Forager Bees Research Articles

Honey Bee Waggle Dance as a Model of Swarm Intelligence

Honey bees are social insects that form colonies (hives), which often consist of more than 10,000 individuals. In a colony, bees allocate jobs (division of labor) and work cooperatively and intelligently to maintain the colony’s activity, such as nursing broods, cleaning, and guarding against enemies. Among worker bees, only forager bees collect food, and success in finding food directly influences colony survival. For more efficient foraging, honey bees share location information pertaining to profitable food sources through specific behavior called “waggle dances.” During such dances, the direction and distance from the hive to the food source are encoded as body movements. Other foragers follow the dancing bees and receive location information. Some of these bees then fly to the advertised location to find the food source. Some of these “recruited bees” subsequently dance to recruit new bees. This process is then repeated. Consequently, many foragers visit the food source, and a colony can rapidly and flexibly collect large amounts of food even in foraging environment that can suddenly change (e.g., flowers disappear or nectar flux increases/decreases). To achieve effective food collection through the waggle dance, the behavior of both the dancers and followers probably contains information for an implementation of “swarm intelligence.” In this review, we introduce the properties of dance behavior at the levels of dancers, followers, and colonies. We found that errors in waggle dance information play an important role in adaptive foraging in dynamically changing environments.

Temporally stacked bee forage species distribution modeling for flower abundance mapping

Predicting spatial distribution of flowering forage availability is critical for guiding migratory beekeeping decisions.Species distribution modelling (SDM) is widely used to predict the geographic distribution or species ranges. Stacked distributions of multiple species (S-SDM) have been used in predicting species richness or assemblages. Here, we present a method for stacking SDMs based on a temporal element, the flowering phenology of melliferous flora species. First, we used presence-only data for thirty key forage species used for honey production in Western Australia, combined with environmental variables for predicting the geographic distribution of species, using MaxEnt software. The output distribution grids were then stacked based on monthly flowering times of each species to develop grids representing the richness of flowering species by grid cell. While designed for modelling flowering forage availability for a migratory beekeeping system, the approach can be used for predicting temporal forage availability for a range of different fauna that rely on melliferous flora.•How to use temporally stacked species distribution modelling for generic distribution of flowering availability using presence-only data.•A procedure for developing flowering richness and availability grids.

Foraging activity and role of stingless bee Tetragonula iridipennis Smith (Hymenoptera: Apidae) in bitter gourd

In the bitter gourd cropping system, honey bees were the primary pollinators. In the Coimbatore district, a field study was conducted to record the foraging activity and pollination efficiency of the stingless bee Tetragonula iridipennis in bitter gourd. Bee foraging activity was recorded separately in male and female flowers, with the number of foragers/flower/min recorded. Fruit set and yield were assessed under three different conditions: pollinator exclusion, bee pollination, and open pollination. Abundance of Pollinators and foraging rate of stingless bees observed on male flower 1.71 bees/ flower/ minute and flower handling time in seconds was (37.86 sec) was higher than female flowers 1.22 bees / flower/ minute and (25.73 sec) respectively. The peak foraging activity of stingless bees was observed between 08:00-10:00 hours with 3.30 bees/ 5 mins. The pollination efficiency index of stingless bees in bitter gourd flowers was 41600. The foraging activity of bees at the hive entrance was at its peak at 08:00 to 10:00 hours. T. Iridipennis colony growth parameters show increased honey sealed area 1464.5 g and brood development. The experiment results show that yield was higher in the managed bee-pollinated condition in terms of number of fruits/plant was (18.2 fruits) and fruit yield per hectare (44.08 t/ha) than in the open pollinated condition (16.5 fruits) and (38.30 t/ha), and with pollinators excluded, no fruit set was recorded.

Altered synaptic organization in the mushroom bodies of honey bees exposed as foragers to the pesticide fipronil

The pesticide fipronil is a GABA receptor antagonist that induces hyperexcitability in the insect nervous system. Its use is controversial because unintentional fipronil exposure may contribute to the ongoing global decline of pollinator populations. Sublethal doses of fipronil have been tentatively linked to reduced colony fitness and impaired learning in the western honey bee, Apis mellifera. The mushroom bodies, insect brain centers important for association learning and memory, contain fipronil-sensitive receptors and may therefore be directly affected by this pesticide. We investigated the synaptic organization of the mushroom bodies in worker honey bees exposed to fipronil using immunolabeling for a pre-synaptic marker and laser scanning confocal microscopy. Exposure of honey bee foragers to fipronil at a feasible field-realistic (1 ppb) concentration decreased the estimated density of immunolabeled microglomerular synaptic complexes in the lip and collar neuropil regions of the mushroom bodies. Effects were also evident after lower (0.1 ppb) and higher (4 ppb) exposures. Other indicators of synaptic organization (bouton number, surface area) were altered by exposure to fipronil in a dose-dependent fashion. These results indicate that sublethal doses of fipronil can result in atypical synaptic organization in the mushroom bodies of honey bees and suggest a mechanism by which fipronil, through perturbation of mushroom body-dependent functions, might diminish honey bee colony survival.

Composition and diversity of bacterial communities associated with honey bee foragers from two contrasting environments.

The honey bee is associated with a diverse community of microbes (viruses, bacteria, fungi, and protists), commonly known as the microbiome. Here, we present data on honey bee microbiota from two localities having different surrounding landscapes - mountain (the Rhodope Mountains) and lowland (the Danube plain). The bacterial communities of abdomen of adult bees were studied using amplicon sequencing of the 16S rRNA gene. The composition and dominance structure and their variability within and between localities, alpha and beta diversity, and core and differential taxa were compared at different hierarchical levels (operational taxonomic units to phylum). Seven genera (Lactobacillus, Gilliamella, Bifidobacterium, Commensalibacter, Bartonella, Snodgrassella, and Frischella), known to include core gut-associated phylotypes or species clusters, dominated (92-100%) the bacterial assemblages. Significant variations were found in taxa distribution across both geographical regions and within each apiary. Lactobacillus (Firmicutes) prevailed significantly in the mountain locality followed by Gilliamella and Bartonella (Proteobacteria). Bacteria of four genera, core (Bartonella and Lactobacillus) and non-core (Pseudomonas and Morganella), dominated the bee-associated assemblages of the Danube plain locality. Several ubiquitous bacterial genera (e.g., Klebsiella, Serratia, and Providencia), some species known also as potential and opportunistic bee pathogens, had been found in the lowland locality. Beta diversity analyses confirmed the observed differences in the bacterial communities from both localities. The occurrence of non-core taxa contributes substantially to higher microbial richness and diversity in bees from the Danube plain locality. We assume that the observed differences in the microbiota of honey bees from both apiaries are due to a combination of factors specific for each region. The surrounding landscape features of both localities and related vegetation, anthropogenic impact and land use intensity, the beekeeping management practices, and bee health status might all contribute to observed differences in bee microbiota traits.

The nutritional landscape in agroecosystems: a review on how resources and management practices can shape pollinator health in agricultural environments

Abstract Pollinator nutrition is a highly complex subject that we are just starting to unravel, from the multidimensional nature of bee forage (pollen and nectar) to how the abiotic environment can affect the resources available to bees. Doing so is of utmost importance, as improving pollinator resource availability and nutrition is one of the proposed mechanisms to improve populations and pollinator health. However, landscape change has changed the resources naturally available for pollinators. Farmland and cropping systems create a unique nutritional landscape for pollinators, with agroecosystems typically containing few crops dominating a landscape along with natural corridors containing noncrop plants. The types of crops planted and the surrounding landscape will ultimately affect the nutritional landscape bees have access to. Even the management practices in agriculture and how pests are controlled will, directly and indirectly, affect bee health and nutrition. Hence, a better understanding of bee nutrition in agricultural ecosystems is warranted. This review synthesizes research on bee nutritional ecology and the agricultural landscapes to advance our understanding of bee health in agriculture.

Applying Artificial Neural Networks to Oxidative Stress Biomarkers in Forager Honey Bees (Apis mellifera) for Ecological Assessment.

Insect pollinators provide an important ecosystem service that supports global biodiversity and environmental health. The study investigates the effects of the environmental matrix on six oxidative stress biomarkers in the honey bee Apis mellifera. Thirty-five apiaries located in urban, forested, and agricultural areas in Central Italy were sampled during the summer season. Enzyme activities in forager bees were analyzed using an artificial neural network, allowing the identification and representation of the apiary patterns in a Self-Organizing Map. The SOM nodes were correlated with the environmental parameters and tissue levels of eight heavy metals. The results indicated that the apiaries were not clustered according to their spatial distribution. Superoxide dismutase expressed a positive correlation with Cr and Mn concentrations; catalase with Zn, Mn, Fe, and daily maximum air temperature; glutathione S-transferase with Cr, Fe, and daily maximal air temperature; and glutathione reductase showed a negative correlation to Ni and Fe exposure. This study highlights the importance of exploring how environmental stressors affect these insects and the role of oxidative stress biomarkers. Artificial neural networks proved to be a powerful approach to untangle the complex relationships between the environment and oxidative stress biomarkers in honey bees. The application of SOM modeling offers a valuable means of assessing the potential effects of environmental pressures on honey bee populations.

Assessment of Post-Harvest Handling Practices of Honey in Erer Zone, Somali Regional State, Ethiopia

Honey is a natural food that honeybees make from nectar or other floral secretions. Although Ethiopia has been producing honey for a long time, the quality of the honey produced there, and in the study region in particular, is still poor because of improper handling practices. The objective of this study was to assess post-harvest handling practices of honey in the Erer zone, Somali regional state, Ethiopia. Two districts namely Lagahida and Fik were selected purposively based on beekeeping potential and three kebeles were selected from each district purposively based on honey production potential, and lastly a total of 156 beekeeping households were randomly selected for this study. The study revealed that sampled households used traditional beekeeping systems and hung their hives on trees away from the homestead in dense forests. Honey is harvested two times a year and the average honey yield from traditional and modern hives was 3.65 & 9.73 kg, respectively. The majority (79.5%) of the respondents used smoke and fire during honey harvesting and honey is harvested at night time and this affects honey quality because smoke and ashes from the fire ends up mixing with the harvested honey. The majority (76.95%) of the beekeepers collect and store honey in plastic containers. However, these containers are not appropriate and can spoil honey and may result in quality deterioration. The majority (80.8%) of the beekeepers do not strain honey and only 19.2% of them strain honey before it is sold by simple drainage to remove the beeswax using hand (13.4%) and sieve (5.8%). The beekeepers who do not strain honey reported that they lacked straining materials (29.5%), lack of knowledge of straining (9.6%), and lack of both knowledge & materials (41.7%). High cost of beekeeping equipment, pests & predators, water scarcity, shortage of bee forage, absconding & marketing problem were the major constraints of honey production in the area. The study concluded that the majority of the beekeepers practice traditional beekeeping systems and improper honey-handling practices. Therefore, awareness creation and training of beekeepers on proper handling measures of honey is very crucial in addition to the provision of improved beekeeping equipment which would significantly contribute to honey quality enhancement. Furthermore, investigations on the implications of poor handling practices on honey quality and from the perspective of public health are also required.

Cold storage as part of a Varroa management strategy: effects on honey bee colony performance, mite levels and stress biomarkers

Placing honey bee colonies in cold storage has been proposed as a way to induce a pause in brood production as part of a Varroa mite treatment plan. Here, we exposed colonies to combinations of with or without an October cold storage period and with or without a subsequent miticide application. We then measured the effects of those treatments on colony-level variables (i.e. colony size, Varroa infestation level, survivorship and hive weight and temperature) and pooled individual-level variables that are associated with nutritional and stress responses. Colonies were assessed before and after cold storage, and again post winter, for a total duration of about 5 months, and the experiment was repeated. Brood levels were significantly lower after cold storage, and hive temperatures indicated that most or all brood had emerged after about two weeks in cold storage. However, Varroa levels at the end of the experiments in February were not significantly different among treatment groups. Colonies kept outside (not subjected to cold storage) and treated with a miticide had higher survivorship on average than any other treatment group, but no other group comparisons were significant, and long-term impact of cold storage on adult bee populations and on colony thermoregulation was low. The bee forage environment was also very different between the 2 years of the study, as rainfall and bee forage availability were much higher the second year. Colonies were over 2.5 times larger on average the second year compared to the first, both in terms of adult bee mass and brood area, and expression levels of nutrition and stress response genes were also significantly higher the second year. The results indicate that limited cold storage would likely have little long-term impact on most colony and individual measures of health, but for such a strategy to succeed levels of stressors, such as Varroa, may also need to be low.

Effect of honey bee forage plants in Tunisia on diversity and antibacterial potential of lactic acid bacteria and bifidobacteria from Apis mellifera intermissa and its products.

Lactic acid bacteria and bifidobacteria (LAB and Bifido), isolated from the gastrointestinal tract of Apis mellifera intermissa (BGIT), honey (H), propolis (P) and bee bread (BB) of hives set in different vegetations (wildflowers, caraway, orange blossom, Marrubium vulgare, Eucalyptus and Erica cinerea), were subjected to analysis of their antibacterial potential. Isolates able to inhibit Staphylococcus aureus were selected and identified with MALDI-TOF MS leading to 154 strains representing 12 LAB and Bifido species. Lactiplantibacillus plantarum, Pediococcus pentosaceus and Enterococcus faecalis were predominantly found in all matrices. BGIT showed the highest LAB and Bifido diversity with exclusive occurrences of five species (including Bifidobacterium asteroides and Limosilactobacillus fermentum). Honey was the second origin harboring an important variety of LAB species of which Apilactobacillus kunkeei and Enterococcus mundtii were characteristic of both H and BGIT. Principal components analysis revealed associations between antibacterial activities of LAB and Bifido, matrices and honey bee forage plants. Inhibition trends of S. aureus and Citrobacter freundii were highlighted with: L. plantarum from BGIT, P, H of bees feeding on E. cinerea; Pediococcus pentosaceus from BGIT, P, BB associated with E. cinerea; and Bifidobacterium asteroides from BGIT/orange blossom system. However, Enterococcus faecium associated with BGIT/Eucalyptus system antagonized Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii. Our findings highlighted noteworthy effects of bee forage plants on the antibacterial activity of LAB and Bifido. Our approach could be useful to identify multiple conditions promoting antibacterial potency of LAB and Bifido under the combined effects of feeding plants and living matrices.

Local influence of floral resource attributes on urban bumble bee foraging activity

IntroductionUrbanization diminishes the extent of uncompacted, exposed soil and the coverage of wild plant species, yet still supports diverse pollinator communities when their habitat is maintained within the built environment. Floral abundance and richness are known to influence bee foraging behavior, and these factors vary across the landscape, especially across heterogeneous urban extents. This study assesses how floral resources are distributed across the city of Madison, WI and how these factors influence the distribution of foraging bumble bees.MethodsWe conducted a systematic walking transect survey of bumble bees across Madison, WI. The resulting point location data associated with more than 5,000 non-lethally surveyed bumble bees were analyzed with regard to floral resource explanatory variables as well as underlying land use zoning on more than 700 transects. We used Moran's I correlograms to investigate spatial autocorrelation in floral resource variables and bumble bee counts, then we fitted a generalized linear model predicting transect bee counts based on floral cover, density, species richness and wild plant species richness on the distribution of foraging bees. We employed a geographically-weighted regression model to explore non-stationarity in the effects of floral resource explanatory variables across the study extent.ResultsWe found significant positive influence of flower cover, species richness, and weakly significant positive influence of wildflower species richness on foraging bee counts within the model as well as a significant positive influence of the land use zoning categorical variable. The effects of floral resource predictors on foraging bumble bees varies based on landscape context across the city.DiscussionThe results of this study show that landscapes with high cover as well as floral diversity maximize bumble bee foraging, and the positive effect of wildflower species richness stands out where floral cover and overall richness are also present. Given that urban landscapes are not homogeneous and that floral resources are not consistently distributed across the cityscape, valuable pollinator habitat should be protected, and supplemented where gaps persist.

Distribution of expansive shrubs under climate change scenarios and their socio-economic impacts in a dry Afromontane Forest

Native plants that expanded into new geographical areas after human-induced disturbances and climate change are referred to as expansive species. This study aimed to model the current and future distribution of Cadia purpurea and Tarchonanthus camphoratus, two expansive shrubs in the Desa'a dry Afromontane Forest in northern Ethiopia, and analyze their socio-economic impacts. Using ArcGIS and MaxEnt, the distributions were modeled under two shared socio-economic pathways (SSP2.6 and SSP8.5) of climate change scenarios for three time periods: 1970–2000 (current), 2050s, and 2070s (future). About 124 records of species occurrence, elevation, aspect, slope, and 19 bioclimatic variables were used to determine the current and future distribution. The socio-economic impacts of the two expansive shrubs were assessed through household surveys, focus group discussions, and interviews with key informants. We used a t-test for continuous variables and a chi-square for categorical variables to test the significance of differences in means between invaded and uninvaded areas by the expansive shrubs using R software. The result showed that the mean area under the curves (AUC) for the replicate runs were 0.901 and 0.903 for Cadia purpurea and Tarchonanthus camphoratus, respectively, indicating that the model's predicted result was very accurate and reliable. Precipitation was determined to be the most significant bioclimatic variable, accounting for 82.6% and 79.5% of the variability in the distribution of Tarchonanthus camphoratus and Cadia purpurea, respectively, in the study area. The socio-economic result indicated that human activities such as illegal cutting, settlement expansion, road construction, agricultural expansion, and free grazing were found to facilitate the spread of these species. The expansive species provide a number of services, such as firewood, charcoal production, construction material, shading, erosion control, bee forage, medicine, and fencing. However, they also have adverse impacts, such as biodiversity loss, reduced crop yields, reduced water sources, suppressed grass growth, and reduced tourism income. Local communities recommended physical, chemical, and biological mechanisms to manage and control the expansion of these species in the Desa'a forest, as their negative impacts outweigh their positive impacts.

Investigating the effects of mesotrione/atrazine-based herbicide on honey bee foragers

A mixture of the herbicides mesotrione and atrazine (Calaris®) is a widely used herbicide in agriculture in several countries. However, the possible toxicological effects of this formulation on non-target organisms require investigation. In this study, the effects of acute oral exposure to Calaris® were evaluated in Apis mellifera foragers. The effect of seven different concentrations of Calaris® on survival and sucrose consumption was studied, while the recommended concentration for field use (FC) and its 10× dilution (0.1 FC) were used to assess overall locomotor activity, respiratory rate, flight, midgut morphology, oxidative and nitrosative stresses, and hemocyte counting. The exposure to FC or 0.1 FC decreased locomotor activity and induced damage to the midgut epithelium. Additionally, the two tested concentrations reduced superoxide dismutase activity, nitric oxide levels, and total hemocyte count. FC also increased malondialdehyde content and 0.1 FC increased respiratory rate and decreased the proportion of prohemocytes. Overall, our findings evidenced significant harmful effects on A. mellifera foragers resulting from the ingestion of the Calaris® herbicide.

Bees just wanna have fungi: a review of bee associations with non-pathogenic fungi.

Bee-fungus associations are common, and while most studies of these focus on entomopathogens, emerging evidence suggests that bees associate with a variety of symbiotic fungi that can influence bee behavior and health. Here, we review non-pathogenic fungal taxa associated with different bee species and bee-related habitats. We synthesize results of studies examining fungal effects on bee behavior, development, survival, and fitness. We find that fungal communities differ across habitats, with some groups restricted mostly to flowers (Metschnikowia), while others are present almost exclusively in stored provisions (Zygosaccharomyces). Starmerella yeasts are found in multiple habitats in association with many bee species. Bee species differ widely in the abundance and identity of fungi hosted. Functional studies suggest that yeasts affect bee foraging, development, and pathogen interactions, though few bee and fungal taxa have been examined in this context. Rarely, fungi are obligately beneficial symbionts of bees, whereas most are facultative bee associates with unknown or ecologically contextual effects. Fungicides can reduce fungal abundance and alter fungal communities associated with bees, potentially disrupting bee-fungi associations. We recommend that future study focus on fungi associated with non-honeybee species and examine multiple bee life stages to document fungal composition, abundance, and mechanistic effects on bees.

Parasites, depredators, and limited resources as potential drivers of winter mortality of feral honeybee colonies in German forests.

Wild honeybees (Apis mellifera) are considered extinct in most parts of Europe. The likely causes of their decline include increased parasite burden, lack of high-quality nesting sites and associated depredation pressure, and food scarcity. In Germany, feral honeybees still colonize managed forests, but their survival rate is too low to maintain viable populations. Based on colony observations collected during a monitoring study, data on parasite prevalence, experiments on nest depredation, and analyses of land cover maps, we explored whether parasite pressure, depredation or expected landscape-level food availability explain feral colony winter mortality. Considering the colony-level occurrence of 18 microparasites in the previous summer, colonies that died did not have a higher parasite burden than colonies that survived. Camera traps installed at cavity trees revealed that four woodpecker species, great tits, and pine martens act as nest depredators. In a depredator exclusion experiment, the winter survival rate of colonies in cavities with protected entrances was 50% higher than that of colonies with unmanipulated entrances. Landscapes surrounding surviving colonies contained on average 6.4 percentage points more cropland than landscapes surrounding dying colonies, with cropland being known to disproportionately provide forage for bees in our study system. We conclude that the lack of spacious but well-protected nesting cavities and the shortage of food are currently more important than parasites in limiting populations of wild-living honeybees in German forests. Increasing the density and diversity of large tree cavities and promoting bee forage plants in forests will probably promote wild-living honeybees despite parasite pressure.

Non‐neonicotinoid pesticides impact bumblebee activity and pollen provisioning

Abstract Bees are essential pollinators of crops and wild plants and their ability to forage and pollinate are key aspects of their behaviour. Bee populations are under threat, with the use of insecticides a contributing factor. Most research has focused on neonicotinoid insecticides and bee mortality, and little is known about impacts on bee foraging and delivery of pollination services. However, other insecticide classes, such as organophosphates and pyrethroids, are increasingly used globally, but little is known about how these widely used substances may impact bees, particularly non‐honeybees. We exposed bumblebee Bombus terrestris colonies to field‐relevant doses of a pyrethroid (lambda‐cyhalothrin) and an organophosphate (dimethoate) and investigated sublethal effects on behaviour at the individual and colony level, in addition to pollination service delivery under semi‐field conditions. We show, for the first time, that exposure to these chemicals impacts the activity and pollen provisioning of bumblebee Bombus terrestris audax colonies, while no short‐term effects on flower handling behaviour or pollination service delivery were detected. We found that colonies exposed to dimethoate were less active, with 67% fewer bees leaving the colony to forage than control colonies, and of those that returned, 92% fewer returned pollen provisions to the nest. Colonies exposed to lambda‐cyhalothrin did not differ in activity; however, 62% fewer of these bees returned with pollen provisions. Policy implications. These findings give important insights into how exposure to different classes of insecticides could impact bumblebee activity and their provision of pollen required for colony development. With a focus on neonicotinoids in terms of policy changes regarding insecticides and bees, we show that other insecticide classes should also be re‐examined in relation to their potential risks for pollinators. We confirm the need to improve risk assessment of insecticides to assess sublethal effects, include non‐honeybee species in risk assessment processes and also consider key behaviours such as foraging and interactions with plants.

DAMPAK SIKLON TROPIS SEROJA TERHADAP KETERSEDIAA N PAKAN, TEMPAT BERSARANG DAN PENDAPATAN PETANI LEBAH MADU HUTAN (Apis dorsata)

This study aims to determine the impact of the availability of forest honey bee feed, the impact of forest honey bee nesting sites and the impact of changes in the income of forest honey bee farmers in Uiasa Village, Semau District, Kupang Regency, East Nusa Tenggara before and after the Tropical Cyclone Storm Seroja. This research was carried out around the Pastello Amalato Protected Forest Area, Uiasa Village, Semau District, Kupang Regency, which was carried out for 1 month, from April to May 2022. This research used purposive sampling, interview and roaming methods with data analysis using descriptive qualitative and descriptive analysis. quantitative.The impact of food availability after the Seroja Tropical Cyclone Storm consists of two factors, namely reduced forage for forest honey bees and disruption of the flowering time of forage plants. The impact of forest honey bee nesting after the Seroja tropical cyclone storm was influenced by the movement of forest honey bee hives from their original place to another and the altitude where the forest honey bee nest trees were found was mostly at an altitude of 25-45 meters above sea level compared to other elevations with the number of honey bee trees is 10 trees and 7 trees at an altitude of 0-25 meters above sea level.

Bees reflect better on their ecosystem health than their products.

Beehives constitute a source of environmental contaminants because forager bees explore their habitat and unintentionally accumulate them while foraging for food. Therefore, this review paper investigated different bee species and products from 55 countries to identify how they can help environmental biomonitoring by giving an overview of the past 11 years. Thereby is presented in this study the beehive's use as a bioindicator for metals, analytical techniques, data analysis, environmental compartments, common inorganic contaminants, reference thresholds for some metal concentrations in bees and honey, and other factors over more than 100 references. Most authors agree that the honey bee is a suitable bioindicator to assess toxic metal contamination, and among its products, propolis, pollen, and beeswax are more suited than honey. However, in some situations, when comparing bees with their products, bees are more efficient as potential environmental biomonitors. Some factors such as the colony location, floral sources, regional effects, and activities surrounding the apiary influence the bees, and the composition of their products is reflected by alterations in their chemical profile, making them suitable bioindicators.

Assessing the influence of variation in forage availability on spatial patterns of beehive migration using a hybrid modelling approach – B-Agent

Bees and beekeeping are increasingly recognised as important contributors to sustainable development. Beekeeping is a landscape-scale process that involves complex interconnectivities between beekeepers, beehives and bee forage. Yet, accounting for these interactions within beekeeping system models is challenging as interactions are dynamic and often influenced by human behaviour and decision making. To this end, this research describes a spatially explicit modelling approach B-Agent, which draws upon multiple stakeholder engagement, a machine-learning algorithm and an agent-based model to simulate beehive migration processes. The Western Australian beekeeping sector provides a case study for model development and testing, to examine changes in (i) distances travelled by beekeepers, (ii) the frequency of beehive migration, and (iii) the spatial distribution of harvest locations resulting from climate related impacts on forage availability. The results indicate an increase in travel distance and frequency of hive migrations for commercial beekeepers under a moderate emissions climate scenario and indicated an eastward shift in the spatial distribution of harvest locations. The approach provides an evidence-base for better-informed management decisions in order to improve the long-term sustainability of beekeeping systems in Western Australia and beyond.

Engineered gut symbiont inhibits microsporidian parasite and improves honey bee survival

Honey bees (Apis mellifera) are critical agricultural pollinators as well as model organisms for research on development, behavior, memory, and learning. The parasite Nosema ceranae, a common cause of honey bee colony collapse, has developed resistance to small-molecule therapeutics. An alternative long-term strategy to combat Nosema infection is therefore urgently needed, with synthetic biology offering a potential solution. Honey bees harbor specialized bacterial gut symbionts that are transmitted within hives. Previously, these have been engineered to inhibit ectoparasitic mites by expressing double-stranded RNA (dsRNA) targeting essential mite genes, via activation of the mite RNA interference (RNAi) pathway. In this study, we engineered a honey bee gut symbiont to express dsRNA targeting essential genes of N. ceranae via the parasite's own RNAi machinery. The engineered symbiont sharply reduced Nosema proliferation and improved bee survival following the parasite challenge. This protection was observed in both newly emerged and older forager bees. Furthermore, engineered symbionts were transmitted among cohoused bees, suggesting that introducing engineered symbionts to hives could result in colony-level protection.