Safeguarding pollinators and their values to human well-being

Dual-readout fluorescence 'turn-on' lateral flow immunoassay for sensitive detection of imidacloprid

Although imidacloprid (IMI) is a widely used, highly efficient, and broad-spectrum insecticide, it poses a serious threat to pollinators such as bees, which can significantly impact crop harvests. Therefore, there is an urgent need to develop a sensitive, portable, and economical method for detecting IMI. This study establishes a novel dual-readout fluorescence 'turn-on' mode lateral flow immunoassay (LFIA) based on the inner filter effect (IFE) for the detection of IMI. The assay combines hollow gold nanoparticles (HAuNPs) and ultra-bright red luminescent bovine serum albumin (BSA)-stabilised gold nanoclusters (BSA-AuNCs) as quencher/donor pairs. HAuNPs effectively quenched the red-emitting fluorescence of BSA-AuNCs due to the higher IFE efficiency resulting from the spectral overlap. The dual-readout immunosensor exhibited fluorescence and colorimetric responses for IMI within 16 min, with limits of detection (LOD) of 7.8 and 47.8 pg/mL for fluorescence and colorimetric modes, respectively. The fluorescence mode thus attained an approximately six-fold decrease in detection limits compared with conventional gold nanoparticle-based LFIA (AuNPs-LFIA). The dual-readout fluorescence 'turn-on' immunosensor showed a good recovery range of 82.40-113.80 % for detecting IMI in real samples, with a relative standard deviation (RSD) below 11.88 %. Thus, the developed immunosensor may be used as a rapid and highly sensitive tool for the detection of hazardous substances in practical applications.

Propolis can reduce Nosema ceranae infection and enhance the immune response in honey bees, without disrupting the gut microbiota

Honey bees (Apis mellifera) play a crucial role in the environment, being essential pollinators and contributing to agricultural production and natural ecosystem diversity. However, honey bee health is threatened by multiple stressors, including infection by mites, viruses and microsporidia. To defend against invaders, these insects have evolved social and individual mechanisms, including the collection and use of propolis. In this study, we found that under laboratory conditions, the consumption of Ethanolic Extract of Propolis (EEP) reduced the infection level of the pathogen Nosema ceranae and increased the expression levels of immune-related genes (hymenoptaecin or glucose oxidase) in challenged bees, enhancing their immunocompetence. Moreover, it did not affect the diversity and composition of the gut microbiota. Despite these promising laboratory results, the administration of EEP to honey bee colonies under field conditions did not produce a beneficial effect on colony strength or pathogen infection levels. Future studies should be conducted to optimize the method and frequency of applications to maximize potential benefits for honey bee colony health.

Romance in peril: A common pesticide impairs mating behaviours and male fertility of solitary bees (Osmiabicornis)

Mating behaviour and fertility are strong selective forces, driving the reproductive trends of animals. Mating disorders may therefore contribute to the recent decline in insect and pollinators health worldwide. While the impact of pesticides on pollinators is widely considered as a driving factor for reducing pollinators health, their effect on mating behaviour and male fertility remains widely overlooked. Here, we assessed the effects of field-realistic exposure to a common pesticide used as a neonicotinoid substitute worldwide, sulfoxaflor, on the behaviour and male physiology of the solitary bee, Osmia bicornis. We measured a variety of parameters focusing on behaviours occurring before, and during mating, as well as sperm quantity. For the first time, we demonstrate that short-term chronic, field-realistic exposure to a common pesticide reduced pre-copulatory display (-36 %) and sounds (-27 %), increased the number of copulations (+110 %) and the mating duration (+166 %), while finally reducing sperm quantity (-25 %) and mating success (-43 %). Our research raises considerable concern on the impact of field-realistic, low sublethal pesticide levels on the fertility and reproductive success of pollinators. Assessing the impact of pesticides on fitness parameters and implementing more sustainable agricultural solutions would allow mitigating the ongoing threat of pesticide pollution on wild insect populations and the broader environment.

Elevated extinction risk in over one-fifth of native North American pollinators

Pollinators are critical for food production and ecosystem function. Although native pollinators are thought to be declining, the evidence is limited. This first, taxonomically diverse assessment for mainland North America north of Mexico reveals that 22.6% (20.6 to 29.6%) of the 1,579 species in the best-studied vertebrate and insect pollinator groups have elevated risk of extinction. All three pollinating bat species are at risk and bees are the insect group most at risk (best estimate, 34.7% of 472 species assessed, range 30.3 to 43.0%). Substantial numbers of butterflies (19.5% of 632 species, range 19.1 to 21.0%) and moths (16.1% of 142 species, range 15.5 to 19.0%) are also at risk, with flower flies (14.7% of 295 species, range 11.5 to 32.9%), beetles (12.5% of 18 species, range 11.1 to 22.2%), and hummingbirds (0% of 17 species) more secure. At-risk pollinators are concentrated where diversity is highest, in the southwestern United States. Threats to pollinators vary geographically: climate change in the West and North, agriculture in the Great Plains, and pollution, agriculture, and urban development in the East. Woodland, shrubland/chaparral, and grassland habitats support the greatest numbers of at-risk pollinators. Strategies for improving pollinator habitat are increasingly available, and this study identifies species, habitats, and threats most in need of conservation actions at state, provincial, territorial, national, and continental levels.

Past aridity and dust drove biodiversity crises and altered pollination in the ancient gymnosperm Ephedra (Gnetales)

The long-term effects of present-day climate change on pollination are unquantified. However, distinguishing climatic drivers of ancient changes in pollination could provide valuable insights into biotic responses to near-future climate states. Herein, we show that pollination in a group of gymnosperm shrubs (Ephedra L., Gnetales) was irrevocably altered by the Cenozoic expansion of drylands on two different continents. In Asia, increased continentality during the mid-Eocene drove aridification and strong, dust-carrying storms that promoted a shift to prevailing wind pollination in the core clade of Ephedra. Surface uplift in the North American interior together with global cooling caused the expansion of aeolian deposition and placed similar evolutionary pressures on ephedras there, beginning in the latest Eocene and continuing across the Eocene-Oligocene transition (EOT). These climatic changes fundamentally altered the abundance and evolution of this ancient plant lineage on both continents and determined pollination mechanisms in the core clade of Ephedra today. Based on fossil evidence, this review demonstrates how climate change may have major and permanent impacts on plant-pollinator networks, as well as demonstrates possible evolutionary consequences of near-future climate scenarios for which we have no modern analogue.

Development of a ptp2-LAMP assay for the specific and sensitive detection of Nosema apis and its comparison with ptp3-LAMP for the detection of Nosema ceranae, in a region endemic for both microsporidium pathogens of the Western honey bee

The Western honey bee plays a pivotal role in global food security as the primary commercial pollinator. The microsporidian pathogens Nosema apis and Nosema ceranae infect the bee midgut, causing nosemosis, a debilitating infectious disease that results in considerable economic losses in apiculture. Traditionally, Nosema spp. infection is diagnosed by microscopic detection and quantification of spores. However, only molecular diagnostics allow differentiation between N. apis and N. ceranae. Loop-mediated isothermal amplification (LAMP) is a rapid, highly specific, and sensitive DNA detection method. The present study aimed to develop a LAMP protocol for N. apis based on the species-specific single copy polar tube protein 2 (ptp2) gene, and to analyze and compare its diagnostic performance with the previously developed polar tube protein 3 (ptp3) gene-based LAMP protocol for N. ceranae. The ptp2- and ptp3-LAMP assays specifically identified N. apis and N. ceranae, respectively. Their analytical sensitivity was tested using serial dilutions of plasmid and genomic DNA, demonstrating that ptp2- and ptp3-LAMP consistently detected down to 103ptp2 and 104ptp3-gene copies, respectively. Amplification was verified by agarose gel electrophoresis (conventional format), and by a change from pink to yellow color after addition of a suitable dye (colorimetric format). The ptp2- and ptp3-LAMP assays and a reference duplex PCR were applied to a panel of field samples (n = 55) from a region endemic for both Nosema spp. Conventional and colorimetric ptp2-LAMP showed an almost perfect test agreement (kappa value > 0.81) compared with duplex PCR. Conventional and colorimetric ptp3-LAMP assays showed a substantial (kappa value > 0.60) and almost perfect test agreement (kappa value > 0.81), respectively. The ptp2- and ptp3-LAMP assays provide excellent performance, ease of implementation, cost savings, and rapid execution, making them ideal choices for molecular detection and differentiation of N. apis and N. ceranae.

Adapting to change: bee pollinator signatures in anthropized environments

Bees are essential pollinators for wild, ornamental, and agricultural plants, but human activities have disrupted their habitats, threatening their persistence. Although bees face numerous challenges in habitats heavily modified by human activities, certain species persist and thrive there. This review synthesizes recent literature on two types of traits that help bees survive in human-modified environments: preadaptive traits, which evolved before these environments existed, and adaptive traits, which have evolved in response to new conditions. This review highlights our limited understanding of adaptive traits and examines how trait combinations, including those influenced by epigenetics, contribute to bees' success in these altered habitats. Additionally, we discuss the promising use of genomic tools to reveal signatures of adaptation in these important pollinators.

Ecotoxicological impact of succinate dehydrogenase inhibitor (SDHI) fungicides on non-targeted organisms: a review

As the global population continues to grow, the use of pesticides to increase food production is projected to escalate. Pesticides are critical in plant protection, offering a powerful defense against fungal diseases such as apple scab, leaf spot, sclerotinia rot, damping off, sheath blight, and root rot, which threaten crops like cereals, corn, cotton, soybean, sugarcane, tuberous vegetables, and ornamentals. Succinate Dehydrogenase Inhibitor (SDHI) fungicides represent a novel class essential for controlling fungal pathogens and bolstering food security. However, the impact of SDHIs on non-target organisms, including freshwater and terrestrial invertebrates, crustaceans, and oligochaetes, remains insufficiently understood. Empirical studies indicate that SDHIs can induce mortality, mitochondrial dysfunction, oxidative stress, and developmental delays in non-target organims. Additionally, the environmental persistence of these compounds raises concerns about their potential for ecological disruption. The effects of SDHIs on pollinating species and the possible transgenerational transmission of harmful effects warrant further investigation. Comprehensive transcriptomic analyses are necessary to elucidate the molecular disturbances and adverse outcome pathways triggered by SDHIs. Furthermore, there are emerging concerns about the endocrine-disrupting potential of SDHIs in aquatic organisms. For the first time, this review aims to synthesize existing knowledge on the ecotoxicological impacts of SDHIs on non-target organisms and identify critical research directions to address the ecological challenges posed by their use.

Efficiency of pantraps for monitoring bees diversity in Brazilian acerola orchards: the role of color diversity

Bee monitoring characterizes the local fauna and determines conservation measures. The study evaluated the influence of pantrap color on bee attraction and the difference in seasonal patterns of these insects. Collections were carried out in commercial plantations of Malpighia emarginata in the Northeast region of Brazil, using yellow, blue and white pantraps. A total of 1,449 bee specimens belonging to 59 species, four subfamilies of Apidae, 18 tribes and 31 genera were captured, with emphasis on the subfamily Apinae (89.6%). Blue pantraps captured 66.5% of the total sampled specimens, followed by white (19.6%) and yellow (13.9%). Melitomella grisescens (29.3%) was the most abundant species, followed by Apis mellifera (10.3%), Melitoma segmentaria (10.1%), Ptilothrix plumata (9.6%) and Melitoma ipomoearum (6.8%). With the exception of A. mellifera, all the most abundant species belonged to the Emphorini tribe (56%). Regarding the Centridini tribe, pantraps were efficient in collecting species, but not individuals. The months of September and November/2019 were the months when the lowest numbers of insects were collected and the lowest rainfall rates were recorded. In this sense, understanding new methodologies becomes essential to identify the diversity of pollinators for the construction of management and conservation plans.

Sublethal pesticide exposure decreases mating and disrupts chemical signaling in a beneficial pollinator

Pesticides provide vital protection against insect pests and the diseases they vector but are simultaneously implicated in the drastic worldwide decline of beneficial insect populations. Convincing evidence suggests that even sublethal pesticide exposure has detrimental effects on both individual- and colony-level traits, but the mechanisms mediating these effects remained poorly understood. Here, we use bumble bees to examine how sublethal exposure to pesticides affects mating, a key life history event shared by nearly all insects, and whether these impacts are mediated via impaired sexual communication. In insects, mate location and copulation are primarily regulated through chemical signals and rely on both the production and perception of semiochemicals. We show through behavioral bioassays that mating success is reduced in bumble bee gynes after exposure to field-relevant sublethal doses of imidacloprid, and that this effect is likely mediated through a disruption of both the production and perception of semiochemicals. Semiochemical production was altered in gyne and male cuticular hydrocarbons (CHCs), but not in exocrine glands where sex pheromones are presumably produced (i.e., gyne mandibular glands and male labial glands). Male responsiveness to gyne mandibular gland secretion was reduced, but not the queen responsiveness to the male labial secretion. In addition, pesticide exposure reduced queen fat body lipid stores and male sperm quality. Overall, the exposure to imidacloprid affected the fitness and CHCs of both sexes and the antennal responses of males to gynes. Together, our findings identify disruption of chemical signaling as the mechanism through which sublethal pesticide exposure reduces mating success.

Imidacloprid and amitraz differentially alter antioxidant enzymes in honeybee (Apis mellifera) hemocytes when exposed to microbial pathogen-associated molecular patterns

Honeybees (Apis mellifera) are increasingly exposed to pesticides and microbial stressors, yet their combined effects on immune defenses remain unclear. Exposure to the neonicotinoid imidacloprid and the acaricide amitraz, alone and in combination, alters antioxidant enzyme activity in hemocytes when challenged with bacterial components such as lipopolysaccharide and peptidoglycan or the fungal-derived molecule zymosan A. The combination of pesticides with zymosan A synergistically suppresses superoxide dismutase and glutathione-S-transferase activity, while catalase activity remains unchanged. In contrast, lipopolysaccharide counteracts pesticide-induced oxidative stress, suggesting immune-pathway-specific modulation. The heightened vulnerability of honeybees to fungal-associated immune challenges in pesticide-contaminated environments compromises their ability to detoxify harmful substances and respond to infections. Such approaches that include comparison of different microbial interactions, pesticide cocktails, and immunity are needed. Understanding these interactions is essential for improving pesticide regulations and pollinator conservation efforts in the face of increasing environmental stressors.

Acute and chronic pesticide exposure trigger fundamentally different molecular responses in bumble bee brains

BACKGROUND

Beneficial insects, including pollinators, encounter various pesticide exposure conditions, from brief high-concentration acute exposure to continuous low-level chronic exposure. To effectively assess the environmental risks of pesticides, it is critical to understand how different exposure schemes influence their effects. Unfortunately, this knowledge remains limited. To clarify whether different exposure schemes disrupt the physiology of pollinators in a similar manner, we exposed bumble bees to acute or chronic treatments of three different pesticides: acetamiprid, clothianidin, or sulfoxaflor. Genome-wide gene expression profiling enabled us to compare the effects of these treatments on the brain in a high-resolution manner.

RESULTS

There were two main findings: First, acute and chronic exposure schemes largely affected non-overlapping sets of genes. Second, different pesticides under the same exposure scheme showed more comparable effects than the same pesticide under different exposure schemes. Each exposure scheme induced a distinct gene expression profile. Acute exposure mainly caused upregulation of genes linked to the stress response mechanisms, like peroxidase and detoxification genes, while chronic exposure predominantly affected immunity and energy metabolism.

CONCLUSIONS

Our findings show that the mode of exposure is critical in determining the molecular effects of pesticides. These results signal the need for safety testing practices to better consider mode-of-exposure dependent effects and suggest that transcriptomics can support such improvements.

Projecting the impacts of climate change on habitat distribution of Varroa destructor in Ethiopia using MaxEnt ecological modeling

Globally, Varroa destructor has been identified as a major drivers of honeybee colony losses. Climate change may worsen its effects by creating conducive conditions for its reproduction, although our understanding of their interaction remains limited. This study hypothesizes that climate change alters the suitable habitat for V. destructor in Ethiopia. It investigated its habitat distributions under current and future climate change scenarios (ssp126, ssp245, and ssp585) using the Maximum Entropy Model (MaxEnt) across the study area (1.16 million Km2), based on 62 occurrence points and 22 predictor variables (19 climatic, 2 topographic and 1 agroecological). Habitats were classified into five categories using natural breaks: unsuitable (<0.10), low suitability (0.10-0.28), moderate suitability (0.28-0.48), high suitability (0.48-0.69), and very high suitability (>0.69). The average AUC and TSS values were 0.908 and 0.7, respectively, indicating excellent model performance and strong agreement between observations and predictions. Under current climatic conditions, approximately 46.4 % of Ethiopia's land mass (538,046.35 km2) is classified as having low to very high suitability for V. destructor. The most significant factors influencing its distribution are annual temperature (43.2 %), agroecology (14.7 %), precipitation of the driest quarter (12.1 %) and annual precipitation (10.2 %). The annual temperature favorable for V. destructor incidence ranges from 5 °C to 16.5 °C, with a notable decline in incidence as temperatures increase to 30 °C. This aligns with the predicted high concentration of suitable habitats in the cool-humid and sub-humid agroecological zones. However, suitable habitats are expected to decline under future climatic conditions. Under ssp585, suitable habitat for V. destructor is projected to decline by 13.72 % by the 2030s and by 31.66 % by the 2090s. Overall, under current and future climate conditions, suitable habitats are concentrated in the cool-humid and sub-humid agroecological zones. Therefore, research and management interventions should target these areas to contain the mite's spread and impact.

Legacy industrial pollutants in the South American black bumblebee Bombus pauloensis inhabiting peri-urban and rural fields from the Argentinean pampas

Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants (POPs), banned worldwide due to their effects on biota. In South America, studies on POPs in wild bees, like Bombus pauloensis, a continentally widespread bumblebee, are lacking, and information on its health is limited. This study assessed, by GC-ECD, PCBs and PBDEs levels in B. pauloensis, flowers and soils from fields located at different distances from urban activities: PU and LF, two peri-urban fields near the local industrial park, with LF also next to an overloaded solid waste landfill, and RU, a rural field. For all matrices, the peri-urban fields registered significant higher pollutant levels compared to RU, especially in workers, where LF showed the highest ∑PCBs and ∑PBDEs levels (21.09 ± 2.57 and 10.29 ± 0.37 ng/g, respectively). In males, PU and LF showed the highest nominal ∑PCBs (PU; 24.97 ± 1.03 ng/g) and ∑PBDE (LF; 10.39 ± 0.77 ng/g) concentrations, which confirms the influence of the landfill. Across matrices, lighter PCB congeners dominated, possibly explained by the past use of PCB mixtures and atmospheric transport, and a biomagnification pattern was observed. PCB concentrations were similar to those proven to cause sublethal effects in bees, and males showed significantly higher POP levels than workers. Thus, drivers and population effects were discussed. This may be one of the first studies of industrial POPs in wild bees in South America, emphasizing the need to look beyond insecticides and unique castes in environmental exposure studies.

Effects of anthropogenic stress on stingless bees Melipona mandacaia inhabiting urban and natural environments

Bees play a crucial role as pollinators, significantly contributing to ecosystem health. However, they face growing threats from human activities. This study uses biomarkers to evaluate the health status of Melipona mandacaia, a stingless bee native to the Caatinga biome, as indicators of anthropogenic stress. Bees were collected from the unique Caatinga biome, which had no recorded human pressure, and from an urban area with high human pressure. These bees were then analyzed for various biomarkers to assess the different levels of anthropogenic stress. The biomarkers included cholinesterases (ChE) to assess neurotoxicity, catalase (CAT) to measure antioxidant responses, glutathione S-transferases (GST) for detoxification pathways, and lipid peroxidation (LPO) as an indicator of oxidative stress. The results reveal that ChE inhibition may be associated with stress levels due to human activities showing an inhibition pattern with increased stress levels (up to 54.4 % inhibition), while the remaining biomarkers showed mixed responses across the different stress-level areas. In addition, the use of a principal component analysis (PCA) allowed a separation between the different groups and the weigh of the measured variables to each anthropogenic stress group. The integrated biomarker response (IBR) index was applied showing a clear distinction among groups. The obtained results could be partly explained by the beekeeping practices in some locations, which may have mitigated the effects of anthropogenic stressors to a certain degree, especially in HS. These findings underscore the importance of monitoring wild bee health in the Caatinga and demonstrate the value of a multifaceted biomarker approach for understanding the impacts of anthropogenic stressors on bee populations in varied environments and the effects of beekeeping.

Forest spatial configuration and local management influence bee pollinator biodiversity in urban and rural landscapes

Forests are crucial for sustainable land planning and they are believed to buffer land use changes and to promote human wellbeing and biodiversity. However, it is not clear how forests could influence bee diversity, that is responsible for the pollination ecosystem service. Here, we investigated bee biodiversity in relation to forests patches in agricultural and urban landscapes, and to urban forest features and flower richness in green areas; we also quantified the amount of pollen transported in relation to nesting and body-size traits. In the results, the importance of landscape variables depended on the macrohabitat: in agricultural lands, bee abundance increased with the number, distance and intermediate cover of forest patches, but in urban environments only forest shape complexity contributed. Moreover, in urban parks with mature urban forests, cavity-nesting bee richness increased with large logs and decaying wood, while bee richness increased with flower species richness in meadows adjacent to forests. Hence, open spaces rich in flowers and forests managed to keep understorey wood are relevant for increasing urban bee richness. Forest management could shape the occurrence of certain bee traits, but the nesting substrate trait will not modify the potential pollination ecosystem service because the amount of pollen transported related more to the body size. This study emphasises the importance of forested areas for bees in agricultural and urban environments. The results could contribute to develop biodiversity-friendly landscape planning and forest management practices when they are focused on ensuring wood elements, flowers and specific forest patch configurations sustaining bees.

Effects of soybean fields on the health of Apis mellifera (Hymenoptera: Apidae) in the Chaco ecoregion

Honey bees (Apis mellifera) are important pollinators for natural and cultivated species. Due to their high sensitivity to stressors, they are also valuable indicators of environmental changes and agricultural management practices. In this study, we compared the performance and incidence of pesticides over sentinel hives within forest remnants with those within linear forest fragments (LFF) surrounded by soybean fields under conventional management. Sentinel hives in LFF showed some signs of deterioration, such as colony collapse, low numbers of brood frames, and pesticide occurrences, but honey production and the number of adult bees were similar to hives in the forest. Soybean pollen was scarce in honey and absent in bee bread, suggesting that bees may be relying more on wild plant species. We detected 5 pesticides (azoxystrobin, carbendazim, chlorpyrifos, imidacloprid, and coumaphos) in hives both at forests and LFF in pollen, bee bodies, and wax; pesticides in honey were detected in old sentinel hives (2 yr of exposition to agricultural conventional management). Only 2 of the 5 pesticides were applied in one of the farms under study, highlighting the importance of considering landscape-scale agricultural management. Our results indicate that conventional agriculture of soybean/maize primarily affected the performance of beehives, and pesticides were detected in honey only after long exposure to hives. Beekeeping in soybean fields in the Chaco could be feasible if cautions were followed, such as the conservation of forest fragments and key plant species, appropriate pesticide schedules, coordinated applications among farms, and linear forest remnants improvements.

Exploring Climate-Driven Mismatches Between Pollinator-Dependent Crops and Honeybees in Asia

In Asia, Apis cerana (native) and Apis mellifera (introduced) are the primary managed honeybee species, vital for pollination and honey production. However, climate change and other threats are driving pollinator declines, while research on their ecology in Asia remains limited. Bridging these knowledge gaps is crucial for developing conservation strategies to sustain pollination services and agricultural systems in the region. In this study, we evaluated the potential impacts of climate change on the spatial interactions between two honeybee species (A. cerana and A. mellifera) and 20 pollinator-dependent crops across 23 countries in Asia. We used species distribution models (SDMs) to generate habitat suitability maps for both honeybees and crops under current and future climate scenarios (SSP585 for 2070). Schoener's D statistic was employed to quantify the spatial overlap, and a novel spatial approach was applied to create mismatch maps that identified areas of increased or decreased interactions. We found that, on average, A. cerana demonstrated higher overlap with 12 crops compared to 8 for A. mellifera in future projections. Key crops like sesame, eggplant, and mango retained strong overlaps with both pollinators, while mismatches were more pronounced for A. cerana, particularly with watermelon, strawberry, and buckwheat. In contrast, A. mellifera showed greater stability and resilience in spatial overlaps with crops such as soybean and sunflower. Overall, A. cerana is expected to face more significant spatial mismatches, highlighting its vulnerability to climate-induced changes and the critical need for targeted conservation efforts. This study highlights the urgent need for region-specific conservation strategies by identifying areas at risk of losing critical pollination services. Our results provide a crucial framework for informed management and policy interventions to safeguard pollination-dependent agricultural systems and biodiversity in Asia amidst accelerating environmental challenges.

Poor air quality raises mortality in honey bees, a concern for all pollinators

Human well-being relies on the presence and role of pollinators, as they contribute to the vitality of ecosystems, support the reproduction of wild plants, increase crop yields, and strengthen overall food security. While wild bee populations are dwindling due to climate and environmental change, there has been a notable 45% rise globally in the number of managed honey bee (Apis mellifera) colonies over the past five decades. Given their economic significance and their relative ease of tracking, honey bees have the potential to serve as bioindicators of global pollinator health. Consequently, honey bees have emerged as a keystone species requiring protection and conservation efforts. Here, we investigate the intricate relationship between air quality, environmental factors, and honey bee mortality across Canada and the United States. Using statistical and machine learning modeling, our findings underscore the honey bee's role as a bioindicator. We found that air quality is an important predictor of honey bee mortality. The risk of honey bee mortality increased with poor air quality (ozone and Air Quality Health Index) but was substantially reduced in regions with greater vegetation availability (Normalized Difference Vegetation Index). Therefore, our study offers a beacon of hope: improving management practices by increasing greenery can significantly mitigate the impact of deteriorating air quality on honey bees, providing a vital solution to safeguard our essential pollinators.

Beebread pollen composition is affected by seasonality and landscape structure

In honey bee diet, pollen is the primary source of proteins and essential nutrients. High pollen diversity and protein content support honey bee health, enhancing resistance to different stressors. Agroecosystem simplification, with few dominant species flowering for a limited period, can lead to a shortage of forage and a reduction in the variety and quantity of food. We therefore investigated how agroecosystem landscape characteristics influence pollen collection patterns. We collected beebread from 25 apiaries, located in Emilia-Romagna (Northeastern Italy), in March and June 2021 and 2022. We evaluated their pollen diversity and protein content and assessed the relationship with landscape heterogeneity and composition in a 1500 m radius around each apiary. A total of 138 pollen taxa were identified, predominantly from the Fabaceae, Rosaceae, and Asteraceae families. Pollen richness was significantly higher in June than in March for both years. Protein content, on the other hand, was higher in 2021 compared to 2022 and, for 2022 only, in June compared to March. Cluster analysis of the 25 sites according to their landscape characteristics revealed three distinct groups: Group 1 (mainly arable land), Group 2 (mixed arable land and forest), and Group 3 (arable land and permanent crops). Group 1 had lower landscape heterogeneity. Pollen composition did not differ significantly among groups, suggesting that honey bees might expand their foraging area (over the 1500 m radius that we consider) in response to landscape homogeneity, as observed in Group 1 areas. On the other hand, pollen diversity was highest in Group 3, likely due to the variety of fruit tree species and spontaneous flora.

Managed honeybees and soil nitrogen availability interactively modulate sunflower production in intensive agricultural landscapes of China

Insects provide important pollination services for cops. While land use intensification has resulted in steep declines of wild pollinator diversity across agricultural landscapes, releasing managed honeybees has been proposed as a countermeasure. However, it remains uncertain whether managed honeybees can close the pollination gap of sunflower (Helianthus annuus L. [Asterales: Asteraceae]) in areas lacking wild pollinators, and how the benefits of honeybees to sunflower production are modulated by soil nutrients. We investigated the effects of 3 pollination treatments (open, self and hand pollination) on sunflower yield parameters. We also estimated the pollination efficiency of managed honeybees (Apis mellifera L. [Hymenoptera: Apidae]), and analyzed the effects of honeybee visitation and soil nitrogen on sunflower yield parameters. Insect pollinators contributed 73% of seed set and 69% of the weight of filled seeds per head in the open pollination of sunflowers, but large pollination deficits still existed. Insect pollination may enhance sunflower yield by augmenting the number and weight of filled seeds per head, but not by altering the total number of seeds. Except for the total number of seeds per head, yield parameters increased significantly with the number of honeybee visits. Low nitrogen accelerated the positive effect of honeybee pollination on sunflowers, and alleviated the negative effect of distance of beehives on honeybee visitation rate. We conclude that managed honeybees could be used to pollinate sunflowers in areas with the shortage of wild pollinators, and sunflower production may benefit from shortening the distance of beehives and lowing of nitrogen fertilizer inputs.

Sublethal pesticide exposure alters stress response, detoxification, and immunity gene expression in larvae of the stingless bee Frieseomelitta varia (Apidae: Meliponini)

During foraging, stingless bees are at risk of pesticide contamination from treated field crops. Frieseomellita varia workers, for example, frequently visit pepper plants that are often treated with the herbicide clomazone (CLZ), the fungicide difenoconazole (DFZ), and the insecticide abamectin (ABM). These pesticides pose a threat not only to adult bees but also to larvae when the chemicals are brought back to the nest. This study aimed to evaluate the effects of sublethal concentrations of CLZ, DFZ, and ABM on the expression of stress marker proteins (HSP70AB and HSP83), detoxification enzymes (CYP9Q3, CYP6SA4, and CYTP450), and antimicrobial peptides (abaecin and defen-1) genes in F. varia larvae. First instar larvae were incubated for 48 h in ELISA plates, divided into five groups: Naive (control), acetone (acetone control), CLZ (0.014 ng a.i./µL), DFZ (0.0098 ng a.i./µL), and ABM (0.007 ng a.i./µL). After incubation, total RNA was extracted and analyzed by RT-qPCR to quantify transcript levels. While larval survival was unaffected, significant changes in gene expression patterns were observed. ABM exposure increased HSP70AB expression and decreased HSP83 expression. No changes in CYTP6SA4 expression were detected in bees exposed to any of the pesticides. DFZ suppressed CYP9Q3 expression, while ABM upregulated CYTP450 expression. Notably, the antimicrobial peptide gene abaecin was downregulated by all three compounds, whereas defen-1 expression increased in response to ABM. These findings suggest that sublethal concentrations of these pesticides can significantly alter the expression of genes associated with stress response, detoxification, and immunity in F. varia larvae. The disruption caused by herbicides and fungicides, alongside the known effects of insecticides, may impact bee physiology and colony homeostasis, with potentially unknown consequences for the survival of stingless bees in their natural environment.

Microsporidian parasite impairs colony fitness in bumblebees

Emerging infectious diseases can have a major impact on fitness of novel hosts, thereby contributing to ongoing species declines. In social insects, collaborative brood care by workers and successful mating of male sexuals are key to colony fitness. The microsporidian endoparasite Nosema ceranae has spread almost globally, shifting across honeybee species and now to bumblebees. However, despite N. ceranae being linked to recent population declines, its possible impact on bumblebee colony fitness remains poorly understood. Here, we show that N. ceranae infections can significantly impact Bombus terrestris worker feeding glands, as well as longevity, sperm quality and mating abilities of drones. In the laboratory, workers and drones were either exposed to the parasite or not. Then, parasite infection rates and loads, as well as lethal and sublethal parameters, were assessed. Infected drones revealed higher parasite infection rates and spore titres, as well as mortality compared with female workers, suggesting sex-specific susceptibility. Furthermore, infections impaired feeding glands, affected sperm traits and altered mating behaviour, all of which are key to colony fitness. Our findings provide a mechanistic explanation on how N. ceranae contributes to the ongoing decline of wild bumblebee populations, calling for respective mitigation measures.

Avoiding the tragedies of parasite tolerance in Darwinian beekeeping

Bee declines have been partly attributed to the impacts of invasive or emerging parasite outbreaks. For western honeybees, Apis mellifera, major losses are associated with the virus-vectoring mite, Varroa destructor. In response, beekeepers have focused breeding efforts aimed at conferring resistance to this key parasite. One method of many is survival-based beekeeping where colonies that survive despite significant Varroa infestations produce subsequent colonies. We argue that this 'hands-off' approach will not always lead to Varroa resistance evolving but rather tolerance. Tolerance minimizes host fitness costs of parasitism without reducing parasite abundance, whereas resistance either prevents parasitism outright or keeps parasitism intensity low. With clear epidemiological distinctions, and as honeybee disease dynamics impact other wild bees owing to shared pathogens, we discuss why tolerance outcomes in honeybee breeding have important implications for wider pollinator health. Crucially, we argue that unintentional selection for tolerance will not only lead to more spillover from honeybees but may also select for pathogens that are more virulent in wild bees leading to 'tragedies of tolerance'. These tragedies can be avoided through successful breeding regimes that specifically select for low Varroa. We emphasize how insights from evolutionary ecology can be applied in ecologically responsible honeybee management.

Climate effects on honey bees can be mitigated by beekeeping management in Kenya

In recent decades, worldwide concerns about the health of honey bees motivated the development of surveys to monitor the colony losses, of which Sub-Saharan Africa has had limited representation. In the context of climate change, understanding how climate affects colony losses has become fundamental, yet literature on this subject is scarce. For the first time, we conducted a survey to estimate the livestock decrease of honey bee colonies in Kenya for the year 2021-2022 to explore the effects of environmental conditions, such as temperature and precipitation, on livestock decrease. We define "livestock decrease" from the beekeeper's perspective, including dead colonies but also, in the specific context of the tropics, the colonies that absconded from the apiary. A total of 589 beekeepers from a variety of areas participated in the survey. Kenyan beekeepers had an average of 36.6% livestock decrease in 2021-2022, with higher decreases during the dry and hot (31.9%) than during the wet and cold season (20.2%). We found that livestock decreases were more important with temperature for both dry and hot and wet and cold seasons. Interestingly, we found that precipitation mitigated temperature effects on livestock decrease for both seasons. Finally, we found that beekeepers practicing water supplementation had up to 10% less livestock decrease during the dry and hot season than those that did not, suggesting it to be a relevant adaptive strategy to mitigate livestock decrease. It is worth noting that beekeepers can renew their stock by trapping swarms, yet this represents a cost in time and baiting materials. Based on climate change projections, we predicted that annual and seasonal livestock decrease would remain in the same range at horizon 2050 and horizon 2100. These results pinpoint difficulties in maintaining livestock for beekeepers in Kenya and provide clues for strategies to pursue in the context of climate change.

Chemical Ecology and Management of the Small Hive Beetle, Aethina tumida (Coleoptera: Nitidulidae)

Over the last 28 years, the small hive beetle, Aethina tumida (Coleoptera: Nitidulidae), a colony pest of wild and managed honey bees (Apis mellifera), and native to sub-Saharan Africa, has been recorded as an invasive and damaging pest of diverse bee species, especially managed honeybee colonies in the Americas, Europe, Asia and Australia. It poses an indirect threat to pollination services and global food security. Efforts to manage the beetle has yielded no permanent solution. However, several studies demonstrate that the small hive beetle uses various sensory cues to locate hosts including chemical and visual cues in the visible wavelength. Here, we review the chemical ecology of the beetle and discuss implications for its future management.

Sub-lethal pesticide exposure interferes with honey bee memory of learnt colours

Neonicotinoid pesticide use has increased around the world despite accumulating evidence of their potential detrimental sub-lethal effects on the behaviour and physiology of bees, and its contribution to the global decline in bee health. Whilst flower colour is considered as one of the most important signals for foraging honey bees (Apis mellifera), the effects of pesticides on colour vision and memory retention in a natural setting remain unknown. We trained free flying honey bee foragers by presenting artificial yellow flower feeder, to an unscented artificial flower patch with 6 different flower colours to investigate if sub-lethal levels of imidacloprid would disrupt the acquired association made between the yellow flower colour from the feeder and food reward. We found that for doses higher than 4 % of LD50 value, the foraging honey bees no longer preferentially visited the yellow flowers within the flower patch and instead, we suspect, reverted back to baseline foraging preferences, with a complete loss of the yellow preference. Our honey bee colour vision modelling indicates that discriminating the yellow colour from the rest should have been easy cognitive task. Pesticide exposure also resulted in a significant increase in Lop1, UVop, and Blop, and a decrease in CaMKII and CREB gene expression. Our results suggest that memory loss is the most plausible mechanism to explain the alteration of bee foraging colour preference. Across bees, colour vision is highly conserved and is essential for efficient pollination services. Therefore, our findings have important implications for ecosystem health and agricultural services world-wide.

The Role of Pathogens in Bumblebee Decline: A Review

Bumblebees, the most important wild pollinators in both agricultural and natural ecosystems, are declining worldwide. The global decline of bumblebees may threaten biodiversity, pollination services, and, ultimately, agricultural productivity. Several factors, including pesticide usage, climate change, habitat loss, and species invasion, have been documented in the decline of bumblebee species, but recent studies have revealed the dominating role of pathogens and parasites over any of these causes. Unfortunately, there is a lack of a full understanding of the role of pathogens and parasites in the decline of bumblebee species. The current study provides a comprehensive review of how pathogens and parasites contribute to the decline of bumblebee species. The study also explores the prevalence of each pathogen and parasite within bumblebee populations. Furthermore, we address the synergistic effects of pathogens and other stressors, such as pesticides, climatic effects, and habitat loss, on bumblebee populations. To summarize, we propose possible conservation and management strategies to preserve the critical role of bumblebees in pollination services and thus to support ecosystem and agricultural health.

Long Non-Coding RNA LOC113219358 Regulates Immune Responses in Apis mellifera Through Protein Interactions

Long non-coding RNAs (lncRNAs) are emerging as critical regulators in honeybee physiology, influencing development, behavior, and stress responses. This study investigates the role of lncRNA LOC113219358 in the immune response and neurophysiological regulation of Apis mellifera brains. Using RNA interference (RNAi) and RNA sequencing (RNA-seq), we demonstrate that silencing lncLOC113219358 significantly alters the expression of 162 mRNA transcripts, including genes associated with detoxification, energy metabolism, and neuronal signaling. Functional enrichment analysis revealed involvement in neuropeptide signaling, ATP synthesis, and oxidative phosphorylation pathways. Acetylcholinesterase (AChE), Glutathione-S-transferase (GST) and cytochrome P450 (CYP450) activities were significantly downregulated with 48 h of RNAi treatment. Additionally, RNA pull-down assays identified 113 proteins interacting with lncLOC113219358, including ATP synthase subunits, heat shock proteins, and major royal jelly proteins, suggesting its role in cellular stress responses and neural activity modulation. These findings provide mechanistic insights into how lncLOC113219358 mediates honeybee responses to environmental stressors, contributing to our understanding of lncRNA-regulated neural and immune functions in pollinators.

Beekeepers' perceptions toward a new omics tool for monitoring bee health in Europe

Pressures on honey bee health have substantially increased both colony mortality and beekeepers' costs for hive management across Europe. Although technological advances could offer cost-effective solutions to these challenges, there is little research into the incentives and barriers to technological adoption by beekeepers in Europe. Our study is the first to investigate beekeepers' willingness to adopt the Bee Health Card, a molecular diagnostic tool developed within the PoshBee EU project which can rapidly assess bee health by monitoring molecular changes in bees. The Bee Health Card, based on MALDI BeeTyping®, is currently on level six of the Technology Readiness Level scale, meaning that the technology has been demonstrated in relevant environments. Using an on-line survey from seven European countries, we show that beekeepers recognise the potential for the tool to improve colony health, and that targeted economic incentives, such as subsidises, may help reduce cost being a barrier to the adoption and frequent use of the tool. Based on the description of the tool, 43% of beekeepers appear to be moderately confident in the effectiveness of the Bee Health Card. This confidence could increase if the tool was easy to use and not time consuming, and a higher confidence could also contribute to raising the probability of accepting extra costs linked to it. We estimate that, in the worst-case scenario, the cost per single use of the Bee Health Card should be between €47-90 across a range of European countries, depending on the labour and postage costs. However, the monetary benefits in terms of honey production could exceed this. In order to successfully tackle colony health issues, it is recommended using the BHC five times per year, from the end to the beginning of winter. Finally, we discuss the knowledge needs for assessing beekeeper health tools in future research.

Varroa Volatiles Offer Chemical Cues to Honey Bees for Initial Parasitic Recognition

Olfaction mediated by the antennae is a vital sensory modality for arthropods and could be applied as a tool in pest control. The ectoparasitic mite Varroa destructor poses a significant threat to the health of the honey bee Apis mellifera worldwide and has garnered global attention. To better understand the chemical ecology of this host-parasite relationship, we collected and characterized the volatile organic compounds (VOCs) from V. destructor and used electroantennography (EAG) to record the responses of honey bee (A. c. cerana and A. m. ligustica) antennae to the different VOCs. Fifteen VOCs were detected from V. destructor using gas chromatography-mass spectrometry (GC-MS), which mainly contained ethyl palmitate, followed by isoamyl alcohol, nonanal, and ethyl oleate. The EAGs for ethyl palmitate were higher at the lowest stimulus loading (5 μg/μL in liquid paraffin) in A. c. cerana compared to A. m. ligustica, suggesting that A. c. cerana may have acute sensitivity to low concentrations of some VOCs from V. destructor. After exposure to ethyl palmitate for 1 h, the relative expression levels of AcerCSP1 and AcerOBP21 in A. c. cerana significantly increased, as well as the level of AmelCSP1 in A. m. ligustica, while AmelOBP8 showed no significant changes. The results indicate that the EAG response was influenced by the VOC composition and concentration. A. c. cerana tended to be more responsive than A. m. ligustica to the VOCs of V. destructor. Our findings offer a deeper understanding of how bees recognize V. destructor, potentially using ethyl palmitate as a chemical cue.

ApisTox: a new benchmark dataset for the classification of small molecules toxicity on honey bees

The global decline in bee populations poses significant risks to agriculture, biodiversity, and environmental stability. To bridge the gap in existing data, we introduce ApisTox, a comprehensive dataset focusing on the toxicity of pesticides to honey bees (Apis mellifera). This dataset combines and leverages data from existing sources such as ECOTOX and PPDB, providing an extensive, consistent, and curated collection that surpasses the previous datasets. ApisTox incorporates a wide array of data, including toxicity levels for chemicals, details such as time of their publication in literature, and identifiers linking them to external chemical databases. This dataset may serve as an important tool for environmental and agricultural research, but also can support the development of policies and practices aimed at minimizing harm to bee populations. Finally, ApisTox offers a unique resource for benchmarking molecular property prediction methods on agrochemical compounds, facilitating advancements in both environmental science and chemoinformatics. This makes it a valuable tool for both academic research and practical applications in bee conservation.

Air pollution modifies colonisation factors in beneficial symbiont Snodgrassella and disrupts the bumblebee gut microbiome

Particulate air pollutants, a major air pollution component, are detrimental to human health and a significant risk to wildlife and ecosystems globally. Here we report the effects of particulate pollutant black carbon on the beneficial gut microbiome of important global insect pollinator, the buff-tailed bumblebee (Bombus terrestris). Our data shows that exposure to black carbon particulates alters biofilm structure, gene expression and initial adhesion of beneficial bee gut coloniser, Snodgrassella alvi. Exposure of adult Bombus terrestris to non-toxic black carbon particulates significantly increased viable bacteria on MRS agar and 16S absolute abundance of beneficial bacteria Bombilactobacillus in Post-treated bumblebees compared to Pre-treated, demonstrating disruption of the bumblebee gut microbiome. These findings show that black carbon exposure has direct, measurable effects on bees' beneficial commensal bacteria and microbiome. Together these data highlight that black carbon, a single type of particulate pollution, is an underexplored risk to insect pollinator health.

Diesel exhaust and ozone adversely affect pollinators and parasitoids within flying insect communities

The effects of air pollution on human and animal health, and on the functioning of terrestrial ecosystems, are wide-ranging. This potentially includes the disruption of valuable services provided by flying insects (e.g. pollination and biological control). However, quantifying the extent of this disruption requires a clearer understanding of insect community responses at field-scale. By elevating diesel exhaust and ozone (O3) pollutants, individually and in combination, over two summers, we investigated the field-scale effects of air pollution on the abundance and diversity of flying insects from pan traps. We quantified which groups of insects were more at risk of air pollution-mediated decline and whether responses to air pollution were influenced by the presence of flowering plants. In addition, a common pest of Brassicaceae, the large cabbage white butterfly (Pieris brassicae L.) was used to investigate the effects on oviposition success of the two interacting air pollutants. Air pollution had the most detrimental effects on pollinators and parasitoids, compared with other insect groups, lowering their abundance by up to 48 % and 32 %, respectively. The adverse effects of O3 and diesel exhaust on pollinators occurred only when flowers were available, indicating the relative importance of floral odors compared with visual cues. Air pollutants resulted in either increased insect herbivore abundance or had no effect, potentially increasing the threat air pollution poses to food security. However, both pollutants resulted in decreased oviposition by cabbage white butterflies, which, if demonstrated to be a more ubiquitous phenomenon, may result in reduced larval pest damage. Quantifying the relative changes in composition and abundance among feeding guilds is valuable for predicting the effects of air pollution on insect communities. Of the groups identified, pollinators are likely to be at the greatest risk of air pollution-mediated decline due to their use of floral odour cues for foraging.

Avenues towards reconciling wild and managed bee proponents

Bees are crucial for food security and biodiversity. However, managed bees are increasingly considered drivers of wild bee declines, leading to stakeholder conflicts and restrictive policies. We propose avenues to reconcile wild and managed bee proponents and point out knowledge gaps that hinder the development of evidence-based policies.

Understanding pesticide-induced tipping in plant-pollinator networks across geographical scales: Prioritizing richness and modularity over nestedness

Mutually beneficial interactions between plants and pollinators are crucial for biodiversity, ecosystem stability, and crop production. A threat to a mutualistic network is the occurrence of a tipping point at which the species abundances collapse to a near zero level. In modern agriculture, there is widespread use of pesticides. What are the effects of extensive pesticide use on mutualistic networks? We develop a plant-pollinator-pesticide model and study its dynamics using 123 mutualistic networks across the globe. We demonstrate that pesticide exposure can lead to a tipping point. Furthermore, while the network characteristics such as richness and modularity exhibit a strong association with pesticide-induced tipping, nestedness shows a weak association. A surprising finding is that the mutualistic networks in the African continent are less pesticide tolerant than those in Europe. We articulate and test a pragmatic intervention strategy through targeted management of pesticide levels within specific plant species to delay or avert the tipping point. Our study provides quantitative insights into the phenomenon of pesticide-induced tipping for safeguarding mutualistic networks that are fundamental to agriculture and ecosystems.

Bumblebees prefer sulfoxaflor-contaminated food and show caste-specific differences in sulfoxaflor sensitivity

More than 30% of human food crop yield requires animal pollination. In addition, successful crop production depends on agrochemicals to control pests. However, agrochemicals can have negative consequences on beneficial insect pollinators, such as bees. We investigated the effects of an emerging class of pesticides, sulfoximines, on the common eastern bumblebee, Bombus impatiens. We performed a series of 96-hour toxicity tests on microcolonies of laboratory-reared B. impatiens. Our data showed that sulfoxaflor (SFX) is significantly less toxic to B. impatiens than historically used neonicotinoid pesticides, such as thiamethoxam. Further, for the first time, we found significant differences among castes in sensitivity to SFX; workers and drones were more sensitive than queens. These findings are notable because they reveal both caste and sex-specific differences in bumblebee sensitivity to pesticides. Interestingly, we found no evidence that bumblebees avoid SFX-contaminated sugar syrup. To the contrary, B. impatiens workers had an apparent preference for SFX-contaminated sugar syrup over sugar syrup alone. Overall, our investigation provides novel information on an important pesticide and may help inform regulatory decisions regarding pesticide use.

Buzz pollination: investigations of pollen expulsion using the discrete element method

Buzz pollination involves the release of pollen from, primarily, poricidal anthers through vibrations generated by certain bee species. Despite previous experimental and numerical studies, the intricacies of pollen dynamics within vibrating anthers remain elusive due to the challenges in observing these small-scale, opaque systems. This research employs the discrete element method to simulate the pollen expulsion process in vibrating anthers. By exploring various frequencies and displacement amplitudes, a correlation between how aggressively the anther shakes and the initial rate of pollen expulsion is observed under translating oscillations. This study highlights that while increasing both the frequency and displacement of vibration enhances pollen release, the rate of release does not grow linearly with their increase. Our findings also reveal the significant role of pollen-pollen interactions, which account for upwards of one-third of the total collisions. Comparisons between two types of anther exits suggest that pore size and shape also influence expulsion rates. This research provides a foundation for more comprehensive models that can incorporate additional factors such as cohesion, adhesion and Coulomb forces, paving the way for deeper insights into the mechanics of buzz pollination and its variability across different anther types and vibration parameters.

Descriptive Mappings of Global-Related Research Studies on Invertebrates in the Context of Agriculture

Invertebrates form a vital component of agricultural ecosystems, and they are chief actors in sustaining the functions of the ecosystem and soil health. Scholarly publications that concentrated on visualizing the research outputs and trends on invertebrates and agriculture are scarce. In this paper, we adopted a bibliometric model to extract trends/research studies on invertebrates and agriculture between 1991 and 2022, using scholarly studies retrieved from the Web of Science (WoS) databank. Therefore, the aim of the study is to assess and analyse publications and findings on research studies/trends on invertebrates and agriculture. A total of 1201 articles were recovered from the WoS databank with average citations per doc and coauthors per document ratio of 31.22 and 4.79, respectively. Studies on invertebrates and agriculture research studies were positively correlated with the number of years (R 2 = 0.7803; y = 3.4661x - 19.659) signifying an upsurge in the amount of publications on this topic in the near future. The United States maintained a top position in terms of published outputs (n = 312) and citations (n = 14,113), followed by Germany (n = 75; n = 3686) and the United Kingdom (n = 70; n = 3117), respectively. Articles from the United States (n = 67) and China (n = 32) had strong networks with other nations of the world. Top subject priorities in this research field in terms of author keywords are agriculture (n = 141), biodiversity (n = 66), arthropods (n = 66) and biological control/ecosystem services (n = 46). From our findings, economically stable nations such as the United States, Germany, China, the United Kingdom and Australia are carrying out more research on this subject matter compared to the developing countries. We also found out that from the thematic evolution and literature results, invertebrate research in the context of agriculture is tending towards biogeography, farmland biodiversity, insecticides and organic agriculture, which are of immense importance to scientists and researchers in this research domain, thus signifying the direction/path of future research.

Flumethrin exposure perturbs gut microbiota structure and intestinal metabolism in honeybees (Apis mellifera)

Flumethrin mitigates Varroa's harm to honeybee colonies; however, its residues in colonies threaten the fitness of honeybee hosts and gut microbiota. Our previous research has shown that flumethrin induces significant physiological effects on honeybee larvae; but the effects of flumethrin on the gut microbiota and metabolism of adult honeybees are still unknown. In this study, 1-day-old honeybees were exposed to 0, 0.01, 0.1, and 1 mg/L flumethrin for 14 days and the impacts of flumethrin on the intestinal system were evaluated. The results showed that exposure to 1 mg/L flumethrin significantly reduced honeybee survival and the activities of antioxidative enzymes (superoxide dismutase and catalase) and detoxification enzymes (glutathione S-transferase) in honeybee heads. Moreover, exposure to 0.01, 0.1, and 1 mg/L flumethrin significantly decreased the diversity of the honeybee gut microbiota. Results from untargeted metabolomics showed that long-term exposure to 0.01, 0.1, and 1 mg/L flumethrin caused changes in the metabolic pathways of honeybee gut microbes. Furthermore, increased metabolism of phenylalanine, tyrosine, and tryptophan derivatives was observed in honeybee gut microbes. These findings underscore the importance of careful consideration in using pesticides in apiculture and provide a basis for safeguarding honeybees from pollutants, considering the effects on gut microbes.

Effects of urbanization on orchid bee diversity and orchid pollination: From neotropical cloud forests to urban cores

Urbanization is a significant driver of land use change, profoundly impacting biodiversity and ecosystem services worldwide. However, its effects in the tropics, which host some of the planet's highest biodiversity, remain inadequately understood. Orchid bees (Apidae: Euglossini) are key pollinators in Neotropical ecosystems, playing crucial roles in maintaining floral diversity and reproductive success of orchids and other plant families. Yet, little is known about how urbanization influences their diversity and pollination. In this study, we analyzed the diversity and composition or orchid bee communities along an urbanization gradient which extends from the city center to the surrounding cloud forests, which bear high orchid endemism while being highly threatened. Along the same gradient, we further evaluated pollination of a model native orchid, Gongora galeata, which is exclusively pollinated by the bee Euglossa obrima. As expected, increasing urbanization led to a decrease in orchid bee diversity, as well as a clear separation in species composition between urban and non-urban sites and a reduction in G. galeata pollination (i.e. fruit production). However, contrary to our expectations, orchid pollination also decreased with environmental heterogeneity and the abundance of its specific pollinator. Despite urban areas still hosting orchid bee species, our results reveal clear negative effects of urbanization not only on diversity, but also on the ecosystem function of a highly threatened group of bees. This study highlights the importance of considering local factors of urban landscapes for preserving not only biodiversity, but also fundamental ecological processes in cities.

Bee pollination and bee decline: A study about university students' Knowledge and its educational implication

Science education plays a crucial role in addressing the pollinator crisis by enhancing knowledge and fostering changes in attitudes toward this environmental challenge. Previous research has been focused on validating a specific instrument related to this subject, although its use for assessing students' knowledge has been little explored. In the present study, we have evaluated the level of awareness regarding the significance of bees as primary pollinators among students of various disciplines at the Universities of Sevilla, in Spain, and Ouro Preto, in Brazil, emphasizing the importance of the plant-bee interaction. 753 students from the fields of biology, agriculture, and education were invited to complete a questionnaire focused on bee biology. The results indicate that knowledge on the subject is closely linked to professional career choice and that the training program for the future teachers effectively increased comprehension of the crucial role played by bees as main supporters of the ecosystem service of pollination.

Transcriptome-wide analysis uncovers regulatory elements of the antennal transcriptome repertoire of bumblebee at different life stages

Bumblebees are crucial pollinators, providing essential ecosystem services and global food production. The success of pollination services relies on the interaction between sensory organs and the environment. The antenna functions as a versatile multi-sensory organ, pivotal in mediating chemosensory/olfactory information, and governs adaptive responses to environmental changes. Despite an increasing number of RNA-sequencing studies on insect antenna, comprehensive antennal transcriptome studies at the different life stages were not elucidated systematically. Here, we quantified the expression profile and dynamics of coding/microRNA genes of larval head and antennal tissues from early- and late-stage pupa to the adult of Bombus terrestris as suitable model organism among pollinators. We further performed Pearson correlation analyses on the gene expression profiles of the antennal transcriptome from larval head tissue to adult stages, exploring both positive and negative expression trends. The positively correlated coding genes were primarily enriched in sensory perception of chemical stimuli, ion transport, transmembrane transport processes and olfactory receptor activity. Negatively correlated genes were mainly enriched in organic substance biosynthesis and regulatory mechanisms underlying larval body patterning and the formation of juvenile antennal structures. As post-transcriptional regulators, miR-1000-5p, miR-13b-3p, miR-263-5p and miR-252-5p showed positive correlations, whereas miR-315-5p, miR-92b-3p, miR-137-3p, miR-11-3p and miR-10-3p exhibited negative correlations in antennal tissue. Notably, based on the inverse expression relationship, positively and negatively correlated microRNA (miRNA)-mRNA target pairs revealed that differentially expressed miRNAs predictively targeted genes involved in antennal development, shaping antennal structures and regulating antenna-specific functions. Our data serve as a foundation for understanding stage-specific antennal transcriptomes and large-scale comparative analysis of transcriptomes in different insects.

Pollen contaminated with a triple-action fungicide induced oxidative stress and reduced longevity though with less impact on lifespan in honey bees from well fed colonies

Experiments were conducted to determine the effects of a triple-action fungicide on bees and whether improved nutrition can ameliorate eventual negative impacts. In cage tests, newly-emerged bees from well fed and from nutritionally-restricted honey bee colonies were fed for five days with pollen from sunflowers that had been sprayed or not with a commercial fungicide containing bixafen, prothioconazole and trifloxystrobin. Bees from well-fed colonies were significantly larger and consumed more uncontaminated pollen. They also exhibited increased glutathione peroxidase activity and higher concentrations of pyridine nucleotides, both of which are involved in antioxidase defense. However, pollen contaminated with fungicide led to an increase in lipoperoxidation, regardless of nutritional status. Bee longevity was reduced by both fungicide contamination of the pollen diet and poor nutritional condition. The fungicide adversely affected bees fed with contaminated pollen, though nutritional supplementation of the bee colonies that reared the bees partially compensated for these effects.

Phytochemical S-methyl-L-cysteine sulfoxide from Brassicaceae: a key to health or a poison for bees?

Intensive agricultural practices impact the health and nutrition of pollinators like honey bees (Apis mellifera). Rapeseed (Brassica napus L.) is widely cultivated, providing diverse nutrients and phytochemicals, including S-methyl-L-cysteine sulfoxide (SMCSO). While the nutritional impact of rapeseed on bees is known, SMCSO's effects remain unexplored. We examined SMCSO and its related metabolites-3-methylthiolactic acid sulfoxide and N-acetyl-S-methyl-L-cysteine sulfoxide-analysing their seasonal fluctuations, colony variations and distribution in body parts. Our findings showed that these compounds in bee gut vary among colonies, possibly due to the dietary preferences, and are highly concentrated in bodies during the summer. They are distributed differently within bee bodies, with higher concentrations in the abdomens of foragers compared with nurses. Administration of SMCSO in a laboratory setting showed no immediate toxic effects but significantly boosted bees' antioxidant capacity. Long-term administration decreased bee body weight, particularly in the thorax and head, and altered amino acid metabolism. SMCSO is found in the nectar and pollen of rapeseed flowers and highly accumulates in rapeseed honey compared with other types of honey. This study reveals the dual impact of SMCSO on bee health, providing a basis for further ecological and physiological research to enhance bee health and colony sustainability.

Pollinator functional group abundance and floral heterogeneity in an agroecological context affect mating patterns in a self-incompatible wild plant

PREMISE

Restoration of seminatural field margins can elevate pollinator activity. However, how they support wild plant gene flow through interactions between pollinators and spatiotemporal gradients in floral resources remains largely unknown.

METHODS

Using a farm-scale experiment, we tested how mating outcomes (expected heterozygosity and paternity correlation) of the wild, self-incompatible plant Cyanus segetum transplanted into field margins (sown wildflower or grass-legume strips) were affected by the abundance of different pollinator functional groups (defined by species traits). We also investigated how the maternal plant attractiveness, conspecific pollen donor density, and heterospecific floral richness and density interacted with pollinator functional group abundance to modulate C. segetum mating outcomes.

RESULTS

Multiple paternity increased (=lower paternity correlation) with greater local abundance of hoverflies (syrphids) and female medium-sized wild bees (albeit the latter's effect diminished with decreasing maternal plant attractiveness), and the presence of male bumblebees (Bombus) under low local floral richness. Cyanus segetum progeny genetic diversity increased with male Bombus presence but decreased with greater abundance of syrphids and honey bees (Apis mellifera).

CONCLUSIONS

Overall, field margins supported plant-pollinator interactions ensuring multiple paternity and conservation of allelic diversity in C. segetum progeny. The contribution to plant mating outcomes of different pollinator functional groups was dictated by their local abundance or traits affecting pollen transfer efficiency. The local floral richness or maternal plant attractiveness sometimes modulated these relationships. This complex response of wild plant mating patterns to community interactions has implications for the use of field margins to restore functional pollination systems in farmed landscapes.

Stingless Bee Foraging Activity Related to Environmental Aspects

The environment where bee colonies are inserted must provide the necessary resources for their survival. Given this, any biotic and abiotic changes in the environment can affect the development and survival of the colonies. We evaluated the foraging activity of Plebeia droryana (Friese), Scaptotrigona bipunctata (Lepetelier), and Melipona quadrifasciata (Lepetelier) in areas with different land uses and land cover. These areas were classified as predominantly (i) urbanized/forest (CDA-Cidade das Abelhas), (ii) agricultural (FER-Fazenda Experimental da Ressacada), and (iii) with dense vegetation (SFB-Sitio Florbela). We correlated the morphometric characteristics of the bees with the pollen load transported. Four colonies from each species were installed in the three areas. We recorded light, wind speed, humidity, and temperature and counted the foragers returning with nectar, pollen, and resin. Plebeia droryana and S. bipunctata collected more resin and nectar in with dense vegetation area compared to agricultural area. Scaptotrigona bipunctata collected more pollen in urbanized/forest area and with dense vegetation area, and M. quadrifasciata did not show differences in foraging activity between areas. Plebeia droryana and M. quadrifasciata showed moderate and strong correlations between morphometric characteristics and pollen load. SFB had higher luminosity and wind speed. CDA had higher average temperature. FER had higher humidity. The three species showed positive and negative correlations between temperature and light and foraging in the different areas. Smaller species showed a higher gathering of resources in the area predominantly covered by dense vegetation. The reduction of vegetation cover can affect the resource collection activity of stingless bees.

Models of bee responses to land use and land cover changes in agricultural landscapes - a review and research agenda

Predictive modelling tools can be used to support the design of agricultural landscapes to promote pollinator biodiversity and pollination services. Despite the proliferation of such modelling tools in recent decades, there remains a gap in synthesising their main characteristics and representation capacities. Here, we reviewed 42 studies that developed non-correlative models to explore the impact of land use and land cover changes on bee populations, and synthesised information about the modelled systems, modelling approaches, and key model characteristics like spatiotemporal extent and resolution. Various modelling approaches are employed to predict the biodiversity of bees and the pollination services they provide, with a prevalence of models focusing on wild populations compared to managed ones. Of these models, landscape indicators and distance decay models are relatively simple, with few parameters. They allow mapping bee visitation probabilities using basic land cover data and considering bee foraging ranges. Conversely, mechanistic or agent-based models delineate, with varying degrees of complexity, a multitude of processes that characterise, among others, the foraging behaviour and population dynamics of bees. The reviewed models collectively encompass 38 ecological, agronomic, and economic processes, producing various outputs including bee abundance, habitat visitation rate, and crop yield. To advance the development of predictive modelling tools aimed at fostering pollinator biodiversity and pollination services in agricultural landscapes, we highlight future avenues for increasing biophysical realism in models predicting the impact of land use and land cover changes on bees. Additionally, we address the challenges associated with balancing model complexity and practical usability.

Bee Phenological Distributions Predicted by Inferring Vital Rates

AbstractHow bees shift the timing of their seasonal activity (phenology) to track favorable conditions influences the degree to which bee foraging and flowering plant reproduction overlap. While bee phenology is known to shift due to interannual climatic variation and experimental temperature manipulation, the underlying causes of these shifts are poorly understood. Most studies of bee phenology have been phenomenological and have only examined shifts of point estimates, such as first appearance or peak timing. Such cross-sectional measures are convenient for analysis, but foraging activity is distributed across time, and pollination interactions are better described by overlap in phenological abundance curves. Here, we make simultaneous inferences about interannual shifts in bee phenology, emergence and senescence rates, population size, and the effect of floral abundance on observed bee abundance. We do this with a model of transition rates between life stages implemented in a hierarchical Bayesian framework and parameterized with fine-scale abundance time series of the sweat bee Halictus rubicundus at the Rocky Mountain Biological Laboratory in Colorado. We find that H. rubicundus's emergence cueing was highly sensitive to the timing of snowmelt but that emergence rate, senescence rate, and population size did not differ greatly across years. The present approach can be used to glean information about vital rates from other datasets on bee and flower phenology, improving our understanding of pollination interactions.

Digging below the surface: Hidden risks for ground-nesting bees

Hidden risks for ground-nesting bees.