We herein constructed a phylogeny of Lepidoptera synthesizing multiple information types, a phylogenomics backbone, a multigene supermatrix with species-comprehensive DNA barcodes, and topological information from a compiled database of standardized machine-readable trees from over 100 previous studies. We then applied the new phylogenetic synthesis as a profiling framework for a large DNA barcode dataset of caterpillars from a tree diversity experiment. The synthesis phylogeny comprised 11,001 species. Phylogenetic information content was taxonomically skewed towards butterflies (i.e., Nymphalidae, Papilionidae and Pieridae), and parts of Macroheterocera (Geometridae, Sphingidae, Saturniidae and Bombycidae), while undersampling of Lepidoptera species diversity was present in Erebidae, Noctuidae, Gelechioidea and Pyraloidea. Caterpillar Phylogenetic Diversity (PD) increased with tree richness in the diversity experiment regardless of processing choices in calculating caterpillar PD, including whether calculated on plot OTU alone, plot OTU placed onto a simple reference phylogeny or plot OTU placed to the comprehensive reference phylogeny. Stronger correlations between tree diversity and uncorrected Faith's PD of caterpillars were observed where OTU were placed onto the full reference tree, and where long branch OTU were removed prior to PD calculation, though no significant differences in the strength of the tree diversity effect across context and processing choice were observed for standardized PD. In calculation of plot-level PD, focus should remain on community sample size, with the results herein supporting the use of any available reference phylogeny as context, though correspondence of PD indices to environmental gradients might be stronger where plot OTU can be placed to a comprehensive reference phylogeny. The phylogeny presented herein enables inference of varied evolutionary information for Lepidoptera DNA barcode sets.

Abstract Saproxylic insect community assembly is structured by deadwood and forest habitat gradients, as well as biotic interactions such as competition, predation, and parasitism. However, co-variation between abiotic and biotic conditions limits our ability to disentangle their contributions. Furthermore, a focus on beetles in temperate and boreal forests has left important taxonomic and geographic knowledge gaps. Here, we tested how experimentally manipulated tree diversity, deadwood position (lying vs. standing), and biotic interactions with a dominant antagonist (ant exclusion) structure communities of deadwood-cavity-nesting bees, wasps, and their parasitoids in a subtropical forest. Lying deadwood supported less diverse and abundant communities than standing deadwood while retaining approximately twice as much moisture. Moreover, host emergence declined along moisture gradients within each deadwood type. Together, these patterns identify substrate moisture as an important factor limiting bee and wasp communities nesting in deadwood – reflecting reduced brood production, survival, or both – and as a candidate driver for their positive association with standing deadwood in forests. By contrast, neither ant exclusion nor observed ant occurrence was associated with host or parasitoid responses. Because standing deadwood is typically scarce in managed forests, our findings support retaining or creating standing deadwood structures alongside lying deadwood and, more broadly, promoting dry and elevated nesting substrates for cavity-nesting bees and wasps in conservation and restoration measures. Graphical abstract

Climate change is driving shifts in species' geographic ranges, and understanding these changes is critical for effective biodiversity conservation. Species Distribution Models (SDMs) are widely used to predict the potential distribution of a given species under climate change. However, most studies focus solely on shifts in suitable habitats without considering whether species can reach these areas within a relevant timeframe. This omission often results in overestimation of future distributions and underestimation of extinction risk. Here, we designed an experiment to assess the impact of dispersal constraints on SDM predictions using 10 species with varying dispersal abilities. We compared the potential future distribution of species under two scenarios: the first, incorporating their dispersal ability and the second, assuming unlimited dispersal. Our results demonstrate that ignoring dispersal leads to an overprediction of suitable habitats for species, which may result in underestimating species extinction risk or overestimating the risk of range expansions by invasive species. This underscores the critical need to integrate dispersal dynamics into SDMs to enhance the accuracy of biodiversity projections. By incorporating realistic movement constraints, SDMs can provide more reliable predictions, leading to improved conservation planning, better management of invasive species, and more effective biodiversity conservation efforts under climate change.

Biodiversity loss can destabilize ecosystem functioning. How biodiversity–stability relationships are interlinked across trophic levels remains poorly investigated, however, limiting our ability to predict ecosystem-level consequences of declining biodiversity. Here, we analyze the drivers of multi-year herbivore community stability—as a key connector between primary producers and higher trophic levels—and its coupling with host tree diversity and growth stability along a subtropical tree diversity gradient. Phylogenetic diversity, abundance asynchrony and population stability of herbivores emerge as key intra-community regulators of herbivore temporal stability. These regulators, in turn, are strongly affected by changes in tree species richness through tree functional diversity, tree growth asynchrony, and tree growth population stability. Importantly, accounting for herbivore dietary specialization unveils clear stabilizing effects of tree species richness on the community stability of specialists but not of generalists. For the overall herbivore community, higher tree richness results in less stable abundance dynamics. Our findings suggest that biodiversity loss will propagate bottom-up to affect the stability of communities at higher trophic levels, and particularly destabilize communities of more vulnerable specialists. Global change and plantation management may thus also compromise biodiversity conservation by reducing abundance and species richness stability of higher trophic levels. The stability of interactions across trophic levels is crucial for ecosystem resilience but remains poorly understood. This study shows that loss of tree diversity destabilizes specialist herbivores, offering new insights into the mechanisms of pest outbreaks.

Freshwater Gammarus species represent important keystone organisms in aquatic ecosystems, and are sensitive to environmental changes. Here, we present the first pseudo-chromosome-level genome of Gammarus nekkensis, endemic to north China. We integrated PacBio HiFi long-read sequencing, Illumina short-read sequencing, and Hi-C scaffolding to generate a high-quality, pseudo-chromosome-scale genome assembly. The assembled genome is approximately 6.24 Gb in size, with a scaffold N50 of 233.63 Mb, and 96.76% of the sequences were successfully anchored to 26 pseudo-chromosomes. A total of 39,474 protein-coding genes were predicted, and approximately 70% of these genes obtained functional annotations. Repetitive elements constituted about 63.93% of the genome, with long interspersed nuclear elements (LINE) being the most abundant (23.98%). BUSCO analysis indicated that both the assembly and annotation are highly complete compared with published amphipod genomes. This high-quality genome enables studies of sex determination, adaptive evolution, and genomic diversity in G. nekkensis, with applications for its conservation and breeding.

The peppered moth Biston betularia L., widely distributed across the Northern Hemisphere, represents an ideal organism for exploring phylogeographic patterns and evolutionary history. In this study, we integrated molecular, morphological, and distributional data of this species to reconstruct its phylogenetic relationships, estimate divergence times, infer the geographic origin, and trace dispersal routes. Molecular analyses identified six monophyletic lineages (HM, NC, HD, E, NA I, and NA II). With the exception of the sympatric North American lineages NA I and NA II, the remaining lineages exhibit allopatric distributions across Eurasia. Ancestral area reconstruction and approximate Bayesian computation (ABC) analyses supported a southern Xizang origin within the Himalayan Mountains, consistent with the "Xizang-origin hypothesis." The colonization of North America occurred twice via the Bering Land Bridge during the Pleistocene glaciation. Collectively, the current genetic pattern is best explained by gradual allopatric differentiation following long-distance dispersal and subsequent isolation. Furthermore, we reconstructed the global dispersal history of B. betularia. These results indicated that in situ speciation within the Himalaya may be more common than previously recognized, challenging the notion that Himalayan fauna are predominantly considered "immigrant." This study enhances our understanding of Himalayan zoogeography and biodiversity through the resolved evolutionary history of a widely distributed species.

Tree species richness can alter forest structure and resource availability, often enhancing ecosystem functioning. However, biodiversity–ecosystem functioning research has largely focused on plant-mediated processes, leaving it unclear whether vertebrate-mediated functions such as carrion scavenging respond similarly to tree species richness. We investigated how tree species richness, canopy cover, and slope steepness influence vertebrate scavenging by quantifying the removal of 2,392 mouse carcasses across 96 plots between 2023 and 2025 in a subtropical forest biodiversity experiment in south-eastern China. Carcass removal was substantially higher in summer 2024 (25.1%) than in spring 2023 (10.5%) and autumn 2025 (10.9%). Across years, carcass removal increased significantly from 7.2% to 15.8% with tree species richness. More carcasses were removed in plots with lower canopy cover in one of the three years. Slope steepness had negligible effects on carcass removal. Overall, these findings underscore the role of forest structure and temporal variation, rather than topography, in shaping the vertebrate scavenging of small carcasses. They further demonstrate that the effects of biodiversity can extend to higher trophic functions not directly linked to primary productivity.

Global declines in insect pollinators have triggered the need for standardised, scalable methods to monitor pollinator populations. Automated photomonitoring and machine-learning-based identification are emerging as promising non-lethal approaches for large-scale insect observation, but their effectiveness requires reliable and consistent monitoring designs. Artificial flowers offer a solution to limitations associated with natural flowers, including variability in floral availability, lack of standardisation, and wind-induced noise in visual data, yet their performance under real field conditions remains largely untested.Here, we developed 3D-printed artificial flowers, using Malva multiflora (Malvaceae) as a model species, incorporating increasingly complex sensory cues and rewards. We evaluated their performance by comparing insect pollinator species richness and visitation rates in artificial and co-occurring natural flowers using visual observations across 16 field sites in Southern Spain. Although artificial flowers received four times fewer species and visits per flower than natural flowers, they nonetheless accounted for around 50% of all recorded species. Variation in sensory cues among artificial flower treatments had little influence on attractiveness. Importantly, pollinator richness and visitation rates on artificial and natural flowers were strongly positively correlated, indicating that artificial flowers can provide reliable relative indicators of pollinator diversity and activity. Smaller-bodied bee species and those with warmer climatic affinities were more likely to visit artificial flowers, suggesting trait-based differences in exploratory behaviour or floral discrimination.Our findings demonstrate the potential of 3D-printed artificial flowers, showing that, while not direct substitutes for natural flowers, they can function as effective, reproducible, and scalable tools for standardised pollinator monitoring.

Wild bees are widely distributed and effective pollinators, yet they face significant threats such as degradation of forests. Forest restoration has been advocated as a strategy to mitigate these threats and stabilize biodiversity. However, there is a lack of understanding of the ecological consequences of forest restoration on bee diversity, particularly regarding interactions with tree diversity and microenvironment. Using data from the world's largest tree diversity experiment (BEF-China), this study examines how tree species richness, canopy cover, understorey vegetation, and microclimatic conditions affect bee diversity in the context of forest restoration. Our analysis of bee diversity data (8341 individuals from 79 species) revealed that these biotic factors had distinct effects on three dimensions of bee diversity. Specifically, canopy cover had a negative effect on bee taxonomic diversity but a positive effect on phylogenetic and functional diversity. However, these patterns were reversed when the cover of understorey vegetation was accounted for. Moreover, tree species richness exerted an indirect influence on bee diversity through understorey microenvironment. Our findings provide nuance into how tree species richness shapes bee communities via vegetation cover and microclimate, which is informative on habitat characteristics in forest restoration and conservation that better enable the safeguarding of pollinators.

Ecological stability is essential for maintaining ecosystem functioning, but may be imperiled by biodiversity loss. Although the scaling of diversity-stability relationships from populations to communities and metacommunities has been studied within single trophic levels, it remains poorly understood when considering interactions between trophic levels. Here, we utilize data collected from a large-scale forest biodiversity experiment to investigate the scaling of temporal stability from populations, to communities, and meta-communities in a plant-herbivore system, allowing us to disentangle the relative role of top-down and bottom-up regulation. We observe that biodiversity has generally stabilizing effects within and between trophic levels. Specifically, species diversity of herbivores shows strong stabilizing top-down effects by enhancing species stability and asynchrony of plants that cascade to higher levels of organization. In contrast, bottom-up effects play a much smaller role. Our study therefore highlights the importance of top-down processes in safeguarding plant stability across levels of organization, while simultaneously providing a framework that allows the investigation of the multi-layered nature of stability mechanisms that needs to be considered for a successful and sustainable ecosystem management.

Biodiversity loss threatens the multifunctionality of ecosystems on which human well-being ultimately depends. Multitrophic species interactions may be key to explaining the ecological consequences of biodiversity loss, but research explicitly linking species interactions and ecosystem multifunctionality remains rare. To fill this gap, we synthesize data from a large-scale biodiversity experiment established in 2009 in subtropical China that manipulates tree species richness (1-24 species). We integrate 11 types of antagonistic and mutualistic species interaction networks, and 34 ecosystem functions associated with a diverse set of species and trophic levels. Our analysis highlights that characterizing the structure of species interaction networks is invaluable for assessing interaction-mediated biodiversity effects and underlying mechanisms. Positive effects of network size align with expected benefits of multitrophic diversity for ecosystem multifunctionality. Positive effects of niche overlap among interacting species and negative effects of highly connected species (i.e. high linkage density) reveal additional, interaction-mediated drivers. The effects of niche overlap suggest benefits of functionally similar species, and the effects of linkage density underscore the importance of specialized interactions in promoting ecosystem multifunctionality. These findings emphasize that ecosystem service provisioning does not only rely on biodiversity across trophic levels, but to a similar degree on how species interact.

Global biodiversity is declining, largely due to the conversion of natural habitats into agricultural land, settlements, and exotic tree plantations. This has left many natural habitats as small, geographically isolated fragments. The cloud forests of the Taita Hills in Kenya have undergone significant changes in recent decades, resulting in the fragmentation of indigenous forests into small remnants. Despite this, these remaining forest patches continue to support high levels of biodiversity. Butterflies, sensitive to habitat changes, serve as key ecosystem indicators. In this study, we investigated how butterfly composition, richness and abundance vary between forest edges and farmlands, across wet and dry seasons using transect counts and baited traps. We recorded 144 butterfly species from 62 genera across 5 families, totaling 17,438 individuals. Species richness, abundance and Shannon diversity were significantly higher at the forest edge than in farmlands. Non-metric multidimensional scaling analysis revealed distinct butterfly communities in the two habitats and seasons. Wet season had higher species richness than dry season, but no significant difference was found in butterfly abundance between seasons. Species richness and abundance did not significantly change with increase in distance from the forest edge. The forest edges support specialist species, including endemics, while farmlands host both savanna and forest specialists. Conservation efforts should focus on protecting remaining pristine forest fragments and creating diverse agricultural landscapes with hedges to aid butterfly conservation.

Two new species of Megaspilinae (Hymenoptera: Megaspilidae) are described and illustrated from China: Conostigmus concavulus Zhao & Wang, sp. nov., and Dendrocerus haizhuensis Zhao & Wang, sp. nov.. Additionally, a key to the Chinese Megaspilinae species is also provided.

Abstract Interactions between plants and pollinators are crucial for maintaining biodiversity and ecosystem stability. Bees, especially wild and solitary bees, play a vital role in this process. However, the mechanisms underlying the relationship between multiple components of plant diversity and cavity-nesting bee diversity remain unclear, particularly in understudied subtropical forests. This study investigated how plant phylogenetic diversity (PD), functional diversity (FD), and specific leaf morphological-chemical traits influenced solitary bee diversity in a large-scale biodiversity experiment in subtropical China. We sampled solitary bees using trap nests across a tree diversity gradient. Results showed that plant leaf area (LA) and leaf dry matter content (LDMC) positively influenced bee species richness, while plant PD and FD had no significant effects. Our findings highlight the importance of specific plant traits over broad diversity metrics in supporting bee diversity and abundance, suggesting that conservation efforts should prioritize functionally diverse plant assemblages rather than maximizing species counts.

Biodiversity-ecosystem functioning (BEF) research has shown that ecosystem functioning and stability are closely linked to biodiversity. A cornerstone of this field is the BEF-China research platform, i.e. the world’s largest forest biodiversity experiment in subtropical China. It has demonstrated that tree diversity enhances productivity, carbon sequestration and ecosystem stability. However, the strength of these positive tree diversity effects varies widely across forests, possibly because higher trophic levels (such as herbivores and predators) mediate how biodiversity influences ecosystem functioning.To better understand how tree diversity influences higher trophic levels and their contributions to forest functioning, the German Research Foundation (DFG) is funding the project MultiTroph. MultiTroph quantifies species interactions and integrates them into food webs to understand when and why ecosystem functions change or destabilise with species loss. We expect that trophic interaction networks reveal how species share or separate their ecological roles, with more niche overlap in species-rich forests and more niche specialisation in species-poor forests.Here, we outline our conceptual framework and research goals. We are convinced that MultiTroph will expand existing BEF research and provide a more holistic understanding of the role of multi-trophic food webs in forest ecosystems.

Predator-prey interactions are key to regulating lower trophic levels and stabilizing ecosystem processes. Therefore, understanding prey selection and prey composition of predators is essential, yet especially the small size and diverse diets of predatory arthropods present a significant challenge to conventional field methods. Here, we employed DNA metabarcoding on gut contents of over 1500 arboreal spiders in a subtropical forest in China to construct a high-resolution spider-prey interaction network. Subsequently, we compared prey diversity, composition, starvation rates, and network metrics (predator niche overlap, generality, and prey vulnerability) across different spider hunting guilds and families. Our results revealed an exceptionally broad diet for these spiders, with spiders themselves constituting a significant proportion of prey (i.e. spider on spider predation), besides a wide range of insects, particularly flies and moths. Although, prey composition was broadly similar at high taxonomic levels and functional groups, distinct dietary partitioning was evident at lower (MOTU) taxonomic level. Interaction networks revealed a broader and more generalized diet spectrum of active-hunters compared to web-builders, which resulted in higher diet overlap within the hunting guild (high prey vulnerability and niche overlap). However, network metrics for active hunters were lower than null expectations, suggesting a structuring role of intraspecific competition, while web-builders displayed greater random associations, possibly reflective of the passive mode of prey capture. Collectively, our study offers a high-resolution overview of the dietary niches of subtropical arboreal spiders, revealing how hunting mode shapes their ecological impact and providing significant implications for leveraging these predators in biological control strategies.

Positive effects of plant diversity on productivity increase over time through stronger complementarity among species 1 . However, whether these temporal dynamics propagate across trophic levels towards higher-order ecosystem functions remains largely unexplored. Here we tested how tree diversity drives attack rates and trophic interactions of host-parasitoid communities over the course of a decade in a young large-scale forest experiment. We found that the effect of tree species richness on parasitism increased over time, driven both by accelerating stand productivity and changes in food web structure. Parasitism increasingly reflected an attenuation of consumer responses to accumulating resources and a shift towards tree and parasitoid diversity-dependent regulation. The influence of parasitoid species richness on parasitism rose over time as generalist parasitoids concentrated interactions on shared hosts, increasing overall resource use and network robustness to species extinctions. Our results reveal that the functional benefits of biodiversity strengthen over time through shifts in the mechanisms linking trophic levels, underscoring the long-term value of diversity-focused restoration.

Abstract 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.