Pollen Consumption Research Articles

Comprehensive assessment of mercury contamination in bees, bee products and moss and lichen bags

Twenty-eight beekeepers around Slovakia were included in the research to evaluate the presence of mercury in honeybee bodies and selected bee-related products: bee pollen and honey. The samples were collected in May, June, and July (honeybee bodies only in May and June). During this period, moss and lichen bags for air quality assessment were exposed around the beehives and relative accumulation factor (RAF) was used for its evaluation. Mercury content in evaluated bioindicators was determined using AMA 254 analyser. Percentage of provisional tolerable intake (%PTWI) and target hazard quotient (THQ) were used to determine health risks related to bee pollen and honey consumption. Around the beehives the proportion of landscape structure elements was determined for each sampling locality, using a geographical informational system QGIS. The aim of the study was a comprehensive evaluation of the mercury content in the environment around beehives using several bioindicators and an assessment of the relationship between the presence of mercury pollution and the proportion of landscape structure elements in the vicinity of the beehives. The study also aimed to evaluate the transfer of contaminants between bee bodies and bee-related products and the health risks resulting from their consumption.

Effect of pollen consumption on development and intraguild predation of two predatory Coccinellidae

Many omnivorous predaceous coccinellids consume both pests like aphids and a range of plant-derived foods including pollen. It is critical to understand how plant-derived food like pollen could affect the fitness and interspecific interactions of predaceous coccinellids. This study investigated the effect of pollen consumption on the development, reproduction and intraguild predation (IGP) of two naturally co-existing aphidophagous ladybirds, Harmonia axyridis and Propylea japonica. Both species were provided with three diets including a moist canola pollen, the aphid Myzus persicae, or moist canola pollen together with aphids. The 1st instar larval of both H. axyridis and P. japonica could not survive and develop to the next larval stage when supplied with water alone. When fed on pollen only, 53 % of the H. axyridis larvae and 25 % of the P. japonica larvae successfully developed to adult. Both species exhibited an elongated development time, shorter larval body length and lower adult body weight than when offered with aphids and the mixed diet. In addition, P. japonica could not reproduce when fed on pollen alone. Interestingly, when pollen was provided as additional food, the overall IGP between larvae of H. axyridis and P. japonica was significantly reduced compared with water control or aphid as food alone. The results of this study indicated that pollen not only supports the survival of H. axyridis and P. japonica when prey is scarce, but also could benefit the co-existence of these species. For future study, it is necessary to investigate how pollinivory could benefit the fitness and biological control potential of H. axyridis and P. japonica under field conditions.

Consumption of pollen contaminated with field-realistic concentrations of fungicide causes sublethal effects in Bombus impatiens (Hymenoptera: Apidae) microcolonies.

Bumble bees are declining across the globe. The causes of this decline have been attributed to a variety of stressors, including pesticides. Fungicides are a type of pesticide that has been understudied in the context of bumble bee health. As a result, fungicides are often applied to flowering plants without consideration of pollinator exposure. Recent work demonstrates that fungicides have sublethal effects in bumble bees, but little is known about how much fungicide it takes to cause these sublethal effects. To address this gap in the literature, we fed microcolonies of the common eastern bumble bee (Bombus impatiens CressonHymenoptera: ApidaeHymenoptera: ApidaeHymenoptera: ApidaeHymenoptera: Apidae) pollen contaminated with a range of fungicide concentrations. We chose these concentrations based on the range of fungicide concentrations in pollen and nectar that were reported in the literature. Results revealed that later-stage pupae and newly emerged males are potentially sensitive to fungicide exposure, showing smaller size and reduced fat reserves at intermediate levels of contamination. Compared to the control, intermediated levels of fungicide-contaminated pollen led to increased pupal mortality and delayed male emergence. Contrary to expectations, higher fungicide levels did not exhibit a linear relationship with negative impacts, suggesting nuanced effects. Because body size and emergence timing are important aspects of bumble bee reproductive behavior, results have implications for mating success, potentially disrupting colony development.

Assessing Mineral Content and Heavy Metal Exposure in Abruzzo Honey and Bee Pollen from Different Anthropic Areas.

Honey and bee pollen offer potential health benefits due to their nutrient and bioactive molecules, but they may also harbor contaminants such as heavy metals. This study aimed to assess the content of different metals, including Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Zn, Cu, As, Rb, Sr, Cd, Cs, Tl, Pb and U, in honey and bee pollen collected from different Abruzzo region (Italy) areas (A1, A2, A3, A4), characterized by different anthropic influences described by Corine Land Cover maps. Differences were observed in the mineral and heavy metal content associated with the influence of biotic and abiotic factors. Honeys were found to be safe in regard to non-carcinogenic risk in all the consumer categories (THQm < 1). A particular carcinogenic risk concern was identified for toddlers associated with Cr (LCTR > 1 × 10-4) in A1, A2 and A3 apiaries. Pb and Ni represent potential non-carcinogenic and carcinogenic health risks in children and adults due to bee pollen consumption, showing high values of THQm and LCTR. The results suggest the advantages of utilizing bee products to screen mineral and heavy metal content, providing valuable insights into environmental quality and potential health risks.

High toxin concentration in pollen may deter collection by bees in butterfly-pollinated Rhododendron molle.

The hypothesis that plants evolve features that protect accessible pollen from consumption by flower visitors remains poorly understood. To explore potential chemical defenses against pollen consumption, we examined the pollinator assemblage, foraging behaviour, visitation frequency and pollen transfer efficiency in Rhododendron molle, a highly toxic shrub containing Rhodojaponin III. Nutrient (protein and lipid) and toxic components in pollen and other tissues were measured. Overall in the five populations, floral visits by butterflies and bumblebees were relatively more frequent than visits by honeybees. All foraged for nectar but not pollen. Butterflies did not differ from bumblebees in the amount of pollen removed per visit, but deposited more pollen per visit. Pollination experiments indicated that R. molle was self-compatible, but both fruit and seed production were pollen limited. Our analysis indicated that the pollen was not protein-poor and had a higher concentration of the toxic compound Rhodojaponin III than petals and leaves, which compound was undetectable in nectar. Pollen toxicity in Rhododendron flowers may discourage pollen robbers (bees) from taking the freely accessible pollen grains, while the toxin-free nectar rewards effective pollinators, promoting pollen transfer. This preliminary study supports the hypothesis that chemical defense in pollen would be likely to evolve in species without physical protection from pollinivores.

Bee colonies map the short- and medium-chain chlorinated paraffin contamination from the apiary environment

Chlorinated paraffins (CPs) are industrial chemicals that have potential adverse effects in the environment and on human health. This study investigated CPs in apiary environment, honeybees, and bee products from two rural areas of Beijing, China. The median concentrations of short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) were 22 and 1.6 ng/m3 in the ambient air, 1350 and 708 ng/g dry mass (dw) in bees, 1050 and 427 ng/g dw in flowers, 37 and 54 ng/g in honey, 78 and 53 ng/g dw in bee pollen, 36 and 30 ng/g dw in soil, and 293 and 319 ng/g dw in bee wax. C10Cl6–7 and C14Cl7–8 dominated SCCPs and MCCPs in these samples, respectively. The concentrations and distributions of CPs in samples from apiaries located in the two regions varied. Long-range transportation of air masses was identified as an important source of CPs in apiaries. A close relationship between CPs in bees and the apiary environment indicated that bees could act as bioindicators for CP contamination in the environment. A human health risk assessment found that there were low risks for adults and children exposed to CPs through consumption of honey and pollen from the studied regions.

Influence of pollination in liquid suspension on the date palm (Phoenix dactylifera L.) Mejhoul cultivar in the Mexicali valley, Mexico

The pollination process is one of the most important contributors to a successful date production since the yield and quality of the fruit depends on its correct successful. Liquid pollination in the date palm production is a recently used technique that seeks to obtain acceptable fruit set percentages (FSP) with lower pollen consumption. In this study, during the 2021 and 2022 growing seasons, the effect of pollination with pollen grains in liquid suspension on the FSP in the date palm cultivar &amp;lsquo;Mejhoul&amp;rsquo; was evaluated in the Mexicali Valley, Mexico. The applications were in various proportions of pollen in liquid suspension (1, 2, 3 and 4 g/L), with approximately 40 mL on each inflorescence. The results revealed that the best treatment was 4 g/L with an average FSP of 67.89 and 68.69% for the years 2021 and 2022 respectively, while the control treatment obtained 54.94 and 57.75%, for the same years. Likewise, this method did not affect the physical and chemical properties and yields. Finally, this study suggests that in addition to consuming a smaller amount of pollen, this method has better pollination efficiency.

Consumption of Citric Acid by Bees Promotes the Gland Development and Enhances Royal Jelly Quality.

The glands of bees are responsible for generating and secreting various biologically active substances that significantly impact bee physiological health and adaptability. This study aimed to investigate the effects of adding citric acid (CA) to bee feed on gland development and royal jelly quality. By formulating feed with varying proportions of CA, evaluation was undertaken of pollen feeding by honeybees under laboratory conditions, along with the impact of CA on the development of major glands, to determine suitable addition proportions. Further optimization of the CA proportion involved feeding colonies and evaluating royal jelly production and quality. The results indicated that feed containing 0.75% CA significantly extended the lifespan of bees and increased their pollen consumption. Gland development in bees showed a positive correlation with CA addition within the range of 0.25% to 0.75%, especially at 0.50% and 0.75%, which notably accelerated the development of mandibular, hypopharyngeal, and cephalic salivary glands, with active proliferation and differentiation of glandular cells and maintenance of normal gland size and morphology. CA added to feed stimulated vigorous secretion of wax glands in worker bees, resulting in prolific wax construction. Colonies consuming feed containing 0.50% CA produced royal jelly with significantly reduced moisture and total sugar content and increased levels of 10-HDA, total phenolic acids, total proteins, and acidity. These findings demonstrate that CA consumption significantly prolongs bee lifespan, increases consumption, promotes gland development, and enhances royal jelly quality. This research provides theoretical guidance for beekeeping practices and feed development, contributing to the sustainable advancement of apiculture.

Age-dependent hypopharyngeal gland size and protein content of stingless bee workers, Tetragonula pagdeni.

Eusocial insects, such as stingless bees (Meliponini), depend on division of labour, overlapping generations, and collaborative brood care to ensure the functionality and success of their colony. Female workers transition through a range of age-specific tasks during their lifespan (i.e., age-polyethism) and play a central role in the success of a colony. These age-specific tasks (e.g., brood care or foraging) often closely coincide with key physiological changes necessary to ensure optimal performance. However, our understanding of how nutrition, age, and polyethism may affect the development of such physiological traits in stingless bees remains limited. Here we show that pollen consumption and age-polyethism govern hypopharyngeal gland (HPG) acini size and protein content in Tetragonula pagdeni. By conducting a controlled laboratory experiment we monitored the effect of pollen consumption on worker bee survival as well as assessed how a pollen diet and age affected their HPG acini width and protein content. Further, we sampled nurses and foragers from field colonies to measure the effect of age-polyethism on HPG acini width. We found that pollen consumption enhanced survival and led to increased HPG acini width and protein content and that HPG acini were as expected largest in nurse bees. Our findings highlight the beneficial effects of an adequate diet for physiological development and health in stingless bees and reveal that age-polyethism is the key factor governing HPG size in worker bees. As HPGs are imperative for collaborative brood care-an essential component of eusociality-the data provide a foundation for future studies to investigate the impact of potential environmental stressors on a critical physiological trait in stingless bees which may serve as a proxy to understand the effects at the colony level.

Diverse pollen nutrition can improve the development of solitary bees but does not mitigate negative pesticide impacts

Floral resource loss and pesticide exposure are major threats to bees in intensively managed agroecosystems, but interactions among these drivers remain poorly understood. Altered composition and lowered diversity of pollen nutrition may reinforce negative pesticide impacts on bees. Here we investigated the development and survival of the solitary bee Osmia bicornis provisioned with three different pollen types, as well as a mixture of these types representing a higher pollen diversity. We exposed bees of each nutritional treatment to five pesticides at different concentrations in the laboratory. Two field-realistic concentrations of three nicotinic acetylcholine receptor (nAChR) modulating insecticides (thiacloprid, sulfoxaflor and flupyradifurone), as well as of two fungicides (azoxystrobin and tebuconazole) were examined. We further measured the expression of two detoxification genes (CYP9BU1, CYP9BU2) under exposure to thiacloprid across different nutrition treatments as a potential mechanistic pathway driving pesticide-nutrition interactions. We found that more diverse pollen nutrition reduced development time, enhanced pollen efficacy (cocoon weight divided by consumed pollen weight) and pollen consumption, and increased weight of O. bicornis after larval development (cocoon weight). Contrary to fungicides, high field-realistic concentrations of all three insecticides negatively affected O. bicornis by extending development times. Moreover, sulfoxaflor and flupyradifurone also reduced pollen efficacy and cocoon weight, and sulfoxaflor reduced pollen consumption and increased mortality. The expression of detoxification genes differed across pollen nutrition types, but was not enhanced after exposure to thiacloprid. Our findings highlight that lowered diversity of pollen nutrition and high field-realistic exposure to nAChR modulating insecticides negatively affected the development of O. bicornis, but we found no mitigation of negative pesticide impacts through increased pollen diversity. These results have important implications for risk assessment for bee pollinators, indicating that negative effects of nAChR modulating insecticides to developing solitary bees are currently underestimated.

A large-sized mammalian coprolite containing ground sloth osteoderms from the Upper Pleistocene Touro Passo Formation of Brazil

Coprolites provide information about the presence, diet, and feeding behavior of the producer, besides the trophic relationships between extinct taxa and the regional paleoclimatic context where these organisms lived. Here, we present a paleobiological and paleoecological investigation of a Late Pleistocene carnivore coprolite found in southern Brazil (Touro Passo Formation, Rio Grande do Sul). Our analyses include morphological and morphometric approaches employing scanning electron microscopy, energy-dispersive X-ray spectroscopy, and CT-scanning. The analyzed coprolite is cylindrical, measuring 180 mm in length and 40 mm maximum in diameter, and contains a high proportion of phosphorus and calcium. Interestingly, it presents a large quantity of 102 osteoderms attributed to a Pleistocene ground sloth (Mylodontidae indet.). The size and contents of the coprolite suggest that it was produced by a large carnivorous animal comparable to representatives of Smilodon or another large carnivore mammal. The structure of the osteoderms resembles the morphological pattern found in Mylodontidae, but they are smaller than those described for adult individuals, suggesting that the coprolite producer possibly fed on a juvenile ground sloth. Palynological analysis was also performed, and the low pollen content indicates accidental consumption of plants or pollen, through the viscera of the prey or with the ingestion of water. These paleoenvironmental data suggest that the coprolite producer may have inhabited floodplain regions near river courses, where the coprolite was deposited. These results help to understand the ecological dynamics during the Late Pleistocene of South America.

Microbial Diversity in Bee Species and Bee Products: Pseudomonads Contribution to Bee Well-Being and the Biological Activity Exerted by Honey Bee Products: A Narrative Review

Bees are important pollinators worldwide, promoting sustainability in agriculture and natural ecosystems. Moreover, honey bees produce a variety of honey bee products (beehive products). Honey is the main edible bee product. The consumption of pollen, bee bread, royal jelly, and propolis is becoming more popular nowadays. All these products are characterized by high nutritional value and/or bioactivity. A high microbial diversity has been reported in bees and beehive products, forming distinct microbial communities. The honey bee gut microbiome actively promotes good health and nutrient availability for the host. Furthermore, it prevents food spoilage and contributes to the maintenance of good hygiene conditions in the hive. Pseudomonads are often reported in investigations on bee and bee product microbiomes. Diverse Pseudomonas species demonstrate high metabolic adaptability, producing a wide range of bioactive enzymes and secondary metabolites. Several studies have provided evidence that Pseudomonads might play a role in bee well-being and the bioactivity exerted by honey bee products, though further research is warranted to fully understand the effects and mechanisms. The aim of this narrative review is to highlight the importance of Pseudomonads in the context of up-to-date knowledge regarding the bee and bee product microbiomes.

Investigating the influence of diet diversity on infection outcomes in a bumble bee (Bombus impatiens) and microsporidian (Nosema bombi) host-pathogen system.

Diet can have an array of both direct and indirect effects on an organism's health and fitness, which can influence the outcomes of host-pathogen interactions. Land use changes, which could impact diet quantity and quality, have imposed foraging stress on important natural and agricultural pollinators. Diet related stress could exacerbate existing negative impacts of pathogen infection. Accounting for most of its nutritional intake in terms of protein and many micronutrients, pollen can influence bee health through changes in immunity, infection, and various aspects of individual and colony fitness. We investigate how adult pollen consumption, pollen type, and pollen diversity influence bumble bee Bombus impatiens survival and infection outcomes for a microsporidian pathogen Nosema (Vairimorpha) bombi. Experimental pathogen exposures of larvae occurred in microcolonies and newly emerged adult workers were given one of three predominantly monofloral, polyfloral, or no pollen diets. Workers were assessed for size, pollen consumption, infection 8-days following adult-eclosion, survival, and the presence of extracellular microsporidian spores at death. Pollen diet treatment, specifically absence of pollen, and infection independently reduced survival, but we saw no effects of pollen, pollen type, or pollen diet diversity on infection outcomes. The latter suggests infection outcomes were likely already set, prior to differential diets. Although infection outcomes were not altered by pollen diet in our study, it highlights both pathogen infection and pollen availability as important for bumble bee health, and these factors may interact at different stages of bumble bee development, at the colony level, or under different dietary regimes.

The impact of heavy metal pollution on wild bee communities in smallholder farmlands

Wild bees provide important pollination services, but they face numerous stressors that threaten them and their ecosystem services. Wild bees can be exposed to heavy metal pollution through the consumption of nectar, pollen, and water, which might cause bee decline. While some studies have measured heavy metal concentrations in honeybees, few studies have monitored heavy metal concentrations in wild bees or explored their potential effects on wild bee communities. To investigate the impact of heavy metal pollution on wild bee communities, heavy metal concentrations, including vanadium (V), chromium (Cr), nickel (Ni), cadmium (Cd), Zinc (Zn) and lead (Pb) in multiple wild bee species were measured. Multiple wild bee species, including: Xylocopa tranquabaroroum, Eucera floralia, Apis cerana, and small bee mixtures (representing multiple small wild bee species) were sampled from 18 sites in Quzhou, Zhejiang Province, China. The findings demonstrated that there were significant differences in heavy metal concentrations among different bee species. The concentrations of V, Zn, Cd, and Pb in X. tranquabaroroum, the largest bee species in this study, were lower than that in the other three sample groups. Furthermore, there were significant negative correlations between heavy metal pollution and wild bee diversity and species richness, but not with abundance. Particularly, there was no significant relationship between heavy metal pollution and the abundance of small bees. Given these worrying findings, monitoring multiple heavy metals in wild bees should be conducted for protecting wild bee diversity and securing their pollination services.

Pollinator visitation closely tracks diurnal patterns in pollen release.

Animal-pollinated plants face a high risk of pollen loss during its transfer. To limit the negative effect of pollen losses by pollen consumption and heterospecific transfer, plant species may adjust and stratify their pollen availability during the day (i.e., "schedule" their pollen presentation) and attract pollinators in specific time frames. We investigated diurnal patterns of pollen availability and pollinator visitation in three coflowering plant species: Succisa pratensis with open flowers and accessible pollen, pollinated mainly by pollen-feeding hoverflies; Centaurea jacea with open flowers and less accessible pollen, pollinated mainly by pollen-collecting bees; and Trifolium hybridum with closed flowers and pollen accessible only after the active opening of the flower, pollinated exclusively by bees. The three plant species differed in the peak pollen availability, tracked by the visitation activity of their pollinators. Succisa pratensis released all pollen in the morning, while pollinator activity was still low and peaked with a slight delay. In contrast, C. jacea and T. hybridum had distinct pollen presentation schedules, peaking in the early afternoon. The pollinator visitation to both of these species closely matched their pollen availability. Stratifying pollen availability to pollinators during the day may be one of several mechanisms that allow coflowering plants to share their pollinators and decrease the probability of heterospecific pollen transfer.

Characteristics of contaminants in the polish-origin bee products and cancer risk assessment.

The aim of this study was to evaluate the concentration of 5-hydroxymethylfurfural (HMF), furfural, polycyclic aromatic hydrocarbons (PAHs), and pesticide residues, as well as assessment of cancer risk of the Polish-origin bee products. The bee product samples were prepared using a modified QuEChERS method, then PAHs and pesticides were analysed by gas chromatography-mass spectrometry (GC-MS), neonicotinoids by high-performance liquid chromatography with a diode array detector (HPLC-DAD), and HMF and furfural by spectrophotometry (HPLC-UV/Vis). The results showed that the highest furfural content was found in bee bread from the northeast part of Poland; moreover, samples obtained from the same region were also characterized with a higher level of HMF. The total sum of PAHs ranged from 324.0 to 866.4μg/kg; the highest content of PAH4 (the sum of benzo[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene) was 21.0μg/kg, but only benzo[a]anthracene and chrysene were detected in the samples. Imidacloprid and acetamiprid were found only in bee bread from the northeast part of Poland, while clothianidin was detected in honey samples. The acceptable cancer risk has been calculated for PAHs due to ingestion of honey, while increasing the risk of cancer was calculated for bee bread and bee pollen. Due to the high concentration of PAHs and excessively high recommended consumption dose, regular consumption of bee bread and pollen may pose a severe threat to human health and should be strictly limited.

Perception, regulation, and fitness effects of pollen phytosterols in the bumble bee, Bombus terrestris.

Many flowering plants depend on insects for pollination and thus attract pollinators by offering rewards, mostly nectar and pollen. Bee pollinators rely on pollen as their main nutrient source. Pollen provides all essential micro- and macronutrients including substances that cannot be synthesized by bees themselves, such as sterols, which bees need for processes such as hormone production. Variations in sterol concentrations may consequently affect bee health and reproductive fitness. We therefore hypothesized that (1) these variations in pollen sterols affect longevity and reproduction in bumble bees and (2) can thus be perceived via the bees' antennae before consumption. We studied the effect of sterols on longevity and reproduction of Bombus terrestris workers in feeding experiments and investigated sterol perception using chemotactile proboscis extension response (PER) conditioning. Workers could perceive several sterols (cholesterol, cholestenone, desmosterol, stigmasterol, β-sitosterol) via their antennae but not differentiate between them. However, when sterols were presented in pollen, and not as a single compound, the bees were unable to differentiate between pollen differing in sterol content. Additionally, different sterol concentrations in pollen neither affected pollen consumption nor brood development or worker longevity. Since we used both natural concentrations and concentrations higher than those found in pollen, our results indicate that bumble bees may not need to pay specific attention to pollen sterol content beyond a specific threshold. Naturally encountered concentrations might fully support their sterol requirements and higher concentrations do not seem to have negative effects.

Differential bumble bee gene expression associated with pathogen infection and pollen diet

BackgroundDiet and parasitism can have powerful effects on host gene expression. However, how specific dietary components affect host gene expression that could feed back to affect parasitism is relatively unexplored in many wild species. Recently, it was discovered that consumption of sunflower (Helianthus annuus) pollen reduced severity of gut protozoan pathogen Crithidia bombi infection in Bombus impatiens bumble bees. Despite the dramatic and consistent medicinal effect of sunflower pollen, very little is known about the mechanism(s) underlying this effect. However, sunflower pollen extract increases rather than suppresses C. bombi growth in vitro, suggesting that sunflower pollen reduces C. bombi infection indirectly via changes in the host. Here, we analyzed whole transcriptomes of B. impatiens workers to characterize the physiological response to sunflower pollen consumption and C. bombi infection to isolate the mechanisms underlying the medicinal effect. B. impatiens workers were inoculated with either C. bombi cells (infected) or a sham control (un-infected) and fed either sunflower or wildflower pollen ad libitum. Whole abdominal gene expression profiles were then sequenced with Illumina NextSeq 500 technology.ResultsAmong infected bees, sunflower pollen upregulated immune transcripts, including the anti-microbial peptide hymenoptaecin, Toll receptors and serine proteases. In both infected and un-infected bees, sunflower pollen upregulated putative detoxification transcripts and transcripts associated with the repair and maintenance of gut epithelial cells. Among wildflower-fed bees, infected bees downregulated immune transcripts associated with phagocytosis and the phenoloxidase cascade.ConclusionsTaken together, these results indicate dissimilar immune responses between sunflower- and wildflower-fed bumble bees infected with C. bombi, a response to physical damage to gut epithelial cells caused by sunflower pollen, and a strong detoxification response to sunflower pollen consumption. Identifying host responses that drive the medicinal effect of sunflower pollen in infected bumble bees may broaden our understanding of plant-pollinator interactions and provide opportunities for effective management of bee pathogens.

A honey bee requirements design study based on multi-objective optimization

The honeybee is a major pollinating insect and plays a vital role in the ecological chain. Therefore, the correct prediction of honeybee population size and optimal beehive configuration is beneficial for developing long-term or phased management plans for bee colonies to obtain high yields of bee products. Through literature analysis, this paper chooses economic benefits and environmental effects as the multiple objectives of the model. The model is also constrained by the maximum number of bees pollinating and the minimum daily pollen consumption of bees to calculate the optimal number of beehives for a given area. In this paper, we adopt the multi-objective equal-weight processing and transform it into a single-objective approach, which is solved using the artificial bee colony algorithm. According to the final calculation, the optimal number of beehives for this area is 54.

Atrazine exposure can dysregulate the immune system and increase the susceptibility against pathogens in honeybees in a dose-dependent manner

Recently, concerns regarding the impact of agrochemical pesticides on non-target organisms have increased. The effect of atrazine, the second-most widely used herbicide in commercial farming globally, on honeybees remains poorly understood. Here, we evaluated how atrazine impacts the survival of honeybees and pollen and sucrose consumption, investigating the morphology and mRNA expression levels of midgut tissue, along with bacterial composition (relative abundance) and load (absolute abundance) in the whole gut. Atrazine did not affect mortality, but high exposure (37.3 mg/L) reduced pollen and sucrose consumption, resulting in peritrophic membrane dysplasia. Sodium channels and chitin synthesis were considered potential atrazine targets, with the expression of various genes related to lipid metabolism, detoxification, immunity, and chemosensory activity being inhibited after atrazine exposure. Importantly, 37.3 mg/L atrazine exposure substantially altered the composition and size of the gut microbial community, clearly reducing both the absolute and relative abundance of three core gram-positive taxa, Lactobacillus Firm-5, Lactobacillus Firm-4, and Bifidobacterium asteroides. With altered microbiome composition and a weakened immune system following atrazine exposure, honeybees became more susceptible to infection by the opportunistic pathogen Serratia marcescens. Thus, considering its scale of use, atrazine could negatively impact honeybee populations worldwide, which may adversely affect global food security.