ocean were particularly divergent. Aedes albopictus populations were generally more similar to each other, though genetically different populations in Sri Lanka and Indonesia point to these having a different history to other populations. Genetic differences between Ae. aegypti populations were larger when populations were geographically distant, while differences between Ae. albopictus populations were larger when populations likely had limited access to human transportation. These results will help improve strategies for controlling these species and stopping their spread around the world.

The arbovirus vectorsAedes aegypti(yellow fever mosquito) andAe. albopictus(Asian tiger mosquito) are both common throughout the Indo-Pacific region, where 70% of global dengue transmission occurs. ForAe. aegyptiall Indo-Pacific populations are invasive, having spread from an initial native range of Africa, while forAe. albopictusthe Indo-Pacific includes invasive populations and those from the native range: putatively, India to Japan to Southeast Asia. This study analyses the population genomics of 480 of these mosquitoes sampled from 27 locations in the Indo-Pacific. We investigated patterns of genome-wide genetic differentiation to compare pathways of invasion and ongoing gene flow in both species, and to compare invasive and native-range populations ofAe. albopictus. We also tested landscape genomic hypotheses that genetic differentiation would increase with geographical distance and be lower between locations with high connectivity to human transportation routes, the primary means of dispersal at these scales. We found that genetic distances were generally higher inAe. aegypti, with Pacific populations the most highly differentiated. The most differentiatedAe. albopictuspopulations were in Vanuatu, Indonesia and Sri Lanka, the latter two representing potential native-range populations and potential cryptic subspeciation respectively. Genetic distances inAe. aegyptiincreased with geographical distance, while inAe. albopictusthey decreased with higher connectivity to human transportation routes. Contrary to the situation inAe. aegypti, we found evidence of long-distanceAe. albopictuscolonisation events, including colonisation of Mauritius from East Asia and of Fiji from Southeast Asia. These direct genomic comparisons indicate likely differences in dispersal ecology in these species, despite their broadly sympatric distributions and similar use of human transport to disperse. Our findings will assist biosecurity operations to trace the source of invasive material and for biocontrol operations that benefit from matching genetic backgrounds of released and local populations.Author SummaryThe mosquitoesAe. aegyptiandAe. albopictusare highly invasive and transmit dengue and other arboviruses. This study investigates the genetics of these mosquitoes in the Indo-Pacific region, where 70% of global dengue transmission occurs and where both species have established widespread invasions by hitch-hiking on human transport vessels. We compared patterns of genetic differentiation to determine the pathways these species have taken while spreading through the Indo-Pacific, and to better understand how they disperse. We sequenced DNA from 480 mosquitoes sampled from 27 locations in the Indo-Pacific, and found many genetic differences between the two species. Populations ofAe. aegypti, which is not native to the region, tended to be genetically different from each other, and populations in the Pacific Ocean were particularly divergent.Aedes albopictuspopulations were generally more similar to each other, though genetically different populations in Sri Lanka and Indonesia point to these having a different history to other populations. Genetic differences betweenAe. aegyptipopulations were larger when populations were geographically distant, while differences betweenAe. albopictuspopulations were larger when populations likely had limited access to human transportation. These results will help improve strategies for controlling these species and stopping their spread around the world.

Dengue is endemic in tropical and subtropical countries and is transmitted mainly by Aedes aegypti. Mosquito movement can be affected by human-made structures such as roads that can act as a barrier. Roads can influence the population genetic structure of Ae. aegypti. We investigated the genetic structure and gene flow of Ae. aegypti as influenced by a primary road, España Boulevard (EB) with 2000-meter-long stretch and 24-meters-wide in a very fine spatial scale. We hypothesized that Ae. aegypti populations separated by EB will be different due to the limited gene flow as caused by the barrier effect of the road. A total of 359 adults and 17 larvae Ae. aegypti were collected from June to September 2017 in 13 sites across EB. North (N1-N8) and South (S1-S5) comprised of 211 and 165 individuals, respectively. All mosquitoes were genotyped at 11 microsatellite loci. AMOVA FST indicated significant genetic differentiation across the road. The constructed UPGMA dendrogram found 3 genetic groups revealing the clear separation between North and South sites across the road. On the other hand, Bayesian cluster analysis showed four genetic clusters (K = 4) wherein each individual samples have no distinct genetic cluster thus genetic admixture. Our results suggest that human-made landscape features such as primary roads are potential barriers to mosquito movement thereby limiting its gene flow across the road. This information is valuable in designing an effective mosquito control program in a very fine spatial scale., Author summary Dengue, a mosquito-borne viral infection is a serious health problem in tropical and subtropical countries such as Philippines. Most dengue prevention programs aim to eradicate its mosquito vector, Aedes aegypti. A successful population control program is reliant in understanding the mosquito behavior and ecology including how human-made structures such as roads influence its expansion and movement. Previous studies have discovered the barrier effect of roads in the movement of mosquitoes. In this study, we examined the influence of roads in the population genetic structure of Ae. aegypti in a fine spatial scale using 11 microsatellite markers. We found significant genetic differentiation of mosquito populations across the road. Our results suggest limited gene flow across the road and supports our hypothesis that roads are potential barriers to mosquito dispersal. This information can be used in designing an effective mosquito population control zones in perceived barrier to mosquito dispersal such as roads.

a b s t r a c t A number of mammal species in Europe, including the Eurasian otter (Lutra lutra), have experienced a decline in population size in the 20th century due to persecution, environmental pollution and ongoing habitat fragmentation. This has often led to a substantial loss of genetic diversity which may threaten population viability. While otters have been studied in some detail genetically, the northern part of the Fennoscandian range has not been covered well so far. By explicitly focussing on the genetics of otter populations from northern Sweden and Finland we aimed at closing that gap. To infer their genetic structure and diversity, we analysed sequences of the mitochondrial control region and 12 nuclear microsatellite markers in 197 Eurasian otters from Sweden and Finland. Variability of the mitochon- drial control region was low overall but still revealed previously undetected haplotypes unique to the Finnish otter population. Expected heterozygosities in Fennoscandia were within the range previously reported. Bayesian cluster analysis of our microsatellite data revealed genetic structuring of the Swedish otter populations. In contrast, we observed a high degree of admixture among the Finnish populations that we also found at the geographic border of the two countries (Lapland). Admixed ancestry in Finnish otters suggests that gene flow from the Swedish to Central European populations is potentially facilitated via the Finnish otter populations connecting the Swedish animals with otter populations in mainland Europe.

We analysed 229 Eurasian otters from eastern and north-western Germany, Denmark and southern Sweden based on sequences of the mtDNA control region and genotypes at 12 polymorphic nuclear microsatellite loci. The main focus of the study lay on the north-west German otters from Schleswig-Holstein, which represent a newly established and expanding population recolonizing a formerly inhabited region, thereby closing the distributional gap between the large eastern population and the long-isolated and genetically depleted Danish population. As found before in this species, mtDNA variability was very low but we identified a hitherto unknown haplotype in Sweden. Expected heterozygosities were between 0.46 and 0.69 and thus within the range known from the literature. There were only weak signs of a founder effect in the Schleswig-Holstein otters with respect to allelic diversity (but not heterozygosity). Nevertheless, there was a statistically significant bottleneck signal based on deviations from mutation-drift equilibrium in Schleswig-Holstein. All statistical approaches (amovas, factorial correspondence analysis, assignment tests and Bayesian structure analysis) unequivocally showed that north-western Germany has so far been predominantly recolonized by otters of east German origin, but we also found evidence of admixture through immigration from Denmark. Both the Danish and the north-west German otter population will benefit from further exchange in the wake of the ongoing range expansion. Zusammenfassung Insgesamt 229 Fischotter aus dem Osten und Nordwesten Deutschlands sowie aus Danemark und Sudschweden wurden auf der Basis von Sequenzen der mitochondrialen Kontrollregion und Genotypen an 12 polymorphen nuklearen Mikrosatellitenloci populationsgenetisch untersucht. Hauptaugenmerk lag auf dem Bestand in Schleswig-Holstein, der in jungster Zeit neu etabliert wurde und sich weiterhin ausbreitet. Damit schliest dieser die Verbreitungslucke zwischen der grosen Population im Osten und den lange isolierten und genetisch verarmten Ottern in Danemark. Im Einklang mit fruheren Studien war die Variabilitat des mitochondrialen Markers sehr gering; es wurde jedoch ein bisher unbekannter Haplotyp in Schweden nachgewiesen. Die erwartete Heterozygotie lag mit Werten zwischen 0.46 und 0.69 im fur Fischotter ublichen Bereich. Es gab schwache Anzeichen eines Grundereffektes fur Schleswig-Holstein in Bezug auf Alleldiversitat, nicht jedoch Heterozygotie. Dennoch war ein Bottleneck-Test basierend auf Abweichungen vom Mutationsdrift-Gleichgewicht fur Schleswig-Holstein statistisch signifikant. Alle statistischen Verfahren (amovas, FCA, Assignment-Tests und Bayesianische Structure-Analyse) zeigten, dass Nordwestdeutschland bisher uberwiegend vom Osten her wiederbesiedelt wird, doch wurden auch genetische Spuren einer Immigration aus Danemark gefunden. Sowohl die danische als auch die nordwestdeutsche Fischotterpopulation werden von einem weiteren genetischen Austausch im Zuge der gegenwartigen Ausbreitung profitieren.

The immense biodiversity of the Atlas Mountains in North Africa might be the result of high rates of microallopatry caused by mountain barriers surpassing 4000 meters leading to patchy habitat distributions. We test the influence of geographic structures on the phylogenetic patterns among Buthus scorpions using mtDNA sequences. We sampled 91 individuals of the genus Buthus from 51 locations scattered around the Atlas Mountains (Antiatlas, High Atlas, Middle Atlas and Jebel Sahro). We sequenced 452 bp of the Cytochrome Oxidase I gene which proved to be highly variable within and among Buthus species. Our phylogenetic analysis yielded 12 distinct genetic groups one of which comprised three subgroups mostly in accordance with the orographic structure of the mountain systems. Main clades overlap with each other, while subclades are distributed parapatrically. Geographic structures likely acted as long-term barriers among populations causing restriction of gene flow and allowing for strong genetic differentiation. Thus, genetic structure and geographical distribution of genetic (sub)clusters follow the classical theory of allopatric differentiation where distinct groups evolve without range overlap until reproductive isolation and ecological differentiation has built up. Philopatry and low dispersal ability of Buthus scorpions are the likely causes for the observed strong genetic differentiation at this small geographic scale.

We analyzed 121 golden jackals (Canis aureus) from six sample sites in Serbia with regard to genetic variability and differentiation as revealed by mitochondrial control region sequences and eight nuclear microsatellite loci. There was no variation at all in the mtDNA sequences, and nuclear variability was very low (average observed and expected heterozygosity of 0.29 and 0.34, respectively). This is in line with the considerable recent range expansion of this species in the Balkans and indicates a strong founder effect in the recently established Serbian population. We did not find evidence of differentiation between the northeastern jackals and those from the plain of Srem or those in between. F-statistics and Bayesian Structure analyses, however, were indicative of a low degree of overall differentiation in the Serbian population. A vagrant Austrian jackal that was also analyzed was genetically indistinguishable from its Serbian conspecifics.

Background Artificial light at night (ALAN) is a typical feature of urban areas and most organisms living in urban or suburban habitats are exposed to low levels of ALAN. Light is one of the most important environmental cues that organisms use to regulate their activities. Studies have begun to quantify the influence of ALAN on the behavior and ecology of organisms, but research on the effects at the molecular level remains limited. Mosquitoes in the Culex pipiens complex (Diptera, Culicidae) are widespread and abundant in urban areas where they are potential disease vectors. It is thus of particular interest to understand how ALAN may influence biologically and ecologically relevant traits. Results We used RNAseq to evaluate the transcriptome response in a Cx. pipiens f. molestus laboratory population that was exposed to near-natural light conditions (light:dark L16:D8 hours, “control”) and ALAN conditions with 3 h of constant low-level light at night (L16 + Llow3:D5 hours, “low-light”). The resulting transcripts were mapped to the reference genome of the closely related Culex quinquefasciatus. Female expression patterns differed significantly between control and treatment conditions at five genes although none showed an absolute fold change greater than two (FC > 2). In contrast, male expression differed at 230 genes (74 with FC > 2). Of these, 216 genes (72 with FC > 2) showed reduced expression in the low-light treatment, most of which were related to gametogenesis, lipid metabolism, and immunity. Of the 14 genes (two with FC > 2) with increased expression, only five had any functional annotation. There was a pronounced sex-bias in gene expression regardless of treatment, with 11,660 genes (51 % of annotated genes; 8694 with FC > 2; 48 % of annotated genes) differentially expressed between males and females, including 14 genes of the circadian clock. Conclusion Our data suggest a stronger response to artificial light by males of Cx. pipiens f. molestus than by females, and that a wide range of physiological pathways may be affected by ALAN at the molecular level. The fact that differences in gene expression appear to be sex-specific may have a strong influence at the population level. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2336-0) contains supplementary material, which is available to authorized users.