Journal of Systematics and Evolution

This investigation aimed at compiling all phylogenetic lineages within and around genus Cyanoboletus. The evolutionary inference obtained from the nuclear ribosomal genes internal transcribed spacer region (ITS) suggests that part of the species currently classified in Cyanoboletus belong in lineages separate from the genus, thus suggesting a narrower boundary that includes only the species that develop a strong staining reaction to touch and to air exposure of the context. The separate lineages are the monotypic Cupreoboletus genus and a few species that do not develop such reaction, which are part of a clade together with genera Cacaoporus and Acyanoboletus, thus broadening the concept of Cacaoporus to encompass all of them. The emerging 3C perspective of Cupreoboletus, Cacaoporus and Cyanoboletus offers a remarkably consistent morphological diagnosis, overcoming the problems of a too broad concept for Cyanoboletus. This work reveals that Boletus neotropicus, B. novae-zelandiae and B. sensibilis belong respectively in Cyanoboletus, Cacaoporus and Lanmaoa, and by studying multigene alignment concatenates it identifies lineages that probably represent undescribed species: at least four in Cacaoporus and at least five in Cyanoboletus. Diagnostic tables and dichotomic keys are presented by geographic region. The present work also includes a study of the phylogenetic position of Neoboletus flavosanguineus, a species once classified in Cyanoboletus. The complexity of assigning species epithets in some lineages is addressed, namely for the boundaries between Cacaoporus instabilis and Ca. fagaceophilus as well as the diversity under the names Cyanoboletus sinopulverulentus and Cy. pulverulentus. The overall picture of evolutionary lineages sets a framework for the choice of reference data that can provide, in future phylogenetic studies that involve the 3C, a balanced and efficient coverage. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=197 SRC="FIGDIR/small/724631v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@7f618corg.highwire.dtl.DTLVardef@dd6a14org.highwire.dtl.DTLVardef@5f7399org.highwire.dtl.DTLVardef@9e7443_HPS_FORMAT_FIGEXP M_FIG C_FIG

O_LIPlants and fungi are major sources of natural products beneficial to society, making the study of distinct species essential for discovering new drugs and bioactive compounds. The medicinal mushroom "Lingzhi" or "Reishi" (Ganoderma lingzhi) is widely used in traditional medicine and extensively studied for its bioactive triterpenoids, yet it is commonly identified as Ganoderma lucidum, the type species of the genus, which lacks a type specimen. C_LIO_LIWe sequenced a G. lucidum specimen preserved in the Kew fungarium, which agreed with the original description and was collected from wood of Corylus avellana in southern England. Using this reference specimen, we compiled genomic and ITS barcoding datasets to explore the genetic and geographic variation within this species. C_LIO_LIWe showed that G. lingzhi and G. lucidum diverged more than 12 million years ago and that all seven "G. lucidum" genomes deposited in public databases belong to other species. More than 1000 barcoding sequences showed that the widely used homology-based ITS barcoding is not working in this group, which can be mitigated by a phylogenetic placement approach. The 149 sequences assigned to G. lucidum with high confidence showed a Eurasian distribution and introductions to North and South America and Africa. C_LIO_LIOur study underscores the importance of accurate species identification and provides guidance for a group of pharmaceutical and socially significant species. To further support future studies and the wider public in differentiating between G. lingzhi and G. lucidum, we propose using "False Lingzhi" as the English name for G. lucidum. C_LI Societal Impact StatementTraditional Chinese Medicine has expanded far beyond Asia, with growing markets in North America and Europe for supplements and functional foods. Lingzhi or Reishi (Ganoderma lingzhi), a well-known medicinal mushroom, is valued for its anti-inflammatory and anticancer properties. However, it is often misidentified with species that may not provide the same health benefits. This confusion poses risks to consumer safety, product regulation, and research. Here, we establish a reference using morphological and molecular tools for the most commonly misidentified species (Ganoderma lucidum) and propose the name "False Lingzhi" to distinguish it, supporting accurate identification, safer product development, and reliable research.

Forest trees pose numerous potential challenges to phylogenomic inference. Their large effective population sizes and relatively long generation times lead to deep allele coalescence and consequently incomplete lineage sorting (ILS), which biases inferences of divergence times toward older ages and introduces gene tree discordance. Deep phylogenetic divergences, reaching back into the Paleocene, introduce reference-mapping biases. Introgression--the movement of genes between lineages--may result in different phylogenies being inferred depending on which individuals are included in analysis, even if the plurality of the genome favors the divergence history unaffected by introgression. These factors influence phylogenetic inference across the Tree of Life but are particularly prevalent in forest trees. Oaks (Quercus) are notable for all three influences. In addition, our knowledge of the oak phylogeny is currently based strongly on restriction site associated DNA sequencing (RADseq) datasets published over the past decade, which may introduce additional sources of uncertainty. In this chapter, we analyze a 322-species RADseq dataset and genome resequencing data from across the genus to address sources of uncertainty in our understanding of the global oak phylogeny, which we hope will serve as a model for other research groups working on comparable woody plant groups.

Phylogenetic network inference methods are increasingly used to detect hybridization and gene flow from genomic data, but their robustness to common sources of model violation remains poorly characterized. We conducted a simulation study to evaluate the effects of hidden paralogy and substitution rate variation on two widely used network inference methods: find_graphs from ADMIXTOOLS 2 and SNaQ. Using an eight-taxon species tree calibrated from an empirical reptile phylogeny, we simulated data under various levels of hidden paralogy (from none to strong) and three levels of rate variation (none, gene-specific, and lineage-specific). We found that hidden paralogy had limited impact on network inference under the conditions examined: both network methods correctly favored a tree without reticulation, and ASTRAL recovered the correct species tree every time. In contrast, lineage-specific rates severely biased find_graphs, inflating worst f-statistic residuals well beyond the standard acceptance threshold. SNaQ correctly selected a tree model almost always across all conditions, though its network with h = 1 reticulation displayed the true species tree with a lower probability under lineage-specific rates. We also show that the standard worst residuals threshold of 3 for find_graphs produces inflated type I error even without rate variation, and we recommend empirical calibration of this threshold within each study system.

Wild bees face declines, and forests may serve as critical habitats for pollinators. However, how forest composition and the associated floral environment shape pollen provisioning and resource partitioning among cavity-nesting bees remains poorly understood. Here, we leveraged BEF-China, a large-scale subtropical forest biodiversity experiment with experimentally controlled plant (tree and shrub) communities, to investigate how forest composition and spatial context shape pollen provisioning, resource partitioning, and reproductive success of cavity-nesting bees. We used DNA metabarcoding to analyze floral composition of pollen provisioned by five cavity-nesting bee species, with samples collected from BEF-China across three years (2022- 2024). By comparing pollen taxonomic composition from whole-nest pooled samples and individual brood-cell samples with the experimentally planted species pool, we characterized dietary patterns and temporal dynamics of five bee species. Bees primarily relied on floral resources from the surrounding landscape, with planted trees providing essential but temporally restricted pollen supplements during specific phenological stages. Co-occurring bee species exhibited staggered nesting phenology and distinct dietary preferences for different plant families, with fine-scale resource differentiation even during periods of phenological overlap. Our results suggest that managed forests support cavity-nesting bees by providing critical woody floral resources during specific phenological gaps and offering stable nesting environments. To mitigate pollinator declines, forest management should prioritize maintaining diverse, phenologically complementary flowering vegetation within and surrounding forest stands. This ensures temporal continuity of pollen availability throughout the nesting season, which is particularly crucial for restoring pollinator services in simplified forest landscapes.

For over four decades, the bivalve Anomalocardia flexuosa has been recorded in Hong Kong coastal waters. However, the known native distribution of this heavily exploited commercial species is restricted to the Atlantic coast of South America, raising questions about the biogeographical validity of the Hong Kong populations. By employing an integrative taxonomic approach combining morphological re-evaluations and molecular phylogenetic analysis of the COI gene, we confirm that the species in Shui Hau, Hong Kong, China, has been historically misidentified. The population belongs to Cryptonema producta (syn. Anomalocardia producta).

Aimto characterize the evolution of climatic niches during the diversification of the Phyllotis darwini species group, in order to assess the extent to which divergences involved in radiation were associated with patterns of conservatism or divergence of climatic niches, and whether the differentiation found among climatic niches correlated with species phylogenetic relationships. Locationsouth-central Andes, surrounding lowlands, and Patagonia, South America. Methodsspecies climatic niches were characterized by sampling contemporaneous precipitation and temperature conditions across occurrence locations and entire distributional ranges. Climatic niches were analyzed and modeled using multivariate statistics (PCA, PERMANOVA), a maximum entropy-based algorithm, and novel methods developed to explore levels of differentiation (niche overlap test) and divergence (niche divergence test) between realized and fundamental niches. Comparative phylogenetic methods were applied using a time-calibrated phylogeny and integrating climate niche data to estimate ancestral environmental niches within geographic and environmental spaces. Resultscomparisons revealed low levels of climatic niche overlap, both among species realized niches and among their fundamental niches, suggesting high levels of niche differentiation during the diversification of Phyllotis species. Quantifications of niche overlap further showed that observed differences among species lay primarily in the multidimensional nature of climatic niches, as unidimensional quantifications exhibited higher levels of overlap. Evolved differences among species climatic niches were better fitted to a Brownian motion model of evolution, but lacked phylogenetic signal and showed no significant association with species phylogenetic distances. Main conclusionslow levels of differentiation between ancestral climatic niches suggest that the early radiation of species in the Phyllotis darwini species group was promoted by geographic isolation, whereas the more recent diversification of extant species was accompanied by climatic niche differentiation, possibly involving local adaptation to regional ecoclimatic changes associated with Quaternary glacial cycles. The spatial separation of sister species, the complete divergence of their climatic niches, and the lack of phylogenetic signal in niche differences suggest a scenario of diversification in which divergences were prompted by the spatial isolation, but also by the divergent selection exerted by regional climatic differences.

Computational workshops are common in evolutionary biology and are used to share discipline-specific tools and skills with researchers. Despite the perceived importance of these workshops, there is no common set of criteria for workshop success, and there are few peer-reviewed studies investigating the efficacy of workshops or assessing the value of particular instructional techniques in this context. Here, we focused on one key element of a successful workshop: its ability to increase participants motivation to use the methods and tools presented during the workshop. We analyzed the goals, perceptions, and future plans of research practitioners engaging in a workshop on phylogenetic methods of historical biogeography using pre- and post-workshop surveys. Overall, the workshop was successful at motivating participants, and survey responses provided insights into participants perceptions of different activities, including "participatory live coding". Apart from this case study, we aim to highlight the importance of developing a common set of workshop goals in collaboration with other workshop stakeholders and the need for specialized, validated tools for assessing the efficacy of computational workshops for researchers.

Understanding how global biodiversity patterns arise is a central theme of biogeography, with contemporary theory recognising the roles of both dispersal and vicariance. Genera that are broadly distributed can provide important systems for disentangling the relative influence of these processes across evolutionary timescales. However, many lesser-studied groups, particularly those in the tropics, lack a densely sampled phylogeny which hinders robust inference of their evolutionary and biogeographic history. This study investigates the global diversification and systematics of the putative pantropical moth genus Parasa Moore (Lepidoptera: Limacodidae), with the aim of assessing the relative importance of dispersal and vicariance in shaping its distribution. Medium-coverage whole genome sequencing of specimens predominantly from museum collections were used to generate a globally sampled time-calibrated phylogeny of Parasa and associated genera (the Parasa-complex). Ancestral range estimation analyses were employed to infer geographical origins and possible dispersal times between bioregions. The Parasa-complex originated in Africa in the late Oligocene ([~]24 Ma) and, through a series of long-distance dispersal events during the early-mid Miocene, expanded into Asia ([~]23 Ma) and the Americas ([~]21 Ma). Across all regions, dispersal was the dominant process shaping present-day distributions, with a limited role of vicariance in some subregions. Phylogenetic analyses further demonstrated that Parasa is not monophyletic, with multiple independent lineages contributing to its apparent pantropical distribution. These findings highlight a central role of long-distance dispersal in generating certain global distributions. The results support a dynamic model of range evolution involving rapid Miocene dispersal and subsequent regional diversification. In addition, the non-monophyly of Parasa requires substantial taxonomic revision, underscoring the importance of robust phylogenetic frameworks for interpreting global biodiversity patterns.

PremiseCentaurea melitensis (Asteraceae) is a problematic invader of grasslands globally, but little is known about its genetic makeup. Here we develop a reference genome to facilitate studies of its invasion history, genetic variation, and evolution. MethodsInbred offspring of a single individual of C. melitensis from its invasion of California, USA were used for flow cytometry to estimate genome size, and for genomic DNA extraction. DNA was sequenced with PacBio HiFi technology (yield = 85.7Gb). The genome was assembled with Hifiasm and annotated with BRAKER3. GENESPACE was used to compare gene order (synteny) with three other species within the subfamily Cichorioideae. ResultsWe estimated a mean genome size of 795.0 Mbp for C. melitensis, and our assembly totaled 696.6 Mbp in 48 contigs (N50 = 55.6 Mbp; BUSCO = 98%), with annotation of 25,157 protein-encoding genes. This included four telomere-to-telomere putative chromosomes, nine additional chromosome arms terminated by telomeric repeats, and a complete chloroplast genome. Synteny varied markedly across the genus and subfamily, suggesting a dynamic history of structural variation in the lineage of C. melitensis. DiscussionWe provide a highly complete and contiguous genome assembly to facilitate the further study of genomic variation in C. melitensis.

Deep-sea corals are vital in maintaining coral ecosystem biodiversity, yet their genetic characteristics remain largely unexplored. Here, we present 11 deep-sea coral genome assemblies, including four Hexacorallia and seven Octocorallia species, significantly contributing new genomic information across two orders. Our analysis reveals the historical dynamics of coral speciation and the influence of environmental factors on the evolution of coral reef ecosystems.Total of 126 horizontal gene transfer (HGT) events were detected, among which genes from the ancestor of symbiodiniaceae indicate that the ancestors of deep-sea corals may have inhabited shallow-sea environments. Notably, several of these HGTs are involved in phosphorus (PhnX/PhnW) and cholesterol (DHCR7) metabolisms within corals, indicating that HGTs may serve as an adaptive survival strategy for the coral holobionts. Deep-sea corals also rely on symbiotic bacteria to synthesize 10 essential amino acids (such as valine and tyrosine), retaining only partial amino acid synthesis capacity. In addition, we investigated the evolution of key biological rhythm genes and temperature adaptation in corals. The loss of key rhythm genes (e.g., clock and cry) in deep-sea corals and copy number difference of genes related to heat stress (e.g., Cbl-b and Rchy) revealed genetic difference between deep-sea and shallow-sea corals. Our new genome assemblies enhance the understanding of deep-sea coral evolution, biodiversity, and adaptation, providing a genetic foundation for coral conservation.

The ichneumonid subfamily Eucerotinae has been thought to be almost absent from the tropics, with the only known Afrotropical species found in Madagascar. We report the subfamily to be present in the mainland Afrotropics, and describe a new species, Euceros species 1 from Uganda and Cameroon (name not yet shown in preprint). The subfamily had likely not been observed in the mainland Afrotropics before due to low abundances and insufficient sampling. More Eucerotinae likely remain to be discovered in tropical Africa and Asia, although tropical America may genuinely have few eucerotine species. Much more extensive sampling will be needed before it is possible to make confident estimates of how eucerotine diversity is distributed globally.

Salinity is a major crop production constraint in dry pea (Pisum sativum L.), making the development of salt-tolerant varieties essential to improve crop productivity and land-use efficiency. The genetic mechanisms of salt tolerance in dry pea is largely unknown, and research on salt-tolerant genes is limited. In this study, we established comprehensive genomic and transcriptomic resources, along with a robust screening protocol, to dissect the genetic basis of salinity tolerance using two germplasm sets: the USDA pea diversity panel, consisting of approximately 200 globally sourced accessions, and a set of 300 modern elite lines from the NDSU Pulse Crops Breeding Program. Genetic variation for the salinity response was assessed based on ten phenotypic traits, with root dry weight, shoot dry weight, and specific root length identified as key indicators based on their heritability. Genome-wide association mapping uncovered significant genomic regions and several candidate genes linked to salt stress, with the strongest association found on chromosome 6. Overlapping QTL signals across traits suggest a shared genetic architecture underlying salinity tolerance. Field-based transcriptomic analysis further identified five putative genes involved in salinity response conserved across multiple crop species. Notably, Psat5g000800, encoding a glycosyl hydrolase gene, was markedly upregulated under salinity stress. These findings highlight the complex, multi-gene regulatory nature of salinity tolerance in dry pea and underscore the importance of functional validation of candidate genes. This study provides key insights and practical tools to support breeding efforts aimed at improving salt tolerance in dry pea.

Recent advances in genome imputation have enabled the application of state-of-the-art statistical methods--originally developed for present-day genomes--to ancient genomes. One class of such methods, known as local ancestry inference (LAI), can model an individuals genome as a mosaic of tracts assigned to different putative ancestral sources, revealing patterns of genetic ancestry across the genome. However, most LAI methods have been designed to study recent admixture events in human history, and they generally assume large panels of present-day genomes. Despite the recent availability of high-quality imputed ancient genomes, it remains unknown to what degree LAI inference is reliable for such datasets. Ancient DNA is often characterized by heterogeneous geographic and temporal sampling, varying degrees of divergence between ancient source proxies and admixing populations, and complex demographic histories. Here, we performed an extensive set of population genetic simulations to evaluate the accuracy of four popular LAI methods-RFMix, FLARE, MOSAIC and simpLAI-under different demographic scenarios, various temporal sampling schemes, sample sizes, and admixture dates. We quantify the accuracy of these methods as a function of different parameters in practically relevant scenarios, and provide general guidelines for future studies utilizing LAI in ancient DNA research.

In this study, the critical gap in understanding how fonio responds to contrasting pedoclimatic conditions, both within and outside its traditional production areas was addressed. A multi-environment trial was carried out to identify high-yielding genotypes with either broad stability or specific adaptation, thereby enabling targeted varietal recommendations to support the expansion of fonio cultivation into new areas. Randomized complete block design was used in six environments with eleven genotypes to evaluate flowering and maturity times, and grain yield. The Additive Main effect and Multiplicative Interaction and the Genotype main effect and Genotype x Environment interaction biplots revealed a significant effect of the genotype-by-environment interactions on traits, with genotypes B12 and G31 identified as high-yielding, while genotypes M5 and M14 were revealed as early-flowering and maturing. Genotypes M14 and M15 were adapted to all environments and early maturing. Boukoumbe, known as the fonio production area in Benin, was the most desirable for earliness, while Ina was the most ideal for grain yield, proving that fonio could be cultivated in Sudanian and Sudano-Guinean areas. Factor analysis revealed precipitation, C:N ratio, soil pH and texture as the main environmental variables influencing the grain yield in fonio. Our findings contributed to selecting stable, adapted genotypes.

Heat tolerance determines the vitality of tree species under climate change independently of drought tolerance, but has been much less studied than tree water relations. We studied species-specific differences and the capacity for seasonal heat acclimation in Central Europes naturally most important tree species, Fagus sylvatica, in comparison with two exotic tree species (Fagus orientalis, Pseudotsuga menziesii) that are considered for silvicultural climate change adaptation in managed forests. Foliage of mature trees was incubated at temperatures from 35-50 {degrees}C for up to 4 h to simulate daily heat maxima during heat waves. The maximum quantum yield (Fv/Fm) of photosystem II (PS II) of dark-adapted leaves was measured, because the PS II is particularly sensitive to heat and its functionality can decide on plant survival under heat. Fagus sylvatica was much more tolerant to heat than Pseudotsuga menziesii, but weakly (albeit significantly) less tolerant than Fagus orientalis. Within its limits, Pseudotsuga menziesii showed high seasonal heat acclimation with constantly increasing tolerance during the growing season. Fagus orientalis, but practically not Fagus sylvatica, also acclimated to heat. This makes Fagus orientalis slightly superior over Fagus sylvatica in terms of heat tolerance, whereas the suitability of Pseudotsuga menziesii for silvicultural climate change adaptation is questionable. Strong heat acclimation, but also overall low heat tolerance, in Pseudotsuga menziesii might be the result of evergreenness, which requires the generation of both cold and heat tolerance during the year.

Pattersons D statistic, also known as the ABBA-BABA statistic, is widely used to detect the presence of archaic genome-wide introgression between two non-sister taxa. Requiring only a single lineage from each of four taxa where one taxon acts as an outgroup to determine the ancestral allele, Pattersons D, counts the imbalance between the number of biallelic sites where either the second and third taxa (ABAB site) or the first and third taxa (BABA site). When there is no introgression, these counts are expected to be equal, and a discordance between counts suggests introgression from the third taxon into either the first or second. Pattersons D is limited to the detection of genome-wide introgression and exhibits a high false-positive rate when applied to smaller genomic segments. Here, we present a new method, D STatistic with Allelic Rarefaction (D*), to address these limitations. D* uses multiple lineages and does not require an outgroup to calculate the imbalance between the number of alleles found exclusively in the second and third taxa and the number of alleles found exclusively in the first and third taxa. D* employs a rarefaction technique to correct for unequal sample-size and allows multiallelic sites. We use simulations to show that D* has better precision and recall for detecting introgressed segments of DNA when compared to similar methods under a wide variety of model parameters and in the presence of technical artifacts common to ancient DNA analyses. We conclude with an analysis of Denisovan DNA introgression in modern day Papuans. Precompiled executables, the manual, and source code can be found at https://github.com/TQ-Smith/DSTAR

O_LIA productivity-driven higher nutrient demand of trees in diverse mixtures is frequently reported. Yet, it remains unclear how tree diversity influences microorganisms-plants interactions, in which microbes facilitate tree nutrient acquisition in exchange for carbon (C) to meet the resource demand of both. C_LIO_LIUsing a long-term tree diversity experiment in the subtropics, we assessed microbial investment in C-, nitrogen (N)-, and phosphorus (P)-acquiring enzymes in litter and mineral soil, testing the effects of tree species richness and mycorrhizal type (arbuscular (AM)- vs. ectomycorrhizal (EcM)-associated tree species). C_LIO_LIWith increasing tree species richness, microbial investment in C acquisition decreased, while investment in N and/or P acquisition increased in litter and in mineral soil. In mineral soil of AM-associated tree mixtures, ecoenzymatic stoichiometry revealed a shift from microbial investment in C toward P acquisition as tree species richness increased. C_LIO_LIOur findings suggest that tree diversity strengthens microbe-tree interactions in terms of C-for-nutrient exchange. This highlights the key role of soil microorganisms, particularly in AM symbiosis, shaping tree diversity-biogeochemical feedbacks. C_LI

Attracting specific pollinators can be favoured by natural selection to avoid reproductive interference between sympatric plant species. However, the ways in which fine differences in floral traits lead to the attraction of specific pollinators are diverse and unknown in many pollination interactions. We surveyed pollinators on three sympatric Aristolochia species (A. clematitis, A. pistolochia and A. rotunda) pollinated by Diptera to investigate if specific pollination occurs. To decipher if specific pollination may be mediated by different floral odours, we characterized the volatile organic compounds (VOCs) emitted by flowers and highlighted those VOCs electrophysiologically detected by pollinators in A. rotunda and A. pistolochia. Among the most abundant pollinators, Forcipomyia monilicornis was a specific pollinator of A. pistolochia while two Dasyhelea species were specific pollinators of A. clematitis. Forcipomyia aristolochiae and T. ruficeps were non-specific pollinators of A. rotunda, although they were more frequently found in A. rotunda flowers. The floral odours of A. rotunda and A. pistolochia differed significantly from each other and elicited specific electrophysiological responses in their respective pollinators. Although several pollinator species visit more than one Aristolochia species, those pollinators are preferentially found in one Aristolochia species. Selective attraction is likely mediated by specific VOCs.

Plants, as structural elements of habitats, contribute greatly to the maintenance of local biodiversity through their biological interactions. In this study we explore whether their rarity, according to Rabinowitzs (1981) three criteria, is related to the richness and diversity of arthropods and other plants they are associated to, in a gypsum-rich steppe. We first analysed whether the geographic abundance and ecological specialisation of 32 characteristic and dominant plant species are related to the diversity (richness and phylogenetic diversity (MPD)) and degree of local specialisation of arthropods associated with them (1,694 taxa). Then, we focused on a non endemic and non specialized plant in the study area (Krascheninnikovia ceratoides) to explore the effect of population size on two types of interactions: aerial arthropods and plant facilitation. Results indicate that: 1) plant species abundance (geographical range) is not related to the richness or MPD of communities of associated arthropods, 2) plant species ecological specialization (edaphic endemisms or gypsophiles) do not contribute differentially to the maintenance of singular arthropod communities, and 3) the community of aerial arthropods and plants interacting with K. ceratoides in a small population are not necessarily less diverse than those in patches of similar size in a large population. Results also revealed that the two plant species with fewer interactions (one rare, one widespread) do show the highest singularity in their interactions with arthropods. Our study illustrates the important contribution of rare plants to the conservation of local biodiversity.