Microevolution of sympatry: landscape genetics of hedgehogs Erinaceus europaeus and E. roumanicus in Central Europe

Economic Valuation of Northern White-Breasted Hedgehog Conservation

The northern white-breasted hedgehog (Erinaceus roumanicus) is a charismatic insectivore mammal threatened by habitat loss, the use of biocides, and collisions with vehicles. We aimed at valorizing hedgehog conservation through the contingent valuation method for estimating the proportion and the amount of willingness to pay (WTP) and the effects of cognitions and sociodemographic characteristics on WTP. We collected data through interviews with 704 residents of four administrative regions of northern Greece. Binary logistic regression and Welsh–Poe interval regression were used for estimating the effects of predictors on the proportion and mean WTP, respectively. Most participants (58.2%) were WTP a mean of EUR 31.7 for hedgehog conservation, totaling EUR 21.9 million annually when projected to the population. Positive attitudes, mutualism wildlife orientations, intention to participate in hedgehog conservation actions, and participation in consumptive and non-consumptive wildlife-related recreational activities increased WTP. Highly educated females, with high income and a pet were more WTP than less educated males, with low income and without a pet. Findings provided necessary information to managers about the value of hedgehog conservation, the potential for raising required funds and the differences in WTP among and within public groups.

Genetic diversity and population structure of the Western European hedgehog, Erinaceus europaeus: conservation status of populations in the Iberian Peninsula

Anthropogenic habitat fragmentation and roadkill mortality are considered important threats to European hedgehogs. Habitat fragmentation isolates hedgehog populations and, as a consequence, reduces their genetic diversity and leads the populations to vulnerable situations. The hedgehog populations in the Iberian Peninsula represent the southern limit of the species. We used microsatellite markers to estimate the genetic diversity and population structure of Erinaceus europaeus on the Iberian Peninsula. The obtained results indicated the presence of two differentiated groups, north-western and north-eastern, which coincided with the distribution of the two phylogeographic mitochondrial lineages described in the Peninsula. Moreover, in the north-eastern group, three genetically different clusters (Girona, Central Catalonia and Zoo) were identified. The highest genetic diversity (Hs = 0.696) was detected in the north-western region. Significant genetic differentiation (FST range = 0.072–0.224) was found among the clusters, indicating that these groups are well differentiated and present low gene flow. We concluded that the north-western group is genetically stable, whereas in the north-eastern region, despite some contact among groups, some populations are isolated and vulnerable.

Juvenile European hedgehogs (Erinaceus europaeus) at rescue centers and their release rate depending on their weight on admission

This study aimed to assess the numbers of juvenile European hedgehogs admitted to rescue centers in the Czech Republic from the viewpoint of their weight on admission, the reason for their admission, and the success rate of their release back into the wild. The results of our study show varying levels of success in the rearing of hedgehogs admitted at different ages (weights) and a varying period required for their rehabilitation. The greatest chance of release was seen in hedgehogs with a weight on the admission of 500-599 g (64.22% released) and 400-499 g (63.31% released). In contrast, the smallest number of young hedgehogs successfully rehabilitated and released was seen in hoglets weighing 200-299 g (35.24% released) on admission, which corresponds to the weight of hedgehogs at the time of weaning. Time spent at a rescue center may pose an undesirable threat to the lives of animals in some categories. Hedgehogs weighing up to 99 g on admission spent the longest period time at rescue centers (a median of 48 days), while hedgehogs weighing 500-599 g on admission spent the shortest time (a median of 7 days). The majority of hedgehogs in the lowest weight categories were admitted due to their inability to survive on their own. A large percentage of hedgehogs of greater weight, in contrast, were juvenile hedgehogs brought to rescue centers needlessly. The percentage of released animals did not exceed 65%, however, even for entirely independent categories of older juveniles. From this perspective, the fact that hedgehogs are often brought to rescue centers in the belief that they are not self-sufficient young, though they are actually juvenile or even adult individuals that do not require human care, can be considered a significant finding.

Sex chromosomes in meiotic, hemiclonal, clonal and polyploid hybrid vertebrates: along the 'extended speciation continuum'

We review knowledge about the roles of sex chromosomes in vertebrate hybridization and speciation, exploring a gradient of divergences with increasing reproductive isolation (speciation continuum). Under early divergence, well-differentiated sex chromosomes in meiotic hybrids may cause Haldane-effects and introgress less easily than autosomes. Undifferentiated sex chromosomes are more susceptible to introgression and form multiple (or new) sex chromosome systems with hardly predictable dominance hierarchies. Under increased divergence, most vertebrates reach complete intrinsic reproductive isolation. Slightly earlier, some hybrids (linked in 'the extended speciation continuum') exhibit aberrant gametogenesis, leading towards female clonality. This facilitates the evolution of various allodiploid and allopolyploid clonal ('asexual') hybrid vertebrates, where 'asexuality' might be a form of intrinsic reproductive isolation. A comprehensive list of 'asexual' hybrid vertebrates shows that they all evolved from parents with divergences that were greater than at the intraspecific level (K2P-distances of greater than 5-22% based on mtDNA). These 'asexual' taxa inherited genetic sex determination by mostly undifferentiated sex chromosomes. Among the few known sex-determining systems in hybrid 'asexuals', female heterogamety (ZW) occurred about twice as often as male heterogamety (XY). We hypothesize that pre-/meiotic aberrations in all-female ZW-hybrids present Haldane-effects promoting their evolution. Understanding the preconditions to produce various clonal or meiotic allopolyploids appears crucial for insights into the evolution of sex, 'asexuality' and polyploidy. This article is part of the theme issue 'Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part II)'.

Trends in intake and outcomes for European hedgehog (Erinaceus europaeus) in the Czech rescue centers

The European hedgehog (Erinaceus europaeus) is a species found in abundance throughout Europe. Nevertheless, it has seen a decline in some regions. This study aimed to analyze trends in intake and outcomes for hedgehogs admitted into rescue centers in the Czech Republic. In the period from 2010 to 2019, 16,967 European hedgehogs were admitted in 34 rescue centers in the Czech Republic. Most hedgehogs were admitted in September (25.30%) and October (22.14%), the fewest in March (0.96%). Most admitted hedgehogs were hoglets (59.49%). The treatment was successful in 44.39% of admitted hedgehogs; those were subsequently released into the wild. On average, they stayed in rescue centers for 48.77 days (median of 30 days). Death or euthanasia was an outcome for 25.27% and 3.15% of admitted hedgehogs, respectively. Only 0.59% of the hedgehogs remained in captivity with a permanent handicap. The highest release rate was achieved in hedgehogs admitted after falls into pits and other openings (83.19%), whereas the least success was achieved in poisoned hedgehogs (13.21%). An increasing trend (rSp = 0.9273, p < 0.01) was found in the number of hedgehogs admitted to rescue centers during the monitored period. Furthermore, not all of them required human care. Given the fact that less than a half of the admitted hedgehogs could be released, raising public awareness of this issue could help to avoid unnecessary interventions (especially in hoglets).

Unexpected Gene-Flow in Urban Environments: The Example of the European Hedgehog

Simple Summary

An urban environment holds many barriers for mammals with limited mobility such as hedgehogs. These barriers appear often unsurmountable (e.g., rivers, highways, fences) and thus hinder contact between hedgehogs, leading to genetic isolation. In our study we tested whether these barriers affect the hedgehog population of urban Berlin, Germany. As Berlin has many of these barriers, we were expecting a strong genetic differentiation among hedgehog populations. However, when we looked at unrelated individuals, we did not see genetic differentiation among populations. The latter was only detected when we included related individuals too, a ‘family clan’ structure that is referred to as gamodemes. We conclude that the high percentage of greenery in Berlin provides sufficient habitat for hedgehogs to maintain connectivity across the city.

Abstract

We use the European hedgehog (Erinaceus europaeus), a mammal with limited mobility, as a model species to study whether the structural matrix of the urban environment has an influence on population genetic structure of such species in the city of Berlin (Germany). Using ten established microsatellite loci we genotyped 143 hedgehogs from numerous sites throughout Berlin. Inclusion of all individuals in the cluster analysis yielded three genetic clusters, likely reflecting spatial associations of kin (larger family groups, known as gamodemes). To examine the potential bias in the cluster analysis caused by closely related individuals, we determined all pairwise relationships and excluded close relatives before repeating the cluster analysis. For this data subset (N = 65) both clustering algorithms applied (Structure, Baps) indicated the presence of a single genetic cluster. These results suggest that the high proportion of green patches in the city of Berlin provides numerous steppingstone habitats potentially linking local subpopulations. Alternatively, translocation of individuals across the city by hedgehog rescue facilities may also explain the existence of only a single cluster. We therefore propose that information about management activities such as releases by animal rescue centres should include location data (as exactly as possible) regarding both the collection and the release site, which can then be used in population genetic studies.

Genetic diversity and structure of the hedgehogs Erinaceus europaeus and Erinaceus roumanicus: evidence for ongoing hybridization in Eastern Europe

Secondary contact zones between related species are key to understanding speciation mechanisms. The Central European sympatry zone of West European (Erinaceus europaeus) and northern white-breasted (Erinaceus roumanicus) hedgehogs is well studied, whereas data on the Eastern European sympatry zone are scarce. We examined the genetic variation in Russian populations using the mitochondrial Cytb gene, TTR intron 1 and 11 microsatellites to assess genetic variability and distribution patterns. In contrast to the Central European sympatry zone, we found evidence of ongoing hybridization between the two species in the sympatry zone of European Russia, where the proportion of individuals with mixed ancestry was c. 20%. Our data indicate bi-directional mtDNA introgression, but with a higher frequency of E. europaeus haplotypes in hybrids. The proportion of pure specimens with introgressed mitotypes is higher in E. roumanicus than in E. europaeus. Nuclear data showed the prevalence of the genetic contribution from E. roumanicus in admixed individuals. Demographic analyses indicated recent population growth in E. europaeus and little change in E. roumanicus, suggesting that E. europaeus colonized East Europe later than E. roumanicus.

Hedgehogs, Squirrels, and Blackbirds as Sentinel Hosts for Active Surveillance of Borrelia miyamotoi and Borrelia burgdorferi Complex in Urban and Rural Environments

Lyme borreliosis (LB), caused by spirochetes of the Borrelia burgdorferi sensu lato (s.l.) complex, is one of the most common vector-borne zoonotic diseases in Europe. Knowledge about the enzootic circulation of Borrelia pathogens between ticks and their vertebrate hosts is epidemiologically important and enables assessment of the health risk for the human population. In our project, we focused on the following vertebrate species: European hedgehog (Erinaceus europaeus), Northern white-breasted hedgehog (E. roumanicus), Eurasian red squirrel (Sciurus vulgaris), and Common blackbird (Turdus merula). The cadavers of accidentally killed animals used in this study constitute an available source of biological material, and we have confirmed its potential for wide monitoring of B. burgdorferi s.l. presence and genospecies diversity in the urban environment. High infection rates (90% for E. erinaceus, 73% for E. roumanicus, 91% for S. vulgaris, and 68% for T. merula) were observed in all four target host species; mixed infections by several genospecies were detected on the level of individuals, as well as in particular tissue samples. These findings show the usefulness of multiple tissue sampling as tool for revealing the occurrence of several genospecies within one animal and the risk of missing particular B. burgdorferi s.l. genospecies when looking in one organ alone.

3D Geometric Morphometrics Reveals Convergent Character Displacement in the Central European Contact Zone between Two Species of Hedgehogs (Genus Erinaceus)

Simple Summary

Hedgehogs, being insectivores with slow metabolisms, are quite sensitive to temperature and food availability. As a consequence, their ranges have oscillated in relation to past climate changes. Species that have evolved in different regions, but their ranges have shifted and overlapped subsequently, often represent intense competitors as a result of ecological similarities. The present study focuses on this phenomenon in the contact zone in central Europe and adjacent regions, using genetic determination of species and description of size and shape of skull, the morphological structure mirroring many selection pressures related to ecology. While animals living outside of the contact zone show marked differences between the two species, individuals within the contact zone are more alike with a smaller skull size and a convergent jawbone shape. Changes in skull size can be related to inter-species competition and also facilitated by selection pressure, mediated by overpopulated medium-sized predators such as foxes or badgers. Since the function of the lower jaw is mainly connected to feeding, we hypothesize that this pattern is due to the selection to size and shape related to competition for food resources. The present study helps to describe general patterns related to species formation, as well as species responses to anthropogenic environmental changes.

Abstract

Hedgehogs, as medium-sized plantigrade insectivores with low basal metabolic rates and related defensive anti-predator strategies, are quite sensitive to temperature and ecosystem productivity. Their ranges therefore changed dramatically due to Pleistocene climate oscillations, resulting in allopatric speciation and the subsequent formation of secondary contact zones. Such interactions between closely related species are known to generate strong evolutionary forces responsible for niche differentiation. In this connection, here, we detail the results of research on the phenotypic evolution in the two species of hedgehog present in central Europe, as based on genetics and geometric morphometrics in samples along a longitudinal transect that includes the contact zone between the species. While in allopatry, Erinaceus europaeus is found to have a larger skull than E. roumanicus and distinct cranial and mandibular shapes; the members of the two species in sympatry are smaller and more similar to each other, with a convergent shape of the mandible. The relevant data fail to reveal any major role for either hybridisation or clinal variation. We, therefore, hypothesise that competitive pressure exerted on the studied species does not generate divergent selection sufficient for divergent character displacement to evolve, instead giving rise to convergent selection in the face of resource limitation in the direction of smaller skull size. Considering the multi-factorial constraints present in the relevant adaptive landscape, reduction in size could also be facilitated by predator pressure in ecosystems characterised by mesopredator release and other anthropogenic factors. As the function of the animals’ lower jaw is mainly connected with feeding (in contrast to the cranium whose functions are obviously more complex), we interpret the similarity in shape as reflecting local adaptations to overlapping dietary resources in the two species and hence as convergent character displacement.

Impacts and Potential Mitigation of Road Mortality for Hedgehogs in Europe

Transport infrastructure is a pervasive element in modern landscapes and continues to expand to meet the demands of a growing human population and its associated resource consumption. Road-induced mortality is often thought to be a major contributor to the marked declines of European hedgehog populations. This review synthesizes available evidence on the population-level impacts of road mortality and the threat to population viability for the five hedgehog species in Europe. Local and national studies suggest that road mortality can cause significant depletions in population sizes, predominantly removing adult males. Traffic collisions are a probable cause of fragmentation effects, subsequently undermining ecological processes such as dispersal, as well as the genetic variance and fitness of isolated populations. Further studies are necessary to improve population estimates and explicitly examine the consequences of sex- and age-specific mortality rates. Hedgehogs have been reported to use crossing structures, such as road tunnels, yet evaluations of mitigation measures for population survival probability are largely absent. This highlights the need for robust studies that consider population dynamics and genetics in response to mitigation. In light of ongoing declines of hedgehog populations, it is paramount that applied research is prioritised and integrated into a holistic spatial planning process.

Evaluating the Impact of Wildlife Shelter Management on the Genetic Diversity of Erinaceus europaeus and E. roumanicus in Their Contact Zone

Simple Summary

Hedgehogs are regularly brought to wildlife shelters. Depending on the area from where animals are accepted, translocation can occur between different regions or populations. In this study, the genetic diversity of wild hedgehog populations was compared with “shelter populations” within central Europe focusing on the western contact zone between both European hedgehog species. Some shelters were hosting both species at the same time, in one this could be shown genetically. Generally, no difference in genetic diversity between shelter individuals and wild populations was found. Two shelters from Innsbruck hosted individuals that probably belong to two subpopulations. This indicates that shelter management-related translocations could facilitate gene flow across a dispersal barrier.

Abstract

Hedgehogs are among the most abundant species to be found within wildlife shelters and after successful rehabilitation they are frequently translocated. The effects and potential impact of these translocations on gene flow within wild populations are largely unknown. In this study, different wild hedgehog populations were compared with artificially created “shelter populations”, with regard to their genetic diversity, in order to establish basic data for future inferences on the genetic impact of hedgehog translocations. Observed populations are located within central Europe, including the species Erinaceus europaeus and E. roumanicus. Shelters were mainly hosting one species; in one case, both species were present syntopically. Apart from one exception, the results did not show a higher genetic diversity within shelter populations, indicating that individuals did not originate from a wider geographical area than individuals grouped into one of the wild populations. Two shelters from Innsbruck hosted individuals that belonged to two potential clusters, as indicated in a distance analysis. When such a structure stems from the effects of landscape elements like large rivers, the shelter management-related translocations might lead to homogenization across the dispersal barrier.

Genetic structure of the European hedgehog (Erinaceus europaeus) in Denmark

Objectives

Low genetic diversity can lead to reduced average fitness in a population or even extinction. Preserving genetic connectivity across fragmented landscapes is therefore vital to counteract the negative consequences of genetic drift and inbreeding. This study aimed to assess the genetic composition and consequently the conservation status of a nationwide sample of European hedgehogs (Erinaceus europaeus) in Denmark.

Methods

We applied an adaptation of the genotyping by sequencing (GBS) technique to 178 individuals from six geographically distinct populations. We used a Bayesian clustering method to subdivide individuals into genetically distinct populations. We estimated individual observed (iH_O), observed (H_O), and unbiased expected (uH_E) heterozygosity, inbreeding coefficient (F_IS), percentage of polymorphic loci (P%) and tested for deviations from Hardy-Weinberg equilibrium (HWE). We used linear models to test for potential anthropogenic effects on the genetic variability of hedgehogs with iH_O, uH_E, P% and F_IS as response variables, and assessed the demographic history of the population.

Results

The Danish hedgehog population is composed of three genetic clusters. We found a mean P% of 54.44–94.71, a mean uH_E of 0.126–0.318 and a mean H_O of 0.124–0.293 in the six populations. The F_IS was found to be significantly positive for three of the six populations. We detected a large heterogeneity of iH_O values within populations, which can be due to inbreeding and/or fragmentation. F_IS values decreased with increasing farmland density, but there was no significant association with human population or road density.

Conclusions

We found a low level of genetic variability and evidence for genetic substructure and low effective population size, which are all consequences of habitat fragmentation. We failed to detect signs of a recent population bottleneck or population increase or decline. However, because the test only identifies recent changes in population size, we cannot reject the possibility of a longer-term decline in the Danish hedgehog population.

Application of a SSR-GBS marker system on investigation of European Hedgehog species and their hybrid zone dynamics

By applying second-generation sequencing technologies to microsatellite genotyping, sequence information is produced which can result in high-resolution population genetics analysis populations and increased replicability between runs and laboratories. In the present study, we establish an approach to study the genetic structure patterns of two European hedgehog species Erinaceaus europaeus and E. roumanicus. These species are usually associated with human settlements and are good models to study anthropogenic impacts on the genetic diversity of wild populations. The short sequence repeats genotyping by sequence (SSR-GBS) method presented uses amplicon sequences to determine genotypes for which allelic variants can be defined according to both length and single nucleotide polymorphisms (SNPs). To evaluate whether complete sequence information improved genetic structure definition, we compared this information with datasets based solely on length information. We identified a total of 42 markers which were successfully amplified in both species. Overall, genotyping based on complete sequence information resulted in a higher number of alleles, as well as greater genetic diversity and differentiation between species. Additionally, the structure patterns were slightly clearer with a division between both species and some potential hybrids. There was some degree of genetic structure within species, although only in E. roumanicus was this related to geographical distance. The statistically significant results obtained by SSR-GBS demonstrate that it is superior to electrophoresis-based methods for SSR genotyping. Moreover, the greater reproducibility and throughput with lower effort which can be obtained with SSR-GBS and the possibility to include degraded DNA into the analysis, allow for continued relevance of SSR markers during the genomic era.

Glacial allopatry vs. postglacial parapatry and peripatry: the case of hedgehogs

Although hedgehogs are well-known examples of postglacial recolonisation, the specific processes that shape their population structures have not been examined by detailed sampling and fast-evolving genetic markers in combination with model based clustering methods. This study aims to analyse the impacts of isolation within glacial refugia and of postglacial expansion on the population structure of the Northern White-breasted hedgehog (Erinaceus roumanicus). It also discusses the role of the processes at edges of species distribution in its evolutionary history. The maternally inherited mitochondrial control region and the bi-parentally inherited nuclear microsatellites were used to examine samples within the Central Europe, Balkan Peninsula and adjacent islands. Bayesian coalescent inference and neutrality tests proposed a recent increase in the population size. The most pronounced pattern of population structure involved differentiation of the insular populations in the Mediterranean Sea and the population within the contact zone with E. europaeus in Central Europe. An interspecies hybrid was detected for the first time in Central Europe. A low genetic diversity was observed in Crete, while the highest genetic distances among individuals were found in Romania. The recent population in the post-refugial area related to the Balkan Peninsula shows a complex pattern with pronounced subpopulations located mainly in the Pannonian Basin and at the Adriatic and Pontic coasts. Detailed analyses indicate that parapatry and peripatry may not be the only factors that limit range expansion, but also strong microevolutionary forces that may change the genetic structure of the species. Here we present evidence showing that population differentiation may occur not only during the glacial restriction of the range into the refugia, but also during the interglacial range expansion. Population differentiation at the Balkan Peninsula and adjacent regions could be ascribed to diversification in steppe/forest biomes and complicated geomorphology, including pronounced geographic barriers as Carpathians.

Mitochondrial Genome Analysis Reveals Historical Lineages in Yellowstone Bison

Yellowstone National Park is home to one of the only plains bison populations that have continuously existed on their present landscape since prehistoric times without evidence of domestic cattle introgression. Previous studies characterized the relatively high levels of nuclear genetic diversity in these bison, but little is known about their mitochondrial haplotype diversity. This study assessed mitochondrial genomes from 25 randomly selected Yellowstone bison and found 10 different mitochondrial haplotypes with a haplotype diversity of 0.78 (± 0.06). Spatial analysis of these mitochondrial DNA (mtDNA) haplotypes did not detect geographic population subdivision (F_ST = -0.06, p = 0.76). However, we identified two independent and historically important lineages in Yellowstone bison by combining data from 65 bison (defined by 120 polymorphic sites) from across North America representing a total of 30 different mitochondrial DNA haplotypes. Mitochondrial DNA haplotypes from one of the Yellowstone lineages represent descendants of the 22 indigenous bison remaining in central Yellowstone in 1902. The other mitochondrial DNA lineage represents descendants of the 18 females introduced from northern Montana in 1902 to supplement the indigenous bison population and develop a new breeding herd in the northern region of the park. Comparing modern and historical mitochondrial DNA diversity in Yellowstone bison helps uncover a historical context of park restoration efforts during the early 1900s, provides evidence against a hypothesized mitochondrial disease in bison, and reveals the signature of recent hybridization between American plains bison (Bison bison bison) and Canadian wood bison (B. b. athabascae). Our study demonstrates how mitochondrial DNA can be applied to delineate the history of wildlife species and inform future conservation actions.

Admixture of Eastern and Western European Red Deer Lineages as a Result of Postglacial Recolonization of the Czech Republic (Central Europe)

Due to a restriction of the distributional range of European red deer (Cervus elaphus L.) during the Quaternary and subsequent recolonization of Europe from different refugia, a clear phylogeographical pattern in genetic structure has been revealed using mitochondrial DNA markers. In Central Europe, 2 distinct, eastern and western, lineages of European red deer are present; however, admixture between them has not yet been studied in detail. We used mitochondrial DNA (control region and cytochrome b gene) sequences and 22 microsatellite loci from 522 individuals to investigate the genetic diversity of red deer in what might be expected to be an intermediate zone. We discovered a high number of unique mtDNA haplotypes belonging to each lineage and high levels of genetic diversity (cyt b H = 0.867, D-loop H = 0.914). The same structuring of red deer populations was also revealed by microsatellite analysis, with results from both analyses thus suggesting a suture zone between the 2 lineages. Despite the fact that postglacial recolonization of Central Europe by red deer occurred more than 10000 years ago, the degree of admixture between the 2 lineages is relatively small, with only 10.8% admixed individuals detected. Direct translocations of animals by humans have slightly blurred the pattern in this region; however, this blurring was more apparent when using maternally inherited markers than nuclear markers.

Wildlife reservoirs for vector-borne canine, feline and zoonotic infections in Austria

Austria's mammalian wildlife comprises a large variety of species, acting and interacting in different ways as reservoir and intermediate and definitive hosts for different pathogens that can be transmitted to pets and/or humans. Foxes and other wild canids are responsible for maintaining zoonotic agents, e.g. Echinococcus multilocularis, as well as pet-relevant pathogens, e.g. Hepatozoon canis. Together with the canids, and less commonly felids, rodents play a major role as intermediate and paratenic hosts. They carry viruses such as tick-borne encephalitis virus (TBEV), bacteria including Borrelia spp., protozoa such as Toxoplasma gondii, and helminths such as Toxocara canis. The role of wild ungulates, especially ruminants, as reservoirs for zoonotic disease on the other hand seems to be negligible, although the deer filaroid Onchocerca jakutensis has been described to infect humans. Deer may also harbour certain Anaplasma phagocytophilum strains with so far unclear potential to infect humans. The major role of deer as reservoirs is for ticks, mainly adults, thus maintaining the life cycle of these vectors and their distribution. Wild boar seem to be an exception among the ungulates as, in their interaction with the fox, they can introduce food-borne zoonotic agents such as Trichinella britovi and Alaria alata into the human food chain.

Ectoparasite loads in sympatric urban populations of the northern white-breasted and the European hedgehog

We investigated abundance and prevalence of ticks and fleas infesting urban populations of two species of hedgehogs: the northern white-breasted hedgehog (Erinaceus roumanicus) and the European hedgehog (Erinaceus europaeus). The hedgehogs were captured in the city of Poznań (western Poland) over the period of 4 years. Both species of hedgehogs were infested with the castor bean tick (Ixodes ricinus), the hedgehog tick (Ixodes hexagonus), and the hedgehog flea (Archeopsylla erinacei). The northern white-breasted hedgehog had higher loads of I. ricinus and A. erinacei than the European hedgehog. The abundance and prevalence of I. hexagonus were similar on both species of hosts. Co-infestation with the two species of ticks was more frequent on the northern white-breasted hedgehog than on the European hedgehog. Therefore, these two closely related species of hedgehogs differ in their importance as hosts of arthropod vectors of pathogens in urban areas and might play a different role in the dynamics of zoonotic diseases.

Different parasite faunas in sympatric populations of sister hedgehog species in a secondary contact zone

Providing descriptive data on parasite diversity and load in sister species is a first step in addressing the role of host-parasite coevolution in the speciation process. In this study we compare the parasite faunas of the closely related hedgehog species Erinaceus europaeus and E. roumanicus from the Czech Republic where both occur in limited sympatry. We examined 109 hedgehogs from 21 localities within this secondary contact zone. Three species of ectoparasites and nine species of endoparasites were recorded. Significantly higher abundances and prevalences were found for Capillaria spp. and Brachylaemus erinacei in E. europaeus compared to E. roumanicus and higher mean infection rates and prevalences for Hymenolepis erinacei, Physaloptera clausa and Nephridiorhynchus major in E. roumanicus compared to E. europaeus. Divergence in the composition of the parasite fauna, except for Capillaria spp., which seem to be very unspecific, may be related to the complicated demography of their hosts connected with Pleistocene climate oscillations and consequent range dynamics. The fact that all parasite species with different abundances in E. europaeus and E. roumanicus belong to intestinal forms indicates a possible diversification of trophic niches between both sister hedgehog species.

Population biology of establishment in New Zealand hedgehogs inferred from genetic and historical data: conflict or compromise?

The crucial steps in biological invasions, related to the shaping of genetic architecture and the current evolution of adaptations to a novel environment, usually occur in small populations during the phases of introduction and establishment. However, these processes are difficult to track in nature due to invasion lag, large geographic and temporal scales compared with human observation capabilities, the frequent depletion of genetic variance, admixture and other phenomena. In this study, we compared genetic and historical evidence related to the invasion of the West European hedgehog to New Zealand to infer details about the introduction and establishment. Historical information indicates that the species was initially established on the South Island. A molecular assay of populations from Great Britain and New Zealand using mitochondrial sequences and nuclear microsatellite loci was performed based on a set of analyses including approximate Bayesian computation, a powerful approach for disentangling complex population demographies. According to these analyses, the population of the North Island was most similar to that of the native area and showed greatest reduction in genetic variation caused by founder demography and/or drift. This evidence indicated the location of the establishment phase. The hypothesis was corroborated by data on climate and urbanization. We discuss the contrasting results obtained by the molecular and historical approaches in the light of their different explanatory power and the possible biases influencing the description of particular aspects of invasions, and we advocate the integration of the two types of approaches in invasion biology.