Two centuries of biodiversity discovery and loss in Singapore.

There is an urgent need for reliable data on the impacts of deforestation on tropical biodiversity. The city-state of Singapore has one of the most detailed biodiversity records in the tropics, dating back to the turn of the 19th century. In 1819, Singapore was almost entirely covered in primary forest, but this has since been largely cleared. We compiled more than 200 y of records for 10 major taxonomic groups in Singapore (>50,000 individual records; >3,000 species), and we estimated extinction rates using recently developed and novel statistical models that account for "dark extinctions," i.e., extinctions of undiscovered species. The estimated overall extinction rate was 37% (95% CI [31 to 42%]). Extrapolating our Singapore observations to a future business-as-usual deforestation scenario for Southeast Asia suggests that 18% (95% CI [16 to 22%]) of species will be lost regionally by 2100. Our extinction estimates for Singapore and Southeast Asia are a factor of two lower than previous estimates that also attempted to account for dark extinctions. However, we caution that particular groups such as large mammals, forest-dependent birds, orchids, and butterflies are disproportionately vulnerable.

The benefits of contributing to the citizen science platform iNaturalist as an identifier.

As the number of observations submitted to the citizen science platform iNaturalist continues to grow, it is increasingly important that these observations can be identified to the finest taxonomic level, maximizing their value for biodiversity research. Here, we explore the benefits of acting as an identifier on iNaturalist.

Bee communities along a prairie restoration chronosequence: similar abundance and diversity, distinct composition.

Recognition of the importance of bee conservation has grown in response to declines of managed honey bees and some wild bee species. Habitat loss has been implicated as a leading cause of declines, suggesting that ecological restoration is likely to play an increasing role in bee conservation efforts. In the midwestern United States, restoration of tallgrass prairie has traditionally targeted plant community objectives without explicit consideration for bees. However, restoration of prairie vegetation is likely to provide ancillary benefits to bees through increased foraging and nesting resources. We investigated community assembly of bees across a chronosequence of restored eastern tallgrass prairies and compared patterns to those in control and reference habitats (old fields and prairie remnants, respectively). We collected bees for 3 yr and measured diversity and abundance of in-bloom flowering plants, vegetation structure, ground cover, and surrounding land use as predictors of bee abundance and bee taxonomic and functional diversity. We found that site-level variables, but not site type or restoration age, were significant predictors of bee abundance (bloom diversity, P = 0.004; bare ground cover, P = 0.02) and bee diversity (bloom diversity, P = 0.01). There were significant correlations between overall composition of bee and blooming plant communities (Mantel test, P = 0.002), and both plant and bee assemblages in restorations were intermediate between those of old fields and remnant prairies. Restorations exhibited high bee beta diversity, i.e., restored sites' bee assemblages were taxonomically and functionally differentiated from each other. This pattern was strong in younger restorations (<20 yr old), but absent from older restorations (>20 yr), suggesting restored prairie bee communities become more similar to one another and more similar to remnant prairie bee communities over time with the arrival of more species and functional groups of bees. Our results indicate that old fields, restorations, and remnants provide habitat for diverse and abundant bee communities, but continued restoration of old fields will help support and conserve bee communities more similar to reference bee communities characteristic of remnant prairies.

The city as a refuge for insect pollinators.

Research on urban insect pollinators is changing views on the biological value and ecological importance of cities. The abundance and diversity of native bee species in urban landscapes that are absent in nearby rural lands evidence the biological value and ecological importance of cities and have implications for biodiversity conservation. Lagging behind this revised image of the city are urban conservation programs that historically have invested in education and outreach rather than programs designed to achieve high-priority species conservation results. We synthesized research on urban bee species diversity and abundance to determine how urban conservation could be repositioned to better align with new views on the ecological importance of urban landscapes. Due to insect pollinators' relatively small functional requirements-habitat range, life cycle, and nesting behavior-relative to larger mammals, we argue that pollinators put high-priority and high-impact urban conservation within reach. In a rapidly urbanizing world, transforming how environmental managers view the city can improve citizen engagement and contribute to the development of more sustainable urbanization.

Measuring partner choice in plant-pollinator networks: using null models to separate rewiring and fidelity from chance.

Recent studies of mutualistic networks show that interactions between partners change across years. Both biological mechanisms and chance could drive these patterns, but the relative importance of these factors has not been separated. We established a field experiment consisting of 102 monospecific plots of 17 native plant species, from which we collected 6713 specimens of 52 bee species over four years. We used these data and a null model to determine whether bee species' foraging choices varied more or less over time beyond the variation expected by chance. Thus we provide the first quantitative definition of rewiring and fidelity as these terms are used in the literature on interaction networks. All 52 bee species varied in plant partner choice across years, but for 27 species this variation was indistinguishable from random partner choice. Another 11 species showed rewiring, varying more across years than expected by chance, while 14 species showed fidelity, indicating that they both prefer certain plant species and are consistent in those preferences across years. Our study shows that rewiring and fidelity both exist in mutualist networks, but that once sampling effects have been accounted for, they are less common than has been reported in the ecological literature.

Historical changes in northeastern US bee pollinators related to shared ecological traits.

Pollinators such as bees are essential to the functioning of terrestrial ecosystems. However, despite concerns about a global pollinator crisis, long-term data on the status of bee species are limited. We present a long-term study of relative rates of change for an entire regional bee fauna in the northeastern United States, based on >30,000 museum records representing 438 species. Over a 140-y period, aggregate native species richness weakly decreased, but richness declines were significant only for the genus Bombus. Of 187 native species analyzed individually, only three declined steeply, all of these in the genus Bombus. However, there were large shifts in community composition, as indicated by 56% of species showing significant changes in relative abundance over time. Traits associated with a declining relative abundance include small dietary and phenological breadth and large body size. In addition, species with lower latitudinal range boundaries are increasing in relative abundance, a finding that may represent a response to climate change. We show that despite marked increases in human population density and large changes in anthropogenic land use, aggregate native species richness declines were modest outside of the genus Bombus. At the same time, we find that certain ecological traits are associated with declines in relative abundance. These results should help target conservation efforts focused on maintaining native bee abundance and diversity and therefore the important ecosystems services that they provide.

Climate-associated phenological advances in bee pollinators and bee-pollinated plants.

The phenology of many ecological processes is modulated by temperature, making them potentially sensitive to climate change. Mutualistic interactions may be especially vulnerable because of the potential for phenological mismatching if the species involved do not respond similarly to changes in temperature. Here we present an analysis of climate-associated shifts in the phenology of wild bees, the most important pollinators worldwide, and compare these shifts to published studies of bee-pollinated plants over the same time period. We report that over the past 130 y, the phenology of 10 bee species from northeastern North America has advanced by a mean of 10.4 ± 1.3 d. Most of this advance has taken place since 1970, paralleling global temperature increases. When the best available data are used to estimate analogous rates of advance for plants, these rates are not distinguishable from those of bees, suggesting that bee emergence is keeping pace with shifts in host-plant flowering, at least among the generalist species that we investigated.

Global patterns and drivers of buzzing bees and poricidal plants.

Foraging behavior frequently plays a major role in driving the geographic distribution of animals. Buzzing to extract protein-rich pollen from flowers is a key foraging behavior used by bee species across at least 83 genera (these genera comprise ∼58% of all bee species). Although buzzing is widely recognized to affect the ecology and evolution of bees and flowering plants (e.g., buzz-pollinated flowers), global patterns and drivers of buzzing bee biogeography remain unexplored. Here, we investigate the global species distribution patterns within each bee family and how patterns and drivers differ with respect to buzzing bee species. We found that both distributional patterns and drivers of richness typically differed for buzzing species compared with hotspots for all bee species and when grouped by family. A major predictor of the distribution, but not species richness overall for buzzing members of four of the five major bee families included in analyses (Andrenidae, Halictidae, Colletidae, and to a lesser extent, Apidae), was the richness of poricidal flowering plant species, which depend on buzzing bees for pollination. Because poricidal plant richness was highest in areas with low wind and high aridity, we discuss how global hotspots of buzzing bee biodiversity are likely influenced by both biogeographic factors and plant host availability. Although we explored global patterns with state-level data, higher-resolution work is needed to explore local-level drivers of patterns. From a global perspective, buzz-pollinated plants clearly play a greater role in the ecology and evolution of buzzing bees than previously predicted.

A review of the anthidiine bees (Apoidea, Megachilidae) in Thailand.

Bees of the tribe Anthidiini (Apoidea: Megachilidae) are notable pollinators consisting of resin bees, wool-carder bees, and cleptoparasitic bees. Twelve anthidiine species were historically reported in Thailand, though the taxonomic information of the group was needed revising. In this study, 165 (97♀, 68♂) anthidiine bee specimens deposited at the Chulalongkorn University Natural History Museum, Thailand, were examined with material obtained from various museum collections. Specimens were principally collected in Thailand with some from Laos and Myanmar. Here, at least eight genera and 15 species of anthidiine bees are recognized: Anthidiellum (5), Bathanthidium (1), Eoanthidium (1), Euaspis (4), Pachyanthidium (1), Pseudoanthidium (1), Stelis (1), and Trachusa (1). Dianthidiumchinensis Wu, 1962, Eoanthidiumchinensis (Wu, 1962), Eoanthidiumsemicarinatum Pasteels, 1972, and Eoanthidiumpunjabensis Gupta & Sharma, 1953 are relegated as junior synonyms of Eoanthidium (Hemidiellum) riparium (Cockerell, 1929), stat. nov. Both Anthidiellum (Pycnanthidium) latipes (Bingham, 1897) from Phang Nga and Euaspisaff.wegneri Baker, 1995 from Chumphon were identified as new records for Thailand. Trachusaaff.vietnamensis Flaminio & Quaranta, 2021 from Phitsanulok is a new record for the genus found in Thailand, whereas Pseudoanthidium (Pseudoanthidium) orientale (Bingham, 1897) is a new record for Laos. Annotated comments are provided for some taxa and identification keys for the Thai anthidiine bees is provided.

A checklist of the bees (Hymenoptera: Apoidea) of Minnesota.

Research studies and conservation actions aimed at improving conditions for bees require a basic understanding of which species are present in a given region. The US state of Minnesota occupies a unique geographic position at the confluence of eastern deciduous forests, northern boreal forests, and western tallgrass prairie, which has led to a diverse and unique bee fauna. In recent years there have been multiple ongoing bee-focused inventory and research projects in Minnesota. Combined with the historic specimens housed in the University of Minnesota Insect Collection and other regional collections, these furnished a wealth of specimens available to form the basis of a statewide checklist. Here, we present the first comprehensive checklist of Minnesota bee species, documenting a total of 508 species in 45 genera. County-level occurrence data is included for each species, and further information on distribution and rarity is included for species of regional or national interest. Some species have their taxonomy clarified, with Perdita citrinella Graenicher, 1910 syn. nov. recognized as a junior synonym of Perdita perpallida Cockerell, 1901, P. bequaerti syn. nov. recognized as a junior synonym of P. pallidipennis Graenicher, 1910 stat. nov., Anthidiellum boreale (Robertson, 1902) stat. nov. recognized as a full species, and Anthidiellium beijingense Portman & Ascher nom. nov. is proposed for A. boreale Wu to resolve the homonymy with A. boreale (Robertson). We further include a list of species that may occur in Minnesota and highlight 11 species occurring in the state that are considered non-native. Recent collecting efforts, as well as increased taxonomic attention paid to Minnesota bees, have resulted in 66 species that have only been documented in the last 10 years. As a first step in determining native bees of conservation concern, we document 38 species that have not been detected in the state during the last 50 years and discuss their conservation status, along with other species for which evidence of decline exists. The checklist of Minnesota bees will continue to grow and change with additional surveys and research studies. In particular, recent surveys have continued to detect new bee species, and many bee groups are in need of taxonomic revision, with the most recent revisions for many genera occurring decades ago. Overall, this checklist strengthens our understanding of the bees of Minnesota and the broader region, informs conservation assessments, and establishes a baseline for faunal change.

A globally synthesised and flagged bee occurrence dataset and cleaning workflow.

Species occurrence data are foundational for research, conservation, and science communication, but the limited availability and accessibility of reliable data represents a major obstacle, particularly for insects, which face mounting pressures. We present BeeBDC, a new R package, and a global bee occurrence dataset to address this issue. We combined >18.3 million bee occurrence records from multiple public repositories (GBIF, SCAN, iDigBio, USGS, ALA) and smaller datasets, then standardised, flagged, deduplicated, and cleaned the data using the reproducible BeeBDC R-workflow. Specifically, we harmonised species names (following established global taxonomy), country names, and collection dates and, we added record-level flags for a series of potential quality issues. These data are provided in two formats, "cleaned" and "flagged-but-uncleaned". The BeeBDC package with online documentation provides end users the ability to modify filtering parameters to address their research questions. By publishing reproducible R workflows and globally cleaned datasets, we can increase the accessibility and reliability of downstream analyses. This workflow can be implemented for other taxa to support research and conservation.

Joint Impacts of Drought and Habitat Fragmentation on Native Bee Assemblages in a California Biodiversity Hotspot.

Global climate change is causing more frequent and severe droughts, which could have serious repercussions for the maintenance of biodiversity. Here, we compare native bee assemblages collected via bowl traps before and after a severe drought event in 2014 in San Diego, California, and examine the relative magnitude of impacts from drought in fragmented habitat patches versus unfragmented natural reserves. Bee richness and diversity were higher in assemblages surveyed before the drought compared to those surveyed after the drought. However, bees belonging to the Lasioglossum subgenus Dialictus increased in abundance after the drought, driving increased representation by small-bodied, primitively eusocial, and generalist bees in post-drought assemblages. Conversely, among non-Dialictus bees, post-drought years were associated with decreased abundance and reduced representation by eusocial species. Drought effects were consistently greater in reserves, which supported more bee species, than in fragments, suggesting that fragmentation either had redundant impacts with drought, or ameliorated effects of drought by enhancing bees' access to floral resources in irrigated urban environments. Shifts in assemblage composition associated with drought were three times greater compared to those associated with habitat fragmentation, highlighting the importance of understanding the impacts of large-scale climatic events relative to those associated with land use change.

The resin bee subgenus Ranthidiellum in Thailand (Megachilidae, Anthidiini): nesting biology, cleptoparasitism by Stelis, and new species.

Resin bees of the subgenus Ranthidiellum, are rare and endemic to Southeast Asia. These bees are known to construct resinous entrance tubes to their nests. Here, the new species Anthidiellum (R.) phuchongensissp. nov. is described along with a description of its nest collected from Phu Chong Na Yoy National Park, Ubon Ratchathani Province, Thailand. In addition, the bee cleptoparasite, Stelis (Malanthidium) flavofuscinularsp. nov., and the male of A. (R.) ignotum Engel, 2009, are described for the first time. A key to Ranthidiellum species is also provided.

Global Patterns and Drivers of Bee Distribution.

Insects are the focus of many recent studies suggesting population declines, but even invaluable pollination service providers such as bees lack a modern distributional synthesis. Here, we combine a uniquely comprehensive checklist of bee species distributions and >5,800,000 public bee occurrence records to describe global patterns of bee biodiversity. Publicly accessible records are sparse, especially from developing countries, and are frequently inaccurate throughout much of the world, consequently suggesting different biodiversity patterns from checklist data. Global analyses reveal hotspots of species richness, together generating a rare bimodal latitudinal richness gradient, and further analyses suggest that xeric areas, solar radiation, and non-forest plant productivity are among the most important global drivers of bee biodiversity. Together, our results provide a new baseline and best practices for studies on bees and other understudied invertebrates.

Resin bees of genus Megachile, subgenera Callomegachile and Carinula (Hymenoptera, Megachilidae) from Thailand with description of a new species.

Resin bees of the genus Megachile subgenus Callomegachile sensu lato (Hymenoptera; Megachilidae) from Thailand are reviewed. The 14 species treated include those described or revised in the subgenus Alocanthedon, a junior synonym of Callomegachile (three species), and in Carinula (one species). One new species is described, Megachile chiangmaiensis Chatthanabun and Warrit, sp. nov. The replacement name Megachile parornata Chatthanabun, Warrit and Ascher, nom. nov., is proposed for M. gigas Wu (not Schrottky), which is recorded for the first time outside China. For each species, maps and full label data for the examined material documenting occurrences in Thailand are provided. In addition, global ranges, floral associations, and other life history data are summarized and a key to the Thai species is provided for females.

Chinese species of Nomia (Gnathonomia) Pauly, 2005 (Hymenoptera: Apoidea: Halictidae: Nomiinae).

Five Chinese species of Nomia (Gnathonomia) Pauly, 2005 are treated in this paper: Nomia fusciventris Zhang Niu, sp. nov. from Fujian Province is described as a new species; N. aurata Bingham, 1897 and N. wahisi Pauly, 2009 are recorded from China for the first time, and the male of N. pieli Cockerell, 1931 is newly reported. An updated diagnosis is provided for the subgenus Nomia (Gnathonomia) to accommodate Chinese endemic species which lack the white integumental bands found in most previously described forms. A key to the known Chinese species is provided.

Bees of the genus Anthidium Fabricius, 1804 (Hymenoptera: Apoidea: Megachilidae: Anthidiini) from China.

The Chinese bees of the genus Anthidium Fabricius, 1804, are reviewed. Twenty-one species are confirmed to occur in China, five of which are described and illustrated as new Chinese endemics: Anthidium (Anthidium) pseudomontanum Niu Zhu, sp. nov., A. (A.) pseudophilorum Niu Zhu, sp. nov., A. (A.) tasitiense Niu Zhu, sp. nov., A. (A.) xuezhongi Niu Zhu, sp. nov., and A. (Proanthidium) qingtaoi Niu Zhu, sp. nov.. The previously unknown female of A. (A.) kashmirense Mavromoustakis, 1937 and male of A. (P.) kashgarense (Cockerell, 1911) are described for the first time. Anthidium (A.) furcatum Wu, 2004 (junior primary homonym, nec Anthidium furcatum Ducke, 1908) is replaced with its valid and available synonym A. (A.) striatum Wu, 2004. New synonymies are also established for A. (A.) kashmirense Mavromoustakis, 1937 = A. (A.) nigroventrale Wu, 1982, syn. nov., and A. (A.) florentinum (Fabricius, 1775) = A. (A.) helianthinum Wu, 2004, syn. nov. The non-Chinese Anthidium amabile Alfken, 1933 (junior primary homonym, nec Anthidium porterae var. amabile Cockerell, 1904) is unavailable and the available name Anthidium (Proanthidium) minimum Pasteels, 1969, is valid for this species. Updated synonymies and distributional data are provided for some widespread Palaearctic species including two now adventive in the New World. For Chinese species, the distribution and floral associations of each are provided along with illustrations and a key to the known species.

The wild bees (Hymenoptera, Apoidea) of the island of Cyprus.

Cyprus, the third largest island in the Mediterranean, constitutes a biodiversity hotspot with high rates of plant endemism. The wild bees of the island were studied extensively by the native George Mavromoustakis, a world-renowned bee taxonomist, who collected extensively on the island from 1916 to 1957 and summarised his results in a series of eight Cyprus-specific papers published from 1949 ["1948"] to 1957. The current work represents the first modern checklist of the wild bees of Cyprus, based on a compilation of previous publications, museum specimens and authors' recent collections. Overall, 369 verified wild bee species have been recorded on the island, with eleven species reported from Cyprus for the first time. The island hosts all six of the globally widespread bee families, with Apidae represented by 110 species, Megachilidae with 91, Andrenidae with 76, Halictidae with 72, Colletidae with 19, and Melittidae with 1. Twenty-one of the recorded bee species are endemic (i.e., 5.7 % endemism rate) and Cyprus ranks third after Lesvos and Sicily in known bee species richness among the Mediterranean islands. Previously unpublished records from various locations on Cyprus for 156 previously reported bee species are also provided in the study. The current work provides a baseline for future studies of wild bee diversity on the island of Cyprus and neighbouring regions.

The wild bees (Hymenoptera: Apoidea) of Morocco.

Morocco is a well known hot-spot of biodiversity in the Mediterranean basin. While some taxa like vascular plants are relatively well recorded, important groups of pollinators like bees are still understudied. This article presents an updated checklist of the bee species of Morocco and includes a summary of global and regional distribution of each species. A total of 961 species belonging to six bee families and 68 genera are recorded: Andrenidae (8 genera, 217 species); Apidae (15 genera, 241 species); Colletidae (2 genera, 74 species), Halictidae (12 genera, 144 species), Megachilidae (28 genera, 271 species) and Melittidae (3 genera, 14 species). Among them, 67 species are recorded for the first time in Morocco. Around 70% of the bee fauna of Morocco consists of widespread Palaearctic species. Only 18% of Moroccan species recorded are restricted to North Africa and 8% are Moroccan single-country endemics (81 species). Afrotropical elements in the Moroccan fauna are few, with only 3% of Morocco species co-occuring in that region. This checklist is intended to stimulate new regional research on bees including their taxonomy and biogeography. As many groups of bees have been understudied, discovery of new species for science and new records for the country can be expected. Additional research including inventorying, monitoring, and integrative taxonomic studies are needed to develop a comprehensive strategy for bee conservation in Morocco.