Bee Habitat Research Articles

The potential of weeds in arable fields to support pollinator assemblages

AbstractTo what extent are weeds on arable land useful to pollinators in an arable‐dominated landscape? We sampled the weed flora in fields under conventional or organic farming in SE Sweden. More specifically, we noted the frequency of flowering among weeds that scored high on a pollinator index, henceforth ‘pollinator‐friendly weeds’. Furthermore, we sampled pollinating insects within cereal crops using transect walks and colour pan traps. As expected, weeds were ubiquitous and occurred in most sampling plots (0.25 m2). In the pan traps, more than 100 species of pollinators were caught, including 26 Syrphidae, 19 social bees, 37 solitary bees and 22 other Hymenoptera. In the transects walks, the probability of encountering bees increased with flowering of pollinator‐friendly weeds, and there was a similar but weaker pattern among hoverflies. Organically grown fields differed from conventional ones by having more pollinator‐friendly weeds, more flowering of such weeds, and more bees. There was also a tendency for hoverflies and other Hymenoptera to be more abundant in organic fields. Three conclusions emerged. First, pollinator‐friendly weeds made up one third to almost half of the weed occurrences recorded. Second, substantial numbers of pollinators searched for flowers within arable fields, and some increased with the abundance of flowering of pollinator‐friendly weeds. Third, flowering pollinator‐friendly weeds and some pollinators were more abundant in organic fields than in conventional ones. Overall, we showed that weeds on arable land are a potential and sought after resource among pollinators, and that even conventionally grown crops should be considered a potential habitat for bees.

Bee pollination affects coffee quality, yield, and trade-offs within them

Bees provide valuable pollination services by increasing crop yields. However, pollination services to crop quality – which often determines nutritional and financial value – have been less studied, particularly in tropical commodities such as coffee. Understanding how pollination affects coffee quality is critical because high-quality coffee on the specialty market fetches higher prices, which can potentially benefit farmers more than just focusing on yield alone. This study aimed to test the effects of bee pollination on coffee yield and quality and to evaluate possible trade-offs within them. We conducted bee-exclusion experiments on 30 coffee plants in the Tarrazú region of Costa Rica, controlling for several factors associated with coffee quality. At the end of the growing season, we harvested the berries and compared yield (that is, fruit set and weight) and quality (that is, the cup profiles of certified coffee tasters) among treatments. Our results indicate that bee pollination can lead to trade-offs in coffee production. Bee pollination significantly increased final fruit set by 9 % and the desired aroma scores by 2 %. However, these fruits weighed 7 % less than self-pollinated berries and displayed more body but less balance in their cup profiles. This is one of the first experimental studies to evaluate pollination services for coffee, considering not just yield but also its cup profile. We provide early evidence suggesting bee pollination improves coffee aroma, a critical quality attribute in specialty coffee. Our research emphasizes the importance of protecting or restoring bee habitats in coffee farms, which can not only improve income for coffee producers but also conserve biodiversity. Integrating these ecological insights into initiatives like 'bee-friendly' coffee production presents an innovative approach for stakeholders in the coffee supply chain and can serve as a strategic nexus of agricultural, economic, and ecological interests.

Urban pavements as a novel habitat for wild bees and other ground-nesting insects

AbstractMunicipal authorities around the world have come to recognize the importance of making conservation and restoration a priority. Multiple urban restoration programs now foster insects and other pollinators through planting and sowing flowering plants, many of them within residential areas. But residents are not only walking next to pollinators visiting flowering sidewalk grass verges, they are also walking on top of them, nesting in the cracks and interstices of urban pavements.Combining morphological and molecular monitoring schemes, we conducted a survey of urban pavements at twelve locations across Berlin and found that pavements can foster a surprising number and quantity of soil dwelling insects—in particular wild bees and wasps. Pavements located within 200 m to an insect-friendly flower garden were covered with significantly more nests of wild bees and solitary wasps, and showed higher species richness of these groups, while the degree of sealed surfaces in the surrounding had no effect per se. This underlines the positive impact that insect-friendly gardens can have for pollinators and other insects, even in highly sealed areas. Also, it shows the potential of cobbled pavements as valuable nesting sites in highly sealed urban areas. We provide a list of 55 species of ground-nesting Hymenoptera found in Berlin pavements, including 28 species of wild bees and 22 apoid wasps. In our study, the molecular approach only detected three Hymenoptera species and did not yield comparable results to classical monitoring. Nonetheless, using eDNA methods might be a promising tool for further studying soil nesting insects in the future, and to gain insights into the web of life in urban pavements.

Current trends in bee conservation and habitat restoration in different types of anthropogenic habitats

Recent declines in bee populations and ranges have been cause for concern due to the valuable pollination service that they provide. Several factors have been proposed to contribute to these declines, including habitat loss, pathogen spread, and pesticide usage, so many pollinator conservation schemes have involved the addition of pollinator-friendly habitat through wildflower plantings and artificial nesting sites. Because of this, many efforts have been made to enhance bee populations across different landscape types, including natural, agricultural, urban, and industrial areas. Many of these schemes have focused on providing habitat for bees and other animal pollinators in agricultural landscapes, but other managed areas, such as cities, suburbs, and industrialized areas may have untapped potential for pollinator conservation. Available green space can be enhanced to provide healthy forage and safe nesting sites for pollinators. As these areas are also often frequented by human residents, the needs and perceptions of people, as well as the potential benefits for pollinators, must be considered to ensure the success of pollinator conservation on anthropogenic habitats.

Native bee habitat restoration: key ecological considerations from recent North American literature

Habitat loss is a primary driver of global biodiversity decline, negatively impacting many species, including native bees. One approach to counteract the consequences of habitat loss is through restoration, which includes the transformation of degraded or damaged habitats to increase biodiversity. In this review, we survey bee habitat restoration literature over the last 14 years to provide insights into how best to promote bee diversity and abundance through the restoration of natural landscapes in North America. We highlight relevant questions and concepts to consider throughout the various stages of habitat restoration projects, categorizing them into pre-, during-, and post-restoration stages. We emphasize the importance of planning species- and site-specific strategies to support bees, including providing floral and non-floral resources and increasing nest site availability. Lastly, we underscore the significance of conducting evaluations and long-term monitoring following restoration efforts. By identifying effective restoration methods, success indicators, and areas for future research, our review presents a comprehensive framework that can guide land managers during this urgent time for bee habitat restoration.

Improving Bee Living Conditions through Ecological Thermal Insulation and Remote Early Anomaly Detection-Vital Step Towards Preserving Bees Population

Abstract This publication underscores the vital role of bees, particularly their contribution to products like honey, pollen, and propolis, which offer significant health benefits. Notably, 79% of the world’s food supply relies on bees; thus, their declining numbers pose a threat to pollination and food security. The study explores an ecological thermal insulation for hives using animal biomass and a monitoring system to detect anomalies in bee habitats early. This approach aims to protect bee populations and enhance global food security through improved data-driven practices.

Are parks as favourable habitats for wild bees as wastelands in watercourse valleys of a large city?

Because of the growing population density and rate of urban development, the question of biodiversity conservation in cities and towns is increasingly important. In general, urban environments provide attractive habitats for a diversity of wild bees, but different types of urban habitats can have different effects on these pollinating insects. In this study, we compared the attractiveness of two different urban habitat types – parks (10 sites) and wastelands (10 sites) located in river and canal valleys in Bydgoszcz (northern Poland) – with respect to abundance, species richness, species composition, and functional trait composition of wild bees. We hypothesized that urban wastelands are more attractive to wild bees than urban parks are. Urban wastelands were characterized by higher abundance and species richness of wild bees compared to urban parks. When habitat type was the only predictor, nonlinearity of wild bee abundance and species richness was significant exclusively for wastelands. Overall, both wild bee abundance and species richness depended on the percentage of total bee food plant coverage, regardless of habitat type. Wild bee community composition also responded significantly to the percentage of total bee food plant coverage. Local and landscape features of the green spaces affected the functional traits of the wild bees recorded there. These findings reveal that formal green spaces, such as managed parks, are not sufficient to conserve wild bee resources in urban environments in river and canal valleys. In contrast, high-quality informal urban green spaces, such as urban wastelands, can promote abundant and rich wild bee communities. Thus it is crucial to strive for appreciation and protection of this persistently overlooked category of urban green spaces.

Dietary foundations for pollinators: nutritional profiling of plants for bee health

Human activities, including urban expansion, intensive farming practices, and the application of pesticides have significantly reshaped bee habitats. Understanding the nutritional content of pollen, the primary source of bees’ proteins and lipids, is important for maintaining their diet and health. In this study, we set out to determine the nutritional composition of pollen from various plant families and genera. Our objectives were to analyze the levels of non-esterified fatty acids (NEFAs), amino acids (AAs), protein-to-lipid (P:L) ratios, and omega-6:3 ratios of 57 pollen species native to North America. These data suggest a potential trade-off between NEFA and AA content within pollen, suggesting that a diverse floral diet may benefit bees more than a single pollen source. The AA profiles showed considerable diversity, with all pollen species providing the essential amino acids (EAAs) required for bee health, except for methionine which was lacking in Rhus glabra pollen. The plant family Asteraceae was especially abundant in EAAs. P:L ratios varied widely further emphasizing bees’ need for access to a diverse array of nutritional profiles. There were no overall nutritional differences between pollen from native and introduced plant species. This study highlights the significance of a diverse array of floral resources to meet the comprehensive nutritional needs of bees, contributing to the support of pollinator populations and the broader ecological system.

Sampling the understory, midstory, and canopy is necessary to fully characterize native bee communities of temperate forests and their dynamic environmental relationships

IntroductionNative bee communities of temperate forests are conventionally sampled from the understory, yet there is growing evidence that bee assemblages in forest canopies are distinct from those in the understory. Therefore, conventional approaches to quantify forest bee–habitat relationships may not comprehensively characterize forest bee communities.MethodsTo examine this, we sampled bees 1–26 m from ground level at 5-m increments at 47 locations in forests located in western Massachusetts, USA. We evaluated bee abundance and species richness responses to a suite of environmental factors measured in the understory with linear and segmented regression comparing four bee sampling strategies: (1) understory sampling only, (2) understory and midstory, (3) understory and canopy, and (4) all strata combined.ResultsWe found that not sampling higher strata underestimated bee abundance and species richness, and linear models had less ability to explain the data when bees of higher strata were included. Among strategies, responses analyzed linearly differed in magnitude due to overall differences in abundance and species richness, but segmented regressions showed relationships with understory characteristics that also differed in slope, which would alter interpretation.DiscussionCollectively, our findings highlight the value of including vertically stratified sampling strategies throughout the flight season to fully characterize native bee and other pollinator communities of forests.

Rapid responses of bees and butterflies but not birds to targeted urban road verge habitat enhancements

Abstract Cities provide opportunities for biodiversity conservation through the design of urban greenspaces as wildlife habitat. A significant proportion of urban public land is narrow linear road verges, though their small size and harsh environmental conditions (e.g. high soil temperatures) may limit their ability to support plants and animals. We worked with a municipal government in a highly urbanised area to test whether conversion of standard road verges (e.g. lawn) to predominantly native understorey plants (forbs, grasses and shrubs) selected for their abilities to tolerate harsh growing conditions and provide habitat increased the abundance and richness of bees, butterflies and birds. We used a before‐after‐control‐impact experiment and characterised temporal dynamics of biodiversity responses 1 year prior to planting and 4 years post‐planting. We also tested whether traits known to influence species responses to urbanisation (body size and feeding specialisation) mediated responses to road verge plantings. Bee species richness and abundance increased at experimental plantings in the first post‐planting year and remained stable thereafter despite fluctuations at control sites. Butterfly abundance but not richness increased, and there was no evidence of bird responses to plantings. Larger bee species, which are known to be most negatively impacted by urbanisation, benefited more from the road verge plantings, while there was no effect of feeding specialisation. Bird and butterfly traits did not mediate responses to plantings. Synthesis and applications. Road verges comprise a significant proportion of urban green spaces, and our results suggest that despite their small sizes and harsh environmental conditions they can provide habitat for bees and to a lesser extent butterflies. We demonstrated that habitat value can be rapidly enhanced by converting standard road verges to native understorey plants and that these benefits may be greatest for the bee species most negatively impacted by urbanisation. Modifications such as additional plant species or wider verges may be required for urban road verges to provide habitat for a greater range of taxa including birds and butterflies.

Unravelling the impact of climate change on honey bees: An ensemble modelling approach to predict shifts in habitat suitability in Queensland, Australia.

Honey bees play a vital role in providing essential ecosystem services and contributing to global agriculture. However, the potential effect of climate change on honey bee distribution is still not well understood. This study aims to identify the most influential bioclimatic and environmental variables, assess their impact on honey bee distribution, and predict future distribution. An ensemble modelling approach using the biomod2 package in R was employed to develop three models: a climate-only model, an environment-only model, and a combined climate and environment model. By utilising bioclimatic data (radiation of the wettest and driest quarters and temperature seasonality) from 1990 to 2009, combined with observed honey bee presence and pseudo absence data, this model predicted suitable locations for honey bee apiaries for two future time spans: 2020-2039 and 2060-2079. The climate-only model exhibited a true skill statistic (TSS) value of 0.85, underscoring the pivotal role of radiation and temperature seasonality in shaping honey bee distribution. The environment-only model, incorporating proximity to floral resources, foliage projective cover, and elevation, demonstrated strong predictive performance, with a TSS of 0.88, emphasising the significance of environmental variables in determining habitat suitability for honey bees. The combined model had a higher TSS of 0.96, indicating that the combination of climate and environmental variables enhances the model's performance. By the 2020-2039 period, approximately 88% of highly suitable habitats for honey bees are projected to transition from their current state to become moderate (14.84%) to marginally suitable (13.46%) areas. Predictions for the 2060-2079 period reveal a concerning trend: 100% of highly suitable land transitions into moderately (0.54%), marginally (17.56%), or not suitable areas (81.9%) for honey bees. These results emphasise the critical need for targeted conservation efforts and the implementation of policies aimed at safeguarding honey bees and the vital apiary industry.

Effect of land-use intensity and adjacent semi-natural habitats on wild and honey bees of meadows

Most terrestrial ecosystems are shaped by the pollination service provided by insects, foremost bees. As bees are also important pollinators of crop plants, they are key for both the pollination of wild plants and for agricultural production. Meadows and semi-natural habitats (SNHs) are important habitats for bees. However, there is limited knowledge on how land-use intensity of meadows affects wild bees and managed Western honey bees. Further, it is unknown whether SNHs adjacent to meadows affect bees in meadows. Here, we examined in a landscape dominated by grasslands, the effects of land-use intensity (nitrogen input, grazing intensity, mowing frequency), flower availability and adjacent SNHs on bee communities in meadows. We recorded more than 5000 individuals of 87 species of bees and found no effect of land-use intensity on wild and honey bees. Flowering plant species richness had a positive effect on bee species richness in one study year. Though we recorded more bee species in SNHs than meadows, overall and specifically in ecologically specialized bee species (e.g. parasitic bees, oligoleges), the availability of adjacent SNHs did not affect bee abundance and richness in meadows. We discuss why land-use intensity and SNHs adjacent to meadows did not affect bees in meadows and conclude that SNHs are important in sustaining functionally diverse bee communities in landscapes dominated by grasslands.

The Impact of Weather Change on Honey Bee Populations and Disease

This review provides an overview of the honey bee (Apis mellifera) which is one of the most important pollinators for agriculture and ecosystems, considered a critical yet fragile contributor to world biodiversity and food security among the countless species facing unprecedented challenges due to uneven climate drivers. Scientists are concerned about the impact of climate change on honey bee habitats. This review study looks at the complicated relationship between climate change and honey bees’ health leading to their genetic and behavioural changes. Further, it also mentions how changes in temperature and weather patterns affect foraging, reproduction and colony survival. This study will focus on the different processes that highlight their susceptibility and emphasise the critical need for comprehensive approaches to mitigate the potential consequences through policy implementation. 

Determining Minnesota bee species' distributions and phenologies with the help of participatory science.

The Minnesota Bee Atlas project contributed new information about bee distributions, phenologies, and community structure by mobilizing participatory science volunteers to document bees statewide. Volunteers submitted iNaturalist (©2016 California Academy of Sciences) photograph observations, monitored nest-traps for tunnel-nesting bees, and conducted roadside observational bumble bee surveys. By pairing research scientists and participatory science volunteers, we overcame geographic and temporal challenges to document the presence, phenologies, and abundances of species. Minnesota Bee Atlas project observations included new state records for Megachile inimica, Megachile frugalis, Megachile sculpturalis, Osmia georgica, Stelis permaculata, and Bombus nevadensis, nesting phenology for 17 species, a new documentation of bivoltinism for Megachile relativa in Minnesota, and over 500 observations of the endangered species Bombus affinis. We also expanded known ranges for 16 bee species compared with specimens available from the University of Minnesota (UMN) Insect Collection. Surveys with standardized effort across the state found ecological province associations for six tunnel-nesting species and lower bumble bee abundance in the Prairie Parkland ecological province than the Laurentian Mixed Forest or Eastern Broadleaf Forest ecological provinces, indicating potential benefit of a focus on bumble bee habitat management in the Prairie Parkland. Landcover analysis found associations for four tunnel-nesting species, as well as a possible association of B. affinis with developed areas. These data can inform management decisions affecting pollinator conservation and recovery of endangered species. By engaging over 2,500 project volunteers and other iNaturalist users, we also promoted conservation action for pollinators through our educational programs and interactions.

Wild bee and pollen microbiomes across an urban-rural divide.

Wild pollinators and their microbiota are sensitive to land use changes from anthropogenic activities that disrupt landscape and environmental features. As urbanization and agriculture affect bee habitats, human-led disturbances are driving changes in bee microbiomes, potentially leading to dysbiosis detrimental to bee fitness. This study examines the bacterial, fungal, and plant compositions of the small carpenter bee, Ceratina calcarata, and its pollen provisions across an urban-rural divide. We performed metabarcoding of C. calcarata and provisions in Toronto by targeting the 16S rRNA, ITS, and rbcL regions. Despite similar plant composition and diversity across bees and their provisions, there was a greater microbial diversity in pollen provisions than in bees. By characterizing the differences in land use, climate, and pesticide residues that differentiate urban and rural landscapes, we find that urban areas support elevated levels of microbial diversity and more complex networks between microbes and plants than rural areas. However, urban areas may lead to lower relative abundances of known beneficial symbionts and increased levels of pathogens, such as Ascosphaera and Alternaria fungi. Further, rural pollen provisions indicate elevated pesticide residues that may dysregulate symbiosis. As anthropogenic activities continue to alter land use, ever changing environments threaten microbiota crucial in maintaining bee health.

Urban wild bees benefit from flower-rich anthropogenic land use depending on bee trait and scale

ContextWild bees are important pollinators for wild and cultivated plants. Besides other causes, their decline has been linked to land-use change such as urbanisation. In contrast, urban habitats are discussed as potential wild bee refuges.ObjectivesTo expand our understanding of cities as wild bee habitats, bee responses to urban land-use types with varying foraging and nesting resources were analysed.MethodsWild bees were sampled with pan traps at 49 study sites in a Central European city. Effects of land-use types on wild bees were examined at 12 scales ranging from 50 to 1500 m from sampling points. For analyses, bees were grouped according to their traits (e.g., size, nesting and pollen-collecting behaviour) to account for species-specific requirements.ResultsLand-use types significantly affected wild bees covering all investigated scales. Anthropogenically managed flower-rich habitats, i.e., long-term allotments and cemeteries, were beneficial for most wild bee groups within varying scales between 200 and 600 m. Impervious surface affected only some of the investigated wild bee groups, mostly in a unimodal manner within a 100 m scale.ConclusionsThis study shows that it is recommended for future investigations to take different scales and different bee traits into account when assessing urban habitat quality for bees. In particular, the non-linear response to impervious surface indicates positive edge effects between urban core and rural areas. Conservation measures and implementation management to support wild bees in urban areas should consider the results on scale and land use to meet species-specific demands effectively.

Biotic and abiotic stresses on honeybee health.

Honeybees are the most critical pollinators providing key ecosystem services that underpin crop production and sustainable agriculture. Amidst a backdrop of rapid global change, this eusocial insect encounters a succession of stressors during nesting, foraging, and pollination. Ectoparasitic mites, together with vectored viruses, have been recognized as central biotic threats to honeybee health, while the spread of invasive giant hornets and small hive beetles also increasingly threatens colonies worldwide. Cocktails of agrochemicals, including acaricides used for mite treatment, and other pollutants of the environment have been widely documented to affect bee health in various ways. Additionally, expanding urbanization, climate change, and agricultural intensification often result in the destruction or fragmentation of flower-rich bee habitats. The anthropogenic pressures exerted by beekeeping management practices affect the natural selection and evolution of honeybees, and colony translocations facilitate alien species invasion and disease transmission. In this review, the multiple biotic and abiotic threats and their interactions that potentially undermine bee colony health are discussed, while taking into consideration the sensitivity, large foraging area, dense network among related nestmates, and social behaviors of honeybees.

Phenologically Targeted Grazing: A Potential Sustainable Strategy for Native Bees in Semiarid Rangelands

Rangelands may offer valuable habitat for invertebrate wildlife, helping conserve ecologically and economically significant organisms, like native bees. In some systems, livestock may affect bees by consuming or trampling blooming plants that bees rely on for food. One potential way to reduce potential negative effects of livestock on bees is to delay grazing on floristically rich parts of the landscape until after peak bloom (i.e., phenologically targeted grazing). To test the outcome of this method, we collected bees using pan traps and counted blooming stems from May to September in grazed and ungrazed sites. Our sites were located in two experimental cattle grazing systems in the Pacific Northwest, United States, in which cattle turnout did not occur until after peak forb bloom. One system was located in bunchgrass prairie, and the other was located in riparian meadows. Our objectives were to 1) quantify seasonal variation in bee and blooming plant communities and 2) measure how or if these communities responded to grazing. In both systems, bee and bloom species richness peaked in June and bloom abundance and diversity were highest in May and June. Bee abundance and diversity were more variable throughout the season. We observed significantly lower abundance, richness, and diversity of blooming species in the riparian system in response to grazing, potentially decreasing floral resource availability for bees, but did not detect a concomitant negative effect on bees. In the bunchgrass system, we observed no significant negative effects of grazing on bees or blooming plants. This suggests that for areas with high-quality bee habitat, site-specific, phenologically targeted grazing may moderate negative effects of livestock on bee and plant communities. Range managers could use alternative grazing locations (e.g., old fields, early senescing sites, more intensively managed pastures), if available, during peak bloom to mitigate potential herbivory effects on bees and blooms.

Location and Creation of Nest Sites for Ground-Nesting Bees in Apple Orchards.

Wild ground-nesting bees are key pollinators of apple (Malus domestica). We explored, (1) where they choose to nest, (2) what influences site selection and (3) species richness in orchards. Twenty-three orchards were studied over three years; twelve were treated with additional herbicide to increase bare ground with the remainder as untreated controls. Vegetation cover, soil type, soil compaction, nest number and location, and species were recorded. Fourteen species of ground-nesting solitary/eusocial bee were identified. Most nests were in areas free of vegetation and areas treated with additional herbicide were utilised by ground nesting bees within three years of application. Nests were also evenly distributed along the vegetation-free strips underneath the apple trees. This area was an important ground-nesting bee habitat with mean numbers of nests at peak nest activity of 873 per ha (range 44-5705), and 1153 per ha (range 0-4082) in 2018 and 2019, respectively. Increasing and maintaining areas of bare ground in apple orchards during peak nesting events could improve nesting opportunities for some species of ground-nesting bee and, combined with flowers strips, be part of a more sustainable pollinator management approach. The area under the tree row is an important contributor to the ground-nesting bee habitat and should be kept bare during peak nesting.

Different semi-natural habitat types provide complementary nesting resources for wild bees

Semi-natural habitats provide refuge for pollinating insects such as wild bees. Different types of semi-natural habitat can provide complementary floral resources throughout the year, but it is uncertain to what extent different semi-natural habitat types provide nesting habitat for wild bees. In this study, nesting resources for wild bees and nest-searching bees were surveyed visually in three different types of semi-natural habitat (i.e., hollow roads, tree rows, and forest edges). The composition of nesting resources for wild bees varied across the three types of semi-natural habitat. We also identified clear indicators of nesting resources within the different habitat types. We conclude that different types of semi-natural habitat provide varying and complementary nesting resources for wild bees. This study further highlights the importance of semi-natural habitat for pollinator conservation and emphasizes the need for further research to increase our understanding how different wild bee species use different habitat types for nesting.