Biology subjects

Bonte, D.

Publications and source records attributed to Bonte, D..

At least 19 recordsLinked to original sources

bioRxiv2026

From strandline vegetation to embryo dunes: natural sand retention along a heavily urbanized coast

1. Sandy beaches along urbanized coasts are increasingly managed through beach nourishment and hard infrastructure, yet these interventions often constrain natural dune-building processes. Along the Belgian coast, where much of the beach-dune interface is bordered by dikes, promenades and intensive recreation, strandline vegetation may provide an overlooked mechanism for retaining sand and initiating embryo dune development. 2. We assessed the potential for four pioneer dune plant species (Cakile maritima, Calamagrostis arenaria, Elymus farctus and Salsola kali) to establish, develop vegetation cover and contribute to sand accumulation along the Belgian coast. Using field surveys from 2017-2023, LiDAR-derived beach elevation and annual sediment dynamics, we modelled species occurrence and abundance/cover in low-disturbance reference zones and projected these relationships across the wider coastline. 3. Occurrence models identified where abiotic conditions allow plants to establish and persist until the late growing season, whereas zero-inflated abundance/cover models estimated expected vegetation development across environmental gradients. Predicted occurrence was widespread for several species, suggesting that the abiotic gradients modelled here are not the primary constraints on potential establishment across large parts of the coast. In contrast, expected abundance/cover showed stronger species-specific responses, particularly to sand accretion, indicating that sediment dynamics mainly affect post-establishment vegetation development rather than occurrence alone. 4. Independent field measurements of embryo dunes showed positive relationships between vegetation cover and local sand accumulation for all four species. When scaled using spatial predictions of potential abundance/cover, pioneer vegetation could retain substantial volumes of sand, with Cakile maritima contributing the largest share, followed by Salsola kali, Elymus farctus and Calamagrostis arenaria. Estimated volumes depended on assumptions about whether vegetation occurs as dispersed units or aggregated patches. 5. Synthesis and applications. Our results show that, even along a heavily urbanized and nourished coastline, abiotic conditions can support strandline vegetation and embryo dune initiation where disturbance is reduced. Management actions such as limiting trampling, adapting beach cleaning and protecting strandline vegetation could enhance the retention of nourished sand and support nature-based coastal defense. Rather than replacing engineered interventions, strandline vegetation may increase the efficiency with which available sediment is retained within the beach-dune system.

ecology↗

bioRxiv2026

Morphological and thermoregulatory responses to urbanization in the European garden spider Araneus diadematus.

Urbanization creates novel environments that can drive phenotypic and behavioural responses, yet how multiple traits respond across spatial scales remains poorly understood. In particular, elevated ambient temperatures via the urban heat island effect may drive morphological and behavioural responses. We investigated body size, abdominal colouration, microhabitat use, behavioural thermoregulation and thermal offset relative to ambient air in the orb-weaving spider Araneus diadematus across rural-urban gradients in northern Belgium. Contrary to predictions from the temperature-size rule, body size increased with urbanization at large spatial scales, whereas size-corrected abdomen area--reflecting body condition and reproductive investment--declined with urbanization, with strongest support at local spatial scales. Abdominal colouration showed no response to urbanization despite evidence for both carotenoid-like pigments and melanin-associated structures. Nevertheless, body size and colouration covaried, with sites containing larger spiders tending to harbour darker individuals, whereas within sites larger individuals were slightly brighter than smaller conspecifics. Thermal responses showed little variation along the urbanization gradient. Retreats were consistently warmer than web hubs, and spiders maintained body temperatures above both their immediate microhabitat and ambient air. Only retreat-associated behavioural thermoregulation showed a weak decline with urbanization at local spatial scales. Our results reveal contrasting trait responses to urbanization across spatial scales and demonstrate that size-colour covariation can persist despite divergent responses of individual traits. These findings highlight the importance of considering multiple traits, their covariation and spatial scale to accurately understand and predict ecological responses of ectotherms to urban environments.

ecology↗

bioRxiv2026

Context-dependent selection and genetic facilitation and constraint on rosette diameter and herbivore resistance across european outdoor common gardens under ambient and reduced precipitation in Fragaria vesca

The expression of plant defensive traits against herbivores often incurs costs to other essential functions, such as growth and reproduction. Understanding how selection acts on putatively functional traits that are expected to trade off across space and time is therefore critical for predicting evolutionary responses to ongoing and future environmental change. Here, we used multiple replicated genotypes of woodland strawberry (Fragaria vesca; Rosaceae) grown over two years in three outdoor common gardens in Spain, Belgium, and Sweden. In each garden, genotypes were exposed to both a reduced-precipitation treatment simulating drought and an ambient precipitation treatment. We estimated directional and correlational selection on rosette diameter (a proxy for growth) and herbivore resistance (measured as the inverse of chewing damage) using fruit and stolon production as proxies for sexual and asexual fitness across all environments (i.e., every site x year x treatment combination). We then combined selection gradients with environment-specific genetic (co)variance among genotypes to quantify the expected response to selection ({Delta}z = G{beta}) and to identify covariance-driven constraints or facilitation therein. Selection consistently favored larger rosette diameter for both fitness proxies across nearly all environments, which, in combination with genetic covariances among genotypes, resulted in a general evolutionary response toward increased rosette diameter, with the strongest response at the wettest site (Belgium). In contrast, selection on resistance and the corresponding among-genotype evolutionary responses were strongly context-dependent. Correlational selection on rosette diameter x resistance occurred in only a few environments, primarily under reduced precipitation. Environment-dependent genetic covariances constrained or facilitated selection on both traits only at the site with the highest herbivory (Sweden) under drought conditions. Overall, our results reveal a context-dependent interplay between selection and genetic architecture, underlining the difficulty of predicting evolutionary trajectories under environmental change, and highlighting how spatially and temporally variable conditions may maintain standing genetic variation in plant traits.

evolutionary biology↗

bioRxiv2026

Highly repeatable phenotypic consequences of whole genome duplication in Spirodela polyrhiza

Whole-genome duplication (WGD) is widespread in plants, yet the extent to which it yields predictable phenotypic outcomes remains unclear. Here we show that the phenotypic consequences of genome doubling in a duckweed model system, Spirodela polyrhiza, are highly repeatable and largely deterministic. We previously generated three independent colchicine-induced autotetraploids from each of nine globally distributed diploid genotypes and, here, quantified growth and morphology across a salt gradient. In benign conditions, diploids grew faster, whereas tetraploids had larger, thicker fronds; with increasing salinity, the diploid advantage diminished and tetraploids often matched or exceeded diploid growth. Variance partitioning revealed that ploidy per se explains more phenotypic variation, including salt tolerance, than genotypic background, with rare within-genotype stochasticity. These results indicate that the shifts in morphology and stress tolerance from genome doubling are predictable and can outweigh the phenotypic effect from genetic sequence diversity.

evolutionary biology↗

bioRxiv2026

Decline of Common Toad populations in Flanders is not linked to surrounding landscape

AimWe aim to quantify population trends of Common Toad in Flanders and assess to which extent population trends depend on general landscape variables (land use identity, structure and change). LocationFlanders, Belgium MethodsUsing standardized time series obtained from citizen science and spanning over four decades, we used an end-begin contrast to get a trend value for 234 populations. Next, we developed a testing strategy to find associations between these trend values and the surrounding landscape ResultsAcross the study region, 40% of the populations have declined significantly, while only 10% show an increase. Declines were not associated with landscape characteristics in our study area, which is one of the most fragmented regions in Europe. Main conclusionsWe discuss how the research region, spatial and temporal resolution, as well as the generalist nature of the species, may explain these findings. Our study suggests limited effects of general landscape characteristics on the decline of Common Toad populations, indicating that other major drivers are likely responsible.

ecology↗

bioRxiv2025

Variation in phenotypic plasticity of metabolic and performance traits along a latitudinal gradient in Woodland Strawberry

Phenotypic plasticity and local adaptation jointly determine plant responses to environmental variation, yet their relative contributions and evolutionary interactions remain poorly understood. We grew fifteen woodland strawberry (Fragaria vesca) genotypes from a European latitudinal gradient in four common gardens for two years, quantifying primary metabolites and biomass, reproduction and herbivore damage-related traits. Considering all measured traits combined, environment explained the largest variance (30%), followed by genotype-by-environment interactions (18%) and genotype effects (9%), indicating substantial heritable plasticity. However, plasticity was not uniform: northern genotypes showed greater plasticity in stress metabolites like succinic acid but more canalized growth traits, whereas southern genotypes maintained constitutively high protective metabolite levels. Latitude explained 4.4% of plasticity profile variation. Phenotypic variation was consistently better explained by long-term temperature than precipitation at the site of origin across all trait groups under study. Our results indicate that plasticity itself is an evolved, trait-specific characteristic shaped by climatic gradients, challenging simple hierarchies of trait lability. Significance StatementWe studied wild strawberries from across Europe and discovered that populations from different regions have evolved distinct adaptive strategies to cope with their local cli-mates. These differences highlight the remarkable diversity of plant solutions to environmental challenges. Understanding these natural adaptations could help us breed strawberries or other plant organisms better suited to future climate conditions.

ecology↗

bioRxiv2025

Dispersal evolution as a driver of island biodiversity

Island biodiversity reflects a tension between isolation and connectivity. Dispersal lies at the heart of this paradox: it enables colonization and ecological opportunity, yet excessive gene flow can constrain divergence and speciation. We use a spatially explicit, individual-based model to ask how dispersal evolution influences speciation and long-term diversity. Across archipelagos, rare long-distance dispersal events trigger colonization and divergence, after which dispersal traits evolve along two trajectories: increasing or decreasing range. These outcomes correlate with island size and isolation. Structured landscapes stabilize species richness through low turnover, whereas continuous landscapes remain species-poor despite high diversification rates. Our results reveal that spatial structure and dispersal evolution jointly govern biodiversity, underscoring the need to integrate movement into theories of speciation. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=146 SRC="FIGDIR/small/690991v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@17d93ddorg.highwire.dtl.DTLVardef@176c011org.highwire.dtl.DTLVardef@13bbeb1org.highwire.dtl.DTLVardef@1646b9d_HPS_FORMAT_FIGEXP M_FIG Visual abstract The paradox of dispersal. Although elevated dispersal levels increases the number of ecological opportunities for individuals, it also increases gene flow. These counteract each other in terms of speciation, resulting in a speciation tug-of-war. C_FIG

evolutionary biology↗

bioRxiv2025

Additive effects of environmental and demographic variation shape the repeatability of evolution across replicated experiments

The repeatability of evolution is fundamentally important for understanding the origin and diversification of life as well as for developing evolutionary forecasting tools. Repeatability is limited by stochasticity, here defined as changes that are independent of genotypic fitness effects. Over short timescales, the two main sources of stochasticity of evolutionary change are environmental stochasticity and demographic (life-history) stochasticity. Quantifying the relative importance of these two sources of stochasticity in driving fitness outcomes is crucially important for predicting evolutionary responses. To gain insights in the effects of stochasticity, five institutes replicated an evolutionary experiment exposing Caenorhabditis elegans to novel rearing conditions. Replication across the institutes led to variation in selective environments, e.g. through divergent microbiomes among institutes. Replication within institutes was done across demographic treatments that influence the potential for population-size dependent fluctuations in allele frequencies (drift) and genetic hitchhiking (draft). We found high among-institute variation in fitness outcomes, which was partially explained by variation in microbiota. Whereas lab-specific effects explained most of the variance in mean fitness, the repeatability of fitness outcomes depended more on demographic heterogeneity. Specifically, population bottlenecks resulted in high among-replicate variation in fitness. When combined, environmental and demographic stochasticity additively reduced repeatability, underlining their additive importance in developing evolutionary forecasting tools. These results further highlight the importance of statistically integrating heterogeneity in experimental evolution to identify factors constraining outcome repeatability and study replicability.

evolutionary biology↗

bioRxiv2025

Is passive dispersal informed? - Experimental evidence for decision-making in phytophagous arthropods

Animals must acquire and decode information to make the right decisions. While active dispersers can evaluate habitats en route, passive dispersers can only control their departure timing. Although the passive strategy is ubiquitous among arthropods, the mechanisms behind their take-off decisions remain poorly understood. We tested whether host niche breadth shapes passive dispersal in phytophagous mites by exposing them to host-derived kairomones and measuring departure rates. Using experimentally evolved specialist and generalist lineages, we found that dispersal depends more on the context in which cues are encountered that on the kairomones themselves. Host specialisation strongly shaped responses: mites left plants more readily when exposed to unfamiliar hosts, with generalists dispersing over twice as often as specialists. Increased number of unfamiliar kairomones strongly inhibited generalists dispersal but barely affected specialists. This suggests specialists use environmental novelty to trigger exploration, whereas generalists need multiple cues to confirm host suitability, revealing a trade-off between host range and environmental sensitivity.

ecology↗

bioRxiv2025

Ecological opportunity and the onset of polyploid niche expansion waves

Polyploidy, the presence of more than two sets of chromosomes, has evolved many times across the tree of life, yet we still do not know why some polyploid lineages persist while most go extinct. The establishment of polyploid populations is often reported to be associated with harsh environmental conditions, and stress tolerance in particular, which have led to the widespread view that polyploidy-specific niche requirements are key to their persistence at ecological and evolutionary timescales. Here, we reevaluate this perspective through a classical mathematical model of polyploid establishment, for which we provide new analytical and numerical results, along with an empirical case study. We show that simple eco-evolutionary processes at the margins of diploid range-expansion waves, more specifically ecological drift and dispersal limitation, can be sufficient to allow polyploid populations to carve out their own space, without any a priori adaptive advantage over their diploid ancestors. Our modelling effort reveals three key insights. First, polyploids most readily gain a foothold at the low-density front of a diploid range expansion wave, where ecological drift is strongest. Second, limited dispersal accelerates spatial clustering of polyploid organisms through assortative mating. Third, once spatially segregated, diploid and polyploid populations experience different environments, so natural selection can drive niche divergence. We illustrate these interconnected principles by simulating the phylogeographic history of a well-documented autopolyploid complex of Neobatrachus Australian burrowing frogs. Altogether, our results provide a neutral baseline against which the ecological consequences of polyploidization can be readily detected and inferred within natural populations. Significance statementPolyploidy, having multiple copies of the entire set of chromosomes, underpins major innovations in both animals and plants and fuels biodiversity. Yet, why some polyploid lineages are successful while others fail remains unclear. Our study shows that simple eco-evolutionary forces, specifically ecological drift at the edge of an expanding range and limited dispersal, can enable polyploids to establish and become geographically separated from their diploid relatives, even without any inherent adaptive benefits. This spatial segregation then exposes each cytotype to distinct environments, setting the stage for natural selection to operate. Our neutral theoretical framework helps biologists disentangle when polyploidy itself drives adaptation and when success is just a matter of being in the right place at the right time.

evolutionary biology↗

bioRxiv2025

Consistent covariation of dispersal, life history and thermal niches across terrestrial arthropods

Arthropods, as ectotherms, are experiencing global declines, with many species facing the need to either acclimate or disperse in response to climate change. Understanding to which degree life history, dispersal and thermal niche traits covary is key to improve distribution forecasting under climate change. We quantified life history, dispersal and thermal range covariation among 4000 Western European arthropod species spanning eight orders, considering phylogenetic relationships to account for common ancestry. We demonstrate the existence of two axes of life history variation: the fast-slow continuum and the reproductive strategy axis. Species at the fast end of the continuum have higher dispersal capacities and broader thermal niches than slower species. The resulting trait syndromes were surprisingly consistent across orders. These trait combinations, which generally enhance range-shifting potential, point to the emergence of two distinct groups of arthropods: those well-suited and those less equipped to mitigate the effects of future climate change.

ecology↗

bioRxiv2025

Polyploid - diploid coexistence in the greater duckweed Spirodela polyrhiza

Polyploidy, resulting from whole-genome duplication (WGD), is widespread among plants and originates in sympatry with their lower-ploidy progenitors. New polyploids can only succeed when they overcome the competitive disadvantage against their progenitors or through sufficient niche differentiation as resulting in a negative frequency dependent growth. Because polyploidy is frequently associated with cold, dry, and saline environments, stress is anticipated to be the key to polyploid success. We examined the invasion of neotetraploid duckweed (Spirodela polyrhiza) strains in populations of their direct diploid progenitors, in control and salt stress conditions in replicated microcosms. We also tested the reverse scenario, that is, the invasion of diploids in neotetraploid populations, to determine if the initial proportion of tetraploids affects the outcome of competition. Our results showed that the proportion of tetraploids declined in all tetraploid and all diploid invasions and it did so at a different rate than expected from only differences in intrinsic growth rate. Salt stress affected the decline in tetraploid proportion differently across strains. We also found evidence for negative frequency dependent growth that, nonetheless, was insufficient to overcome competitive disadvantages of neopolyploids towards their diploid progenitor. We showcase a robust quantitative pipeline from flow cytometry of mixed-ploidy populations to population model fitting. In doing so, we demonstrate the important effect of competition and frequency dependency on neopolyploid establishment. Therefore, we caution for inferring neopolyploid success from intrinsic growth rates alone.

plant biology↗

bioRxiv2024

An in-depth dataset of northwestern European arthropod life histories and ecological traits

In response to the ongoing biodiversity crisis among arthropods, it is essential to implement efficient conservation strategies to safeguard both species diversity and the vital ecosystem services they provide. Developing such strategies requires reliable predictive models that can identify the species that are the most vulnerable to current and future threats, including those posed by climate and land-use change. Species life histories are central to these models, as they influence both population dynamics and spread rates. To support this effort, we compiled a dataset with key traits for arthropods based on several literature sources and expert knowledge. The dataset contains data on body size, life history, thermal niche and ecology for 4874 northwestern European species across 10 different orders. By gathering these essential trait data, we aim to create a robust foundation for predicting species vulnerability and anticipating shifts in arthropod communities in response to global change.

ecology↗

bioRxiv2024

The Rise of Polyploids During Environmental Catastrophes

Polyploidy, or whole-genome duplication (WGD), serves as both a significant evolutionary force and a potential evolutionary dead end, occurring extensively across the tree of life, particularly among angiosperms. Despite the prevalence of polyploid organisms, instances of ancient polyploidy are surprisingly rare, presenting a paradox that remains poorly understood. In this study, we constructed a comprehensive genomic dataset of 470 angiosperm species to address this issue. We developed a highly congruent evolutionary timescale and dated 132 ancient WGD events that are non-randomly distributed, revealing a clustering around pivotal periods of environmental upheaval and extinction. Notably, our findings highlight a strong correlation between waves of paleopolyploidization and significant events such as the Middle Miocene Disruption, the Eocene-Oligocene transition (EOT), the Paleocene-Eocene Thermal Maximum (PETM), the Cretaceous-Paleogene (K-Pg) extinction, and different oceanic anoxic (OAE) events, several of which can be linked to extinction events impacting flowering plant genera. By integrating multiple lines of evidence, we propose that polyploid organisms have an increased chance of survival during times of great environmental turmoil, a conclusion with important implications in the context of contemporary climate change and rapid global warming.

evolutionary biology↗

bioRxiv2024

Drivers of plant-associated invertebrate community structure in West-European coastal dunes

The organisation of species assemblages is affected by environmental factors acting at different spatial scales. To understand the drivers behind the community structure of invertebrates associated with marram grass -the dominant dune-building ecosystem engineer in European coastal dunes-, we set up a stratified sampling scheme in six biogeographic sectors along the North Sea. We tested to which degree local invertebrate species composition is affected by the spatial organisation of marram grass tussocks. We used distance-based RDA and a joint species distribution modelling approach to understand how species traits and their phylogeny contribute to invertebrate community composition. We show biogeography to be the most important driver, followed by species-specific responses to marram grass cover and vitality. Traits and phylogeny had a minor influence on the species distribution patterns. The residual species covariation suggests negative interactions between groups of specialist and generalist species. From an applied perspective, our research indicates that the biological value of nature-based solutions for the restoration and design of coastal dunes can be optimized by the design of a heterogeneous marram grass planting scheme and/or development.

ecology↗

bioRxiv2024

Urban Cepaea nemoralis snails are less likely to have nematodes trapped within their shells

Urbanization is a major human-induced environmental change which can impact not only individual species, but also the way these species interact with each other. As a group, terrestrial molluscs interact frequently with a wide diversity of parasites, yet the way these interactions vary across space and in response to environmental pressures is poorly documented. In this study we leveraged a recently discovered defence mechanism, by which snails trap parasitic nematodes in their shells, to explore how snail-nematodes interactions may vary in response to city life. We examined shells from the generalist snail Cepaea nemoralis sampled in three urban areas in Belgium for trapped nematodes, and attempted to link this to urbanization and shell phenotypic traits. We found that even a small degree of urbanization led to large decreases in the rates of shell encapsulation, and that larger snails were more likely to contain trapped nematodes. However, we found no evidence that shell colour, which had been previously linked to immune function, was correlated to encapsulation rates. We discuss how between-population variation in encapsulation rates can result from urbanization-induced changes on the nematodes side, the snail side, or both, and suggest potential tests for future studies aiming to disentangle these mechanisms.

ecology↗

bioRxiv2023

A successional shift enhances stability in ant symbiont communities

Throughout succession, communities undergo structural shifts, which can alter the relative abundances of species and how they interact. It is frequently asserted that these alterations beget stability, i.e. that succession selects for communities better able to resist perturbations. Yet, whether and how alterations of network structure affects stability during succession in complex communities is rarely studied in natural ecosystems. Here, we explore how network attributes influence stability of different successional stages of a natural network: symbiotic arthropod communities forming food webs inside red wood ant nests. We conducted extensive field sampling to compare the composition of the symbiont community across 51 host nests of varying age, representing different succession stages. We recorded abundance of 16 functional groups of symbionts spanning different specialization and trophic levels. Joint species distribution modelling indicated nest age as the driver of the compositional shifts: symbiont communities in old nests contained a greater proportion of specialists and more even species abundance distributions. We then reconstructed community matrices and showed that this enhanced evenness lead to an augmented food web stability of the symbiont communities in older nests. Overall, this study demonstrates that succession begets stability in a natural ecological network by making the community more even.

ecology↗

bioRxiv2023

Interspecific transfer of genetic information through polyploid bridges

Many organisms have more than two sets of chromosomes, due to whole genome duplication (WGD), and are thus polyploid. Despite usually being an ephemeral state in the history of life, polyploidy is widely recognized as an important source of genetic novelty over macroevolutionary scales. More recently, polyploidy has also been shown to facilitate interspecific gene flow, circumventing reproductive barriers between their diploid ancestors. Yet, the implications of WGD-linked introgression on community-level evolutionary dynamics remain unknown. Here, we develop a model of cytotype dynamics within mixed-ploidy populations to demonstrate that polyploidy can in fact serve as a bridge for gene flow between diploid lineages, where introgression is fully or partially hampered by the species barrier. Polyploid bridges emerge in the presence of triploid organisms, which despite critically low levels of viability, can still allow the transfer of alleles between diploid states of independently evolving mixed-ploidy species. Notably, while marked genetic divergence prevents WGD-mediated interspecific gene flow, we show that increased recombination rates can offset these evolutionary constraints, which allows a more efficient sorting of alleles at higher-ploidy levels before introgression into diploid gene pools. Additionally, we derive an analytical approximation for the rate of gene flow at the tetraploid level necessary to supersede introgression between diploids with non-zero introgression rates, which is especially relevant for plant species complexes, where interspecific gene flow is ubiquitous. Altogether, our results illustrate the potential impact of polyploid bridges on evolutionary change within and between mixed-ploidy populations.

evolutionary biology↗