John S. Ascher

John S. Ascher
National University of Singapore | NUS · Department of Biological Sciences

PhD

About

151
Publications
122,196
Reads
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5,780
Citations
Introduction
John S. Ascher currently works at the Department of Biological Sciences, National University of Singapore and is a Research Associate of the Lee Kong Chian Natural History Museum and of the American Museum of Natural History. John does research on insect diversity including Systematics (Taxonomy), Urban Ecology, and Conservation. He specializes in Hymenoptera, especially bees and related wasps in superfamily Apoidea. Current projects include the Singapore-NRF/China NSF-funded "Integrative Systematics on Apoidea in China and adjacent countries in Southeast Asia" and also detailed systematic and ecological studies of the bees of Singapore. He continues to update his online compilations on global bee diversity and to mobilize specimen records for ecological and conservation publications.
Additional affiliations
June 2013 - present
National University of Singapore
Position
  • Professor (Assistant)
September 2003 - June 2013
American Museum of Natural History
Position
  • Research Associate
Description
  • I continue to remotely supervise the AMNH Bee Database Project
Education
September 1996 - January 2004
Cornell University
Field of study
  • Entomology
September 1989 - May 1994
Wesleyan University
Field of study
  • Biology

Publications

Publications (151)
Article
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Climate change (CC) is expected to negatively impact global biodiversity and ecosystems, resulting in profound ecological impacts and placing complex networks of biological interactions at risk. Despite this worrying scenario, the existing knowledge deficiencies may be overcome with species distribution models (SDMs), providing estimates of the eff...
Article
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Article URL: https://lkcnhm.nus.edu.sg/wp-content/uploads/sites/10/2022/01/RBZ-2022-0004.pdf Reports of global bee declines have raised an urgent call for assessments of the conservation status of these key pollinators. The first published checklist and conservation status assessment for the bee fauna of a Southeast Asian country is presented here...
Article
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Nectar is one of the most important resources used by bees. It has long been known that some bees concentrate nectar externally with their mouthparts, including honey bees and stingless bees. However, observations of this behavior in disparate bee groups suggest this behavior is widespread. Here, we combine accounts and images from publications, co...
Article
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1. Increasing crop configurational heterogeneity – smaller crop fields with more field margins – has been repeatedly found to support farmland biodiversity. But research on compositional crop heterogeneity – the number and evenness of crop types – has usually shown only weak effects. However, much of this research has been conducted in large‐scale...
Article
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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.) phuchongensis sp. nov. is described along with a description of its nest collected from Phu Chong Na Yoy National Park, Ubon Ratchathani Province, Thailan...
Article
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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 fragm...
Article
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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...
Article
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Citation: Chatthanabun N, Ascher JS, Pinkaew N, Thanoosing C, Traiyasut P, Warrit N (2020) Resin bees of genus Megachile, subgenera Callomegachile and Carinula (Hymenoptera, Megachilidae) from Thailand with description of a new species. ZooKeys 997: 95-144. https://doi. Abstract Resin bees of the genus Megachile subgenus Callomegachile sensu lato (...
Article
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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 biodivers...
Book
Our City in Nature would not be complete without the array of beautiful bee species that serve as some of our most important pollinators. A collaboration between the National Parks Board and the University of Singapore, this guide reveals the remarkable diversity of bees found in various habitats across Singapore, from tiny honey-producing stingles...
Article
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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.) xuezhong...
Article
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The Wallacean shortfall—lack of adequate knowledge of a species’ distribution in the geographic space—hinders practical actions towards species conservation, and such severe data deficit is ubiquitous when dealing with insect species. Considering the effects of human activities on Earth, especially in the last 50 years, proper delimitation of speci...
Article
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Our objective was to examine how bee foraging preferences on dioecious willows are influenced by plant sex, time of day, by sampling date on multiple sites and across different willow species. In a common garden experiment examining diurnal pollinator visitation patterns of Andrena bees (andrenids), there was a strong preference for male willow pla...
Article
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In their article entitled “Climate change contributes to widespread declines among bumblebees across continents” recently published in Science and reported upon worldwide, Soroye, Newbold & Kerr (1) used extensive specimen records to explore patterns of geographic range loss and expansion of bumble bees in Europe and North America, and, in line wit...
Article
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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...
Article
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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 ei...
Article
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The science of taxonomy faces many challenges at present. Many questions remain as to how we can best continue the vital practice of describing and understanding biodiversity. Here, we discuss how best to modernize taxonomy, how we might improve taxonomy in developing countries, and how taxonomists can better interface with other fields to better s...
Article
Species invasions are expected to increase continuously with undeniable impact upon native biodiversity, being an important process in relation to the decline of native pollinators. We used species distribution models and multivariate analyses to assess the climatic niche properties of the red dwarf honey bee, Apis florea Fabricius (Apidae: Apini),...
Article
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A preliminary study of leaves cut by Megachile leafcutter bees were documented in Singapore through photographic surveys from March to August 2014 (86 observations), pressed leaves from 2016 to 2019 (51 observations), and crowd-sourced photographs from 2017 to 2019 (24 observations). Of the 161 plant observations, 130 were identified to species (64...
Article
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This revision of the bee genus Bathanthidium Mavromoustakis, 1953, treats 12 species, with 11 recorded from China, including Bathanthidium fengkaiense Niu & Zhu, sp. nov.. Two species are proposed as new combinations in genus Bathanthidium: Anthidium (s. str.) bicolor Wu, 2004, A. (s. str.) monganshanensis Wu, 2004. The two new combinations (B. bic...
Article
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The Chinese bees of the genus Trachusa Panzer, 1804 are reviewed. Nine species are confirmed to occur in China. Three new species are described and illustrated: Trachusa (Paraanthidium) pingdaensis Niu, sp. nov., T. (P.) staabi Niu, sp. nov. and T. (P.) wuae Niu, sp. nov. The distribution of each species is given. An illustrated key to the Chinese...
Article
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Southeast (SE) Asia holds high regional biodiversity and endemism levels but is also one of the world's most threatened regions. Local, regional and global threats could have severe consequences for the future survival of many species and the provision of ecosystem services. In the face of myriad pressing environmental problems, we carried out a r...
Article
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As a unique coastal hill dipterocarp forest remnant in Singapore, Bukit Timah Nature Reserve is a key refuge for flowering plants, but little information has been available about its bee pollinators and their floral associations. Historical and recent surveys of bees (Hymenoptera: Apoidea: Anthophila) at Bukit Timah and vicinity were compiled, yiel...
Article
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Traditional conservation techniques for mapping highly biodiverse areas assume there to be satisfactory knowledge about the geographic distribution of biodiversity. There are, however, large gaps in biological sampling and hence knowledge shortfalls. This problem is even more pronounced in the tropics. Indeed, the use of only a few taxonomic groups...
Article
Predicting the long‐term consequences of habitat alteration for the preservation of biodiversity and ecosystem function requires an understanding of how ecological filters drive taxonomic and functional biodiversity loss. Here, we test a set of predictions concerning the role of ecological filters in restructuring native bee assemblages inhabiting...
Article
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[This corrects the article DOI: 10.1371/journal.pone.0151482.].
Chapter
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Presenta información sobre el conocimiento actual de la fauna de abejas de Mesoamérica, analizando las areas de las que se tiene mas información y que sitios requieren ser mejor estudiados.
Article
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A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
Article
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Taxonomy is a scientific discipline that has provided the universal naming and classification system of biodiversity for centuries and continues effectively to accommodate new knowledge. A recent publication by Garnett and Christidis [1] expressed concerns regarding the difficulty that taxonomic changes represent for conservation efforts and propos...
Technical Report
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Megachile laticeps cutting leaf of Dendrolobium umbellatum
Article
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Reports of world-wide decline of pollinators, and of bees in particular, raise increasing concerns about maintenance of pollination interactions. While local factors of bee decline are relatively well known and potential mitigation strategies at the landscape scale have been outlined, the regional and continental-scale threats to bee diversity have...
Technical Report
Findings 1. Blue vane traps, colored bowl/cup traps and hand-netting along transects are adept at capturing thousands of bee pollinators to biomonitor sensitive ecological responses to perturbation to the insect community. 2. These trapping methods can be integrated and incorporated by solar energy personnel and ecologists into a functioning USSE f...
Article
Large aggregations of solitary bees have been reported from natural and managed landscapes where abundant nesting habitat and floral resources co-occur. Here we describe an unusually large aggregation of the bee Anthophora (Melea) bomboides Kirby, 1838 (Hymenoptera: Apidae) nesting in a coastal bluff in San Juan County, Washington State. Nest densi...
Article
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We present a new county checklist developed from bee research in Maine since the 1800s. The list contains 278 bee species in 37 genera and 6 families, of which all but 8 are native, with ≥50 taxa each in Andrena and Lasioglossum. Data for 16 counties from publications, museum collections, and recent surveys varied in number of species from 8 (Andro...
Article
More than 120 native bee species have been documented in Maine since 1930 in association with the native plant Vaccinium angustifolium (Lowbush Blueberry). We report 3 studies in commercial Lowbush Blueberry fields: (1) a survey of diversity in Osmia (mason bees) and closely related Megachile (leaf-cutter bees) using trap nests in 93 fields from 19...
Article
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A new species of the panurgine bee genus Mermiglossa Friese (Panurginae) is described and figured from females captured near Voi in the southern part of the former Coast Province, Kenya, a historical type locality for several bee species. Mermiglossa voicola Ascher & Engel, new species, is distinguished from the only other species of the genus, M....
Article
The state of Michigan occupies an area between the Great Plains and the northeastern United States, bordering four Great Lakes, with diverse biogeographical regions. Michigan also has the second most diverse agriculture in the country, with many crops that depend on bees for pollination. This unique combination provides a wide range of opportunitie...
Article
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Nomia (Maculonomia) xiongjiuensis Niu & Zhu, sp. nov., one of non- colored bands nomiine bees in subgenus Nomia (Maculonomia) from China, is described and illustrated for the first time to science, the type specimens were deposited in the Insect Collection of Institute of Zoology, Chinese Academy of Sciences, Beijing, China (IZCAS). Furthermore, a...
Data
Bee data were assembled from various digital resources and unpublished original data digitized by the authors and checked for taxonomic and geographic errors. Reference: Bystriakova N, Griswold T, Ascher JS, Kuhlmann M (2017) Key environmental determinants of global and regional richness and endemism patterns for a wild bee subfamily. Biodivers Con...
Article
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Despite a large number of ecological studies that document diversity loss resulting from anthropogenic disturbance, surprisingly few consider how disturbance affects temporal patterns of diversity that result from seasonal turnover of species. Temporal dynamics can play an important role in the structure and function of biological assemblages. Here...
Data
List of study plots in coastal sage scrub reserves and habitat fragments. (PDF)
Data
Species list of bees collected in this study. (PDF)
Data
R scripts used in core analyses. (PDF)
Data
Description and explanation of study sites. (PDF)
Article
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Although Brazil is a megadiverse country and thus a conservation priority, no study has yet quantified conservation gaps in the Brazilian protected areas (PAs) using extensive empirical data. Here, we evaluate the degree of biodiversity protection and knowledge within all the Brazilian PAs through a gap analysis of vertebrate, arthropod and angiosp...
Article
The relationship between biodiversity and the stability of ecosystem function is a fundamental question in community ecology, and hundreds of experiments have shown a positive relationship between species richness and the stability of ecosystem function. However, these experiments have rarely accounted for common ecological patterns, most notably s...
Article
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The highly social (eusocial) corbiculate bees, comprising the honey bees, bumble bees, and stingless bees, are ubiquitous insect pollinators that fulfill critical roles in ecosystem services and human agriculture. Here, we conduct wide sampling across the phylogeny of these corbiculate bees and reveal a dynamic evolutionary history behind their mic...
Article
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Urban ecology research is changing how we view the biological value and ecological importance of cities. Lagging behind this revised image of the city are natural resource management agencies' urban conservation programs that historically have invested in education and outreach rather than programs designed to achieve high-priority species conserva...
Article
We document a novel exotic bee for North America, Hylaeus ( Hylaeus ) communis Nylander, 1852 (Hymenoptera: Colletidae), and determine whether it is likely to spread widely across the continent. To evaluate the extent to which H. communis behaves as a generalist and would be able to adapt to novel North American environments, we compare the breadth...
Article
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 USA, restoration of tallgrass...
Article
Mature larvae of five species representing each of the three principal groups within the genus Megachile sensu lato (i.e., including Creightonella and Chalicodoma, which are often recognized at generic rank) are described and are revealed to be quite similar to one another. On the basis of their descriptions a larval description of the genus is for...