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Habitat loss is causing declines in native bees and reducing pollination services. Revegetation can be used to reverse these declines, and this restoration technique attracts growing efforts and resources. However, how the quality of revegetation affects native bee abundance, diversity and their pollination services is not well understood, and this limits opportunities to improve revegetation outcomes. To assess this gap, we surveyed floral and bee diversity in revegetated landscapes ranging in habitat quality, and compared these among each other and to remnant habitat and cleared areas. We also measured pollination services using two native phytometer species, which can be pollinated by native bees only, or by both native and introduced honey bees (Apis mellifera). We found that bee diversity and richness were higher within treatments that were higher in floral diversity. In addition, while pollination services provided by honey bees were uniform across treatments, remnant vegetation supported greater pollination services to the plant species pollinated by native bees only. These results indicate that higher quality revegetation characterized by the establishment of a more diverse set of plant species, has the potential to restore native bee diversity and associated pollination services. However, for the plant species investigated, restoration of pollination services had not occurred and might require more time. These results suggest preserving remnant vegetation should be the highest priority conservation action, and that restoration practitioners and landowners wishing to support landscape‐level bee diversity and pollination services, should aim for revegetation using high flowering plant diversity. [ABSTRACT FROM AUTHOR]

Agalinis is a diverse and wide-ranging genus within the Orobanchaceae. Species may be either widespread or restricted in range. Natural populations tend to be small and isolated being distributed across natural grassland or open habitats that are frequently fragmented due to habitat loss. We ask whether patterns of distribution and limited occurrence may be related to visiting bee diversity. We conducted a review of the bee taxa recorded visiting flowers of the genus Agalinis involving 15 published surveys plus our own field observations. We assessed the association of visiting bee diversity on flower size, geographical distribution, regional distribution, and conservation status of 14 species of Agalinis. From a total of 160 floral records, we found 5 families, 18 genera and 58 bee taxa have been documented visiting flowers of Agalinis. Halictidae (43.1%) and Apidae (29.3%) constituted the largest proportion of bees. The number of bee taxa recorded for a species of Agalinis showed a significant positive relationship with geographic range across the United States and Canada. However, no differences in bee diversity at the level of family were noted for flower size, regional distribution or conservation status. Bee diversity patterns recorded to date suggest a generalized pollination system not associated with the limited distribution or small population sizes of many Agalinis species. Nevertheless, previous studies indicate a level of specialization with respect to flower form and bee foraging behavior. The gibbous to ventricose corolla, combined with dimorphic stamens bearing filament trichomes facilitate inverted bee foraging for pollen gathering. [ABSTRACT FROM AUTHOR]

Conversion of land for agricultural use is a leading driver of global biodiversity loss. Natural and semi‐natural lands within agricultural landscapes are targeted for protection because they provide habitat for many organisms.Pothole (or kettle) wetlands occur across the Northern Hemisphere and are a focus for conservation both because of their location within agriculturally intensive landscapes and their importance to vertebrates, especially migratory birds.Recent evidence suggests that wetlands may also be an important habitat for arthropods, including insects that provide ecosystem services. To understand how insects associate with wetlands and landscape features, we examine the relationship between bumblebees (Bombus), and wetland area, cropland area and wetland perimeter‐area ratio.We found that wetland area is significantly positively associated with the occurrence and abundance of the species studied. We also found that the relationship between bumblebees and wetland perimeter‐area ratio varied across the growing season. This suggests that the importance of wetland edge as a foraging habitat varies across the season.These results show the utility of wetlands to bees, though their resources are likely not being used uniformly by all bumblebee species or across the entire growing season. Our results also suggest that pothole wetlands in agricultural landscapes are likely to support biodiversity, and their conservation contributes to overall ecosystem health and function. [ABSTRACT FROM AUTHOR]

Abstract Landscape context influences wild bee abundance and diversity, alongside pollination‐related services. Growing evidence supports the positive effects of landscape heterogeneity on bee diversity and fruit production for pollination‐dependent crops in flatlands. However, little remains known about these relationships in mountainous environments where the landscape matrix surrounding crops is often more complex than in lowlands. We conducted our study in apple orchards in South Tyrol, an Alpine region in Italy, using pan‐traps, direct observations of visitation frequency and a pollinator exclusion experiment. We investigated the scale‐dependent effects of landscape heterogeneity and other parameters on wild bee assemblages and the related pollination service they provide at five spatial scales (radius 100–2000 m). We found that landscape heterogeneity positively affected the abundance and richness of wild bees, with the strongest effect at 500 m. We calculated a multidiversity index, reflecting the land‐use intensity based on the species richness of vascular plants, grasshoppers, butterflies, birds and bats. We identified a positive relationship between this multidiversity index and wild bee richness. Additionally, we found that visitation rate of wild bees was negatively affected by crop cover and that abundance of honeybees did not influence wild bee visitation rate or reproductive success. Finally, reproductive success was positively related to semi‐natural habitat cover. Landscape heterogeneity should be maintained in apple orchards to continue to reap the benefits of vital pollination‐related services. Diversification strategies should be implemented to promote habitat diversity at small scales, even in regions with more than 80% of (semi‐)natural habitats.

Abstract Species of Opuntia (prickly pears), widely propagated for human use, are present in many agroforestry systems. Like other perennials, they are subject to environmental pressures that influence their reproductive ecology and reproductive output. Here, we studied floral biology, breeding system, and flower-bee interactions of Opuntia atropes, which is subject to management, to better understand its reproductive ecology. We documented floral phenology, morphology, and mating system by observing live flowers, measuring fixed flowers, and performing pollination treatments. We recorded frequency, behavior, and floral visitors’ handling time to determine the most effective pollinator. Opuntia atropes has large, herkogamous flowers and high P/O ratios. These traits promote outcrossing, which was supported by the results of pollination treatments. Fruit weight and seed set exhibited moderate pollen limitation. Floral visitors comprised nine bee species. Diadasia sp. was the most effective pollinator according to frequency and behavior. Opuntia atropes shows preferential outcrossing through pollination by a specialist bee despite being in a modified habitat. Pollen limitation and variation in reproductive success may lead to mating system evolution in O. atropes. The observed bee diversity suggests that O. atropes is an important source of floral resources in the dry season in semi-arid environments under moderate human disturbance.

This study deals with the species diversity of leaf-cutter and resin bees from three tribes, four genera, and seven subgenera of the family Megachilidae from Central India. Before this study, only a few species were known from Central India. During the surveys undertaken in 2019-2022, 10 species, including two cleptoparasitic bee species of the family Megachilidae, were collected and examined. Megachile lanata Fab. was the predominant species in all the survey locations. Seven species were discovered for the first time in Central India. This paper provides details of the Megachilidae species with an updated distribution and brief diagnosis. [ABSTRACT FROM AUTHOR]

The Cheadle Center at UCSB manages the North Campus Open Space (NCOS), which is a project that has restored 136 acres of upland and wetland habitats that existed before the area was converted into the Ocean Meadows Golf Course in the 1960s. The NCOS restoration project began in 2017 with a fine-scale grading of the site in order to recreate the salt marsh and use the excavated soil to rebuild the upland habitats to the southwest, which are now called the NCOS Mesa. In addition to re-establishing native biodiversity, a key goal of the restoration is to utilize the site as an educational, scientific, and recreational resource. This archived version of the May 2020 newsletter includes updates on Visitor Plaza and Discovery Trail construction, spring wildlife sightings, and online species lists. The feature story focuses on bee research being done at NCOS. Community photos include Western Pygmy Blue Butterfly (Brephidium exilis), White-Faced Ibis (Plegadis chihi), and Caspian Tern (Hydroprogne caspia).

The reproduction process of Apis mellifera L. (Hymenoptera: Apidae) occurs in defined congregation areas where natural mating occurs and males and unfertilized queen bees from different colonies converge. This work focused on the identification and characterization of a congregation drone zone in a biogeographic region of the low montane dry forest corridor, in the upper Andean valley of Sugamuxi-Tundama, for the density of bee colonies established there, considering the climatic factors of the environment and the description of biometric characters of bees and drones collected, and which constitutes the first report of a congregation zone for Colombia. In the study area, dry summer periods predominate alternating with short winter, cloudy days, and intense cold, with thermal sensations between 8 to 19°C. The drone movement route was established with an unmanned flight vehicle, through the interaction between the vehicle and bee specimens. The path of movement of drones was established operated between 10 and 60 m in North-South direction. Specimens of worker bees were collected identifying African, European, or Eastern European lines and drones of two types, yellow and black, evaluating biometric parameters and estimating the discriminant factor. The activity of the drones, occurs in two periods of 10:00 to 12:00 hours and 15:00 to 17:00 hours, flying regularly between round trips up to a 1 km radius. This work describes a methodology for monitoring congregation areas and consolidates itself as a tool for beekeepers for the conservation of regional ecotypes through bee reproductive planning.

Urbanization poses a major threat to biodiversity and food security, as expanding cities, especially in the Global South, increasingly compete with natural and agricultural lands. However, the impact of urban expansion on agricultural biodiversity in tropical regions is overlooked. Here we assess how urbanization affects the functional response of farmland bees, the most important pollinators for crop production. We sampled bees across three seasons in 36 conventional vegetable‐producing farms spread along an urbanization gradient in Bengaluru, an Indian megacity. We investigated how landscape and local environmental drivers affected different functional traits (sociality, nesting behavior, body size, and specialization) and functional diversity (functional dispersion) of bee communities. We found that the functional responses to urbanization were trait specific with more positive than negative effects of gray area (sealed surfaces and buildings) on species richness, functional diversity, and abundance of most functional groups. As expected, larger, solitary, cavity‐nesting, and, surprisingly, specialist bees benefited from urbanization. In contrast to temperate cities, the abundance of ground nesters increased in urban areas, presumably because larger patches of bare soil were still available beside roads and buildings. However, overall bee abundance and the abundance of social bees (85% of all bees) decreased with urbanization, threatening crop pollination. Crop diversity promotes taxonomic and functional diversity of bee communities. Locally, flower resources promote the abundance of all functional groups, and natural vegetation can maintain diverse pollinator communities throughout the year, especially during the noncropping season. However, exotic plants decrease functional diversity and bee specialization. To safeguard bees and their pollination services in urban farms, we recommend (1) preserving seminatural vegetation (hedges) around cropping fields to provide nesting opportunities for aboveground nesters, (2) promoting farm‐level crop diversification of beneficial crops (e.g., pulses, vegetables, and spices), (3) maintaining native natural vegetation along field margins, and (4) controlling and removing invasive exotic plants that disrupt native plant–pollinator interactions. Overall, our results suggest that urban agriculture can maintain functionally diverse bee communities and, if managed in a sustainable manner, be used to develop win–win solutions for biodiversity conservation of pollinators and food security in and around cities. [ABSTRACT FROM AUTHOR]

Understanding the drivers of biodiversity in cities is a central goal of urban ecology. There is currently intense scientific and public interest in the factors that influence pollinator diversity in cities and their surroundings. Existing studies point to a variety of landscape and local factors as potentially important, including urbanization (often defined as impervious surface cover in the surrounding lands), tree canopy cover and the diversity and abundance of locally flowering plants. However, few studies have sought to weigh the relative importance of these predictors of bee community metrics. Using a set of 27 residential yards chosen to represent a gradient of both urbanization and tree canopy cover at a landscape scale, we used pan trapping and netting to assess the abundance and diversity of local bee communities across the City of Ottawa, Ontario, Canada. Surprisingly, the landscape factors (urbanization and tree cover) described only a tiny fraction (

Ecologists consider biological invasions one of the primary drivers of global change. Many remaining grasslands in North America have extensive invasions of exotic grass species that have replaced native plant species. In the Northern Great Plains, exotic cool-season grasses Kentucky bluegrass (Poa pratensis) and smooth brome (Bromus inermis), paired with human alterations to the landscape and historical disturbance regimes, have resulted in functionally and structurally altered grassland plant communities. These changes may extend to impact species that rely on these plant communities, such as bees. Bees are ecologically diverse and serve important pollinator roles but are at risk from the loss and change of floral and nesting resources in plant communities. Our objectives were to determine whether Kentucky bluegrass and smooth brome alter the bee and forb species richness in invaded Northern Great Plains grasslands and how litter accumulation, grass cover, the amount of bare ground, and forb species richness interact with bee functional traits. To do this, we surveyed 67 grassland sites from 2017 to 2020 with two bee-sampling methods (268 netting and bee bowl surveys total) and vegetation cover surveys at each site. We collected 20,559 bees from 201 bee species and observed 249 forb and shrub species in vegetation surveys. Bee richness and Shannon diversity were associated with greater forb richness while forb richness was significantly lower with thicker litter depths and higher with a greater coverage of all grasses other than Kentucky bluegrass and smooth brome. Bee trait analyses showed varying relationships with plant community variables. Of these, litter depth and Kentucky bluegrass cover were associated with lower ground-nesting bee abundance while small-bodied bee abundance was positively associated with increasing bare ground. While our results support the close relationship between bee and plant diversity, we also found litter depth, in particular, contributed to the structure of these two communities. Specifically, Kentucky bluegrass and smooth brome are two exotic grass species associated with thatch-forming litter layers, especially under idle management that appear to simplify bee and forb communities. Our results make apparent the importance in maintaining structural and compositional diversity in invaded grasslands to support diverse bee communities.

The reproduction process of Apis mellifera L. (Hymenoptera: Apidae) occurs in defined congregation areas where natural mating occurs and males and unfertilized queen bees from different colonies converge. This work focused on the identification and characterization of a congregation drone zone in a biogeographic region of the low montane dry forest corridor, in the upper Andean valley of Sugamuxi-Tundama, for the density of bee colonies established there, considering the climatic factors of the environment and the description of biometric characters of bees and drones collected, and which constitutes the first report of a congregation zone for Colombia. In the study area, dry summer periods predominate alternating with short winter, cloudy days, and intense cold, with thermal sensations between 8 to 19°C. The drone movement route was established with an unmanned flight vehicle, through the interaction between the vehicle and bee specimens. The path of movement of drones was established operated between 10 and 60 m in North-South direction. Specimens of worker bees were collected identifying African, European, or Eastern European lines and drones of two types, yellow and black, evaluating biometric parameters and estimating the discriminant factor. The activity of the drones, occurs in two periods of 10:00 to 12:00 hours and 15:00 to 17:00 hours, flying regularly between round trips up to a 1 km radius. This work describes a methodology for monitoring congregation areas and consolidates itself as a tool for beekeepers for the conservation of regional ecotypes through bee reproductive planning. [ABSTRACT FROM AUTHOR]

Understanding the drivers of biodiversity in cities is a central goal of urban ecology. There is currently intense scientific and public interest in the factors that influence pollinator diversity in cities and their surroundings. Existing studies point to a variety of landscape and local factors as potentially important, including urbanization (often defined as impervious surface cover in the surrounding lands), tree canopy cover and the diversity and abundance of locally flowering plants. However, few studies have sought to weigh the relative importance of these predictors of bee community metrics. Using a set of 27 residential yards chosen to represent a gradient of both urbanization and tree canopy cover at a landscape scale, we used pan trapping and netting to assess the abundance and diversity of local bee communities across the City of Ottawa, Ontario, Canada. Surprisingly, the landscape factors (urbanization and tree cover) described only a tiny fraction (< 1%) of the total variance in bee abundance and diversity across sites. This was true regardless of the scale of analysis at which the landscape factors were measured. Instead, a yard's floral richness, and, to a somewhat lesser extent, its floral abundance, emerged as the most important predictors of a yard's bee community abundance and diversity. Our study offers an important counterpoint to a growing body of work emphasizing the impacts of landscape factors on bee communities. Instead, our research suggests that improving bee floral resources by increasing the plant species richness and abundance locally is a powerful tool to support bee conservation, regardless of the level of urbanization or tree cover in the surrounding landscape. Our work highlights that the practice of promoting 'bee-friendly' plantings in private yards, currently being undertaken by a number of non-profits around the world, can play an important role in restoring and maintaining urban pollinator communities. [ABSTRACT FROM AUTHOR]

The present three-year study traces the diversity of four bee communities in fragmented pedemontane areas of Volcano Etna (Catania province, Sicily) near the Metropolitan City of Catania, under different land management regimes. The selected areas comprise two different urban parks within Catania (Parco Gioeni and Parco degli Ulivi), a Nature Reserve (Complesso Immacolatelle e Micio Conti, San Gregorio di Catania), and an agroecosystem (a citrus orchard, Aci Catena). Previous data obtained from a well-investigated area (Leucatia, north of Catania) have been used as a control for bee diversity for this study. The results include an outline of bee species richness, data on the composition of bee communities, and seasonal patterns, using several diversity indexes. The study of bee diversity shows a total of 163 species, arranged in five families. The four investigated locations include 104 species arranged in four families: Andrenidae (20 species), Halictidae (15 species), Megachilidae (31 species), and Apidae (38 species); with a similar number of species (102) recorded in the control site (Leucatia). The study highlights strong seasonal variations of bee communities in all investigated sites, with differentiated seasonal patterns, whose compositions are affected mainly by forage sources, suitable nesting sites, as well as human activities. The data obtained provide a rough but basilar framework to assess management strategies to maintain adequate levels of bee diversity, especially for those areas with moderate to high environmental fragmentation. Our findings highlight the importance of season-long sampling of bee population factors if used as indicators in ecological studies.

The present three-year study traces the diversity of four bee communities in fragmented pedemontane areas of Volcano Etna (Catania province, Sicily) near the Metropolitan City of Catania, under different land management regimes. The selected areas comprise two different urban parks within Catania (Parco Gioeni and Parco degli Ulivi), a Nature Reserve (Complesso Immacolatelle e Micio Conti, San Gregorio di Catania), and an agroecosystem (a citrus orchard, Aci Catena). Previous data obtained from a well-investigated area (Leucatia, north of Catania) have been used as a control for bee diversity for this study. The results include an outline of bee species richness, data on the composition of bee communities, and seasonal patterns, using several diversity indexes. The study of bee diversity shows a total of 163 species, arranged in five families. The four investigated locations include 104 species arranged in four families: Andrenidae (20 species), Halictidae (15 species), Megachilidae (31 species), and Apidae (38 species); with a similar number of species (102) recorded in the control site (Leucatia). The study highlights strong seasonal variations of bee communities in all investigated sites, with differentiated seasonal patterns, whose compositions are affected mainly by forage sources, suitable nesting sites, as well as human activities. The data obtained provide a rough but basilar framework to assess management strategies to maintain adequate levels of bee diversity, especially for those areas with moderate to high environmental fragmentation. Our findings highlight the importance of season-long sampling of bee population factors if used as indicators in ecological studies. [ABSTRACT FROM AUTHOR]

Abstract Meliponines, popularly known as stingless bees, present a great diversity of species widely distributed in tropical regions. Some species are rationally reared to obtain bee products like honey, pollen and wax, and most of them are important pollinators of the native and cultivated flora in Brazil. Nevertheless, stingless bees are little investigated in their natural range throughout the country, especially in NE Brazil. This work is the first comprehensive survey sampling stingless bee species throughout the state of Ceará investigating their occurrence and distribution in different phytoecological units. In this sense, the study evaluated the species richness; the distribution in the diverse types of vegetation and relief formations; and reviewed the list of species with occurrence already described and incorporated 20 new occurrences for Ceará, increasing the number of species reported to the state from 29 to 49. We also indicate rare species and those once common but presently threatened mainly due to habitat loss, demonstrating the need of conservation efforts and potential for sustainable exploitation of these bee species and their habitats through meliponiculture. It also shed light in the potential richness of stingless bee species in NE Brazil.

Abstract Extreme weather events are increasing in frequency due to the warming climate. Such extremities can jeopardize ecosystem services and create economic imbalances. Tropical developing countries are predicted to suffer the maximum consequences of such events. We examined the impact of such an event—extreme rainfall fluctuation—on a critical ecosystem service—pollination, which can be intricately linked to a country's economy. We performed this study in a dominant peri‐urban vegetable hub of an agriculture‐dependent developing country. We found that the yield of all pollinator‐dependent crops grown across a large spatial scale (district) over multiple years (six) drastically declined with the decrease in rainfall. At the local scale, we found that the dominant crop (representative horticultural crop) had a significant drop in yield during drought, likely due to the production of fewer female flowers and a significant shift in the pollinator community. We found that Trigona sp. (one of the four pollinators) was the critical pollinator positively influencing fruit‐to‐flower ratio (FFR) (an indicator of pollination service) in the normal rainfall year. However, despite its sharp decline during drought, the FFR remained unaffected. We found that during drought, Apis dorsata was crucial in maintaining FFR and compensated for the decline of the critical pollinator across 67% farmlands. Our study demonstrates the role of ecosystem stabilizing mechanism rescuing the crucial ecosystem service during climatic variability over the temporal scale.

Disturbances associated with intensive agriculture facilitate the spread of invasive plants that become dominant along habitat edges in fragmented landscapes. Many invasive woody plants offer large quantities of floral resources to bees, but little is known about how invasive plants affect the use of flowering resources in the forest canopy and understory by native bee communities. We sampled the bee community at vertical strata along forest-agriculture edges that varied in density of a dominant invasive shrub Lonicera maackii before, during, and after the flowering period. We also recorded diameters and species identities of woody stems. Bee and woody plant abundance, diversity, and life-history traits were then spatially and temporally compared in response to L. maackii density. Overall, we found that L. maackii structured bee communities through its floral resources by altering bee species composition and supporting greater abundances and species richness of bees during and after its flowering period. We also demonstrated a diverse and abundant bee community up to 16 m high in the forest canopy that is supported by floral resources of native shrubs and trees but sensitive to woody shrub invasion. These findings collectively suggest that this invasive shrub structures the bee community in favor of species that use its own flowers and competes with co-flowering woody species at different vertical strata. Our study emphasizes the importance of forest trees and shrubs for bees in agricultural landscapes and demonstrates potential risks for early-season bees as well as those that cannot use floral resources of this invasive shrub. [ABSTRACT FROM AUTHOR]

Background: Here we present a checklist of the bee species found on the C. Hart Merriam elevation gradient along the San Francisco Peaks in northern Arizona. Elevational gradients can serve as natural proxies for climate change, replacing time with space as they span multiple vegetation zones over a short geographic distance. Describing the distribution of bee species along this elevation gradient will help predict how bee communities might respond to changing climate. To address this, we initiated an inventory associated with ecological studies on pollinators that documented bees on the San Francisco Peaks. Sample sites spanned six life zones (vegetation zones) on the San Francisco Peaks from 2009 to 2019. We also include occurrence data from other studies, gathered by querying the Symbiota Collection of Arthropods Network (SCAN) portal covering the San Francisco Peaks region (hereafter referred to as "the Peaks"). New information: Our checklist reports 359 bee species and morphospecies spanning five families and 46 genera that have been collected in the Peaks region. Prior to our concerted sampling effort there were records for 155 bee species, yet there has not been a complete list of bee species inhabiting the Peaks published to date. Over a 10-year period, we documented an additional 204 bee species inhabiting the Peaks. Our study documents range expansions to northern Arizona for 15 species. The majority of these are range expansions from either southern Arizona, southern Utah, or the Rocky Mountain region of Colorado. Nine species are new records for Arizona, four of which are the southernmost record for that species. An additional 15 species are likely undescribed. [ABSTRACT FROM AUTHOR]

The terrestrial biota of the French Polynesian archipelago presents a unique opportunity for study due to a relatively poor understanding of its biology. Among the terrestrial invertebrates, the Apoidea are one of many taxa with incompletely documented biodiversity. This study investigated the diversity of the bees on the island of Mo'orea, part of the Society Islands in French Polynesia. Across a range of elevations, I collected 239 individual bees and observed the floral visits of an additional 266 bees. The visited floral species were recorded to assess apoid use of floral resources, and vegetation surveys of collection sites were conducted to assess the available floral community. A total of five genera of bees were found on Mo'orea, including two which are recorded for the first time in the Society Islands. This study suggests that introduced species, rather than native species, comprise the bee biota of Mo'orea, with the longest established species seemingly introduced at or around the time of colonization by early Polynesians. With the exception of the genera Lithurgus and Megachile, bee genera were found to rely predominantly on non-native floral resources. Floral visitation predilection by Mo'orean bees may prove to further the spread of introduced and invasive floral species.

Extreme weather events are increasing in frequency due to the warming climate. Such extremities can jeopardize ecosystem services and create economic imbalances. Tropical developing countries are predicted to suffer the maximum consequences of such events.We examined the impact of such an event—extreme rainfall fluctuation—on a critical ecosystem service—pollination, which can be intricately linked to a country's economy. We performed this study in a dominant peri‐urban vegetable hub of an agriculture‐dependent developing country.We found that the yield of all pollinator‐dependent crops grown across a large spatial scale (district) over multiple years (six) drastically declined with the decrease in rainfall.At the local scale, we found that the dominant crop (representative horticultural crop) had a significant drop in yield during drought, likely due to the production of fewer female flowers and a significant shift in the pollinator community.We found that Trigona sp. (one of the four pollinators) was the critical pollinator positively influencing fruit‐to‐flower ratio (FFR) (an indicator of pollination service) in the normal rainfall year. However, despite its sharp decline during drought, the FFR remained unaffected. We found that during drought, Apis dorsata was crucial in maintaining FFR and compensated for the decline of the critical pollinator across 67% farmlands.Our study demonstrates the role of ecosystem stabilizing mechanism rescuing the crucial ecosystem service during climatic variability over the temporal scale. [ABSTRACT FROM AUTHOR]

Many varieties of sweet cherry are self-incompatible. Therefore, sweet cherry orchards require a huge population of pollinator bees to carry out an adequate amount of pollen transfer between the different varieties. Our study was conducted to evaluate the differences in the richness and diversity of these pollinators within very closely located sweet cherry orchards, and to understand the underlying effects causing these differences. The study was conducted in the Sultandağı Reservoir (Turkey) which covers the towns of Sultandağı (Afyonkarahisar) and Akşehir (Konya). In order to avoid a sampling bias, Malaise traps were used to collect bee samples. Sampling collections were repeated for three years; from 2007 to 2009, between April and May. The traps were set in the bud-swell period and lifted in the green-fruit period. Climatic data were taken from meteorology stations near the orchards. Vegetation in the surrounding areas was also inspected. The composition of pollinator bee species was determined and compared between orchards. In total, 83 bee species and 38 plant species were recorded. It was found that Halictidae is the most abundant and richest group among the pollinator bees. The effects of the quantity of the Malaise traps on bee sampling success were also tested. It was found that one trap per 325 trees is enough for an adequate sampling. Apart from the annual fluctuations of bee richness in the orchards, general differences in the bee diversity among orchards might be affected by the surrounding vegetation and especially from different agricultural practices such as tilling the ground.

Native bees (Hymenoptera: Anthophila) were sampled using bee bowls in two states to determine biodiversity in commercial cotton fields of the southern United States. In both states, native bee communities found in cotton fields were dominated by generalist pollinators in the genera Agapostemon, Augochloropsis, Halictus, and Lasioglossum (Hymenoptera: Halictidae), and Melissodes (Hymenoptera: Apidae). Melissodes tepaneca (Cresson) was the most abundant species found in cotton fields in both states. Some species collected are known specialists on other plant taxa, suggesting they may be tourist species. Here we provide a baseline species list of native bees found in cotton. Ordination indicated separation between the communities found in the two states when pooled by genus, but these differences were not significant. While cotton is grown in highly managed and disturbed landscapes, our data suggest that a community of common generalist native pollinators persists. Many of these species are also found in other cropping systems across North America.

Sustained pollinator services within coffee farms depend substantially on a diverse bee community. While studies have been conducted to understand the impacts of forest proximity and farm level management on pollinators, few have examined the interaction between these two spatial scales. We surveyed pollinator communities within 18 sites on a large organic farm surrounded by native forest in southern Costa Rica. We selected sites 0, 50 and 150 m from the forest edge within shaded and sparsely-shaded (sun) portions of the farm to quantify the influence of both shade management and distance to contiguous forest on pollinator communities. Contrary to similar studies, native bees dominated the composition of pollinators on this farm. Overall, pollinator diversity and activity did not differ significantly neither between the shade management types nor among the sites 0, 50 or 150 m from the forest edge. However, pollinator diversity was found to be significantly higher at sun sites near forest (0 m) compared with further away, whereas the diversity was the same for the shade sites regardless of forest proximity. We found that greater numbers of coffee flowers within each site increased bee abundance and flower visitation frequency. Bee abundance was greater in sites with less ground cover and bee diversity and visitation frequencies were higher in sites with greater amounts of shade canopy cover and trees in flower. Based on our results, we suggest including flowering shade trees that provide high levels of canopy cover, maintaining or re-establishing forested areas within or surrounding farms, and eliminating or reducing agrochemical use to increase native pollinator activity and diversity within coffee farms. [ABSTRACT FROM AUTHOR]

A growing body of evidence suggests that wild bees play an important role in agricultural pollination. It is very difficult, however, to accurately quantify the contribution of wild bees relative to honeybees in most crop systems. We quantified the relative contribution of honeybees and wild bees to the pollination of an economically important, insect-pollinated crop (apple). We use an empirical dataset to identify which of three functional traits (body size, pollen load purity, and flower handling behavior) contribute significantly to seed set. We find that flower handling behavior and abundance were the only functional traits that significantly predict seed set. When we take into account flower handling behavior and abundance, wild bees contributed significantly more to seed set than honeybees in the apple orchards we surveyed. Our findings suggest that land managers may benefit from focusing on supporting communities of wild bees, rather than investing in honeybee hive rental. [ABSTRACT FROM AUTHOR]

• Flower size is a trait determining pollinators' attraction. • Larger flowered species have three times more species of flower visitors. • There is a morphological fit between poricidal flowers and bee size. • Regardless of the flower size, the most frequent bees make vibrations. Flower size is a crucial trait for pollinator attraction. In flowers with poricidal anthers, the plant constraints the pollinator's access to the flower's rewards by enclosing pollen grains in poricidal anthers. The pollen is only released by mechanical vibrations applied mainly by bee species during buzz pollination. Although buzz-pollinated flowers exhibit a large size variation across species, their influence over patterns of flower visitation by different pollinator species remains to be elucidated. To fill such gap, we asked how flower size influences flower visitor assemblage, especially bees, across plant species and how flower size is related to body size and vibrating behavior of the most frequent bee species. We hypothesized that the assemblage of animals, especially bees, visiting larger flowers have higher taxonomic and functional diversity than smaller flowers, and the most frequent bee species visiting larger flowers have larger body size and a mandatory vibrating behavior. To test this hypothesis, we conducted a systematic review of pollination studies that reported patterns of flower visitation in plant species with poricidal anthers, describing the relationship between flower size and flower visitor metrics. We found that large-flowered species were visited by three times more species than small-flowered species, including vibrating and non-vibrating bee species. Unlike our expectations, non-vibrating bees were largely absent from small-flowered species. The most frequent bee species visiting flowers, irrespective of flower size, exhibited vibrating behavior. The most frequent bee species visiting large flowers were twice the body size of those visiting small flowers, highlighting a morphological match between flowers and pollinators. Although larger flowers are more susceptible to interactions with exploiters, reproductive success should be favored owing to the higher probability of their interaction with vibrating, large-bodied bee species. Still, a reduction in flower size probably prevents interactions with non-vibrating bees, while favoring vibrating small-bodied bee species. [ABSTRACT FROM AUTHOR]

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We assessed bee diversity and abundance in a botanical garden in the city of Buenos Aires during two consecutive spring–summer periods. Every 15 days, we collected by hand-netting bee specimens seen foraging on flowers during five-minute censuses at every entomophilous herbaceous plant. A total of 66 bee species (Hymenoptera: Apoidea) were recorded. Richness and abundance of native, generalist, and above-ground nesting (cavities) species were higher than that of exotic, specialist, and below-ground (soil) nesting ones, respectively. Social bees were more abundant, while the richness of solitary species was higher than that of social bees. Cleptoparasitic species were represented by a high number of species, even though only a few individuals were captured. Our results suggest that the studied area is an important bee reservoir within the city. [ABSTRACT FROM AUTHOR]

Bees are important pollinators of agricultural crops, and bee diversity has been shown to be closely associated with pollination, a valuable ecosystem service. Higher functional diversity and species richness of bees have been shown to lead to higher crop yield. Bees simultaneously represent a mega-diverse taxon that is extremely challenging to sample thoroughly and an important group to understand because of pollination services. We sampled bees visiting apple blossoms in 28 orchards over 6 years. We used species rarefaction analyses to test for the completeness of sampling and the relationship between species richness and sampling effort, orchard size, and percent agriculture in the surrounding landscape. We performed more than 190 h of sampling, collecting 11,219 specimens representing 104 species. Despite the sampling intensity, we captured <75% of expected species richness at more than half of the sites. For most of these, the variation in bee community composition between years was greater than among sites. Species richness was influenced by percent agriculture, orchard size, and sampling effort, but we found no factors explaining the difference between observed and expected species richness. Competition between honeybees and wild bees did not appear to be a factor, as we found no correlation between honeybee and wild bee abundance. Our study shows that the pollinator fauna of agroecosystems can be diverse and challenging to thoroughly sample. We demonstrate that there is high temporal variation in community composition and that sites vary widely in the sampling effort required to fully describe their diversity. In order to maximize pollination services provided by wild bee species, we must first accurately estimate species richness. For researchers interested in providing this estimate, we recommend multiyear studies and rarefaction analyses to quantify the gap between observed and expected species richness. [ABSTRACT FROM AUTHOR]

Insect-mediated pollination is critical for lowbush blueberry (Ericaceae: Vaccinium angustifolium Aiton) fruit development. Past research shows a persistent presence of wild bees (Hymenoptera: Apoidea) providing pollination services even when commercial pollinators are present. We undertook the study to 1) provide a description of bee communities found in lowbush blueberry-growing regions, 2) identify field characteristics or farm management practices that influence those communities, 3) identify key wild bee pollinators that provide pollination services for the blueberry crop, and 4) identify non-crop plants found within the cropping system that provide forage for wild bees. During a 4-year period, we collected solitary and eusocial bees in over 40 fields during and after blueberry bloom, determining a management description for each field. We collected 4,474 solitary bees representing 124 species and 1,315 summer bumble bees representing nine species. No bumble bee species were previously unknown in Maine, yet we document seven solitary bee species new for the state. These include species of the genera Nomada, Lasioglossum, Calliopsis, and Augochloropsis. No field characteristic or farm management practice related to bee community structure, except bumble bee species richness was higher in certified organic fields. Pollen analysis determined scopal loads of 67-99% ericaceous pollen carried by five species of Andrena. Our data suggest two native ericaceous plants, Kalmia angustifolia L. and Gaylussacia baccata (Wangenheim), provide important alternative floral resources. We conclude that Maine blueberry croplands are populated with a species-rich bee community that fluctuates in time and space.We suggest growers develop and maintain wild bee forage and nest sites. [ABSTRACT FROM AUTHOR]

This paper reports on phenology, breeding system and dependence on pollinators of two sympatric Dichorisandra species. Dichorisandra incurva is a chamaephyte with continuous growth and precocious flowering, whereas D. hexandra is a geophyte with seasonal growth and delayed flowering. Flowering and fruiting occur mainly in the wet season; thus moisture can be important for both species. Besides moisture, photoperiod seems also to be related to the flowering only of D. incurva. Flowers of both species are poricidal, oligandrous, zygomorphic and buzz-pollinated by Apidae and/or Halictidae bees. Dichorisandra incurva is self-compatible, while D. hexandra shows a late-acting self-incompatible system. Moreover, herkogamy and poricidal anthers prevent spontaneous self-pollination in D. incurva. Therefore, medium- to large-sized Apidae are the most suitable pollinators as they make regular contact with anthers and stigmas and are further known to perform trapline foraging. This behaviour is particularly important for D. hexandra where Halictidae are considered pollen robbers, thus wasting pollen which, consequently, causes low reproductive efficacy in this species. Nevertheless, bee diversity is probably advantageous for the reproductive success of both Dichorisandra species. While the efficiency of each bee species is not known, further studies will show whether additional benefits are gained from the maintenance of these interactions. [ABSTRACT FROM AUTHOR]

The article discusses research into pollen loads and bee diversity at the Bridger Plant Materials Center (BPMC) wildflower seed production facility in Montana. The facility features various flowering angiosperms which include Dalea candida, Ratibida columnifera and Pacific aster. It describes the bee sampling procedures and pollen load size and composition analysis performed. It is noted that majority of the bee species collected were honey bees and bumble bees. The relative rarity of honey bees on Ratibida columnifera is also explored.

Species richness and seasonality of a bee community were studied in a restinga area in Palhoca, Santa Catarina, southern Brazil. Twice a month during a year, from September 2004 to September 2005, bees were collected on flowers, in flight and with trap-nests. A total of 784 individuals belonging to 64 species of the families Apidae, Colletidae, Halictidae and Megachilidae were collected. Halictidae was the most rich and abundant family, followed by Apidae. Species richness peaks in summer whereas only a few species of Apidae and mainly Halictidae were active in the coldest months of the year. This clear seasonal pattern of activity appears to be a general characteristic of subtropical bee communities in Brazil. Comparison with others studies in restinga of Santa Catarina was made, as also the total apifauna of restinga in Rio Grande do Sul, Santa Catarina and Parana are presented. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the effect of nesting suitability, plant community composition, fire history, and land use on bee distribution throughout an open-forest gradient in northwest Indiana. The study shows the correlation of the differences in bee community composition and woody vegetation gradient with relative abundance of diet specialist or oligolectic bees. Its results indicate that these patterns are considered as primary bee community pattern determinants.

Nectar production has been proposed as an adaptation to attract pollinators that benefit from this resource. Energetic investments may be expensive, so some species such as Prosopis glandulosa have developed a dimorphic system of nectar production, which is expected to affect floral visitor behaviour and then plant fitness. We quantified bee diversity during a 2 year period in a population of the honey mesquite in order to determine changes in bee diversity due to the presence of nectar, bee preferences to collect either nectar of pollen, and to determine between year variations of bee faunas. Floral visitors were captured at three different times of the day during the flowering seasons of 1994 and 1995, in a population of Prosopis glandulosa which has a 1:1 proportion of nectar: nectarless individuals. Pollinators were clearly distinct between nectar morphs, bee species diversity and relative abundance of visits were significantly greater on nectarful than on nectarless plants, with species on nectarless individuals being a subset of those in the nectarful morph. Our results suggest differences in the function of floral rewards (i.e., nectar and pollen) to attract floral visitors. For the Chihuahuan arid environment, mesquite provides floral rewards with ease, quantity and quality for close to 10% of all bee fauna making them important components of these communities. [ABSTRACT FROM AUTHOR]

Natural small, xeric hill prairies in forested landscapes throughout the Midwest United States often contain high diversity and unique species of some organisms because of their unusual landscape context and microclimate. We measured the diversity, richness, and abundance of the bee communities of five hill prairies located in northeastern Iowa and we compared these to values for large prairie preserves in northwestern Iowa, using a Monte Carlo resampling approach to standardize sampling effort between habitat types. We also measured the diversity and richness of the flowering forb communities at the hill prairies and we quantified percentage of the landscape at a 1 km radius in different landscape elements. Bee diversity at the five hill prairies spanned the range of diversity values for large prairies preserves, so although the hill prairies are small (<5 ha), their bee communities are not uniformly depauparate compared to larger western prairie preserves. Bee diversity was significantly related to flowering forb diversity, and may have been influenced by landscape features within 1 km—particularly the percentage of agricultural row crops and open water, which may negatively affect bee diversity at the sites. Iowa’s hill prairie bee communities were largely composed of widespread eastern species, although about 10% of the bee species have more northern or western ranges and appear to be taking advantage of the region’s unique habitat features. Given the dependence of the bee communities on the plant diversity of the sites, management of the plant community to maintain its diversity will also likely benefit bee diversity. [ABSTRACT FROM AUTHOR]

Insects provide essential ecological services in both the natural environment and in human-dominated habitats. Because pollinator declines associated with land use change have been reported across the globe, there is great concern that pollinators and the ecosystem services they provide will be negatively affected. This study examines the diversity and abundance of bee pollinators in grasslands in Boulder County, Colorado, USA. Over five years, 5,200 bees were collected in grassland plots with different levels of urbanization. Most of the difference in species composition among three levels of urbanization was due to rare species that may not have been discovered in all plots. Neither the number of species nor their abundance differed significantly among the plot types, although the trend indicated increasing diversity with increasing distance from urbanization. Most notably, measures of urbanization, such as the amount of pavement and development, were not correlated with diversity. The most important factor affecting bee abundance, particularly for ground-nesting bees, was grazing regime. Bee abundance also was positively related to the number of flowering plant species. Other studies of different insects (grasshoppers and butterflies) in these plots showed results similar to ours. In contrast, previous studies on song-birds, raptors, and rodents showed significant differences between urban edge and remote plots in terms of organism abundance and diversity. Together, these results suggest that factors other than the degree of urbanization are important in determining insect abundance and diversity. [ABSTRACT FROM AUTHOR]

The article focuses on a study related to examining the effects of different methods of future land use and land cover change on pollination services and related yields of small-scale coffee agroforestry systems in Sulawesi, Indonesia. A new spatially explicit land use model was used during the study. The economic value of the pollination services of present forests was also evaluated. It was found that pollination services are expected to decline continuously and reduce coffee yields by up to 18% and net revenues per hectare up to 14% within the next two decades.

Abstract: Mediterranean landscapes comprise a complex mosaic of different habitats that vary in the diversity of their floral communities, pollinator communities and pollination services. Using the Greek Island of Lesvos as a model system, we assess the biodiversity value of six common habitats and measure ecosystemic ‘health’ using pollen grain deposition in three core flowering plants as a measure of pollination services. Three fire-driven habitats were assessed: freshly burnt areas, fully regenerated pine forests and intermediate age scrub; in addition we examined oak woodlands, actively managed olive groves and groves that had been abandoned from agriculture. Oak woodlands, pine forests and managed olive groves had the highest diversity of bees. The habitat characteristics responsible for structuring bee communities were: floral diversity, floral abundance, nectar energy availability and the variety of nectar resources present. Pollination services in two of our plant species, which were pollinated by a limited sub-set of the pollinator community, indicated that pollination levels were highest in the burnt and mature pine habitats. The third species, which was open to all flower visitors, indicated that oak woodlands had the highest levels of pollination from generalist species. Pollination was always more effective in managed olive groves than in abandoned groves. However, the two most common species of bee, the honeybee and a bumblebee, were not the primary pollinators within these habitats. We conclude that the three habitats of greatest overall value for plant-pollinator communities and provision of the healthiest pollination services are pine forests, oak woodland and managed olive groves. We indicate how the highest value habitats may be maintained in a complex landscape to safeguard and enhance pollination function within these habitats and potentially in adjoining agricultural areas. [Copyright &y& Elsevier]

The abundance and species richness of highly social bees (Apinae: Meliponini, Apini) were studied at 12 dipterocarp forest sites in Sabah, northern Borneo, using standardized honey-water baiting assays. The 12 sites were grouped in five localities varying in the degree and history of disturbance from selective logging. A baiting assay consisted of spraying diluted honey on vegetation along transects and recording bee arrival on the same day. Repeated assays of the same sites were run in two consecutive years, 1998 and 1999. One-way repeated-measures ANOVAs were calculated on bee abundance and species richness, with locality and year as independent factors. There were significant or marginally significant effects of forest locality on all measures of bee abundance and species richness. However, there were also significant interactions between year and locality on these variables, thwarting conclusions on the effects of logging on bee communities. The diverging results of the two years are likely related to spatio-temporal variation of flowering activity prior to and during the assays, with between-year differences being amplified by pronounced differences in climatic conditions (ENSO). Local or regional differences in flowering phenology complicate the application of resource-based baiting techniques for between-site comparisons of bee diversity. [ABSTRACT FROM PUBLISHER]

Pollinators provide essential ecosystem services, and declines in some pollinator communities around the world have been reported. Understanding the fundamental components defining these communities is essential if conservation and restoration are to be successful. We examined the structure of plant-pollinator communities in a dynamic Mediterranean landscape, comprising a mosaic of post-fire regenerating habitats, and which is a recognized global hotspot for bee diversity. Each community was characterized by a highly skewed species abundance distribution, with a few dominant and many rare bee species, and was consistent with a log series model indicating that a few environmental factors govern the community. Floral community composition, the quantity and quality of forage resources present, and the geographic locality organized bee communities at various levels: (1) The overall structure of the bee community (116 species), as revealed through ordination, was dependent upon nectar resource diversity (defined as the variety of nectar volume-concentration combinations available), the ratio of pollen to nectar energy, floral diversity, floral abundance, and post-fire age. (2) Bee diversity, measured as species richness, was closely linked to floral diversity (especially of annuals), nectar resource diversity, and post-fire age of the habitat. (3) The abundance of the most common species was primarily related to post-fire age, grazing intensity, and nesting substrate availability. Ordination models based on age- characteristic post-fire floral community structure explained 39-50% of overall variation observed in bee community structure. Cluster analysis showed that all the communities shared a high degree of similarity in their, species composition (27-59%); however, the geographical location of sites also contributed a smaller but significant component to bee community structure. We conclude that floral resources act in specific and previously unexplored ways to modulate the diversity of the local geographic species pool, with specific disturbance factors, superimposed upon these patterns, mainly affecting the dominant species. [ABSTRACT FROM AUTHOR]