Corbicular Pollen Research Articles

Application of a robust MALDI mass spectrometry approach for bee pollen investigation

Pollen collected by pollinators can be used as a marker of the foraging behavior as well as indicate the botanical species present in each environment. Pollen intake is essential for pollinators’ health and survival. During the foraging activity, some pollinators, such as honeybees, manipulate the collected pollen mixing it with salivary secretions and nectar (corbicular pollen) changing the pollen chemical profile. Different tools have been developed for the identification of the botanical origin of pollen, based on microscopy, spectrometry, or molecular markers. However, up to date, corbicular pollen has never been investigated. In our work, corbicular pollen from 5 regions with different climate conditions was collected during spring. Pollens were identified with microscopy-based techniques, and then analyzed in MALDI-MS. Four different chemical extraction solutions and two physical disruption methods were tested to achieve a MALDI-MS effective protocol. The best performance was obtained using a sonication disruption method after extraction with acetic acid or trifluoroacetic acid. Therefore, we propose a new rapid and reliable methodology for the identification of the botanical origin of the corbicular pollens using MALDI-MS. This new approach opens to a wide range of environmental studies spanning from plant biodiversity to ecosystem trophic interactions.Graphical

Productivity of bee families and biomonitoring of corbicular pollen and war-affected honeybee foraging sites with cultivated honey clover (Melilotus albus)

As a result of military actions, some territories of Ukraine have suffered technogenic loading on the environment. Of special concern is disturbed agricultural soils that are significant for food safety of the country. Soils affected by military actions require control of contamination and restoration of fertility. The studies revealed the advantages of cultivating honey clover (Melilotus albus) in war-affected soils and controlling content of heavy metals in soils and corbicular pollen from honey clover cultivated in those soils. In gray forest average-loamy soils that had been affected by military actions, nitrogen content increased 6.3% thanks to cultivation of M. albus. High nitrogen content in soil improves its fertility. Cultivation of M. albus in affected soils promoted more intensive growth of the bee families, encouraging them to gather nectar more actively. As a result, this apiary produced greater amounts of honey, corbicular pollen, and bee pollen. The conducted studies revealed heightened levels of lead, cadmium, and zinc in the war-impacted agricultural land, compared with the territory beyond the impact zone. This caused increased content of heavy metals in corbicular pollen from M. albus. Contamination of corbicular pollen from M. albus manifested in excess over the allowable norms of cadmium, lead, and zinc. At the same time, the highest coefficient of transfer from soil into corbicular pollen was found for zinc. The high degree of contamination of the soil with heavy metals as a result of military action promoted a high level of ingress of lead and cadmium into the corbicular pollen, compared with the situation in clean territory. The study results expand the available data on biomonitoring of apiary products and foraging lands in contaminated areas. Analysis of the corbicular pollen and pollen can give information about the level of environmental contamination and help evaluate the ecological state of melliferous sites. Such a monitoring can be useful for decision making regarding the protection of the environment and healthcare.

Diversity matters: Diet of Apis cerana in southeast India includes one consistently occurring and several seasonally available floral sources

Little is known about the agroecological implications of the Asian honey bee Apis cerana Fabricius in its vast native range including southeast India. To identify the foraging preferences of this generalist species, we collected 388 corbicular pollen samples over three years at Merveille, an eco-restoration site in Puducherry region, southeast India. Pollen was collected twice or thrice weekly from March 2018 to December 2021 in three locations within the site. We used canonical correspondence analysis to evaluate how average daily temperature, humidity and other meteorological changes over the years would influence A. cerana’s diet. We show that (1) A. cerana has a large dietary niche (87 pollen taxa), but essentially feeds on Cocos nucifera (all year long) and on Borassus flabellifer, Turnera, Acacia, Mollugo/Trianthema, Leucaena/Prosopis, Portulaca, Poaceae, Syzygium-t, Dodonaea viscosa and Boerhavia seasonally; these were most frequently and abundantly foraged at all locations. (2) In all locations, bees preferentially feed on arboreal plants (44 taxa). (3) Bees' pollen diet varies in composition according to seasons. It is also least diverse in the hottest and driest months (March-May) with 2–4 taxa against 7–13 taxa in other months. (4) In 2021, which was more humid and slightly cooler than 2018 and 2019, bee diet included more pollen of Cyperaceae, Dodonaea viscosa, Liliaceae and fallow land weeds such as Boerhavia and Mimosa pudica. In conclusion, corbicular pollen loads of Apis cerana provide a long and continuous record of the bee’s diet and its changes through time and space. The diet changed according to subtle changes in humidity and temperature as also drastic changes in rainfall at the study site, likely reflecting changes in the floral resource availability and the bees’ preference. The sustained presence of this bee species within its native ranges can be a bellwether of pollinator friendly habitats.

Validation of a questionary for measuring corbicular pollen consumer preferences via structural equations models

Boyacá is one of the main bee pollen (or corbicular pollen) producers in Colombia. However, pollen consumer preferences in this region are unknown; therefore, there is no background to develop marketing strategies aiming at profiting beekeepers and consumers. This study presents the design and statistical validation of a questionary to assess the preferences of bee pollen consumers and the model that supports the relationships between the constructs characterizing them. Model development was based on the premise that pollen quality perception affects consumer satisfaction. To test this premise, a reflexive measure model was used to design the Pollen Preferences Determination Questionary (PPDQ). Data from a pilot sample were used to evaluate the measure and structural models via structural equations models fitted through partial least squares (SEM-PLS). The results showed the validity of the PPDQ since the indicators load its constructs appropriately, particularly for satisfaction and intrinsic quality.

Management practices and seasonality affect stingless bee colony growth, foraging activity, and pollen diet in coffee agroecosystems

Stingless bees are essential pollinators in tropical ecosystems. Yet compared to their temperate zone counterparts, we know very little about how they respond to agriculture-associated land use, or how this effect is modulated by seasonal variation. Coffee, a dominant crop across the tropics, is grown under diverse management practices, making coffee agroecosystems an important context in which to investigate effects of agricultural management on stingless bees. We evaluated the performance and pollen diet of replicated experimental colonies of the stingless bee Scaptotrigona mexicana in three habitats in a coffee-dominated landscape in southern Chiapas, Mexico: a conventional sun coffee farm, a shaded organic coffee farm, and a forest fragment. We asked how habitat and seasonality influenced colony weight, forager activity, and pollen diet over one year. We placed eight experimental colonies in three habitats (three each in coffee farms; two in forest) and monitored them monthly for colony weight and forager activity. We collected corbicular pollen loads from returning foragers and identified pollen morphospecies. We compared performance and diet metrics across habitats and between wet and dry seasons. Colony performance was dramatically worse in the sun coffee farm; all sun coffee colonies died during the study. Colony performance did not differ between shade coffee and forest. Pollen diet richness was lower in the sun coffee colonies, but all habitats shared the same core pollen morphospecies. Across habitats, colony weight and activity and pollen diet richness decreased during the wet season. Our study suggests that conventional sun coffee cannot support stingless bee colonies, likely because of combined effects of agrochemical exposure and floral resource scarcity. By contrast, shade coffee is equivalent to forests in supporting stingless bee colonies.

Accelerated abdominal lipid depletion from pesticide treatment alters honey bee pollen foraging strategy, but not onset, in worker honey bees.

Honey bee abdominal lipids decline with age, a change thought to be associated with the onset of foraging behavior. Stressors, such as pesticides, may accelerate this decline by mobilizing internal lipid to facilitate the stress response. Whether bees with stressor-induced accelerated lipid loss vary from controls in both the onset of foraging and nutritional quality of collected pollen is not fully understood. We asked whether stressors affect foraging behavior through the depletion of abdominal lipid, and whether stress-induced lipid depletion causes bees to forage earlier and for fattier pollen. We tested this by treating newly emerged bees with one of two pesticides, pyriproxyfen (a juvenile hormone analog) and spirodiclofen (a fatty acid synthesis disruptor), that may affect energy homeostasis in non-target insects. Bees fed these pesticides were returned to hives to observe the onset of foraging behavior. We also sampled foraging bees to assay both abdominal lipids and dietary lipid content of their corbicular pollen. Initially, spirodiclofen-treated bees had significantly more abdominal lipids, but these declined faster compared with controls. These bees also collected less, yet more lipid-rich, pollen. Our results suggest that bees with accelerated lipid decline rely on dietary lipid content and must collect fattier pollen to compensate. Pyriproxyfen treatment reduced the age at first forage but did not affect abdominal or collected pollen lipid levels, suggesting that accelerated fat body depletion is not a prerequisite for precocious foraging.

Pesticide contamination and their botanical sources in pollen loads collected by honeybees in Kenya: A spatio-temporal context

Honeybees are generalists, and therefore, a wide range of flowering plants can easily be identified from their collected pollen loads. In this study, the levels of pesticide contamination on corbicular pollen were investigated using two approaches; (i) unsorted colony level collected and (ii) sorted pollen samples (according to botanical origin). Sorted samples were palynologically identified up to the family level to establish the types of pesticides used across landscapes and identify their botanical sources. This study was carried out between November 2019 and October 2020 in Murang’a county, Kenya, across three landscape types. The landscape was characterized according to the degree of greenness using the Normalized Difference Vegetation Index (NDVI) into high, medium, and low classes. Pollen Hazard Quotient (PHQ) was used to estimate the risk to honeybees of each detected pesticide. In the unsorted samples, five different pesticides were detected with concentrations ranging between 0.12 and 37.97 µg kg-1. From the results, 11 pesticides were detected, nine insecticides and two fungicides. These pesticides were further traced to 11 plant families, from which Poaceae, Rubiceae, and Astereceae were contaminated with more than 70% of the 11 detected pesticides. Acetamiprid concentration in March was found to be extremely higher (1202.50 µg kg-1) the recommended EU limit (50 µg kg-1). Additionally, chlorpyriphos concentration was found to be higher than the EU set limit of 10 µg kg-1 in months of July, September, and October. Additionally, pollen from Rubiaceae and Poaceae plant families were the most collected during the period of this study. It was further noted that pesticides and plant families identified varied across sampling time, but not across landscapes.

Honey bees change the microbiota of pollen

Background: Pollen, as all other plant tissues, harbors different microorganisms. As honey bees (Apis mellifera) collect and pack pollen they add regurgitated nectar to moisten and glue the pollen grains, possibly changing the microbial composition. Hypothesis: We hypothesize that while packing pollen into their corbiculae, honey bees change the pollen microbiota. Studied species: Brassica napus L., Apis mellifera L. Study site and dates: Avignon, France, 2018. Methods: In this study, we compared the microbiota of clean Brassica napus (Brassicaceae) pollen with that of bee-worked corbicular pollen by 16S rRNA gene targeted amplicon sequencing. We also compared these bacterial communities with those present in nectar, the bee gut and the bee surface as potential inoculum sources. Results: We found that by working pollen, bees increase the bacterial diversity of pollen, by adding honey bee symbionts such as Bombella, Frischella, Gilliamella and Snodgrassella, bee pathogens as Spiroplasma and nectar dwelling Lactobacillus to the new pollen microbiota. Conclusions: The bee gut is an important source of inoculum of the corbicular pollen microbiota. We discuss the implications of these findings and propose future research avenues.

Survival, Body Condition, and Immune System of Apis mellifera liguistica Fed Avocado, Maize, and Polyfloral Pollen Diet.

Nutritional stress is the major factor contributing to decline in the honey bee (Apis mellifera L.) populations given the high degree of dependence on floral resources, and due to the habitat loss. In this sense, monocultures of maize and avocado have great extensions in Mexico, but their impact on the physiology and morphology of A. mellifera is unknown. This research evaluated the effect of total protein content in monofloral (maize or avocado pollen diets) and polyfloral (using five types of pollen: Persea americana Mill., Zea mays L., Melampodium perfoliatum Cav., Drymaria villosa Cham Schltdl., and Lopezia racemosa Cav.) on their survival, body condition (controlled density, head mass, and development of hypopharyngeal glands; protein content in hemolymph), and immune response [lytic activity and activity of prophenoloxidase in the hemolymph (proPO)]. Corbicular pollen of P. americana had the highest protein content, followed by the corbicular pollen of Z. mays, M. perfoliatum, D. villosa, and L. racemosa. Polyfloral diet seems to be better for A. mellifera than the monofloral maize and avocado. Bees fed polyfloral pollen diet showed a high content of protein in the hemolymph in comparison with that fed maize or avocado pollen diets. Bees fed polyfloral and avocado pollen diet had the highest lytic activity but showed a decrease in proPO activity. In conclusion, polyfloral diets seem to be better for A. mellifera than the monofloral maize and avocado.

Effects of Thiamethoxam-Dressed Oilseed Rape Seeds and Nosema ceranae on Colonies of Apis mellifera iberiensis, L. under Field Conditions of Central Spain. Is Hormesis Playing a Role?

Simple SummaryThe collapse of the honey bee colonies is a complex phenomenon in which different factors may participate in an interrelated manner (e.g., pathogen interactions, exposure to chemicals, beekeeping practices, climatology, etc.). In light of the current debate regarding the interpretation of field and monitoring studies in prospective risk assessments, here we studied how exposure to thiamethoxam affects honey bee colonies in Central Spain when applied as a seed treatment to winter oilseed rape, according to the good agricultural practice in place prior to the EU restrictions. Under the experimental conditions, exposure to thiamethoxam, alone or in combination with other stressors, did not generate and maintain sufficient chronic stress as to provoke honey bee colony collapse. The stress derived from exposure to thiamethoxam and honey bee pathogens was compensated by adjustments in the colony’s dynamics, and by an increase in the worker bee population, a behavior known as hormesis. An analysis of the factors underlying this phenomenon should be incorporated into the prospective risk assessment of plant protection products in order to improve the future interpretation of field studies and management practices.To study the influence of thiamethoxam exposure on colony strength and pathogen prevalence, an apiary (5 colonies) was placed in front of a plot sown with winter oilseed rape (wOSR), just before the flowering phase. Before sowing, the seeds were treated with an equivalent application of 18 g thiamethoxam/ha. For comparison, a second apiary (5 colonies) was located in front of a separate 750 m plot sown with untreated wOSR. Dead foragers at the entrance of hives were assessed every 2–3 days throughout the exposure period, while the colony strength (number of combs covered with adult honey bees and brood) and pathogens were monitored each month until the following spring. Foraging on the wOSR crop was confirmed by melissopalynology determination of the corbicular pollen collected periodically, while the chemical analysis showed that exposure to thiamethoxam was mainly through nectar. There was an increase in the accumulation of dead bees in the apiary exposed to thiamethoxam relating with the control, which was coped with an increment of bee brood surface and adult bee population. However, we did not find statistically significant differences between apiaries (α = 0.05) in terms of the evolution of pathogens. We discuss these results under hormesis perspective.

Espectro de polen corbicular de Apis mellifera en muestras de Huejotitán, Jalisco, México

This study examines the different plants visited by the honeybee (Apis mellifera L.) during the honey harvest season (August to November) 2012. The work consisted in identifying the corbicular pollen pellets collected by the bees in one apiary in the village of Huejotitan, municipality of Jocotepec, state of Jalisco, Mexico. Three hives were selected and sampled monthly by means of Ontario modified pollen traps. The samples were tagged and frozen and later processed by acetolysis technique to remove the exine; permanent glycerine slides were made for the preservation and analysis. Identification and counting of pollen grains was performed using an Olympus BH-2® upright microscope equipped with a 100X ocular micrometer to measure each individual species pollen grain, using immersion oil. Wild plants in bloom were also collected monthly, tagged, pressed and taken to the herbarium for identification; the pollen was extracted, processed and identified for a reference collection that served as an ancillary means of identification and as a seasonal reference to the blooming species. In the corbicular pollen, 23 types of plants were identified: 13 at species level, five at genus level and five at family level belonging to 17 plant families. Myrtaceae resulted the most frequently represented family followed by Asteraceae, Fabaceae and Lamiaceae.

Microbial communities associated with honey bees in Brazil and in the United States

Honey bee colony losses worldwide call for a more in-depth understanding of the pathogenic and mutualistic components of the honey bee microbiota and their relation with the environment. In this descriptive study, we characterized the yeast and bacterial communities that arise from six substrates associated with honey bees: corbicular pollen, beebread, hive debris, intestinal contents, body surface of nurses and forager bees, comparing two different landscapes, Minas Gerais, Brazil and Maryland, United States. The sampling of five hives in Brazil and four in the USA yielded 217 yeast and 284 bacterial isolates. Whereas the yeast community, accounted for 47 species from 29 genera, was dominated in Brazil by Aureobasidiumsp. and Candida orthopsilosis, the major yeast recovered from the USA was Debaryomyces hansenii. The bacterial community was more diverse, encompassing 65 species distributed across 31 genera. Overall, most isolates belonged to Firmicutes, genus Bacillus. Among LAB, species from Lactobacillus were the most prevalent. Cluster analysis evidenced high structuration of the microbial communities, with two distinguished microbial groups between Brazil and the United States. In general, the higher difference among sites and substrates were dependents on the turnover effect (~ 93% of the beta diversity), with a more pronounced effect of nestedness (~ 28%) observed from Brazil microbiota change. The relative abundance of yeasts and bacteria also showed the dissimilarity of the microbial communities between both environments. These results provide a comprehensive view of microorganisms associated with A. mellifera, highlighting the importance of the environment in the establishment of the microbiota associated with honey bees.

Collection and Identification of Pollen from Honey Bee Colonies.

Researchers often collect and analyze corbicular pollen from honey bees to identify the plant sources on which they forage for pollen or to estimate pesticide exposure of bees via pollen. Described herein is an effective pollen-trapping method for collecting corbicular pollen from honey bees returning to their hives. This collection method results in large quantities of corbicular pollen that can be used for research purposes. Honey bees collect pollen from many plant species, but typically visit one species during each collection trip. Therefore, each corbicular pollen pellet predominantly represents one plant species, and each pollen pellet can be described by color. This allows the sorting of samples of corbicular pollen by color to segregate plant sources. Researchers can further classify corbicular pollen by analyzing the morphology of acetolyzed pollen grains for taxonomic identification. These methods are commonly used in studies related to pollinators such as pollination efficiency, pollinator foraging dynamics, diet quality, and diversity. Detailed methodologies are presented for collecting corbicular pollen using pollen traps, sorting pollen by color, and acetolyzing pollen grains. Also presented are results pertaining to the frequency of pellet colors and taxa of corbicular pollen collected from honey bees in five different cropping systems.

A 3D Printed Pollen Trap for Bumble Bee (Bombus) Hive Entrances.

To verify the plant sources from which bumble bees forage for pollen, individuals must be collected to remove their corbicular pollen loads for analysis. This has traditionally been done by netting foragers at nest entrances or on flowers, chilling the bees on ice, and then removing the pollen loads from the corbiculae with forceps or a brush. This method is time and labor intensive, may alter normal foraging behavior, and can result in stinging incidents for the worker performing the task. Pollen traps, such as those used on honey bee hives, collect pollen by dislodging corbicular pollen loads from the legs of workers as they pass through screens at the nest entrance. Traps can remove a large quantity of pollen from returning forager bees with minimal labor, yet to date no such trap is available for use with bumble bee colonies. Workers within a bumble bee colony can vary in size making size selection of entrances difficult to adapt this mechanism to commercially reared bumble bee hives. Using 3D printing design programs, we created a pollen trap that successfully removes the corbicular pollen loads from the legs of returning bumble bee foragers. This method significantly reduces the amount of time required by researchers to collect pollen from bumble bee foragers returning to the colony. We present the design, results of pollen removal efficiency tests, and suggest areas of modifications for investigators to adapt traps to a variety of bumble bee species or nest box designs.

Different Dynamics of Bacterial and Fungal Communities in Hive-Stored Bee Bread and Their Possible Roles: A Case Study from Two Commercial Honey Bees in China.

This study investigated both bacterial and fungal communities in corbicular pollen and hive-stored bee bread of two commercial honey bees, Apis mellifera and Apis cerana, in China. Although both honey bees favor different main floral sources, the dynamics of each microbial community is similar. During pH reduction in hive-stored bee bread, results from conventional culturable methods and next-generation sequencing showed a declining bacterial population but a stable fungal population. Different honey bee species and floral sources might not affect the core microbial community structure but could change the number of bacteria. Corbicular pollen was colonized by the Enterobacteriaceae bacterium (Escherichia-Shiga, Panteoa, Pseudomonas) group; however, the number of bacteria significantly decreased in hive-stored bee bread in less than 72 h. In contrast, Acinetobacter was highly abundant and could utilize protein sources. In terms of the fungal community, the genus Cladosporium remained abundant in both corbicular pollen and hive-stored bee bread. This filamentous fungus might encourage honey bees to reserve pollen by releasing organic acids. Furthermore, several filamentous fungi had the potential to inhibit both commensal/contaminant bacteria and the growth of pathogens. Filamentous fungi, in particular, the genus Cladosporium, could support pollen preservation of both honey bee species.

High-severity wildfire limits available floral pollen quality and bumble bee nutrition compared to mixed-severity burns.

High-severity wildfires, which can homogenize floral communities, are becoming more common relative to historic mixed-severity fire regimes in the Northern Rockies of the U.S. High-severity wildfire could negatively affect bumble bees, which are typically diet generalists, if floral species of inadequate pollen quality dominate the landscape post-burn. High-severity wildfires often require more time to return to pre-burn vegetation composition, and thus, effects of high-severity burns may persist past initial impacts. We investigated how wildfire severity (mixed- vs. high-severity) and time-since-burn affected available floral pollen quality, corbicular pollen quality, and bumble bee nutrition using percent nitrogen as a proxy for pollen quality and bumble bee nutrition. We found that community-weighted mean floral pollen nitrogen, corbicular pollen nitrogen, and bumble bee nitrogen were greater on average by 0.82%N, 0.60%N, and 1.16%N, respectively, in mixed-severity burns. This pattern of enhanced floral pollen nitrogen in mixed-severity burns was likely driven by the floral community, as community-weighted mean floral pollen percent nitrogen explained 87.4% of deviance in floral community composition. Only bee percent nitrogen varied with time-since-burn, increasing by 0.33%N per year. If these patterns persist across systems, our findings suggest that although wildfire is an essential ecosystem process, there are negative early successional impacts of high-severity wildfires on bumble bees and potentially on other pollen-dependent organisms via reductions in available pollen quality and nutrition. This work examines a previously unexplored pathway for how disturbances can influence native bee success via altering the nutritional landscape of pollen.

Pollen Resources Used by Two Species of Stingless Bees (Meliponini) in a Tropical Dry Forest of Southern Ecuador.

Pollinators are crucial for ecosystem functionality; however, little is known about the plant species used by some of these, such as stingless bees. In this study, for the first time, pollen resources used by Melipona mimetica Cockerell (Hymenoptera: Apidae: Meliponini) and Scaptotrigona sp. Moure (Hymenoptera: Apidae: Meliponini) were identified through analysis of corbicular pollen found on worker bees in a dry forest in southern Ecuador. In total, 68 pollen types were identified belonging to 31 botanical families. The most represented plant families were Fabaceae (16%), Malvaceae (7%), and Boraginaceae (7%). Both stingless bee species exhibited a polylectic behavior, with an average of 16 pollen types collected by individual bees. Differences in abundances of pollen types collected by each species indicated distinct uses for these two bee species.

Polen recolectado por nannotrigona mellaria (Apidae : Meliponini) en dos ambientes urbanos (Valle del Cauca – Colombia).

Objetivos: Conocer los hábitos de pecoreo respecto al polen colectado por Nannotrigona mellaria en dos ambientes urbanos del Valle del Cauca. Alcance: Inventario de las especies vegetales mayormente utilizadas por este grupo de abejas como fuente de polen para su dieta. Metodología: Se recolectó polen corbicular de obreras en cuatro nidos: tres en la Universidad del Valle (Cali, Colombia) y uno en la Universidad Nacional Sede Palmira, durante un periodo de 24 semanas entre junio de 2013 y enero de 2014, del mismo modo se recolectó polen de especies vegetales cercanas al sitio de nidificación y se realizó la comparación. Se hizo un análisis de agrupamiento para determinar similitud entre las dietas y un análisis de especie indicadora de Dufrêne y Legendre’s con el fin de determinar el tipo de polen relacionado con cada colmena. Principales resultados: La especie recolecta polen de 29 familias vegetales y 73 especies diferentes, siendo las especies de la familia Fabaceae las más representadas entre el material recolectado (29% de los registros) y Leucaena leucocephala la especie más frecuente (18% de los registros); se reportaron 14 especies con un valor indicador significativo (p<0,05), siendo la colmena de la Universidad Nacional la que presentó un mayor número (siete en total). Conclusiones: La especie N. mellaria recolecta polen de una gran variedad de plantas en los sitios de estudio por lo que tiene un gran potencial como polinizador en zonas urbanas. Además, esta especie tiene preferencia en la recolección de polen de leguminosas debido posiblemente a su abundancia en el área de estudio y a que su floración es abundante, atractiva visualmente a los Apidae y puede ofrecer néctares además de polen.

Wild bumble bee foraging preferences and fat content in highbush blueberry agro-ecosystems

Agricultural intensification can impact the availability and quality of resources. We analyzed resource use by bumble bees (Bombus spp.), important pollinators of highbush blueberry (Vaccinium corymbosum), collected from conventional highbush blueberry farms, organic highbush blueberry farms, and nearby natural areas in the lower Fraser River valley of British Columbia, Canada. We identified corbicular pollen and measured bee fat content as an indicator of body condition. Bumble bees use non-crop resources, including pollen from plant species not found on farms. Bees from natural areas had higher pollen protein content in corbicular pollen and higher body fat content than those from conventional and organic farms. There was no difference between farm types, and we could not demonstrate a relationship between pollen protein and bee fat content. Our findings illustrate the importance of resource availability throughout agro-ecological landscapes, including not only farms but also off-farm areas.

Analysis of pesticide residues in honeybee (Apis mellifera L.) and in corbicular pollen. Exposure in citrus orchard with an integrated pest management system

In the last years, the honeybee population is facing growing threats such as expansion of pathogens, incorrect use of phytosanitary products and environmental contaminants, loss or fragmentation of habitat, invasive species and climate change.The citrus cropping by Integrated Pest Management (IPM) in Spain combines strategies to reduce pest populations preventing environmental problems and reducing levels of damage by using chemicals only when it is strictly necessary.The goal of this study is to develop a simple analytical method to evaluate pesticide residue levels in honeybees and corbicular pollen when honeybees are exposed to plant protection products (PPPs) used in integrated pest management citrus orchards. The proposed method is based in an ultrasound assisted extraction procedure followed by a dispersive solid phase extraction (d-SPE) clean-up with alumina and LC-MS/MS pesticides determination. The method was validated in samples of honeybee and corbicular pollen for 10 pesticides commonly used in citrus orchards under IPM. This procedure was compared with QuEChERS methodologies for these matrices. The developed method was applied to determine pesticides in both matrices in a two -year study in citrus orchards.