Influence of honey bee (Hymenoptera: Apidae) density on the production of canola (Crucifera: Brassicacae)

Pollination is an essential step in the seed production of canola, Brassica napus L. It is achieved with the assistance of various pollen vectors, but particularly by the honey bee, Apis mellifera L. Although the importance of pollination has been shown for the production of seed crops, the need to introduce bee hives in canola fields during flowering to increase oil seed yield has not yet been proven. With the purpose of showing this, hives of A. mellifera were grouped and placed in various canola fields in the Chaudière-Appalaches and Capitale-Nationale regions (nine fields; three blocks with three treatments; 0, 1.5, and 3 hives per hectare). A cage was used to exclude pollinators and bee visitations were observed in each field. After the harvest, yield analyses were done in relation to the bee density gradient created, by using pod set, number of seeds per plant, and weight of 1000 seeds. Results showed an improvement in seed yield of 46% in the presence of three honey bee hives per hectare, compared with the absence of hives. The introduction of honey bees contributed to production and consequently, these pollinators represented a beneficial and important pollen vector for the optimal yield of canola.     

Pollinator genetics and pollination: do honey bee colonies selected for pollen‐hoarding field better pollinators of cranberry Vaccinium macrocarpon?

1. Genetic polymorphisms of flowering plants can influence pollinator foraging but it is not known whether heritable foraging polymorphisms of pollinators influence their pollination efficacies. Honey bees Apis mellifera L. visit cranberry flowers for nectar but rarely for pollen when alternative preferred flowers grow nearby. 2. Cranberry flowers visited once by pollen‐foraging honey bees received four‐fold more stigmatic pollen than flowers visited by mere nectar‐foragers (excluding nectar thieves). Manual greenhouse pollinations with fixed numbers of pollen tetrads (0, 2, 4, 8, 16, 32) achieved maximal fruit set with just eight pollen tetrads. Pollen‐foraging honey bees yielded a calculated 63% more berries than equal numbers of non‐thieving nectar‐foragers, even though both classes of forager made stigmatic contact. 3. Colonies headed by queens of a pollen‐hoarding genotype fielded significantly more pollen‐foraging trips than standard commercial genotypes, as did hives fitted with permanently engaged pollen traps or colonies containing more larvae. Pollen‐hoarding colonies together brought back twice as many cranberry pollen loads as control colonies, which was marginally significant despite marked daily variation in the proportion of collected pollen that was cranberry. 4. Caloric supplementation of matched, paired colonies failed to enhance pollen foraging despite the meagre nectar yields of individual cranberry flowers. 5. Heritable behavioural polymorphisms of the honey bee, such as pollen‐hoarding, can enhance fruit and seed set by a floral host (e.g. cranberry), but only if more preferred pollen hosts are absent or rare. Otherwise, honey bees' broad polylecty, flight range, and daily idiosyncrasies in floral fidelity will obscure specific pollen‐foraging differences at a given floral host, even among paired colonies in a seemingly uniform agricultural setting.     

Honey bee waggle dance communication increases diversity of pollen diets in intensively managed agricultural landscapes

The benefits of honey bee dance communication for colony performance in different resource environments are still not well understood. Here, we test the hypothesis that directional dance communication enables honey bee colonies to maintain a diverse pollen diet, especially in landscapes with low resource diversity. To test this hypothesis, we placed 24 Apis mellifera L. colonies with either intact or experimentally disrupted dance communication in eight agricultural landscapes that differed in the diversity of flowering plants and in the dominance of mass‐flowering crops. Pollen from incoming foragers was collected and identified via DNA metabarcoding. Disrupting dance communication affected the way the diversity of honey bee pollen diets was impacted by the dominance of mass‐flowering crops in available flower resources (p = .04). With increasing dominance of mass‐flowering crops in resource environments, foragers of colonies with intact communication foraged on an increasing proportion of available plant genera (p = .01). This was not the case for colonies with disrupted dance communication (p = .5). We conclude that the honey bee dance communication benefits pollen foraging on diverse plant resources and thereby contributes to high quality nutrition in environments with low‐resource diversity.     

Hive‐stored pollen of honey bees: many lines of evidence are consistent with pollen preservation,not nutrient conversion

Honey bee hives are filled with stored pollen, honey, plant resins and wax, all antimicrobial to differing degrees. Stored pollen is the nutritionally rich currency used for colony growth and consists of 40–50% simple sugars. Many studies speculate that prior to consumption by bees, stored pollen undergoes long‐term nutrient conversion, becoming more nutritious ‘bee bread’ as microbes predigest the pollen. We quantified both structural and functional aspects associated with this hypothesis using behavioural assays, bacterial plate counts, microscopy and 454 amplicon sequencing of the 16S rRNA gene from both newly collected and hive‐stored pollen. We found that bees preferentially consume fresh pollen stored for <3 days. Newly collected pollen contained few bacteria, values which decreased significantly as pollen were stored >96 h. The estimated microbe to pollen grain surface area ratio was 1:1 000 000 indicating a negligible effect of microbial metabolism on hive‐stored pollen. Consistent with these findings, hive‐stored pollen grains did not appear compromised according to microscopy. Based on year round 454 amplicon sequencing, bacterial communities of newly collected and hive‐stored pollen did not differ, indicating the lack of an emergent microbial community co‐evolved to digest stored pollen. In accord with previous culturing and 16S cloning, acid resistant and osmotolerant bacteria like Lactobacillus kunkeei were found in greatest abundance in stored pollen, consistent with the harsh character of this microenvironment. We conclude that stored pollen is not evolved for microbially mediated nutrient conversion, but is a preservative environment due primarily to added honey, nectar, bee secretions and properties of pollen itself.     

Unique Honey Bee (Apis mellifera) Hive Component-Based Communities as Detected by a Hybrid of Phospholipid Fatty-Acid and Fatty-Acid Methyl Ester Analyses

Microbial communities (microbiomes) are associated with almost all metazoans, including the honey bee Apis mellifera. Honey bees are social insects, maintaining complex hive systems composed of a variety of integral components including bees, comb, propolis, honey, and stored pollen. Given that the different components within hives can be physically separated and are nutritionally variable, we hypothesize that unique microbial communities may occur within the different microenvironments of honey bee colonies. To explore this hypothesis and to provide further insights into the microbiome of honey bees, we use a hybrid of fatty acid methyl ester (FAME) and phospholipid-derived fatty acid (PLFA) analysis to produce broad, lipid-based microbial community profiles of stored pollen, adults, pupae, honey, empty comb, and propolis for 11 honey bee hives. Averaging component lipid profiles by hive, we show that, in decreasing order, lipid markers representing fungi, Gram-negative bacteria, and Gram-positive bacteria have the highest relative abundances within honey bee colonies. Our lipid profiles reveal the presence of viable microbial communities in each of the six hive components sampled, with overall microbial community richness varying from lowest to highest in honey, comb, pupae, pollen, adults and propolis, respectively. Finally, microbial community lipid profiles were more similar when compared by component than by hive, location, or sampling year. Specifically, we found that individual hive components typically exhibited several dominant lipids and that these dominant lipids differ between components. Principal component and two-way clustering analyses both support significant grouping of lipids by hive component. Our findings indicate that in addition to the microbial communities present in individual workers, honey bee hives have resident microbial communities associated with different colony components.     

Studies on the possible competition for pollen between the honey bee, Apis mellifera sudanensis, and the imported dwarf honey bee Apis florea (Hym., Apidae) in North-Khartoum (Sudan)

Abstract:   Based on identification of collected pollen, in the area of North Khartoum, 21 plant genera (ca. 21 spp.) proved to be the main pollen sources for the honey bee Apis mellifera sudanensis . The imported dwarf honey bee Apis florea exploited 11 of these. The main pollen flow in the study area occurred between early December and late March. This is reflected by the amount of pollen collected by colonies of A. mellifera sudanensis . In spite of observations conducted soon after the introduction of A. florea , which gave hints of competition between the two bee species, further studies showed that A. mellifera sudanensis and A. florea do seem to coexist. This coexistence is based on different daily rhythms of pollen collection. A. mellifera collected pollen of Acacia seyal , date palm, and onions early in the morning (and partly in the late afternoon), while A. florea started pollen collection mostly later in the morning and ended it earlier in the afternoon. But in contrast to A. mellifera, A. florea was collecting pollen all day without interruption, even at very high air temperatures. Niche overlap (concerning the times of visits to flowers) between the two bee species was very low in date palms, and of medium importance in Acacia seyal . But it is remarkable that in total, A. florea is always present in higher numbers than A. mellifera sudanensis , on flowers. The significance of the introduction of A. florea to Sudan for pollination is discussed.     

Crop Pollination Exposes Honey Bees to Pesticides Which Alters Their Susceptibility to the Gut Pathogen Nosema ceranae

Recent declines in honey bee populations and increasing demand for insect-pollinated crops raise concerns about pollinator shortages. Pesticide exposure and pathogens may interact to have strong negative effects on managed honey bee colonies. Such findings are of great concern given the large numbers and high levels of pesticides found in honey bee colonies. Thus it is crucial to determine how field-relevant combinations and loads of pesticides affect bee health. We collected pollen from bee hives in seven major crops to determine 1) what types of pesticides bees are exposed to when rented for pollination of various crops and 2) how field-relevant pesticide blends affect bees’ susceptibility to the gut parasite Nosema ceranae. Our samples represent pollen collected by foragers for use by the colony, and do not necessarily indicate foragers’ roles as pollinators. In blueberry, cranberry, cucumber, pumpkin and watermelon bees collected pollen almost exclusively from weeds and wildflowers during our sampling. Thus more attention must be paid to how honey bees are exposed to pesticides outside of the field in which they are placed. We detected 35 different pesticides in the sampled pollen, and found high fungicide loads. The insecticides esfenvalerate and phosmet were at a concentration higher than their median lethal dose in at least one pollen sample. While fungicides are typically seen as fairly safe for honey bees, we found an increased probability of Nosema infection in bees that consumed pollen with a higher fungicide load. Our results highlight a need for research on sub-lethal effects of fungicides and other chemicals that bees placed in an agricultural setting are exposed to.     

Detection of deformed wing virus in the greenhouse for possible horizontal transmission of virus in honey bee colony

The honey bee Apis mellifera L. is a crucial insect in the agricultural industry and natural ecosystem by being a major pollinator. Nevertheless, honey bee population has been recently facing a decline. Among the several factors responsible for this decline, deformed wing virus (DWV) is considered a primary cause that negatively affects honey bee health. DWV is a cosmopolitan honey bee pathogen and causes morphological disadvantages in individual honey bees and colony collapse. Regarding the horizontal transmission of DWV, in addition to Varroa destructor, a well-known major vector of DWV, flowers have recently been implied as a transmission route. Therefore, in this study, we detected DWV from various substances, including flowers, honey bee feces, pupa, larva, nurse bee, surface of nurse bee, pollen collected by forager bee, and forager bee samples in four strawberry greenhouses, which could suggest the potential for the horizontal transmission of DWV in the semi-field condition. We also detected DWV in pollen collected by DWV-negative forager bees, implying that flowers can serve as a potential source of virus infection. These findings suggest that the surrounding environment such as shared floral sources affects the spread of DWV.     

Key factors influencing forager distribution across macadamia orchards differ among species of managed bees

To achieve maximised and sustainable crop productivity, it is critical that we develop crop-specific strategies for managing pollination. Honey bees (Apis mellifera) and stingless bees (Tetragonula carbonaria) are considered effective pollinators of macadamia (Macadamia integrifolia). The introduction of managed honey bee or stingless bee hives into orchards is likely to boost the numbers of these insects visiting flowers; however, there is a lack of published information and consensus regarding their management for pollination. Here, we identify factors that affect the distribution of both honey bees and stingless bees across cultivated macadamia, and establish whether increased flower visitation leads to higher nut set. A gradient of bee visitation rates was created by placing colonies on the ends of a four-hectare block, and mixed-effect models were applied to assess forager abundance and nut set with respect to distance from hive, time of day, cultivar, and floral display size. Distance from colony had a strong effect on stingless bee numbers, with >96% of individuals recorded within 100 metres of colonies, whereas the distribution of honey bees was more closely related to daily floral display: trees with greater numbers of flowers attracted more honey bees. Simplified surveys conducted in a further 17 macadamia blocks confirm that these are broadly occurring distribution patterns. Bee abundance alone did not significantly predict nut production; however, an indirect effect of bee visits to flowers is inferred, as nut production increased with size of floral display. To encourage a more even distribution of bees and uniform pollination, we recommend placement of stingless bee hives to maximise their distribution through a block (e.g. at 100-m intervals) and management practices that promote even distributions of flowers across trees.     

Competition between honey bees and wild bees and the role of nesting resources in a nature reserve

The European honey bee exploits floral resources efficiently and may therefore compete with solitary wild bees. Hence, conservationists and bee keepers are debating about the consequences of beekeeping for the conservation of wild bees in nature reserves. We observed flower-visiting bees on flowers of Calluna vulgaris in sites differing in the distance to the next honey-bee hive and in sites with hives present and absent in the Lüneburger Heath, Germany. Additionally, we counted wild bee ground nests in sites that differ in their distance to the next hive and wild bee stem nests and stem-nesting bee species in sites with hives present and absent. We did not observe fewer honey bees or higher wild bee flower visits in sites with different distances to the next hive (up to 1,229 m). However, wild bees visited fewer flowers and honey bee visits increased in sites containing honey-bee hives and in sites containing honey-bee hives we found fewer stem-nesting bee species. The reproductive success, measured as number of nests, was not affected by distance to honey-bee hives or their presence but by availability and characteristics of nesting resources. Our results suggest that beekeeping in the Lüneburg Heath can affect the conservation of stem-nesting bee species richness but not the overall reproduction either of stem-nesting or of ground-nesting bees. Future experiments need control sites with larger distances than 500 m to hives. Until more information is available, conservation efforts should forgo to enhance honey bee stocking rates but enhance the availability of nesting resources.     

Effect of several different pollens on the bio-ecological parameters of the predatory mite Typhlodromus athenas Swirski and Ragusa (Acari: Phytoseiidae)

The development, survivorship, and reproduction of the predacious mite Typhlodromus athenas Swirski and Ragusa were studied in the laboratory by rearing the predator on nine different plant pollens [almond(Prunus amygdalis Batsch), apple (Malus domestica Borkh.), apricot (Prunus armeniaca L.), cherry (Prunus avium L.), pear (Pyrus communis L.), plum (Prunus domestica L.), walnut (Juglans regia L.), olive (Olea europaea L.), Typha sp.], and pollen collected from bee hives. All experiments were conducted in environmental chambers at 20 ± 1°C, 65% RH, and a photoperiod of 16:8 (L:D) h. Survival during immature development ranged from 81.1 to 96.0%. The shortest mean developmental time from egg to adult with respect to the range of pollen species was recorded for females and males fed on almond pollen (10.76 ± 0.18 and 10.45 ± 0.21 d, respectively), while the longest was on beehive pollen (26.97 ± 0.23 and 24.00 ± 0.25 d for females and males, respectively). Female longevity varied from 51.63 ± 5.52 d (olive pollen) to 102.81 ± 6.60 d (pear pollen), while fecundity ranged from 5.33 ± 2.35 eggs per female (beehive pollen) to 26.43 ± 1.73 eggs per female (almond pollen). The diet consisting of almond pollen resulted in the highest intrinsic rate of natural increase (r(m)) (1.00 d(-1)) and pollen collected from bee hives resulted in the lowest (0.013 d(-1)). These results showed that various pollen could favor the development of T. athenas, and also support the view that alternative food resources may play an important role in the field for sustaining and increasing the predator's population.     

Influence of honey bee, Apis mellifera, hives and field size on foraging activity of native bee species in pumpkin fields

The purpose of this study was to identify bee species active in pumpkin fields in New York and to estimate their potential as pollinators by examining their foraging activity. In addition, we examined whether foraging activity was affected by either the addition of hives of the honey bee, Apis mellifera L., or by field size. Thirty-five pumpkin (Cucurbita spp.) fields ranging from 0.6 to 26.3 ha, 12 supplemented with A. mellifera hives and 23 not supplemented, were sampled during peak flowering over three successive weeks in 2008 and 2009. Flowers from 300 plants per field were visually sampled for bees on each sampling date. A. mellifera, Bombus impatiens Cresson, and Peponapis pruinosa (Say) accounted for 99% of all bee visits to flowers. A. mellifera and B. impatiens visited significantly more pistillate flowers than would be expected by chance, whereas P. pruinosa showed no preference for visiting pistillate flowers. There were significantly more A. mellifera visits per flower in fields supplemented with A. mellifera hives than in fields not supplemented, but there were significantly fewer P. pruinosa visits in supplemented fields. The number of B. impatiens visits was not affected by supplementation, but was affected by number of flowers per field. A. mellifera and P. pruinosa visits were not affected by field size, but B. impatiens visited fewer flowers as field size increased in fields that were not supplemented with A. mellifera hives. Declining A. mellifera populations may increase the relative importance of B. impatiens in pollinating pumpkins in New York.     

Wildflower plantings promote blue orchard bee,Osmia lignaria (Hymenoptera: Megachilidae), reproduction in California almond orchards

Concerns over the availability of honeybees (Apis mellifera L.) to meet pollination demands have elicited interest in alternative pollinators to mitigate pressures on the commercial beekeeping industry. The blue orchard bee, Osmia lignaria (Say), is a commercially available native bee that can be employed as a copollinator with, or alternative pollinator to, honeybees in orchards. To date, their successful implementation in agriculture has been limited by poor recovery of bee progeny for use during the next spring. This lack of reproductive success may be tied to an inadequate diversity and abundance of alternative floral resources during the foraging period. Managed, supplementary wildflower plantings may promote O. lignaria reproduction in California almond orchards. Three wildflower plantings were installed and maintained along orchard edges to supplement bee forage. Plantings were seeded with native wildflower species that overlapped with and extended beyond almond bloom. We measured bee visitation to planted wildflowers, bee reproduction, and progeny outcomes across orchard blocks at variable distances from wildflower plantings during 2015 and 2016. Pollen provision composition was also determined to confirm O. lignaria wildflower pollen use. Osmia lignaria were frequently observed visiting wildflower plantings during, and after, almond bloom. Most O. lignaria nesting occurred at orchard edges. The greatest recovery of progeny occurred along the orchard edges having the closest proximity (80 m) to managed wildflower plantings versus edges farther away. After almond bloom, O. lignaria nesting closest to the wildflower plantings collected 72% of their pollen from Phacelia spp., which supplied 96% of the managed floral area. Phacelia spp. pollen collection declined with distance from the plantings, but still reached 17% 800 m into the orchard. This study highlights the importance of landscape context and proximity to supplementary floral resources in promoting the propagation of solitary bees as alternative managed pollinators in commercial agriculture.     

澜沧江流域北部中华蜜蜂有毒蜂蜜孢粉学和营养生态位分析

为分析澜沧江流域北部人食用蜂蜜中毒的原因,于2013年6—9月份,对该区域蜜蜂和蜜源植物的分布情况进行了调查,观察蜜蜂采集有毒蜜源植物的行为,并进一步调查了蜜蜂巢内蜂蜜、蜂花粉的储存情况,采集了中华蜜蜂蜂蜜样品,进行蜂蜜孢粉学与营养生态位分析。该区域有大量采用传统方式进行人工饲养的中华蜜蜂(Apis cerana cerana),及少量野生中华蜜蜂、黑色小蜜蜂(Apis audreniformis)、黑色大蜜蜂(Apis laboriosa smith)群体分布;人工饲养的中华蜜蜂蜂巢内部结构与野生中华蜜蜂蜂巢相似,为自然蜂巢,内有充足的蜜粉储存,部分蜂群蜂巢内虫害严重。该区域内主要蜜源植物为荞麦(Fagopyrum esculentum Moench),其他零星辅助蜜源较多,部分地点南烛(Vaccinium bracteatum Thunb)、昆明山海棠(Tripterygium hypoglaucum(Levl.)Hutch)连片集中分布。对中华蜜蜂蜂蜜进行孢粉学和营养生态位分析,结果表明:中华蜜蜂蜂蜜标本中含有有毒蜜源植物南烛、昆明山海棠花粉,部分样品中南烛、昆明山海棠的花粉含所占比例较高;中华蜜蜂的营养生态位宽度为0.22,比其他地区中华蜜蜂生态位指数小,推测澜沧江水电枢纽的修建等人为原因已对蜜蜂种类、蜜源植物的物种组成、群落结构造成了较大影响。     

Maize pollen foraging by honey bees in relation to crop area and landscape context

The increasing demand for insect pollinated crops and high recent losses of honey bee colonies raise concerns about food security. Systemic insecticides are recognized as one of the drivers of worldwide honey and wild bee declines. Particularly honey bees in agricultural environments are exposed to pesticides when they collect crop pollen and nectar. However, landscape scale studies which analyze pollen use and foraging distances of honey bees on mass-flowering crops like maize to evaluate potential exposure risks are currently lacking. In an experimental approach on a landscape scale we took advantage of intra-colonial dance communication to gather information about the location of utilized pollen resources. During maize flowering, four observation hives were placed in and rotated between 11 different landscapes which covered a gradient from low to high maize acreage. A higher frequency of dances for foraging locations on maize fields compared to other land use types shows that maize is an intensively used pollen resource for honey bee colonies. Mean foraging distances were significantly shorter for maize pollen than for other pollen origins. The percentage of maize pollen foragers did not increase with maize acreage in the landscape. The proportion of grassland area providing alternative pollen sources did not reduce the percentage of maize pollen foragers. Our findings allow estimating the distance-related exposure risk of honey bee colonies to pollen from surrounding maize fields treated with systemic insecticides. Similarly, the results can be used to estimate the exposure to transgenic maize pollen, which is relevant for honey production in European countries. Provision of alternative pollen resources within agri-environmental schemes could potentially reduce exposure risk to pesticide contaminated crop pollen.     

Pollen Types Used by the Native Stingless Bee, <Emphasis Type="Italic">Tetragonisca angustula</Emphasis> (Latreille), in an Amazon-Chiquitano Transitional Forest of Bolivia

Samples of corbicular and stored pollen gathered by Tetragonisca angustula (Latreille, 1811) in an Amazon-Chiquitano transitional forest during the dry season were analyzed. The pollen spectrum was established as well as the dynamics of the relationship between the stingless bee and the surrounding flora. Pollen samples obtained from three rational hives were subjected to acetolysis and 55 pollen types were identified, the most frequent being from Anadenanthera (Fabaceae), Chenopodiaceae, and Dydimopanax (Araliaceae). Significant differences in pollen families used between hives along the months of collection were found in stored pollen and non-significant differences in corbicular pollen. Mean values of alpha diversity (H′) showed T. angustula as a generalist while beta diversity qualitatively showed that pollen composition was similar between two hives both of which differed from the third hive. Pollen types in corbicular and stored pollen were in general related with richness of flowering plants in the foraging area; the pollen offer was less diverse than the pollen collected, and a trend to prefer the collection of pollen from the most abundant flowering species could be discerned. T. angustula showed polylectic feeding habits and a capacity to adapt to food availability.     

Honey bees and wild pollinators differ in their preference for and use of introduced floral resources

Introduced plants may be important foraging resources for honey bees and wild pollinators, but how often and why pollinators visit introduced plants across an entire plant community is not well understood. Understanding the importance of introduced plants for pollinators could help guide management of these plants and conservation of pollinator habitat. We assessed how floral abundance and pollinator preference influence pollinator visitation rate and diversity on 30 introduced versus 24 native plants in central New York. Honey bees visited introduced and native plants at similar rates regardless of floral abundance. In contrast, as floral abundance increased, wild pollinator visitation rate decreased more strongly for introduced plants than native plants. Introduced plants as a group and native plants as a group did not differ in bee diversity or preference, but honey bees and wild pollinators preferred different plant species. As a case study, we then focused on knapweed (Centaurea spp.), an introduced plant that was the most preferred plant by honey bees, and that beekeepers value as a late‐summer foraging resource. We compared the extent to which honey bees versus wild pollinators visited knapweed relative to coflowering plants, and we quantified knapweed pollen and nectar collection by honey bees across 22 New York apiaries. Honey bees visited knapweed more frequently than coflowering plants and at a similar rate as all wild pollinators combined. All apiaries contained knapweed pollen in nectar, 86% of apiaries contained knapweed pollen in bee bread, and knapweed was sometimes a main pollen or nectar source for honey bees in late summer. Our results suggest that because of diverging responses to floral abundance and preferences for different plants, honey bees and wild pollinators differ in their use of introduced plants. Depending on the plant and its abundance, removing an introduced plant may impact honey bees more than wild pollinators.     

The pollination efficiency of a pollinator depends on its foraging strategy,flowering phenology,and the flower characteristics of a plant species

Honey bees and stingless bees are generalist visitors of several wild and cultivated plants. They forage with a high degree of floral fidelity and thereby help in the pollination services of those plants. We hypothesized that pollination efficiency might be influenced by flowering phenology, floral characteristics, and resource collection modes of the worker bees. In this paper, we surveyed the foraging strategies of honey bees (Apis cerana, Apis dorsata, and Apis florea) and stingless bees (Tetragonula iridipennis) concerning their pollination efficiencies. Bees showed different resource gathering strategies, including legitimate (helping in pollination as mixed foragers and specialized foragers) and illegitimate (serving as nectar robbers and pollen thieves) types of flower visitation patterns. Foraging strategies are influenced by the shape of flowers, the timing of the visitation, floral richness, and bee species. Honey bees and stingless bees mainly acted as legitimate visitors in most plants studied. Sometimes honey bees served as nectar robbers in tubular flowers and stingless bees as pollen thieves in large-sized flowers. Among the legitimate categories, mixed foragers have a comparatively lower flower visitation rate than the specialized nectar and pollen foragers. However, mixed foragers have greater abundance and higher values of the single-visit pollination efficiency index (PEi) than nectar and pollen foragers. The value of the combined parameter ‘importance in pollination (PI)’ was thus higher in mixed foragers than in nectar and pollen foragers.     

European bee-eaters (<Emphasis Type="Italic">Merops apiaster</Emphasis>) and apiculture: understanding their interactions and the usefulness of nonlethal techniques to prevent damage at apiaries

Finding a balance between wildlife conservation and land use protection when conflicts arise requires applying measures based on scientific knowledge and applicability. This is because of the complexity of interactions and the social dimensions of human–wildlife relationships. One of the conflicts in the Mediterranean basin is between European bee-eaters Merops apiaster and beekeeping. The objective of this study was to evaluate the activity of bee-eaters in relation to honey bees Apis mellifera in Extremadura (W Spain), and the possible correlation with traits and viability of beehives. We also aimed to assess the effectiveness of damage prevention measures, to be able to predict whether they could assist in the future sustainability of apicultural management. A monitoring program was conducted in 58 apiaries to observe bee and bee-eater activity and abundance. Additionally, we measured the effect of environmental variables and the amount of resources in the hives, by means of honey, pollen, and brood. We found that bee-eater negatively correlated to honey bee activity and the more abundant it was the fewer resources (honey, pollen, and brood) and lower abundance of bees in the hives, mainly during their migratory season (August). However, there were no negative effects on the survival and viability of the hives. The preventive and deterrent measures offered promising results, especially the installation of shading meshes around the apiary that prevented the predation of bees in the immediate surroundings of the beehives. Further studies on the effectiveness of preventive techniques and their practical implementation through different mechanisms of economic compensation must be enhanced to reduce this social conflict.     

Bumble bees exhibit daily behavioral patterns in pollen foraging

In response to global declines in bee populations, several studies have focused on floral resource provisioning schemes to support bee communities and maintain their pollination services. Optimizing host-plant selection for supplemental floral provisioning requires an understanding of bee foraging behavior and preferences for host-plant species. However, fully characterizing these preferences is challenging due to multiple factors influencing foraging, including the large degree of spatiotemporal variability in floral resources. To understand bee pollen foraging patterns, we developed a highly controlled mechanistic framework to measure pollen foraging preferences of the bumble bee Bombus impatiens to nine plant species native to Pennsylvania. We recorded continuous observations of foraging behavior of the experimental bee community and individual bees, while simultaneously standardizing for the number of foragers in the environment and differences in floral display of each plant species, while controlling for flowering phenology such that bees only foraged when all plant species’ flowers were open. Our results demonstrate that B. impatiens exhibit predictable daily patterns in their pollen foraging choices, and their preferences are dominated by the host-plants they visit first. We hypothesize that these patterns at the community and individual levels are driven by the interplay between pollen abundance and quality. We recommend that daily cycles of host-plant visitation be considered in future studies to ensure precise and accurate interpretations of host-plant preference. Such precision is critical for comprehensive analyses of the proximate and ultimate mechanisms driving bee foraging behavior and the selection of host-plant species to use in habitat restoration protocols.