Michael C. Orr

The theory of island biogeography (TIB) explains species richness patterns, yet its extension to compositional dissimilarity (β diversity), particularly from multidimensional perspectives, remains limited. Using butterfly assemblages across 44 land‐bridge islands in the Zhoushan Archipelago, China, we applied an integrative framework to unravel how island geography and species traits shape multi‐faceted β diversity. We partitioned taxonomic, phylogenetic, and functional β diversity into turnover and nestedness components, quantified species and site contributions, and distinguished roles of widespread versus restricted species. Key findings reveal: 1) dimensionality‐specific geographic drivers: inter‐island isolation differences primarily influenced nestedness in taxonomic and phylogenetic dimensions, suggesting its role as a filter for ordered species loss. In contrast, island area differences consistently affected both turnover and nestedness across all dimensions, underscoring its role as a master filter of resources and habitat. Island geographic attributes (e.g. isolation) only explained local community uniqueness in the taxonomic dimension. 2) A trait‐mediated mechanism: species with weaker dispersal capacity (smaller thorax area) contributed more to β diversity (higher species contribution), providing direct trait‐based evidence for dispersal limitation. 3) Internal metacommunity structure: nestedness was predominantly structured by widespread species, whereas turnover was driven mainly by the idiosyncratic distributions of restricted species. Our study demonstrates that island community assembly emerges from deterministic filtering (area and isolation shaping the widespread species backbone) interacting with stochastic processes (governing restricted species). This integrates TIB with β diversity by showing that TIB's core predictors (area and isolation) differentially shape the components of β diversity and offers a multidimensional, mechanistic framework for island conservation that emphasizes protecting island networks, source islands, and unique species and habitats.

Tropical Asia hosts an exceptionally diverse and unique biota, but comprehensive estimates of species diversity and endemism are unavailable for its many subregions, and gaps in biodiversity knowledge and conservation assessments remain unexplored. Here, we synthesize biodiversity data from tropical Asia to assess patterns of species richness, endemism, data completeness, species discovery, and extinction risk across major plant and animal groups. We show that the Asian tropics harbour nearly one quarter of the known global diversity among taxa examined on average while being much smaller in extent than other tropical realms, probably due to its insular and archipelagic geography. Rates of species discovery remain high for many terrestrial and freshwater groups especially in Indochina, South Asia and Borneo, indicating substantial undocumented diversity. Considerable spatiotemporal shortfalls in species occurrence data exist, particularly across Indonesia. Among assessed species, about one-third of vascular plants, one fifth of the land and freshwater vertebrate fauna, one-third of reef-building corals, and almost half of the region’s shark and ray species are threatened with extinction. However, conservation assessments are lacking for many invertebrate species, and almost one-sixth of assessments are over a decade old and thus may not be keeping pace with intensifying human pressures across the region. Our analysis highlights the critical need for increased investment and effort to better document, monitor, study, and safeguard tropical Asia’s rich natural heritage.

Andrena melaleuca Pérez is reported for the first time from Italy (Sicily), representing the first record of this species in Europe. We discuss its known distribution and potential route of entry and designate a lectotype. The Andrena Fabricius of Sicily are discussed as a melting pot of North African and south-eastern European faunal elements.

Aim: Stingless bees are the most species‐rich group of eusocial bees, predominantly found in tropical and subtropical regions of the world. However, despite their diversity and importance, significant gaps remain in our understanding of their distribution patterns and the factors driving them, as these aspects have yet to be thoroughly investigated on a global scale. In this study, we aimed to fill this gap by mapping global habitat suitability for stingless bees. Location: Global. Taxon: Stingless bees (Apidae:Apinae:Meliponini). Method: We compiled over half a million spatiotemporal occurrence records from 361 species of stingless bees at an unprecedented scale from both public and private databases optimised using a recently published data‐cleaning workflow. Through a species distribution model approach, we assessed the relationship between stingless bee distribution, diversity, and environmental factors, ultimately characterising their ecological niche and producing the first habitat suitability maps for the bee tribe Meliponini. Results: Our results reveal significant discrepancies in occurrence records across the Neotropical, the Afrotropical, and the Indo‐Malayan, Papuasian, and Australian regions, as well as among taxa. Habitat suitability hotspots were identified in tropical forests and were associated with relatively high temperatures and humidity throughout the year. Projection maps further suggested that some temperate, xeric, and savannah regions could also be suitable habitats for stingless bees. Our results rescale the known environmental niche of stingless bees, demonstrating that suitable habitats exist well beyond the tropical and subtropical boundaries typically described in the literature. Main Conclusion: This study presents a novel, model‐based assessment of stingless bee distribution, revealing that it extends beyond tropical forests into drier, colder, and temperate regions more broadly than previously recognised. These findings highlight substantial gaps in ecological and distributional data, emphasising the need for taxonomic revision, targeted fieldwork, digitisation of collections, and foundational research on stingless bee ecology and evolution. Addressing these gaps will improve predictions of species responses to environmental change, inform conservation strategies, and advance understanding of stingless bees as essential providers of ecosystem services.

Aim: Species occurrence data provides the basis for any analysis of species distributions, biodiversity patterns and change, and progress towards biodiversity targets. Yet whilst data has grown exponentially over the last decade, there have been no assessments of how representative this growth is, spatially or taxonomically. We provide the first global comparison of all major distribution databases, systematically analyze how biases vary spatially and taxonomically, assess the taxonomic completeness for different regions, and explore where we are and are not seeing representative growth.,Location: Global,Time Period: 2007-2025,Major Taxa Studied: All taxa,Methods: We collated data from all major species distribution and monitoring databases including GBIF, OBIS, BIEN, BioTime, Predicts and the Living Planet. We assessed spatial and taxonomic coverage within each dataset, as well as how data coverage and representativeness has changed over time.,Results: Despite increasing data volumes, most of the world's most biodiverse regions still lack data. Overall, whilst countries such as Japan and South Korea have seen expansions of spatial data coverage by over 60% over the last decade, major parts of the world including North Africa, Central Asia, and the High-Seas have not witnessed comparable growth. Furthermore, growth in these regions is not sufficiently representative, and in some cases is driven by single research projects on a single taxon. Where representative growth has been witnessed it is underpinned by government efforts, whereas growth in many other areas comes from citizen science data.,Main Conclusions: Different databases display different biases, often reflecting different strategies and priorities in data mobilization. Whilst citizen science has increased spatial coverage, this data is dominated by birds, from accessible regions in high-income economies. Overcoming these biases requires efforts to mobilise, consolidate, and standardise existing data, including published data, and museum and government records, emulating the strategies of countries which successfully remedied previous data coverage challenges.

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.

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.

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.

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.

Evolutionary trees are of central importance in biology to develop explanatory frameworks for many kinds of studies, including studies of behaviour, ecology, and conservation. Since the last major estimate of evolutionary relationships among many bumblebee species two decades ago, there have been revisions to their taxonomy, descriptions of new species, and sequencing of many rarer species. By combining: (1) earlier data mostly from slow-evolving nuclear genes as a backbone tree; with (2) new data from fast-evolving mitochondrial COI barcodes to resolve more of the twigs on the tree, including sequences obtained from rare old specimens with ancient DNA techniques; as well as (3) the results from broader genomic data for resolving deep relationships, we make a Bayesian estimate of evolutionary relationships with BEAST 2 among all 289 published and accepted extant bumblebee species, an increase of more than 29% of the species on the previous largest tree. The new tree will serve as a framework for future comparative studies that should enable broader insights into the evolution and ecology of all bumblebees. We illustrate this with an analysis of the evolution of some male morphological characters related to male mate-searching behaviour. We also present a novel map of spatial variation in net diversification rates among bumblebee species world-wide, which indicates an especially rapid net diversification within the more recent Mesoamerican and South American faunas.