Apidae Research Articles

Morphological and Histological Structure of Adexinal Glands of some Solitary Bee Species (Hymenoptera – Apoidea)

Solitary bees are diverse and very important for plant and crop pollination. They are extensively studied taxonomically, but little is known about their anatomy and physiology compared to honey bees. Dufour’s gland is important for many physiological functions in social and solitary bees. The present study addresses the morphological and histological structure of Dufour’s gland in ten bee species representing bee families Andrenidae, Colletidae, Halictidae, Melittidae, Megachilidae, and Apidae. Results indicated that the shape and size of the glands tend to differ from one species to the other. However, on histological bases, the intern seems to be the same among the secretion cell types. The gland varied in length and size in the studied species, probably due to nesting behavior differences: ground and cavity nesting. Further studies are needed to clarify the different secretions produced by Dufour’s gland and their functions in each species.

Evaluation of wild bee diversity in fruit orchards within the Ba Den mountain area, Tay Ninh Province, Vietnam

Wild bees are commonly found and play a vital role in pollinating various crops. Unfortunately, the number of wild bee species is experiencing a steep decline, attributed to deforestation, the application of agricultural pesticides, escalating environmental pollution, and the spread of urbanization. Hence, research on bee diversity is essential for the protection of these crucial pollinators. The objective of this study was to conduct a comparative assessment of wild bee richness and abundance within fruit orchards. From February to May 2023, the study was conducted in the Ba Den mountain area of Tay Ninh Province, encompassing Tay Ninh City and the Duong Minh Chau district. Malaise traps were used to collect bee samples during the flowering season of the fruit orchards. Simultaneously, the flowering plants in the surrounding vicinity were meticulously identified and observed. The composition of wild bees was determined and compared between orchards. In total, 836 bee specimens belonging to 27 distinct wild bee species spanning three families, along with 30 flowering plant species across 17 families, were recorded. It was found that the Apidae family stood out as the most abundant and diverse group within the wild bee population. Additionally, the abundance of Ceratina smaragdula was noted across three orchards. Within the fruit orchards, the Fabaceae and Asteraceae families emerged as widely prevalent among flowering plants. Importantly, the first fruit orchard exhibited a greater richness and abundance of wild bees, coupled with a higher count of flowering plant species, in comparison to the other fruit orchards. The amassed data in this study, which encompasses insights into biodiversity, distribution patterns, and variations across different orchards, not only aids in the preservation of these pivotal pollinators but also lends essential support to the realm of agricultural production.

A novel parasitic beetle, Procoryphaeus violaceus, in stingless bees, Tetragonula pagdeni

Two beetle parasites of social bees are known to cause colony collapse: small hive beetles, Aethina tumida, in honey bees and Haptoncus luteolus in stingless bees. Here, we report for the first time parasitic beetles, Procoryphaeus violaceus, causing colony collapse in stingless bees, Teteragonula pagdeni.

Melipona stingless bees and honey microbiota reveal the diversity, composition, and modes of symbionts transmission.

The Melipona gut microbiota differs from other social bees, being characterized by the absence of crucial corbiculate core gut symbionts and a high occurrence of environmental strains. We studied the microbial diversity and composition of three Melipona species and their honey to understand which strains are obtained by horizontal transmission (HT) from the pollination environment, represent symbionts with HT from the hive/food stores or social transmission (ST) between nestmates. Bees harbored higher microbial alpha diversity and a different and more species-specific bacterial composition than honey. The fungal communities of bee and honey samples are also different but less dissimilar. As expected, the eusocial corbiculate core symbionts Snodgrassella and Gilliamella were absent in bees that had a prevalence of Lactobacillaceae - including Lactobacillus (formerly known as Firm-5), Bifidobacteriaceae, Acetobacteraceae, and Streptococcaceae - mainly strains close to Floricoccus, a putative novel symbiont acquired from flowers. They might have co-evolved with these bees via ST, and along with environmental Lactobacillaceae and Pectinatus (Veillonellaceae) strains obtained by HT, and Metschnikowia and Saccharomycetales yeasts acquired by HT from honey or the pollination environment, including plants/flowers, possibly compose the Melipona core microbiota. This work contributes to the understanding of Melipona symbionts and their modes of transmission.

A review on recent taxonomic updates of gut bacteria associated with social bees, with a curated genomic reference database.

Honeybees and bumblebees play a crucial role as essential pollinators. The special gut microbiome of social bees is a key factor in determining the overall fitness and health of the host. Although bees harbor relatively simple microbial communities at the genus level, recent studies have unveiled significant genetic divergence and variations in gene content within each bacterial genus. However, a comprehensive and refined genomics-based taxonomic database specific to social bee gut microbiomes remains lacking. Here, we first provided an overview of the current knowledge on the distribution and function of social bee gut bacteria, as well as the factors that influence the gut population dynamics. We then consolidated all available genomes of the gut bacteria of social bees and refined the species-level taxonomy, by constructing a maximum-likelihood core genome phylogeny and calculating genome-wide pairwise average nucleotide identity. On the basis of the refined species taxonomy, we constructed a curated genomic reference database, named the bee gut microbe genome sequence database (BGM-GDb). To evaluate the species-profiling performance of the curated BGM-GDb, we retrieved a series of bee gut metagenomic data and inferred the species-level composition using metagenomic intra-species diversity analysis system (MIDAS), and then compared the results with those obtained from a prebuilt MIDAS database. We found that compared with the default database, the BGM-GDb excelled in aligned read counts and bacterial richness. Overall, this high-resolution and precise genomic reference database will facilitate research in understanding the gut community structure of social bees.

An update on gynandromorphism records in the Meliponini tribe (Hymenoptera: Apidae): first case in Melipona flavolineata

Gynanders are individuals with genetic anomalies that express characteristics of both sexes in the same individual. Gynandromorphism is very recurrent in solitary bees but with few records in social stingless bees. In this article, we describe a gynander for Melipona flavolineata, compile the literature records for the Meliponini tribe compared with them, and discuss the causes and implications of this anomaly. The described specimen shows mosaic gynandromorphism. Of the five cases already available in the literature, two referred to mosaic gynanders and two to bilateral gynanders. No transverse gynandromorphs in Meliponini have been recorded to date. With this study, there are now a total of five gynanders published in the literature for Meliponini, but there is no defined morphological pattern between the different reports. We suggest that polyploidy is the main factor responsible for the randomness in the expression of anomalous traits.

An automatic bioinformatic system for Identification and classification of Hymenoptera (The Apidae family)

In this paper we illustrate our bioinformatics system destined for an automatic insect classification in different taxonomic categories corresponding to different levels of precision according to their morphological characteristics such as: size; color; antennae; wings; mouthpart; etc. Our main goal is to automate the research; classification and to create an exhaustive database of insects in order to create a common directory of insects to save significant research time and facilitate classification. Our system is considered as a bioinformatics system, it uses artificial intelligence techniques to create an inference engine able to automatically recognize and classify a new insect. It also uses database creation techniques to create the knowledge and fact bases necessary for the proper functioning of the inference engine. Due to its interactive graphic interface, and by guiding its user, step by step, the system starts with the introduction of the morphological characteristics of the insect and the result is to automatically classify the insect in the database in the appropriate species. Our classification is focused on Hymenoptera precisely on the Apidae family, we have given a detailed classification of the Apidae family with its three subfamilies: Apinae, Xylocopinae and Nomadini. Our system is implemented completely in JAVA programming language using phpMyadmin as a database management system.

Insight on kleptoparasitic bee, Melecta chinensis (hymenoptera: Apidae), in the Republic of Korea: Morphology, biology and molecular characteristics

AbstractThis study focused on a kleptoparasitic bee, Melecta chinensis, which is not well‐known in the Republic of Korea. We provided a detailed morphological illustration of the adult bees and their nesting biological characteristics with distributional data. Additionally, the complete mitochondrial genome of the species is presented for the first time, and its phylogenetic position within the family Apidae is estimated.As a result, we could suggest a full redescription of M. chinenesis for identification and a newly reported potential flower host for it. In addition, the mitochondrial DNA (mtDNA) of M. chinensis is revealed as 15,489 base pairs (bp) long, with 35 eukaryotic mitochondrial genes (13PCGs, 2 rRNAs, and 20 tRNAs) and a 706 bp AT‐rich region. The overall base composition is 75.82% AT and 24.18% GC. The 13 protein‐coding genes (PCGs) started with a typical ATN codon (ATA in nine genes and ATG in four genes) and terminated with TNN (TAN in 10 genes and TTT in one gene) or ANN (AAC in one gene and ATT in one gene). The phylogenetic results based on 13 PCGs showed that M. chinensis is distantly positioned to bumble bees (Bombus) and honey bees (Apis) but closely related to a stingless bee, Frieseomelitta varia, within the family.

Mechanisms for polyandry evolution in a complex social bee

Polyandry in social Hymenoptera is associated with reduced within-colony relatedness and increased colony-level ecologic fitness. One explanation for this sees increasing within-nest genetic diversity as a mechanism for improving group task efficiency and colony competitiveness. A queen on her mating flight captures nearly 90% of her breeding population’s allele potential by her tenth effective mating (me ~ 10 males). Under this population allele capture (PAC) model, colony fitness gains track mating number in an asymptotic manner, leveling out after about the tenth mating. A supporting theory we call the genotype composition (GC) model sees genetic novelty at mating levels higher than the me ~ 10 asymptote, the hyperpolyandry zone, resulting from unique genotype compositions whose number are potentially infinite. Colony fitness gains under the GC model will track mating number in a linear manner. We set up field colonies with Apis mellifera queens each instrumentally mated with 1, 2, 4, 8, 16, or 32 males, creating a polyandry gradient bracketing the qualitative divide of me ~ 10, measured tokens of colony level fitness, and collected observation hive data. Our results lead us to conclude that (1) ancestral colony traits fundamental to eusociality (cooperative brood care) respond to mating level changes at or below me ~ 10 in a manner consistent with the PAC model, whereas (2) more derived specialized colony phenotypes (resistance to the non-native parasite Varroa destructor) continue improving with increasing me in a manner consistent with the GC model. By either model, (3) the mechanism for increasing colony fitness is an increase in worker task specialisms and task efficiency.Significance statementPolyandry is a female’s practice of mating with many males, storing their sperm, and using it to produce genetically diverse offspring. In complex social bees, a queen captures nearly 90% of her breeding population’s diversity potential by her tenth mating; however, queens in nature routinely mate with many more than ten males. We tested two models that, together, explain how social bee colonies ecologically benefit from queen mating numbers ranging from 2 to potential infinity. A population allele capture (PAC) model focuses on colony fitness gains at mating numbers at or below 10, and we provide evidence that it was at these polyandry levels that significant gains were made in an ancestral eusocial trait, cooperative brood care. A genotype composition (GC) model focuses on colony fitness gains at higher mating numbers, and we believe these gains are centered around more recently evolved ecologic specialisms such as parasite resistance.

Distinct fungal microbiomes of two Thai commercial stingless bee species, Lepidotrigona terminata and Tetragonula pagdeni suggest a possible niche separation in a shared habitat.

Stingless bees, a social corbiculate bee member, play a crucial role in providing pollination services. Despite their importance, the structure of their microbiome, particularly the fungal communities, remains poorly understood. This study presents an initial characterization of the fungal community associated with two Thai commercial stingless bee species, Lepidotrigona terminata (Smith) and Tetragonula pagdeni (Schwarz) from Chiang Mai, Thailand. Utilizing ITS amplicon sequencing, we identified distinct fungal microbiomes in these two species. Notably, fungi from the phyla Ascomycota, Basidiomycota, Mucoromycota, Mortierellomycota, and Rozellomycota were present. The most dominant genera, which varied significantly between species, included Candida and Starmerella. Additionally, several key enzymes associated with energy metabolism, structural strength, and host defense reactions, such as adenosine triphosphatase, alcohol dehydrogenase, β-glucosidase, chitinase, and peptidylprolyl isomerase, were predicted. Our findings not only augment the limited knowledge of the fungal microbiome in Thai commercial stingless bees but also provide insights for their sustainable management through understanding their microbiome.

Heatwaves increase larval mortality and delay development of a solitary bee

Abstract Heatwaves are expected to increase in frequency, intensity and duration due to climate change. For organisms like insects with discrete development, sensitivity may differ among life stages. Thermal sensitivity is of particular concern for species like bees that provide critical ecosystem services. Although social bees moderate nest temperatures through worker behaviour, solitary bees do not thermoregulate their nests, making immobile developing offspring especially vulnerable to such extreme events. We studied the effects of heatwaves on larval development in the solitary bee, Osmia lignaria, an important orchard pollinator and model species for solitary bee biology. We used a factorial design to assess the impacts of heatwave temperature and duration on larval mortality and development rate. Larvae were exposed to heatwaves under realistic diel temperature regimes, with daytime maxima of 31 or 37°C for 4 or 7 days at the beginning of development. Heatwave temperature strongly affected larval mortality. Exposure to 37°C heatwaves increased larval mortality by 130%, but the cooler 31°C heatwaves did not significantly impact mortality. Heatwave duration did not impact larval mortality. Larval development time also was affected by heatwave exposure. Compared with the no‐heatwave‐control, bees in the 31°C heatwave developed faster, and bees in the 37°C heatwave developed slower. Our study reveals the importance of stage‐specific effects of extreme events and suggests that the timing and maximum temperature of projected heatwaves may be more detrimental to populations than heatwave duration.

Contributions to the wild bee fauna in Argentina (Hymenoptera: Anthophila)

Argentina is the country with the second highest number of bee species in the Neotropics after Brazil. Fifteen new records of wild bees belonging to genera of the families Apidae, Andrenidae, Colletidae, Halictidae, and Megachilidae are presented. Species of genera Callonychium Brèthes (Andrenidae), Gaesischia Michener, LaBerge & Moure, Melitoma Lepeletier & Serville, Trichocerapis Cockerell (Apidae), Hylaeus Fabricius (Colletidae), Habralictus Moure, Megalopta Smith, Neocorynura Schrottky, Pseudaugochlora Michener, Rhectomia Moure, Thectochlora Moure (Halictidae), and Bothranthidium Moure (Megachilidae) are recorded for the first time for Argentina. Whereas the genera Trichocerapis, Megalopta, Rhectomia, and Bothranthidium are cited for the first time in the country.

Pengaruh bentuk morfologi bunga tanaman refugia terhadap ketertarikan serangga polinator dan musuh alami Ordo Hymenoptera

The refugia plant is a flowering plant that functions as a shelter and food source for natural enemy insects and pollinator insects. The number of natural enemy insects and pollinators visiting plants is due to differences in morphological characters, flower color, nectar, flowering time and aroma. insects like small flowers, open petals, easy-to-reach pollen locations and also a longer flowering time. Randomized Block Design (RBD) with 4 replications and 8 treatments of flower types, namely Cosmos caudatus, Zinna elegans, Melampodium divaricatum, Tegestes erecta, Cucumis sativus L., Bassica rapa, Solanum melongena L., Lycopersicum esculentum Mill. The results showed that the percentage of Melampodium divaricatum Produced the percentage of parasitoid insects from the Chalcidade family is 17% and Braconidae 16?. Most of the visitors to C. caudatus flowers are parasitoid insects from the Braconidae family, 18%. In Zinnia sp flowers, parasitoid insect visits from the Pompilidae family were 19%. T. erecta flowers that visit pollinator insects from the family Apidae 23%. In the type of horticultural flower, namely C. sativus , the largest in the predatory insect family Ampulicidae is 25%. , whereas in the flowers of the B. rapa family Barconidae 39%, S. melongena L. Ichenumonidae and Braconidae 33% , L. esculentum Mill. Icneumonidae as much as 38% of these insects as parasitoids. Best treatment for M. divaricatum flowers with open flower types, pollen location outside, crown diameter 23.44 mm, base diameter 11.48 mm, flower tube length 5.22 mm, flowering time 24.25 days.

Pollinator intraspecific body size variation and sociality influence their interactions with plants

Abstract Species morphological and behavioural traits are key determinants of which pollinator species interact with which plant species. However, individuals within species are not identical in their traits and this diversity could help us understand plant–pollinator interaction patterns. Using three independent data sets, we assessed whether bee intraspecific body size variation (ITV) and sociality influenced pollinator interaction specialisation, intraspecific niche partitioning, centrality in the interaction network and phylogenetic diversity of the plants visited. We found that solitary pollinators were more specialised in their interactions with plants and had lower intraspecific niche partitioning compared to social pollinators. Furthermore, solitary pollinators with higher ITV had higher centrality in the network and visited a higher phylogenetic diversity of plants compared to solitary species with lower ITV, whereas the opposite pattern emerged for social pollinators. Pollinator ITV did not differ between social and solitary bee species. Our findings show that the effect of pollinator body size variation on plant–pollinator interactions depends on pollinator species sociality. Specifically, solitary pollinators with higher ITV and social pollinators with lower ITV seem to be the most important contributors to maintaining the evolutionary diversity of the plant community, and also the species with the largest potential to affect (via cascade effects) the entire plant–pollinator network. Read the free Plain Language Summary for this article on the Journal blog.

Diversity of Pollinators on Sunflower

Sunflower crop was grown during rabi 2021 and summer 2022 at the M S Swaminathan School of Agriculture, Centurion University of Technology and Management, Gajapati, Odisha. Investigation has been made on diversity of different pollinating agents associated with sunflower by observing their abundance, diversity, percentage contribution following the statistical diversity indices. The present study revealed eighteen different pollinators associated with sunflower. The Indian honey bee, Apis cerana indica (F)was recorded as the most dominant hymenopteran pollinator followed by the rock bee Apis dorsata(F)from family Apidae. The foraging activity of A. c. indica was observed to be maximum during midflowering stage (1.72± 1.23 and 2.78± 1.81 bees/ capitulum/ min in 1st and 2nd season, respectively) withhighest activity during 01:00-02:00 PM (3.02 bees/ capitulum/min.) and 10:00 to 11:00 AM (4.42 bees/capitulum/ min) during first and second seasons respectively. The Apidae family members’ i.e. A. c. indica and A. dorsata have attained eudominant and other pollinators were belonging mostly to the recedentand subrecedent classes based on dominance status. The diversity indices showed mid flowering stageattracted the most diversified group of pollinators.

Exposure to a fungicide for a field-realistic duration does not alter bumble bee fecal microbiota structure.

Social bees are frequently exposed to pesticides when foraging on nectar and pollen. Recent research has shown that pesticide exposure not only impacts social bee host health but can also alter the community structure of social bee gut microbiotas. However, most research on pesticide-bee gut microbiota interactions has been conducted in honey bees; bumble bees, native North American pollinators, have received less attention and, due to differences in their ecology, may be exposed to certain pesticides for shorter durations than honey bees. Here, we examine how exposure to the fungicide chlorothalonil for a short, field-realistic duration alters bumble bee fecal microbiotas (used as a proxy for gut microbiotas) and host performance. We expose small groups of Bombus impatiens workers (microcolonies) to field-realistic chlorothalonil concentrations for 5 days, track changes in fecal microbiotas during the exposure period and a recovery period, and compare microcolony offspring production between treatments at the end of the experiment. We also assess the use of fecal microbiotas as a gut microbiota proxy by comparing community structures of fecal and gut microbiotas. We find that chlorothalonil exposure for a short duration does not alter bumble bee fecal microbiota structure or affect microcolony production at any concentration but that fecal and gut microbiotas differ significantly in community structure. Our results show that, at least when exposure durations are brief and unaccompanied by other stressors, bumble bee microbiotas are resilient to fungicide exposure. Additionally, our work highlights the importance of sampling gut microbiotas directly, when possible.IMPORTANCEWith global pesticide use expected to increase in the coming decades, studies on how pesticides affect the health and performance of animals, including and perhaps especially pollinators, will be crucial to minimize negative environmental impacts of pesticides in agriculture. Here, we find no effect of exposure to chlorothalonil for a short, field-realistic period on bumble bee fecal microbiota community structure or microcolony production regardless of pesticide concentration. Our results can help inform pesticide use practices to minimize negative environmental impacts on the health and fitness of bumble bees, which are key native, commercial pollinators in North America. We also find that concurrently sampled bumble bee fecal and gut microbiotas contain similar microbes but differ from one another in community structure and consequently suggest that using fecal microbiotas as a proxy for gut microbiotas be done cautiously; this result contributes to our understanding of proxy use in gut microbiota research.

Landscape and land use affect composition and nutritional values of bees’ food

Bees are primary pollinators across various terrestrial biomes and rely heavily on floral resources for sustenance. The composition of landscapes can influence bee foraging behavior, while human activities can directly affect both the composition and nutritional value of bee food. We aimed to assess how landscape structure and land use practices can impact the composition and nutritional value of food sources for two generalist social bee species, Apis mellifera and Scaptotrigona postica. Food samples were collected from twenty-five colonies of A. mellifera and thirteen of S. postica to examine how food composition and nutritional value may vary based on the extent of human land use and the composition of landscapes surrounding beekeeping sites. The pollen composition and nutritional value of A. mellifera were influenced by both land use practices and landscape heterogeneity. The number of patches determined total sugar and lipid content. Landscape heterogeneity affected pollen composition in S. postica, primarily due to the number of patches, while total sugar was affected by landscape diversity. Pollen nutritional value in S. postica was linked to land use, mainly meadow and vegetation, which influenced total sugar and dry matter. S. postica showed a higher sensitivity to land use changes compared to A. mellifera, which was more affected by landscape heterogeneity. Assuring landscape heterogeneity by preserving remaining forest patches around apiaries and meliponaries is crucial. Thoughtful land use planning is essential to support beekeeping activities and ensure an adequate quantity and quality of bee food resources.

Systemic pesticides in a solitary bee pollen food store affect larval development and increase pupal mortality

Solitary bees are often exposed to various pesticides applied for pest control on farmland while providing pollination services to food crops. Increasing evidence suggests that sublethal toxicity of agricultural pesticides affects solitary bees differently than the social bees used to determine regulatory thresholds, such as honey bees and bumblebees. Studies on solitary bees are challenging because of the difficulties in obtaining large numbers of eggs or young larvae for bioassays. Here we show the toxic and sublethal developmental effects of four widely used plant systemic pesticides on the Japanese orchard bee (Osmia cornifrons). Pollen food stores of this solitary bee were treated with different concentrations of three insecticides (acetamiprid, flonicamid, and sulfoxaflor) and a fungicide (dodine). Eggs were transplanted to the treated pollen and larvae were allowed to feed on the pollen stores after egg hatch. The effects of chronic ingestion of contaminated pollen were measured until adult eclosion. This year-long study revealed that chronic exposure to all tested pesticides delayed larval development and lowered larval and adult body weights. Additionally, exposure to the systemic fungicide resulted in abnormal larval defecation and increased mortality at the pupal stage, indicating potential risk to bees from fungicide exposure. These findings demonstrate potential threats to solitary bees from systemic insecticides and fungicides and will help in making policy decisions to mitigate these effects.

Insularity and its impact on stingless bee honey properties: A case study in the Zanzibar Archipelago (Tanzania)

AbstractBackgroundIslands are known to host unique flowering plant assemblages visited by insular insects, including by social bees, a phenomenon thought to potentially impact the honey composition and associated medicinal applications. In this study, we characterized several physical–chemical parameters of honey produced by the stingless bee Meliponula (Axestotrigona) ferruginea with samples collected both from continental (Kenya) and insular (Tanzania) ecosystems.ResultsOur results show that stingless bees in islands produce a honey whose composition significantly differs from those produced in the continent, with a significantly higher concentration of bioactive phytochemicals.ConclusionOur results illustrate how insularity might drive different and unique compositional profiles in honeys and provide evidence that certain groups of compounds found in stingless bee honey from the Afrotropical region have potential therapeutic benefits with medicinal applications that largely remain to be explored.

Bees go up, flowers go down: Increased resource limitation from late spring to summer in agricultural landscapes

Abstract The loss of floral resources is a leading cause of wild bee decline in agricultural landscapes, but little is known about the temporal aspects of floral resource limitation for both social and solitary bees. Understanding when floral resources are most needed is crucial for the optimal design of pollinator conservation measures. We surveyed bees and flowers in 160 semi‐natural habitat patches multiple times per year (May–July) for 5 years. We identified the seasonality of floral resources and wild bees and examined inter‐ and intra‐annual patterns of floral resource limitation at both local and landscape scales. Floral resource availability varied across years but generally peaked in late May, after which it declined and remained low through July. Bumblebee and solitary bee abundances increased across the season, leading to stronger floral resource limitation for both groups later in the season. Bumblebee abundance was marginally positively associated with the cumulative amount of landscape‐scale floral resources as well as the floral resources of the previous year. Solitary bee abundance was only predicted by local‐scale floral resources. Synthesis and applications: Our results indicate that agri‐environmental management should target the provision of summer floral resources for both social and solitary bees. Local‐scale enhancement of floral resources can likely benefit solitary bees, but bumblebees probably require the management of floral resources at the landscape scale. Increasing the floral resources and the flowering period of herbaceous habitats that cover large proportions of the landscape, such as pastures, has the greatest potential to improve summer floral resources for bees.