Ecological and genetic interactions among conspecific populations play an important role in population viability, but these interactions are not always fully considered in strategies to recovery endangered taxa. The Southern Resident Killer Whales are a high-profile population listed as endangered by both the U.S. and Canada. Risks to the population are well known, and include insufficient prey, inbreeding depression, disturbance, and environmental contaminants. Here, we argue that a fifth factor–interactions with other sympatric killer whale populations–plays an under-appreciated role in the population’s current and potential status. Based on studies conducted over the past two decades, we illustrate that consumption of shared prey, behavioral interactions in shared habitat, and shared DNA through potential interbreeding with other populations will strongly influence the future trajectory of the Southern Resident Killer Whales.

1. Testing inter- and intraspecific competition is essential for understanding the processes that maintain diversity within communities and populations. Pairwise growth assays are well-established methods to study the outcome of competition between bacterial genotypes or species. However, distinguishing bacterial competitors in coculture remains a major challenge due to their small cell size, similar cell morphology and often large population sizes. Current approaches are either labour intensive and require prior morphological and sequence-based characterisation, or genetic modification of the bacteria. 2. We present a simple assay that tracks the relative abundances of two competing bacterial species or genotypes of the same species through transient staining of one competitor with a fluorescent dye. The use of a transient dye relieves of prior characterisation or genetic modification. Our approach uses a sample-dependent threshold evaluation for the fluorescent intensity, enabling the quantification of bacteria frequencies over generations. The method provides a high accuracy for tracking of competing genotypes and species. 3. The outcome of competition often depends on frequency-dependent fitness effects and/or environmental variables. Therefore, our method tests across different initial abundances and can also assess the role of a biotic interaction (presence/absence of a predator) on the outcome of competition. 4. Our method presents a simple and high-throughput assay for competition. Absence of genetic modifications and applicability to little characterised competitors make it particularly useful for assays involving bacterial isolates from evolving populations.

We document honeybees collecting latex from breadfruit in Puerto Rico, a rare interaction that reveals how plant chemical diversity can shape bee foraging, plant-insect dynamics, and evolutionary trajectories---highlighting the role of nonnative species in driving eco-evolutionary change in tropical ecosystems.

Western Melanesia sits at the junction of three major tectonic plates, characterised by dynamic plate interactions and geological diversity. Tectonic activity in this region has given rise to modern New Guinea, a relatively young island with extreme topographic heterogeneity and evolutionarily complex biota. New Guinea—particularly the East Papuan Composite Terrane (EPCT)—supports exceptional frog diversity; however, evolutionary histories of many frogs of the EPCT are poorly understood. The microhylid frog genus Mantophryne currently includes five described species (M. axanthogaster, M. insignis, M. louisiadensis, M. menziesi and M. lateralis), with the first four confined to small portions of the EPCT and the last distributed across the eastern half of New Guinea. The biogeographic history of these frogs remained incompletely resolved at the time of our study. We estimate that Mantophryne diverged from other microhylid genera approximately 14.4 million years ago (MYA) and began to speciate ca. 8.5 MYA. We recover eight distinct lineages within frogs assigned to M. lateralis, which started to diverge ca. 5.5 MYA. Dispersal of Mantophryne out of the EPCT occurred in the late Pliocene, around the time the Central Highlands expanded eastward to connect with the EPCT. Six pairs of sister lineages arose during a time of significant climate reorganisation in the Late Pliocene – Early Pleistocene when it is possible that areas to the north of the Central Highlands experienced increased precipitation, while areas south of the Central Highlands experienced lower rainfall, resulting in contraction of rainforests and expansion of savannahs

Sequential pollen presentation is a reproductive strategy adopted by plants to enhance the efficiency and accuracy of pollen export and receipt, as well as to promote outcrossing. Actinidia arguta exhibits a typical characteristic of sequential pollen presentation. In this study, indoor and field observation methods were employed to conduct a tracking investigation on the anther dehiscence mode, pollen presentation strategy of male, and the floral characteristics and pollination traits of both female and male.The results showed that: The anthers of female A. arguta are dark brown, with multi-lobed stigmas. The anthers of male are black, and the petals of female are significantly larger than male. The anther dehiscence mode of male A. arguta is “unzipping” longitudinal dehiscence for pollen release, and its pollen presentation strategy is sequential presentation. The peak period of pollen release effectively overlaps with the periods of pollen viability, stigma receptivity, and nectar secretion at different flowering stages. This maximizes the reduction of pollen waste and promotes outcrossing pollination. Male A. arguta produce a large amount of pollen and secrete more nectar than female. This attracts more pollinating insects, indicating that A. arguta is a typical insect-pollinated plant. Apis cerana and Bombus are the main pollinators, and pollination is accomplished by relying on these pollinating insects to transfer pollen from male to the stigmas of female. Dioecy can effectively promote outcrossing, increase genetic diversity, and enhance the evolutionary potential of the species to adapt to the environment. Studying the pollen presentation mechanism and pollination characteristics of A. arguta is of great significance for improving its pollination efficiency and promoting reproductive success, and can provide a theoretical basis for the reproductive breeding of this species.

Intraspecific trait variation (ITV) is critical for plant adaptation, particularly under increasing drought. ITV arises from phenotypic plasticity and genetic differentiation, so identifying its sources improves understanding of population responses to drought. This study investigates how climate and genetics shape ITV and drought responses in Andropogon gerardi, a foundational Great Plains grass. To quantify climatic determinants of ITV, we conducted a common‐garden greenhouse experiment with 25 A. gerardi populations spanning wide temperature (4–21°C; Minnesota–Texas) and precipitation (350–1400 mm yr⁻¹; Colorado–North Carolina) gradients, measuring 17 functional traits. To test drought as a selective pressure, eight populations across a precipitation gradient (470–1350 mm yr⁻¹) were exposed to experimental drought (15% moisture vs. 30% control). Populations were also genotyped to assess the genetic basis of ITV, and greenhouse–field trait comparisons were used to separate genetic and environmental effects. We hypothesized that climate of origin, particularly precipitation, predicts ITV: dry populations would express drought‐adaptive traits (higher water‐use efficiency, shorter stature), whereas wet populations would exhibit competitive traits (greater height, biomass). We further predicted that drought would reduce growth and delay flowering, with stronger effects in wet populations, and that trait variation would correspond with genetic differentiation. Precipitation and aridity were the strongest predictors of ITV. Principal component analyses revealed that wet populations displayed competitive traits (taller stature, larger leaves), while arid populations showed drought‐adaptive traits (higher water‐use efficiency, reduced stature). Under drought, wet populations exhibited greater declines in biomass and photosynthesis, indicating drought as a key selective force. Congruent genetic and trait PCAs confirmed a strong genetic basis for ITV, and consistent greenhouse–field patterns reinforced genetic control. Overall, ITV in A. gerardi is primarily shaped by precipitation through coordinated, genetically based trait responses, offering a predictive framework for grassland adaptation under future climate change.

1. The interactions between phytophagous insects and their host plants show a strong trend towards specialization. However, the reasons behind this trend remain largely unclear, at both the evolutionary and mechanistic level. 2. One possible explanation is an increased energy expenditure for digesting and metabolizing more challenging hosts included in a broader host repertoire, which may reduce the energy available for other processes such as growth and development (“metabolic load hypothesis”). Differences in the performance across various hosts could reflect such costs. 3. Using the polyphagous Polygonia c-album (comma butterfly), we tested whether observed performance differences can be linked to variation in the energetic requirements. For this, we measured the metabolic rate of larvae feeding on three different host plants and converted it into the amount of CO2 produced per gram of mass gain (“growth cost”) to assess how much energy is allocated to growth vs digestion and assimilation. 4. The metabolic rate of larvae feeding on a chemically more challenging plant (Ribes uva-crispa) was similar to that of individuals on the host supporting the highest growth rate (Urtica dioica). 5. However, larvae on Ribes uva-crispa exhibited a higher energy demand per unit of growth and a lower growth rate, indicating a different energy allocation in growing larvae than when they were reared on a chemically less challenging plant. 6. Our findings suggest that energy expenditure for digesting different hosts varies and can have direct consequences for the larval performance. This indicates that the trend towards ecological specialization may, at least partly, be driven by selection to reduce the energetic costs for detoxification and digestion, in support of the metabolic load hypothesis.

While there is abundant theoretical work on the evolution of phenotype plasticity, empirical support has lagged. One model for the evolution of phenotype plasticity is by genetic accommodation. Under this model of evolution when a population encounters a new environment there are widely variable responses amongst different genotypes, which are then pruned by selection into a single adaptive response. Because of the requirement to replicate genotypes, testing this prediction requires inbred lines as well as populations that are both adapted and not adapted to a resource. We previously demonstrated that D. melanogaster adapted to ethanol through genetic accommodation using D. simulans as an ancestral proxy lineage. However, we wondered how generalizable these results were. Using a new population of D. melanogaster from France and an ancestral range population from Zambia we demonstrated here that the Zambian population is not adapted to ethanol and that the French population has evolved ethanol resistance through genetic accommodation. We also investigated alternative splicing in response to ethanol and find that gene expression and splicing appear to evolve independently of one another, and that the splicing response to ethanol is largely distinct between populations. Thus, we have independently replicated evidence for evolution by genetic accommodation in D. melanogaster, suggesting that the evolution of plasticity may be an important contributor to the ability to exploit novel resources.

Protist biogeography, speciation, and systematics continue to generate debate and inquiry because protist distributions and dispersal remain poorly resolved. Identifying potential vectors and basibionts for epibiont protists would contribute to our limited understanding of their ecology. Migratory animals seasonally link disparate landscapes, incidentally transporting other organisms in the process. Waterbirds are known microbe dispersers, but evidence for other avian groups is limited—such as taxa that often migrate longer distances. We asked whether terrestrial songbirds (Passeriformes) host diatoms (Bacillariophyta) by sampling tail plumage of four thrush species (Hermit Thrush Catharus guttatus, Swainson’s Thrush C. ustulatus, Wood Thrush Hylocichla mustelina, American Robin Turdus migratorius) spanning multiple migration strategies. Unexpectedly, we found diatoms in all seven samples, yielding 224 individuals of 25 genera and 9 orders: primarily benthic, freshwater, raphe-bearing genera (e.g., Encyonopsis, Navicula, Nitzschia). Several diatoms contained chloroplasts prior to digestion and slide mounting, consistent with potential viability. These natural history observations suggest that songbirds are overlooked carriers of hitchhiking diatoms, implying an undescribed but potentially important avian-algal relationship.

Studies of Taiwanese mammals reveal varied patterns of population divergence. Low-mobility species such as mole-shrews and Formosan wood mice exhibit strong north–south splits. Surprisingly, similar patterns also occur in mobile taxa like Formosan serow and sambar deer. In contrast, other mobile species, including flying squirrels, and Reeves’s muntjac, show weak or no population structure. This recurring north–south divergence across taxa with diverse ecologies suggests that shared environmental and geographic gradients, in addition to historical isolation, may underlie these patterns. If so, species occupying similar habitats may exhibit comparable genetic breaks regardless of life history traits. Prior studies based solely on mitochondrial DNA may have missed fine-scale structure in species like muntjac; high-resolution SNP data now offer improved resolution. Here, we analyzed genome-wide SNPs from 71 Taiwanese Reeves’s muntjac and comparative Chinese samples. We detected deep divergence from Chinese muntjac (~0.24 MYA), and further north–south subdivision within Taiwan (~0.06 MYA). Demographic modeling revealed a complex history involving glacial isolation and asymmetric gene flow, mainly from north to south. Within Taiwan, genetic differentiation was shaped by both geography and climate, especially temperature annual range (Bio7), with niche models showing environmental separation. Selection scans identified PLA2-associated genes, potentially linked to thermal adaptation. This is the first study to demonstrate that both geographic and environmental heterogeneity jointly contribute to mammalian divergence in Taiwan. The repeated north–south split across ecologically diverse species highlights shared climatic and topographic factors driving parallel population structure in Taiwan’s montane ecosystems.

As the wild progenitor population of cultivated apricots, Xinjiang wild apricots hold irreplaceable significance in maintaining ecosystem functions and conserving germplasm resources. This study employed a combined approach utilising chloroplast DNA fragments (rpl32-trnL and ndhC-trnV) and a single-copy nuclear gene (DXH) to conduct a systematic phylogeographic analysis of wild apricot resources within the Ili wild fruit forests of Xinjiang. Results indicate significant divergence between genetic structures revealed by chloroplast DNA and nuclear genes, reflecting complex evolutionary processes driven by natural selection, genetic drift, and gene flow across distinct genetic systems. Genetic variation predominantly resided within populations, with weak differentiation between them. Neutrality tests and mismatch analysis indicated that wild apricot maternal lineages had not undergone significant historical expansions, suggesting a possible shared population contraction (bottleneck effect). Conversely, nuclear gene data supported recent expansion, with the Yining County population exhibiting the most pronounced expansion signal, indicating effective recording of this event by the nuclear genome. Niche modelling using the MaxEnt approach indicates that key environmental factors influencing wild apricot distribution include precipitation during the wettest season (100~135 mm), precipitation during the warmest season (90~120 mm), and soil sand content (6%~38%). The current suitable habitat is primarily concentrated in the Ili Kazakh Autonomous Prefecture, while projections under future climate scenarios indicate an expansion trend in its suitable range. This study systematically elucidates the genetic diversity characteristics and phylogeographic patterns of Xinjiang wild apricot, clarifying its population history dynamics and future distribution potential. It provides theoretical foundations and practical guidance for the scientific conservation and sustainable utilisation of germplasm resources for this species.

Caragana, a dominant leguminous plant in the barren semi-fixed deserts of northern China, forms critical symbiotic nitrogen-fixing associations with Mesorhizobium, which are vital for ecosystem functioning globally. However, the genetic adaptation of Caragana-associated Mesorhizobium symbionts driven by membrane transporters and nucleotide repair genes remained poorly illustrated. Recognizing the pivotal roles of membrane transporters (cysW, exoY, idhA) and nucleotide repair genes (mutS, uvrC) in microbial environmental resilience, this study investigated the adaptive dynamics of 68 representative Mesorhizobium strains isolated from Caragana across five geographically distant areas (A–E) in this desert belt. Phylogenetic analyses based on the five target genes revealed that strains clustered primarily by genospecies rather than geographic origin, with high topological congruence between membrane transporter, nucleotide repair and core gene trees. Genetic differentiation and frequent interspecific gene flow were predominantly driven by recombination (over mutation), indicative of active horizontal gene transfer (HGT) as a key evolutionary force. Notably, despite geographic separation, strains from the same genospecies exhibited extensive sequence homology in both gene sets, suggesting shared adaptive traits disseminated through HGT. Collectively, our results demonstrated that Caragana-associated Mesorhizobium have evolved primarily through adaptive processes shaped by homogeneous harsh desert environments, rather than geographic isolation. The membrane transporters likely facilitated rapid acquisition of nutrient uptake and stress-tolerance traits via recombination, while nucleotide repair genes maintained genomic integrity under extreme conditions. This dual genetic strategy underscores how HGT and purifying selection synergistically drive ecological adaptation in desert microbiomes.

Forest composition and structural diversity play a key role in shaping habitat availability and biodiversity, particularly influencing the occurrence of saproxylic species associated with tree-related microhabitats (TreMs). TreMs and deadwood are essential features of forest ecosystems, offering critical habitats for saproxylic arthropods that contribute to decomposition, nutrient cycling, and overall forest resilience. Understanding the complex interactions between forest structures, TreMs, and arthropod communities is crucial for biodiversity conservation and sustainable forest management. This study explores how forest composition, deadwood, and TreMs together influence arthropod diversity and community composition in temperate forests, using a large-scale eDNA metabarcoding approach. We assessed arthropod communities across 135 forest plots in the Black Forest, Germany with varying degrees of retention. Our findings reveal that specific TreMs, such as cavities, mosses, and insect galleries, significantly contribute to arthropod richness, particularly for Collembola, Coleoptera, and Arachnida. Canopy closure, deadwood volume, and snag availability emerged as key determinants of community composition, while low degrees of retention negatively impacted terrestrial arthropods biodiversity by reducing habitat complexity. These findings reveal that species richness and community composition are driven by different ecological factors, highlighting the complexity of forest ecosystems. They underscore the need for forest management strategies that preserve deadwood and TreMs, enhance structural heterogeneity, and consider broader indicators of forest naturalness to effectively support arthropod biodiversity.

Breeding systems can impact population dynamics and genetic diversity, especially when a population is small or isolated. Here, we used a long-term dataset of demographic data combined with 1,745 single nucleotide polymorphisms to investigate mating patterns within a population of the eastern quoll (Dasyurus viverrinus) reintroduced to a conservation-fenced reserve. Pedigree reconstruction revealed that 47.62% of eastern quoll litters exhibited multiple paternity, containing up to three sires. Trait-based generalised linear mixed-modelling showed reproductive success was significantly correlated with bodyweight, age, and colour-morph. A cross-species comparison within the Dasyuridae (which includes the eastern quoll) showed that shorter lifespan increased the rate of multiple paternity, but the degree of sexual size-dimorphism or intersex aggression does not. Our study indicated that individual traits can predict reproductive success, but the likelihood of multiple paternity can depend on the evolutionary/life history of the species (e.g., lifespan). Further research should focus whether the interaction between breeding system and life history may predict patterns of multiple paternity within a species.

Abstract Urbanisation and human population growth have significantly increased the presence of anthropogenic materials in natural environments, prompting growing interest in how wildlife may be adapting to these changes. One such behavioural response is the incorporation of anthropogenic materials into animal nests, a phenomenon that has raised concerns due to its potential harmful effects, such as entanglement or ingestion. While this behaviour has been documented widely in birds, it remains underreported in other taxa, partly due to the difficulty of locating nests. In this study, we describe multiple instances of anthropogenic materials (including plastic) being incorporated into the hibernation nests of European hedgehogs, Erinaceus europaeus. These findings suggest that hedgehogs may opportunistically use available anthropogenic materials in nest construction, potentially as a response to urban environments. Our findings help broaden the understanding of mammalian responses to urbanisation and emphasize the need to investigate whether the incorporation of these materials is likely to be harmful or adaptive to hedgehogs or for mammals generally.

Lilium tsingtauense Gilg is a rare and endangered wild plant, but the correlation between plant seed traits and environmental factors is insufficient. In order to explore the response of seed trait variation to the change of growth environment, 37 plots were selected in the altitude range of 200-1000 m in Laoshan scenic spot of Qingdao for investigation and statistics, and mature fruit and soil samples were brought back to measure soil nutrient content, fruit size, seed number and seed germination rate. The results showed that: (a) The habitat characteristics of L. tsingtauense had obvious population differences. There were significant differences in altitude, slope direction, light, soil water content, soil electrical conductivity, soil organic matter content and soil total nitrogen content among different populations. (b) The sensitivity of seed setting ability to environmental changes was higher than that of fruit and seed traits. Fruit length, width and thousand-grain weight were more stable than single fruit seed number and seed germination rate. (c) There was a significant correlation between longitude, altitude, illumination, soil water content, soil conductivity and soil total phosphorus content and seed traits. Among them, altitude was the key factor affecting the difference of seed traits of L. tsingtauense. And L. tsingtauense could produce more fruits and higher seed germination rate in high altitude growth environment. The results of this study revealed the environmental variation of seed traits and its influencing factors, which is of great significance for the renewal and protection of wild L. tsingtauense resources.

Interactions in single-host–parasite systems provide a tractable framework for understanding the ecological mechanisms that maintain community stability. Here, we integrated network topology, multidimensional niche analysis, and functional group delineation to investigate the adaptive strategies and assembly rules of a 12-species flea community on Mongolian gerbils (Meriones unguiculatus). The host–flea network was characterized by a stable, nested structure and exhibited strong seasonal dynamics, with connectivity peaking in summer and modularity increasing in autumn. To understand the niche mechanisms driving these patterns, we identified four key ecological gradients (Seasonal Climate, Host Physiology, Weather Exposure, Host Behavior) and quantified the niche breadth of each species along these axes. Our analysis revealed that the community was organized along a steep hierarchy of generalization. Two ”hyper-generalist” species (Nosopsyllus laeviceps kuzenkoui and Xenopsylla conformis conformis) dominated the community, exhibiting near-maximal niche breadth across all four dimensions and occupying the core of the co-occurrence network. A broad niche was a major determinant of a species’ role, correlating strongly with a wider range of exploited hosts (p < 0.05). In contrast, specialist species, such as the ”extreme specialist” (Ophthalmopsylla jettmari), were confined to the network’s periphery and a narrow subset of ecological conditions. Clustering based on the multidimensional niche profiles identified four distinct functional groups, reflecting a clear hierarchy of ecological strategies from dominant hyper-generalists to highly restricted specialists. Overall, by integrating a multidimensional niche framework with network analysis, this study demonstrates that a hierarchical niche structure, rather than complex trade-offs, is the primary organizing principle in this seasonally dynamic community, providing a more nuanced understanding of stability in parasitic systems.

Species boundaries are not always straightforward, especially during early stages of divergence, when gene flow may still take place. Nipponocypris koreanus, a widely distributed freshwater fish species endemic to Korea, was recently classified as a separate species from its relative Nipponocypris temminckii. However, morphological differences between the two species are ambiguous and genetic differences between and within species remain largely unexplored. In this study, using mitochondrial DNA cytochrome oxidase I (COI), control region (CR) and our developed 9 microsatellite loci, we determined phylogenetic relationships and population genetic structure of N. koreanus among geographically separated six river basins in comparison with N. temminckii. We found that N. koreanus evolved relatively well-separated clades in each basin, and that some morphologically N. koreanus individuals were genetically N. temminckii, suggesting the possibility of natural hybridization between the two species. Nipponocypris koreanus individuals from the Nakdong and Seomjin Rivers are the most closely related to N. temminckii, and they probably represent cryptic species complex as they showed a genetic distance of 2.2~2.9%, although N. koreanus had a distinct genetic structure. Comparisons of the whole mitogenomes from different rivers further support the notion that the Nakdong and Seomjin River populations constitute cryptic species in N. koreanus rather than a single species. The results of this study will shed an intriguing insight into understanding how Korean freshwater fishes have evolved in response to geographically isolated major river/stream environments. The evolutionary mechanisms underpinning the cryptic species diversity in freshwater systems are worth to be further studied.