Doñana Biological Station

Dispersal by waterbirds and wild mammals is known to be important for maintaining biodiversity among wetlands. Cattle are known to be important seed dispersers in terrestrial habitats; however, the role of cattle in plant dispersal among wetlands is poorly known. We analyzed the potential for the dispersal of aquatic plants (seeds, diaspores and whole plants) by cattle (Bos taurus) through endozoochory in Neotropical wetlands. Ten fresh fecal samples per site (total 30 samples) were collected in three farms of the Pampa region, southern Brazil, between September and November of 2023. A total of 982 propagules and whole plants from 37 wetland plant taxa, belonging to 14 angiosperm and two fern families, were reported. Ten of these taxa are aquatic, seven terrestrial, and 19 grow both in water and on land. Viability was confirmed for seeds from 10 angiosperm families and for 26% of all seeds tested. Our results suggest cattle provide an important ecosystem service for wetland biodiversity in grassland areas through seed dispersal.

In this study we have compiled the information from official databases about Iberian ibex, Capra pyrenaica, hunting yields, hunting trophies and hunting licenses in the Spanish regions where the species is present and hunted. Such quotas showed an increasing trend between 2005-2021 and, on average, during this period, ≈ 6400 animals were yearly harvested. Despite this number decreased in 2019 and 2020 (in this last year, mainly due to the lock down caused by the COVID pandemia), the annual quota raised, reaching over 12,000 ibexes in 2021. The number of trophies increased since the 1970s and peaked in the period 2001-2005, and then declined during the period 2006-2020. At national level, the number of hunting licenses decreased from 2006 to 2021 by a 36.5%. The regional average hunting yield was significantly correlated with a regional-based ibex abundance estimation. The current situation of continued population increase together with the trophy reduction might suggest that the overall population is exceeding the carrying capacity. In this context, if hunting activity was one of the main factors involved in local extinction of the species, currently it should be considered a tool for sustainable managing of ibex populations in an scenario of increasing demographic trends and generalized absence of predators.

The Wildlife Malaria Network (WIMANET) is an EU‐COST‐funded global network of researchers and stakeholders interested in wildlife malaria and related haemosporidian parasites. The network has six working groups covering a diverse range of core topics within wildlife malaria research, focusing on genetics and genomics, species identification, vectors, haematology, communities, and communication. Up to now, the network includes 229 members from 45 countries including Europe, America, Africa, and Asia, but this number is continually growing. This review outlines the aims and goals of WIMANET, providing a summary of activities and plans for each of the six working groups for the next years. The network is open to new members, and we provide details on how both new and existing members can get involved in the network and take part in activities. WIMANET provides a global platform for collaborative and innovative research, and we encourage all members of the wildlife malaria community (and beyond) to take advantage of the opportunities the network offers.

Optimal Foraging Theory (OFT) integrates both the consumer and the resource, yet their simultaneous assessment is uncommon. Vultures represent an ideal model for OFT studies because carrion requires no capture effort and minimal handling, allowing them to focus primarily on food searching. Here, we combined GPS tracking of 61 Iberian griffon vultures (consumers) with photo-trapping monitoring of 49 carcasses (resources) to assess the determinants of vulture foraging and the consequences for carrion consumption in two areas with different carrion abundances. First, we determined the importance of different factors (distance to the resource, hunger and competition) in the decisions of individuals of whether to descend or not on a carcass. Second, we compared carrion consumption patterns (time of carcass discovery and consumption, and maximum number of vultures gathered around the carcass) between areas. We found that distance, rather than hunger, is the primary factor determining whether a vulture descends to a carcass. In parallel, carrion was consumed similarly in areas with different resource availabilities. These findings indicate that vultures tend to eat whenever a nearby opportunity arises, consistent with a type-I functional response.

The emergence, spread and potential zoonotic importance of pathogenic‐resistant bacteria (e.g., Escherichia coli) has fuelled the research on epidemiology and vector movement dynamics. However, little is known about the effects that apparently asymptomatic carriage may have on host behaviour. Here, we analysed and compared movement patterns and habitat use (focused on the different risk of exposure to Antibiotic Resistance) of yellow‐legged gulls (Larus michahellis) carrying (n = 10) and not carrying (n = 29) Antibiotic‐resistant Escherichia coli. Using data from GPS devices coupled with accelerometers, we found evidence that individuals carrying resistant E. coli, although previously considered asymptomatic, had lower accumulated travelled distances and moved over smaller areas. Antibiotic resistance carriage may affect movement patterns to some extent, as in this case, potentially reducing pathogen dispersal over large areas.

Aim Non‐native plants have the potential to harm ecosystems. Harm is classically related to their distribution and abundance, but this geographical information is often unknown. Here, we assess geographical commonness as a potential indicator of invasive status for non‐native flora in the United States. Geographical commonness could inform invasion risk assessments across species and ecoregions. Location Conterminous United States. Time Period Through 2022. Major Taxa Studied Plants. Methods We compiled and standardised occurrence and abundance data from 14 spatial datasets and used this information to categorise non‐native species as uncommon or common based on three dimensions of commonness: area of occupancy, habitat breadth and local abundance. To assess consistency in existing categorizations, we compared commonness to invasive status in the United States. We identified species with higher‐than‐expected abundance relative to their occupancy, habitat breadth or residence time. We calculated non‐native plant richness within United States ecoregions and estimated unreported species based on rarefaction/extrapolation curves. Results This comprehensive database identified 1874 non‐native plant species recorded in 4,844,963 locations. Of these, 1221 species were locally abundant (> 10% cover) in 797,759 unique locations. One thousand one hundred one non‐native species (59%) achieved at least one dimension of commonness, including 565 species that achieved all three. Species with longer residence times tended to meet more dimensions of commonness. We identified 132 species with higher‐than‐expected abundance. Ecoregions in the central United States have the largest estimated numbers of unreported, abundant non‐native plants. Main Conclusions A high proportion of non‐native species have become common in the United States. However, existing categorizations of invasive species are not always consistent with species' abundance and distribution, even after considering residence time. Considering geographical commonness and higher‐than‐expected abundance revealed in this new dataset could support more consistent and proactive identification of invasive plants and lead to more efficient management practices.

Life on Earth is adapted to rhythmic cycles in environmental conditions throughout the day and year via diel patterns of behavioural activity. Urban conditions can disrupt such behavioural rhythms of activity. However, most studies so far have investigated urban effects on patterns of activity of single species in a single season. Additionally, we know little about the level of between‐ and within‐individual variation in urban and non‐urban populations, and whether they differ. Here, we use automated radio telemetry to record patterns of daily activity in six passerine species (blackbird, robin, great tit, blue tit, dunnock and chaffinch) across two urban and two forest populations during the pre‐breeding and post‐breeding seasons. We investigate urban effects on five activity‐related traits: time of activity onset, time of activity end, duration of diurnal activity, level of diurnal activity and level of nocturnal activity. We employ statistical tools that allow us to estimate urban effects on mean phenotypic values but also quantify urban versus forest differences in between‐individual and within‐individual phenotypic variation. We found the strongest urban effects on time of activity onset in blackbirds and robins during both the pre‐ and post‐breeding seasons: urban populations of blackbird and robin started their daily activity earlier than their forest counterparts. We did not find this effect in the other species. Urban populations of all species showed higher levels of nocturnal activity than forest populations, but this effect was not offset by lower diurnal activity, suggesting that urban birds may incur higher daily energetic demands. Lastly, our analysis revealed large and consistent differences in variation in the investigated timing traits. Onset and end of daily activity were more variable in urban birds between individuals, implying lower population synchronisation, and more variable within individuals, implying less consistent behaviour, than in their forest counterparts. Conversely, activity levels were more variable in forest birds. We conclude that, for birds, urban life is associated with less rest, less consistency and lower synchronicity, but that effect sizes depend on species and time of the year. Our results warn against generalising the effects of urbanisation on daily rhythms of birds and call for future studies to understand the mechanisms behind species and seasonal differences.

Plant biogeography and ongoing changes in plant distributions are influenced by long‐distance dispersal (LDD) of seeds, and migratory waterfowl (Anatidae: Ducks, geese and swans) are particularly important for the dispersal of plants in and around wetlands through gut passage (endozoochory). However, this dispersal is not contemplated by classical dispersal syndromes; hence, currently we have limited understanding of what angiosperm traits predict seed dispersal by waterfowl and any differences due to avian trait variation among waterfowl species. We conducted a literature search for data on the presence of seeds in the alimentary canal or faeces of North American waterfowl as a proxy for dispersal interactions, since an important fraction of these seeds survives gut passage. We present a list of North American flowering plant species ( N = 536) from 95 families potentially dispersed by 38 waterfowl species, together with traits of these plants and their vectors. Owing largely to limited sampling effort, 47% of plant species and 35% of plant genera recorded were only found in a single waterfowl species. A suite of analytical approaches revealed major differences in the traits of plants whose seeds are ingested and likely dispersed between foraging groups (guilds) and in relation to other waterfowl traits. Diving ducks and sea ducks are associated with sublittoral plants that have submerged or floating leaves, and hence with the classical hydrochory syndrome. Dabbling ducks and herbivorous waterfowl (notably geese) are associated with terrestrial herbaceous plants, and also with the unspecialised dispersal syndrome common in terrestrial plants. Plants with larger seeds or of greater height are more likely to be dispersed by dabbling ducks, whereas shorter plants are more likely to be dispersed by geese than by other waterfowl. Network analyses of interactions between waterfowl species and plant traits were generally consistent with these results, but also provided evidence that not all geese, dabbling ducks, or sea duck species are alike in their interactions with plants along the terrestrial–aquatic gradient, but instead occupy distinct dispersal niches. The traditional classification of waterfowl into guilds therefore does not accurately reflect their differing roles in the ingestion and dispersal of plant seeds. Aquatic plant species had more vector species than terrestrial ones. Detailed studies of waterfowl endozoochory and more trait determinations for North American plants are needed to facilitate predictions of LDD as waterfowl population sizes and migration patterns vary in the future with climate change.

The effects of climate and plant phenological changes on herbivorous species are widely recognized, yet less research has focused on predatory species, even though vegetative components can account for large proportions of their diet. The historical focus on predation through the lens of simple interactions between obligate carnivores and their prey oversimplifies many species' roles within ecological communities and minimizes other, equally important community functions. We used a long‐term, individual‐based dataset on an omnivorous species, the brown bear (Ursus arctos), to identify long‐term diet patterns and factors contributing to annual variation in diet. We used carbon and nitrogen stable isotopes measured in hair and Bayesian mixing models to determine annual diet among three demographic classes and then used linear mixed models to relate diet to indices of food availability. Variation in both carbon and nitrogen values were explained by bilberry (Vaccinium myrtillus) productivity. Additionally, even as the moose population increased over time, there was no increase in the proportion of moose in the diet. The variation in the proportion of moose in the diet slightly decreased throughout the study, while the proportion of bilberry became increasingly more variable. Our results highlight that even though vegetative diet components are typically considered less important to predator ecology, brown bear diet in Sweden responded to changes in berry availability, regardless of prey availability. It will be crucial to put more emphasis on the vegetative parts of diets as we predict how species and ecological communities respond to climate change because predators serve many more functions within their community besides predation alone.

Background Culex theileri (Theobald, 1903) is distributed in Afrotropical, Paleartic, and Oriental regions. It is a mainly mammophilic floodwater mosquito that is involved in the transmission of West Nile virus (WNV, renamed as Orthoflavivirus nilense by the International Committee on Taxonomy of Viruses [ICTV]) in Africa. This virus is a mosquito-borne flavivirus that is kept in an enzootic cycle mainly between birds and mosquitoes of the Culex genus. Occasionally, it affects mammals including humans and equines causing encephalopathies. The main purpose of the present study was to evaluate the vector competence of a European field-captured Cx. theileri population for circulating WNV lineages (1 and 2). Methods Field-collected Cx. theileri larvae from Sevilla province (Spain) were reared in the laboratory under summer environmental conditions. To assess the vector competence for WNV transmission, 10–12 day old Cx. theileri females were fed with blood doped with WNV lineages 1 and 2 (7 log10 TCID50/mL). Females were sacrificed at 14- and 21- days post exposure (dpe), and their head, body, and saliva were extracted to assess infection, dissemination, and transmission rates, as well as transmission efficiency. Results A Culex theileri population was experimentally confirmed as a highly competent vector for WNV (both lineages 1 and 2). The virus successfully infected and disseminated within Cx. theileri mosquitoes, and infectious virus isolated from their saliva indicated their potential to transmit the virus. Transmission efficiency was 50% for lineage 1 (for both 14 and 21 dpe), while it was 24% and 37.5% for lineage 2, respectively. There was barely any effect of the midgut infection barrier for lineage 1 and a moderate effect for lineage 2. The main barrier which limited the virus infection within the mosquito was the midgut escape barrier. Conclusions In the present study, the high transmission efficiency supports that Cx. theileri is competent to transmit WNV. However, vector density and feeding patterns of Cx. theileri mosquitoes must be considered when estimating their vectorial capacity for WNV in the field. Graphical Abstract

An increase in biotic interactions towards lower latitudes is one of the most consistent patterns in ecology. Higher temperatures and more stable climatic conditions at low latitudes are thought to enhance biotic interactions, accelerating biological evolution and leading to stronger anti-herbivore defences in plants. However, some studies report contradictory findings, highlighting the need for further investigation into the underlying mechanisms. We used a combination of field observations and feeding trials in controlled environments to investigate the effect of climate on chemical defences and insect herbivory in pedunculate oak (Quercus robur L.) throughout most of its geographic range in Europe, while controlling for physical defences. The concentration of lignin, flavonoids, and total phenolics increased significantly with temperature, whereas both field herbivory and weight of spongy moth (Lymantria dispar L.) larvae were negatively influenced by temperature. Lignin concentration positively influenced the weight of spongy moth larvae whereas it had no effect on field herbivory. We found no evidence of strong positive relationships between insect herbivory and larvae growth with leaf defences. Our study underscores the complexity of plant–herbivore interactions along climatic gradients and highlights the need for further research to disentangle these intricate relationships.

According to Bergmann's and Allen's rules, climate change may drive morphological shifts in species, affecting body size and appendage length. These rules predict that species in colder climates tend to be larger and have shorter appendages to improve thermoregulation. Bats are thought to be sensitive to climate and are therefore expected to respond to climatic changes across space and time. We conducted a phylogenetic meta‐analysis on > 27 000 forearm length (FAL) and body mass (BM) measurements from 20 sedentary European bat species to examine body size patterns. We assessed the relationships between body size and environmental variables (winter and summer temperatures, and summer precipitation) across geographic locations, and also analysed temporal trends in body size. We found sex‐specific morphological shifts in the body size of European bats in response to temperature and precipitation patterns across space, but no clear temporal changes due to high interspecific variability. Across Europe, male FAL decreased with increasing summer and winter temperatures, and BM increased with greater precipitation. In contrast, both FAL and BM of female bats increased with summer precipitation and decreased with winter temperatures. Our data can confirm Bergmann's rule for both males and females, while females' BM variations are also related to summer precipitation, suggesting a potential link to resource availability. Allen's rule is confirmed only in males in relation to summer temperature, while in females FAL and BM decrease proportionally with increasing temperature, maintaining a constant allometric relationship incompatible with Allen's rule. This study provides new insights into sex and species‐dependent morphological changes in bat body size in response to temperature and precipitation patterns. It highlights how body size variation reflects adaptations to temperature and precipitation patterns, thus providing insights into potential species‐level morphological responses to climate change across Europe.

Chromosomal inversions, by suppressing recombination, can profoundly shape genome evolution and drive adaptation. In the common quail (Coturnix coturnix), a highly mobile bird with a vast Palearctic breeding range, we previously identified a massive inversion on chromosome 1 associated with distinct phenotypes and restricted geographic distribution. Here, using a new de novo genome assembly, we characterise this inversion and uncover additional, ancient structural variation on chromosome 2 that segregates across the species' range: either two putatively linked inversions or a single, large inversion that appears as two due to scaffolding limitations. Together, the inversions encompass a remarkable 15.6% of the quail genome (153.6 Mbp), creating highly divergent haplotypes that diverged over a million years ago. While the chromosome 1 inversion is linked to phenotypic differences, including morphology and migratory behaviour, the chromosome 2 inversion(s) show no such association. Notably, all inversion regions exhibit reduced effective population size and a relaxation of purifying selection, evidenced by elevated nonsynonymous‐to‐synonymous substitution ratios (N/S). This suggests that inversions, particularly the geographically restricted one on chromosome 1, may act as engines of diversification, accelerating the accumulation of functional variation and potentially contributing to local adaptation, especially within isolated island populations. Our findings demonstrate how large‐scale chromosomal rearrangements can compartmentalise a genome, fostering distinct evolutionary trajectories within a single, highly mobile species.

Climate change is predicted to drive geographical range shifts that will result in changes in species diversity and functional composition and have potential repercussions for ecosystem functioning. However, the effect of these changes on species composition and functional diversity (FD) remains unclear, especially for mammals, specifically bats. We used species distribution models and a comprehensive ecological and morphometrical trait database to estimate how projected future climate and land‐use changes could influence the distribution, composition, and FD of the European bat community. Future bat assemblages were predicted to undergo substantial shifts in geographic range and trait structure. Range suitability decreased substantially in southern Europe and increased in northern latitudes. Our findings highlight the potential for climate change to drive shifts in bat FD, which has implications for ecosystem function and resilience at a continental scale. It is important to incorporate FD in conservation strategies. These efforts should target species with key functional traits predicted to be lost and areas expected to experience losses in FD. Conservation strategies should include habitat and roost protection, enhancing landscape connectivity, and international monitoring to preserve bat populations and their ecosystem services.

Long‐distance bird migration is one of the most metabolically and immunologically challenging feats in the animal kingdom, with birds often needing to double their weight in a matter of days and facing increased exposure to novel pathogens. The physiological and behavioural adaptations required to survive such journeys may be facilitated by the gut microbiome, a diverse community of symbiotic microbes that produce rare nutrients, fatty acids, and immune compounds that can confer rapid physiological adaptations to changing environmental conditions. However, the causal role of the gut microbiome in regulating migration physiology remains a mystery. In this review, we synthesize current knowledge of gut microbiome composition and function during migration, outline possible mechanisms by which changes in the gut microbiome could benefit migrants, and identify future research priorities. We find that active migration is usually associated with reduced diversity of the gut microbiome and with the expansion of several study‐specific taxa. Additionally, some microbial traits have been found to correlate with host condition and fat deposits during migration. However, there remains little understanding of how changes in the gut microbiome during migration relate to most physiological parameters, the molecular mechanisms linking the gut microbiome to host physiology during migration, or the underlying ecological, dietary, and intrinsic drivers of gut microbiome changes across the migratory cycle. Our review draws from examples across non‐migratory systems to explore how gut microbiomes could adaptively regulate physiological traits relevant to migration. We highlight the need for studies that connect gut and circulating metabolites and for experimental studies that test the underlying drivers of gut microbial and metabolite dynamics in controlled settings. Given its diverse physiological demands and ubiquity, bird migration presents an excellent model system to investigate the adaptive potential of the gut microbiome in natural populations.

Aim In highly mobile species, Migratory Connectivity (MC) has relevant consequences in population dynamics, genetic mixing, conservation and management. Additionally, in colonially breeding species, the maintenance of the breeding geographical structure during the non‐breeding period, that is, a strong MC, can promote isolation and population divergence, which ultimately can affect the process of lineage sorting. In geographically structured populations, studying the MC and differences in environmental preferences among colonies, populations, or taxa can improve our understanding of the ecological divergence among them. Location Atlantic Ocean and Mediterranean Sea. Methods We investigated the MC and non‐breeding ecological niche of three seabird taxa from the genus Calonectris (n = 805 individuals). Using 1346 year‐round trips from 34 different breeding colonies, we assess the level (from taxa to colony) at which MC and non‐breeding spatial and environmental segregation emerge. Results At a taxon level, we found a clear difference in the non‐breeding distributions between Cory's (C. borealis) and Scopoli's (C. diomedea) shearwaters, and a clear ecological divergence between Cory's and Cape Verde (C. edwardsii) shearwaters. At an intermediate aggregation level, we found that birds breeding in proximity had similar non‐breeding habitat preferences, while birds breeding in very distant colonies (and therefore classified in different populations) had different non‐breeding habitat preferences. Furthermore, within each taxon, we found more structure (i.e. stronger MC) and non‐breeding divergence at an intermediate aggregation level than at the colony scale, where MC was weak. Main Conclusions These results suggest that conspecifics from nearby colonies mix in common non‐breeding areas, but not with birds from more distant colonies or different taxa. These results support the need for management and conservation strategies that take into account this structure when dealing with migratory species with high connectivity.

Modern birds have diversified into a striking array of forms, behaviours and ecological roles. Analyses of molecular evolutionary rates can reveal the links between genomic and phenotypic change1, 2, 3–4, but disentangling the drivers of rate variation at the whole-genome scale has been difficult. Using comprehensive estimates of traits and evolutionary rates across a family-level phylogeny of birds5,6, we find that genome-wide mutation rates across lineages are predominantly explained by clutch size and generation length, whereas rate variation across genes is driven by the content of guanine and cytosine. Here, to find the subsets of genes and lineages that dominate evolutionary rate variation in birds, we estimated the influence of individual lineages on decomposed axes of gene-specific evolutionary rates. We find that most of the rate variation occurs along recent branches of the tree, associated with present-day families of birds. Additional tests on axes of rate variation show rapid changes in microchromosomes immediately after the Cretaceous–Palaeogene transition. These apparent pulses of evolution are consistent with major changes in the genetic machineries for meiosis, heart performance, and RNA splicing, surveillance and translation, and correlate with the ecological diversity reflected in increased tarsus length. Collectively, our analyses paint a nuanced picture of avian evolution, revealing that the ancestors of the most diverse lineages of birds underwent major genomic changes related to mutation, gene usage and niche expansion in the early Palaeogene period.

Aim Beta diversity quantifies the similarity of ecological assemblages. Its increase, known as biotic homogenisation, can be a consequence of biological invasions. However, species occurrence (presence/absence) and abundance‐based analyses can produce contradictory assessments of the magnitude and direction of changes in beta diversity. Previous work indicates these contradictions should be less frequent in nature than in theory, but a growing number of empirical studies report discrepancies between occurrence‐ and abundance‐based approaches. Understanding if these discrepancies represent a few isolated cases or are systematic across a diversity of ecosystems would allow us to better understand the general patterns, mechanisms and impacts of biotic homogenisation. Location United States. Time Period 1963–2020. Major Taxa Studied Vascular plants. Methods We used a dataset of more than 70,000 vegetation survey plots to assess differences in biotic homogenisation with and without invasion using both occurrence‐ and abundance‐based metrics of beta diversity. We estimated taxonomic biotic homogenisation by comparing beta diversity of invaded and uninvaded plots with both classes of metrics and investigated the characteristics of the non‐native species pool that influenced the likelihood that these metrics disagree. Results In 78% of plot comparisons, occurrence‐ and abundance‐based calculations agreed in direction, and the two metrics were generally well correlated. Our empirical results are consistent with previous theory. Discrepancies between the metrics were more likely when the same non‐native species was at high cover at both plots compared for beta diversity, and when these plots were spatially distant. Main Conclusions In about 20% of cases, our calculations revealed differences in direction (homogenisation vs. differentiation) when comparing occurrence‐ and abundance‐based metrics, indicating that the metrics are not interchangeable, especially when distances between plots are high and invader diversity is low. When data permit, combining the two approaches can offer insights into the role of invasions and extirpations in driving biotic homogenisation/differentiation.

West Nile virus (WNV) disease, a mosquito‐transmitted Flavivirus infection, represents a substantial public health research interest. This virus was unknown in the Western hemisphere until it was introduced in 1999 into an immunologically naïve population. WNV caused an epizootic and epidemic in New York City. The infection then swept over North America, causing mass mortality in birds and cumulatively 60,000 human cases, half of whom were hospitalised, mostly with neurological symptoms. The virus closely resembled a goose virus isolated in Israel in 1998. Mosquitoes of the genus Culex were identified as the insect viral vectors. WNV can infect more than 300 bird species, but in the US, the American robin (Turdus migratorius) represented the ecologically most important bird viral reservoir. Mosquito‐to‐mosquito viral transmission might amplify the viral spread, and iatrogenic WNV transmission was also observed, leading to the screening of blood products. Compared with African WNV isolates, the New York WNV isolate NY99 showed a mutation in the nonstructural protein NS3 that increased its virulence in birds and was also observed in WNV outbreaks from Romania in 1996 and from Russia in 1999. During its spread across the US, NY99 acquired a mutation in the envelope gene E that favoured viral infection in the insect vector. Europe reported 1200 annual WNV cases in 2024, with a focus in Mediterranean countries, but a northward spread of the infection to Germany and The Netherlands was also noted. Global warming is likely to affect the geographical distribution of vector‐borne infections such that people living in temperate climate areas might be increasingly exposed to these infections. Therefore, research on temperature effects on WNV transmission by Culex mosquitoes has become a recent focus of research. Pertinent climate aspects of WNV infections are retraced in the present review.