Peer Community Journal

Hyalomma marginatum tick establishment has been recorded in southern mainland France for around ten years. This two-host species is one of the main vectors of the Crimean-Congo haemorrhagic fever (CCHF) virus. Knowing the phenology of the tick is a prerequisite for a better understanding of its spread and of CCHF virus dispersal. A six-year study was carried out in a horse herd to determine the seasonal variations of H. marginatum infestation. Adult ticks started infesting their hosts from the beginning of March. Infestation peaked during the first weeks of May and then steadily decreased until the end of August. This represented an average annual infestation of more than 300 H. marginatum per horse. Birds are parasitised by H. marginatum immatures (larvae and nymphs) in summer, between mid/late June to the end of September. The larvae are therefore not yet active when the migratory birds pass through in spring. Blackbirds, Turdus merula, were the most infested species: sixty percent of those examined in summer were parasitised by H. marginatum. This bird species could be a good sentinel host for monitoring the establishment of the species in currently H. marginatum-free areas. To complete this multi-year survey, an experimental study was carried out in quasi-natural conditions, with engorged ticks placed in cages in the garrigue. It was shown that the nymphs moulted into adults within 3-4 weeks in July-August. However, they remain completely immobile in the litter, undergoing a behavioural diapause, until the following spring. On the other hand, almost all the nymphs deposited later, in September or October, died during the cold and rainy season. It was also observed that engorged females are able to survive the cold conditions up to 6-8 months before laying eggs. The study also suggested that there were predators of H. marginatum, likely ants and spiders, in the study area. The hosts monitored over all these years were not only infested by H. marginatum. The phenology of other tick species parasitizing horses (Dermacentor marginatus, Haemaphysalis punctata, Rhipicephalus bursa) and birds (Ixodes frontalis, I. ricinus, Hae. punctata) was also highlighted for this study area.

The pinewood nematode is a dangerous organism for the health of Pine forests and has already demonstrated its impact in Portugal and Spain. This organism was recently detected (november 2025) in France. It can spread over long distances (e.g., through wood transport) or short distances via its insect vector flights (about fifteen km), Monochamus galloprovincialis. The spatiotemporal distribution of the population of this insect vector is poorly understood in France. In this study, we propose to estimate the Monochamus population using official but heterogeneous in space and time trapping data. This spatiotemporal modeling is based on two Bayesian approaches (an INLA-based generalized additive model, and a mecanistic-statistical approach) and integrates environmental covariates as well as laboratory-derived experiments data about the insect vector. The results provide estimates and predictions of the spatiotemporal distribution of Monochamus galloprovincialis in France. This distribution varies according to environmental conditions and biological characteristics of the insect; the population dynamics thus can thus be estimated at all points in space and time. They will significantly improve the pinewood nematode surveillance plan to better monitor free zones and buffer zones around the outbreak.

Host choice is a determining component of tick population and pathogen transmission dynamics. In Europe, ticks of the genus Hyalomma, which are involved in the transmission of several pathogens such as the Crimean Congo Haemorrhagic fever (CCHF) virus, are suspected to be spreading into new territories where they were previously unreported. Therefore, we performed a systematic review of the tick-host relationship of Hyalomma spp in Europe with a focus on Hyalomma marginatum, combined with a meta-analysis and meta-regression to describe its host preference pattern using three outcome values. Our initial qualitative analysis highlighted an increase in tick-host interaction rate in the last decades mostly in South-eastern and Central Europe. H. marginatum also appeared as the species holding the highest citation rate in terms of its association with hosts, and for which the largest number of host species were reported. The meta-analysis on Hyalomma marginatum host choice revealed preferential interactions for horses in the adult stage and birds of the Emberizidae and Strigidae families, in immature stages. Nevertheless, most of the heterogeneity of tick-host interactions remained unexplained suggesting the involvement of multiple drivers such as environmental or climatic conditions. Our results suggest that H. marginatum is a generalist tick whose distribution depends primarily on environmental conditions such as climate and habitat. Current limitations of our meta-analysis approach to identify hosts preference for H. marginatum and suggestions ways for improvement are further discussed.

Bird ringing is used for a long time for scientific investigation of migration routes and to better understand breeding events as well as population ecological aspects. It is applied as an inexpensive method although the well-known and major disadvantage of bird ringing is the usually low response rate. In the case of rarer species such as the Red-Footed Falcon (RFF), however, this quota could be higher due to the exclusivity and greater attention of observers. Motivated by own field observations of color-ringed RFF south of Brunswick, Germany in 2019 and no clear and comprehensive publication of verified additional recoveries and ringings, we did further research regarding this issue by following methods: 1) Contacting European Bird Ringing Centers and associated projects, 2) Query and comparison of files with the three national German Bird Ringing Stations, 3) Expanded literature research, 4) Evaluating reports in the citizen science platform ornitho.de, 5) Checking websites of ringing projects (in particular satellite tracking programs) and 6) Own observations. Surprisingly, this study revealed 18 recovered RFF ringed in foreign countries (14 Hungary, 3 Italy, 1 Romania (GPS tracked bird)) during migration or post-nuptial pre-migration time. Additionally, 1 RFF that was caught and ringed in Germany was recovered abroad. This result updates and increases the number of recoveries of RFF in Germany compared to the actual published state on the order of 18 (so far none) and on the order of 6 concerning ID-encoded RFF (GPS-bird excluded) compared to documentation state of the three Bird Ringing Centers in Germany (so far 3 at Beringungszentrale [BZ] Hiddensee, 1 at Institut fur Vogelforschung [IfV] Heligoland). Our research and evaluation of raw data succeeded to a 100% identification rate of the birds origin countries (n=18) while the rate of ID-encoded RFF by color ring codes revealed 58.8% (n=10, GPS-bird excluded). The reported-by-observer response rate was 41.2%. Interesting data of about the phenology, age and origin of the RFF recovered in Germany are presented. Questions and considerations about the recent reporting system of ringed birds and the increased numbers of RFF during the last years in Germany are discussed.

Northern Bald Ibis (NBI) have disappeared from Europe already in Middle Age. Since 2003 a migratory population is reintroduced in Central Europe. We conducted demographic analyses of survival and reproduction of 384 NBI over a period of 12 years (2008-2019). These data also formed the basis for a population viability analysis (PVA) simulating the possible future development of the NBI population in different scenarios. We tested life-stage specific survival rates for differences between these stages, raising types and colonies as well as the influence of stochastic events and NBI supplements on the population growth. Stage specific survival rates ranged from 0.64 to 0.78. 61% of the mature females reproduce with a mean fecundity of 2.15 fledglings per nest. The complementary PVA indicated that the release population is close to self-sustainability with a given lambda 0.95 and 24% extinction probability within 50 years. Of the 326 future scenarios tested, 94 % reached the criteria of <5% extinction probability and population growth rates >1. In case of positive population growth, stochastic events had a limited effect. Of 820 sub-scenarios with different stochastic event frequencies and severities 87 % show population growth despite the occurrence of stochastic events. Predictions can be made based on the results of the individual-based model as to whether and under what circumstances the reintroduced NBI population can survive. This study shows that a PVA can support reintroduction success that should work closely together with the project in the field for mutual benefit, to optimize future management decisions.

The fossil record documents ecological responses to past climate transitions, providing insights into future scenarios of marine ecosystems and taxa under climate change. In this study, we compared shell growth dynamics, specifically linear extension and net calcification rates, of the bivalve Chamelea gallina between Northern Adriatic Sea (NAS) assemblages from the Holocene Climate Optimum (HCO, 9-5 kyr cal. B.P.) and today. This species is a valuable economic resource, currently threatened by climate warming and numerous anthropogenic stressors. During the HCO, regional sea surface temperatures were warmer than today, making it a potential analog for exploring ecological responses to increasing seawater temperatures predicted in the coming decades. By combining standard aging methods with reconstructed sea surface temperatures, we observed a significant reduction in linear extension and net calcification rates in warmer HCO assemblages. During the HCO, immature C. gallina specimens developed a denser shell, especially during their early growth stages, at the expense of a linear extension rate, which was lower than modern specimens. This resulted in an average delay of 3-4 months in reaching sexual maturity, which is currently reached after ~ 13-14 months or at a length of ~18 mm. Several environmental factors are probably responsible for these differences between fossil and modern assemblages. Temperature indirectly impacted the geomorphologic evolution of the NAS over the Early-Mid Holocene, shaping the outlet structure of the Po and other NAS rivers. This, in turn, affected environmental factors such as nutrient load, seawater transparency, salinity, and phytoplankton. In addition, recent anthropogenically-derived decreases in natural NAS predators of infaunal bivalves may have reduced the natural predation pressure on modern C. gallina, thus favoring those populations characterized by faster linear extension rates (at the expense of a higher shell density), especially during the initial stages of life, hence facilitating a quicker attainment of sexual maturity.

Nature-Based Solutions are increasingly promoted to address current urban challenges. While their potential effects on vector-borne disease risks have been documented, data on Aedes albopictus, a known arbovirus vector, remain limited in France. A previous study showed that urban vegetation moderately increases the abundance of adult mosquitoes of this species, but the monitoring period lasted only six months. Using ovitraps, we monitored Ae. albopictus egg density dynamics over multiple years (2022 to 2024) and analysed its environmental predictors in various urban environments. We included lagged meteorological variables, land cover metrics, and the cumulated egg densities recorded in the previous weeks as environmental predictors. Both parametric (GLMM) and non-parametric (Random Forest) models were fitted to weekly egg counts per trap. Our findings highlight that (i) egg density dynamics were related to how vegetation classes structured the landscape, (ii) growing degree days and cumulated number of eggs recorded in specific lagged time windows were the main contributors to egg density, and (iii) the non-parametric and parametric models performed similarly in terms of prediction accuracy.

Phenotypic plasticity is an important feature of biological systems that is likely to play a major role in the future adaptation of organisms to the ongoing global changes. It may allow an organism to produce alternative phenotypes in responses to environmental cues. Modifications in the phenotype can be reversible but are sometimes enduring and can even span over generations. The notion of phenotypic plasticity was conceptualized in the early 20th century by Richard Woltereck. He introduced the idea that the combined relations of a phenotypic character and all environmental gradients that influence on it can be defined as \"norm of reaction\". Norms of reaction are specific to species and to lineages within species, and they are heritable. He postulated that reaction norms can progressively be shifted over generations depending on the environmental conditions. One of his biological models was the water-flee daphnia. Woltereck proposed that enduring phenotypic modifications and gene mutations could have similar adaptive effects, and he postulated that their molecular bases would be different. Mutations occurred in genes, while enduring modifications were based on something he called the Matrix. He suggested that this matrix (i) was associated with the chromosomes, (ii) that it was heritable, (iii) it changed during development of the organisms, and (iv) that changes of the matrix could be simple chemical substitutions of an unknown, but probably polymeric molecule. We reasoned that the chromatin has all postulated features of this matrix and revisited Wolterecks classical experiments with daphnia. We developed a robust and rapid ATAC-seq technique that allows for analyzing chromatin of individual daphnia and show here (i) that this technique can be used with minimal expertise in molecular biology, and (ii) we used it to identify open chromatin structure in daphnia exposed to different environmental cues. Our result indicates that chromatin structure changes consistently in daphnia upon this exposure confirming Wolterecks classical postulate.

Disclaimer statementThe authors have withdrawn their manuscript due to disagreement of several aspects regarding the interpretation of the results reported in this paper. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.

Migratory behaviour in birds shows a remarkable variability at species, population and individual levels. Short-distance migrants, in particular, often adopt a partial migratory strategy and tend to have a rather flexible migration schedule which allows them to respond more effectively to extreme environmental variations, like those due to climate change. Weather seasonality and environmental heterogeneity at regional and local scales have been reported as significant factors in the diversification of migratory behaviour for some species of Mediterranean migrants. Relatively few studies, however, investigated the migration patterns of non-passerine birds migrating within this area. In this study we investigated the migratory strategy of the Eurasian Stone-curlew Burhinus oedicnemus using data collected on 40 individuals tagged with geolocators and GPS-GSM tags, belonging to two continental and two Mediterranean populations of the Italian peninsula. The proportion of migrants was significantly higher in continental populations, but we observed a significant variability also within Mediterranean populations. GPS-tagged migrants traveled less than 1000 km, spending the winter within the Mediterranean basin. Continental Stone-curlews i) departed earlier in spring and later in autumn and ii) covered longer distances than those from Mediterranean areas. The speed of migration did not change between seasons for continental birds, while Mediterranean individuals tended to migrate faster in spring. The likelihood of departure for autumn migration of GPS-tagged birds significantly increased when temperatures were near or below 0 {degrees}C suggesting that Stone-curlews tend to delay departure weather conditions worsen abruptly. Thus it can be speculated that the frequency of migratory birds in the considered populations may decrease in the near future due to the effect of global warming in the Mediterranean. This could have a significant effect on the distribution of species throughout the year and should be taken into account when targeting conservation measures.

Minute insects such as parasitic micro-wasps have high basic and applied importance, for their widespread use as biocontrol agents. Their dispersal is a phenotype of particular interest. Classically, it is evaluated using field releases, but those are time consuming, costly, and their results highly variable, preventing high-throughput and repeatability. Alternatively, dispersal can be studied using small-scale assays, but those neglect important higher-scale processes. Consequently, proper evaluation of dispersal is often complicated or lacking in academic studies and biocontrol breeding programs. Here we introduce a new method, the double-spiral maze, that allows the study of spatial propagation at relevant scales (several hours and meters), retaining high throughput and experimental power. The method records the location of every individual at every time, enabling accurate precise estimates of diffusion coefficients or other dispersal metrics. We describe this affordable, scalable, and easy-to-implement method, and illustrate its application with a species of agricultural interest.

Mosquitoes are well known for their ability to transmit pathogens, including various arthropod-borne viruses (arboviruses) of veterinary and medical interest. The threat of (re-)emerging arboviruses in Europe is increasing due to globalization and climate warming. This also applies to temperate regions, where the transmission of viruses is becoming possible due to an increase of the ambient temperature, shortening of the extrinsic incubation period. Culex pipiens s.s./Cx. torrentium are the primary vectors of Usutu virus and West Nile virus in Europe and are found in and around human settlements. The prediction of spatial-temporal abundance allows for the early assessment of arbovirus transmission risk and the planning of effective intervention meth-ods, such as vector control. Therefore, a process-based model was developed to predict the spatial-temporal occurrence of Cx. pipiens s.s./Cx. torrentium in Germany with a particular focus on depicting realistic overwintering behaviour, e.g. diapause induced through photoperiod and temperature in the larval stage. The model output is driven by local temperature and rain-fall data. Evaluated with field data from 116 sampling sites in Germany, the model accurately identified the peak in abundance, with a mean absolute off-set of 0 days between the simulated and observed peak, and offsets of 8 and 1 days for the start and end of the mosquito season, respectively. A significant linear relationship between simulated and observed mosquito abundance was found for 78.45% of the sampling sites, with an overall significant linear relationship across all sites (Estimate = 0.16, Standard Error = 0.003, t-value = 48.54, degrees of freedom = 2724, p-value < 0.0001, marginal R2= 0.47). This model offers a robust framework for the prediction of the mosquito population dynamics of Cx. pipiens s.s./Cx. torrentium under current and future climate scenarios, thereby supporting vector surveillance and control strategies across Europe. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=143 SRC="FIGDIR/small/624534v2_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@14bb74aorg.highwire.dtl.DTLVardef@1ee9562org.highwire.dtl.DTLVardef@916655org.highwire.dtl.DTLVardef@1d57270_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIAccurate depiction of the phenology of Culex pipiens s.s./ Cx. torrentium, including the time point of the start, end and peak of the mosquito season. C_LIO_LILarge-scale and site-specific validation using nation-wide mosquito abundance data from 116 sampling sites from five collection years, indicated a significant linear relationship between field data and model output for 78.45% of the sampling sites. C_LIO_LIFirst biologically accurate simulation of the overwintering behaviour of Culex pipiens s.s./ Cx. torrentium. C_LIO_LIEurope-wide raster map showing the maximum number of consecutive generations per season. C_LI

Improving the understanding of the causes and effects of anthropogenic hybridization is fundamental to ensure the conservation of wild species, particularly in the case of hybridization between wild species and their domestic relatives. Knowledge is missing for many species also because of a lack of appropriate tools for hybrid identification. Here, coupling genotype and phenotype analysis, we carried out an extensive investigation of ongoing hybridization in Alpine ibex Capra ibex, a mountain ungulate of conservation concern from a genetic perspective. By genotyping at 63 diagnostic and 465 neutral SNPs 20 suspected hybrids and 126 Alpine ibex without suspicious phenotype, representing eight populations across a major part of the species distribution, we found evidence for ongoing hybridization between Alpine ibex and domestic goat. We identified different levels of hybridization including back crosses into both Alpine ibex and domestic goat. Our results suggest a lack of reproductive barriers between the two species and good survival and reproductive success of the hybrids. Hybridization was locally intense, alike a hybrid swarm, but not spread across the rest of the species distribution. Most of the hybrids were discovered in two locations in the North-West of Italy, while random sampling of individuals from different areas did not provide evidence of recent hybridization. Our method, based on Amplicon sequencing of 63 diagnostic SNPs specifically developed for this purpose, allowed us to identify hybrids and back crosses up to the 4th-5th generation and was suitable for genetic samples of different quality, although with varying levels of certainty regarding the exact number of generations passed since hybridization. Based on the paired analysis of genotype and phenotype we provide guidelines for a first identification of hybrids in the field and suggest a procedure for the reliable identification of hybrids.

1. IntroductionTiming of birth is a major determinant of individuals reproductive success and survival, and is driven by multiple internal and external factors. However, there is currently no quantitative assessment of the extent and support received by the drivers of the phenology of births in mammals. Due to their diverse phenology of births, large herbivores represent an ideal case study to quantify this. 2. Aimsour objective was to identify the different drivers tested for their effect on the phenology of births in large herbivores and how much empirical support they received, as well as determine thematic, taxonomic and spatial gaps in the literature. 3; MethodsWe conducted a systematic review focusing on the drivers of the phenology of births in wild large herbivores. We extracted the outcomes of 124 relevant articles and assessed the reliability of their findings using a general index based on the quality of the data and methods used. 4. Results and DiscussionAs expected, the two dominant hypotheses (seasonality and predation) received strong support regarding their effect on birth timing and synchrony, respectively. The effect of female, offspring and population characteristics remained marginally accounted for, even though there was evidence of their importance in the determination of the phenology of births. We identified a major research gap in Asian and South and Central American species. 5. ConclusionsWe encourage research in these understudied domains, as well as large scale multi-species comparative analyses to fill in the gaps and improve our understanding of reproductive phenology. Graphical abstract legend O_FIG O_LINKSMALLFIG WIDTH=113 HEIGHT=200 SRC="FIGDIR/small/694258v1_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@1ff01dforg.highwire.dtl.DTLVardef@d3dc99org.highwire.dtl.DTLVardef@137e41corg.highwire.dtl.DTLVardef@610382_HPS_FORMAT_FIGEXP M_FIG This systematic review confirmed the strong support received by the two dominant drivers of births phenology, the seasonality and predation hypotheses. Even though there is evidence of their importance, the effects of female, offspring and population characteristics remain marginally accounted for. Asian and South/Central American species are currently understudied. C_FIG

Demographic models are crucial for uncovering the mechanisms underlying changing populations trajectories and structure and to identify the drivers of such changes. Common pochard populations of North east/North west Europe have experienced a sharp decline accompanied by an increase in male proportions among adults since the mid-1990. We used a two-sex, two-stage deterministic matrix population model, to perform a prospective perturbation analysis and to explore, through simulations, some plausible causes underlying the observed decline and change in sex structure. We show that Common pochard populations are more sensitive to changing survival than to changes in productivitys components (clutch size, nest survival...). However, due to an environmental variance much higher than that of survival, components of productivity, especially nest survival, would be the main drivers of Common pochard populations growth rate, a finding supported by empirical data. More importantly, we show that although sex-specific changes in survival at any stage of the life cycle are potent drivers of both population growth rate and changing sex ratio, there is no need to resort to them for explaining the increasing proportions of males such as observed in Common pochard. Because adult males display higher survival than adult females (0.74 against 0.64 on average), any factor affecting recruitment (nest or first year survival) increases the weight of adults into the populations and hence the proportion of males. Thus, in species displaying sex-biased mortality, such as many ducks, decreasing recruitment can underly declining population size and changes in sex structure at the same time, emphasising the importance of accounting for males in monitoring schemes and demographic models.

The recent large-scale circulation of High Pathogenicity Avian Influenza (HP AI) viruses H5Nx of clade 2.3.4.4b has been responsible for massive die-offs in wild species, notably in long-lived seabirds, with unknown implications for the immunity of surviving individuals. In the North Atlantic, northern gannet colonies were heavily affected in 2022, with more than 40% mortality observed among breeding adults and some surviving individuals developing dark irises. Using samples collected in 2023 and 2024 on Rouzic colony (France), we report persistent individual anti-AI antibody levels and seroneutralisation titres, with most of the immune individuals showing dark irises. A modelling approach further stressed the importance of long-lasting immunity in such species by showing that the proportion of individuals which kept their immunity between years strongly limited decreases in population size in case of repeated outbreaks. Overall, our results highlight the existence and importance of long-lasting immunity in long-lived species for population persistence.

Grazing horses are infected by a wide range of strongylid species mostly located in the large intestine. Despite their impact on equine health and the emergence of drug resistant isolates, the phenology of these nematodes has been poorly characterized and the rules structuring their assembly as a community are not understood. Here, we compiled data on 46 equine strongylid species collected worldwide at the regional or horse scales (upon deworming or after necropsy) to analyse their richness, diversity and associated factors of variation. Worldwide, twelve species from the Cylicocyclus (n = 4), Cylicostephanus (n = 3), Coronocyclus (n = 2) and Cyathostomum (n = 2) genera were found in at least 75% of sites. Geoclimatic conditions had a limited effect on strongylid communities, but reduced species richness was found under the temperate European area. The recovery method did not affect species richness and differences on the temporal and sampling effort scales between studies applying either methods underpinned heterogeneous variances in community diversity. At the horse level, rarefaction curves correlated poorly to parasite egg excretion, suggesting little contribution of community diversity to this trait. Using a diversity partitioning approach, we found that within-host diversity represented half of overall diversity underscoring the importance of host density and environmental contamination to the diversity of strongylid communities. While this is expected to erase diversity across communities, species turnover between age classes was the second most important contributor to overall diversity (23.9%). This was associated with a network of positive co-occurrences between the four most prevalent genera that we resolved at the anatomical niche level. Altogether this pattern of {beta}-diversity maintenance across age classes combined with positive co-occurrences may be grounded by priority effects between major species. Our findings set the first assembly rules of equine strongylid communities.

Withdrawal StatementThe authors have withdrawn this manuscript as we carry out reanalysis and reinterpretation of our results. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.

The role of megafaunal exploitation in early human evolution remains debated. Occasional use of large carcasses by early hominins has been considered by some as opportunistic, possibly a fallback dietary strategy, and for others a more important survival strategy. At Olduvai Gorge, evidence for megafaunal butchery is scarce in the Oldowan of Bed I, but becomes more frequent and widespread after 1.8 Ma in Bed II, coinciding with the emergence of Acheulean technologies. Here, we present the earliest direct evidence of proboscidean butchery, including a newly documented elephant butchery site (EAK). This shift in behavior is accompanied by larger, more complex occupation sites, signaling a profound ecological and technological transformation. Rather than opportunistic scavenging, these findings suggest a strategic adaptation to megafaunal resources, with implications for early human subsistence and social organization. The ability to systematically exploit large prey represents a unique evolutionary trajectory, with no direct modern analogue, since modern foragers do so only episodically.

Some species of woodpecker (Picidae), such as in the genus Dendrocopos, are known to occasionally hybridize. The distribution, biology and ecology of the Syrian Woodpecker (D. syriacus) and the Great Spotted Woodpecker (D. major) are fairly well-known (less so in the case of Syrian), but these closely related species are seldom treated together in studies. This review summarizes the published data on these species in order to evaluate the omissions and inaccuracies in research and surveys on their sympatric populations. As research that deals with both species together is scant, the need to examine interactions, both antagonistic and hybridization, is advisable in order to properly understanding their ecology, ethology, breeding biology and demography.