Bee Pollen Loads Research Articles

The Abundance and Pollen Foraging Behaviour of Bumble Bees in Relation to Population Size of Whortleberry (Vaccinium uliginosum)

Habitat fragmentation can have severe effects on plant pollinator interactions, for example changing the foraging behaviour of pollinators. To date, the impact of plant population size on pollen collection by pollinators has not yet been investigated. From 2008 to 2010, we monitored nine bumble bee species (Bombus campestris, Bombus hortorum s.l., Bombus hypnorum, Bombus lapidarius, Bombus pascuorum, Bombus pratorum, Bombus soroensis, Bombus terrestris s.l., Bombus vestalis s.l.) on Vaccinium uliginosum (Ericaceae) in up to nine populations in Belgium ranging in size from 80 m2 to over 3.1 ha. Bumble bee abundance declined with decreasing plant population size, and especially the proportion of individuals of large bumble bee species diminished in smaller populations. The most remarkable and novel observation was that bumble bees seemed to switch foraging behaviour according to population size: while they collected both pollen and nectar in large populations, they largely neglected pollen collection in small populations. This pattern was due to large bumble bee species, which seem thus to be more likely to suffer from pollen shortages in smaller habitat fragments. Comparing pollen loads of bumble bees we found that fidelity to V. uliginosum pollen did not depend on plant population size but rather on the extent shrub cover and/or openness of the site. Bumble bees collected pollen only from three plant species (V. uliginosum, Sorbus aucuparia and Cytisus scoparius). We also did not discover any pollination limitation of V. uliginosum in small populations. We conclude that habitat fragmentation might not immediately threaten the pollination of V. uliginosum, nevertheless, it provides important nectar and pollen resources for bumble bees and declining populations of this plant could have negative effects for its pollinators. The finding that large bumble bee species abandon pollen collection when plant populations become small is of interest when considering plant and bumble bee conservation.

Floral sources to Tetragonisca angustula (Hymenoptera: Apidae) and their pollen morphology in a Southeastern Brazilian Atlantic Forest

The stingless bees are important flowers visitors of several plant species, due to their feeding habits and foraging behavior, constituting an important group to maintain biodiversity and the dynamics of tropical communities. Among stingless bees, Tetragonisca angustula is widely distributed in tropical habitats, and has been considered an important pollinator of different plant families. To support a rational economic use of this group, there is a need to characterize the plant species that represent important sources as part of their diet, as preferred, alternative or casual food sources. The aim of this survey was to distinguish the plant species that T. angustula visited most often. The study was undertaken in four regions of the Atlantic Rainforest in Rio de Janeiro state (Brazil) over a year from March 2008 to February 2009. For this, we collected bees, flowering plants and bee pollen loads from the four sites, and evaluated pollen morphology in the laboratory. Field observations showed the presence of plants belonging to ten different families and pollen loads showed the presence of pollen types belonging to 26 plant families. There were strong differences between pollen types, especially regarding pollen grain shape. The present survey suggests a high value of these plant species as trophic resources for the T. angustula in the understory of Atlantic Rainforest. Changes in these fragments of this forest may compromise the availability of resources for Tetragonisca angustula species and other stingless bees.

Discernment of bee pollen loads using computer vision and one-class classification techniques

In this paper, we propose a system for authenticating local bee pollen against fraudulent samples using image processing and classification techniques. Our system is based on the colour properties of bee pollen loads and the use of one-class classifiers to reject unknown pollen samples. The latter classification techniques allow us to tackle the major difficulty of the problem, the existence of many possible fraudulent pollen types.Also presented is a multi-classifier model with an ambiguity discovery process to fuse the output of the one-class classifiers. The method is validated by authenticating Spanish bee pollen types, the overall accuracy of the final system of being 94%. Therefore, the system is able to rapidly reject the non-local pollen samples with inexpensive hardware and without the need to send the product to the laboratory.

The antimicrobial activity of honey, bee pollen loads and beeswax from Slovakia

The aim of this study was to test the antimicrobial activity of propolis, bee pollen loads and beeswax samples collected in the year 2009 from two locations in Slovakia to pathogenic bacteria, microscopic fungi and yeasts. The antimicrobial effect of the bee product samples were tested using the agar well diffusion method. For extraction, 99.9% and 70% methanol (aqueous, v/v) and 96% and 70% ethanol (aqueous, v/v) were used. Five different strains of bacteria, i.e. Listeria monocytogenes ccM 4699, Pseudomonas aeruginosa ccM 1960; Staphylococcus aureus ccM 3953; Salmonella enterica ccM 4420, Escherichia coli ccM 3988, three different strains of microscopic fungi, Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, and seven different strains of yeasts Candida krusei, Candida albicans, Candida glabrata, Candida parapsilosis, Candida tropicalis, Geotrichum candidum, Rhodotorula mucilaginosa, were tested. After 48 hours S. aureus was the bacterium most sensitive to the 70% ethanol extract of pollen, A. fumigatus was the most sensitive microscopic fungus (70% ethanol) and C. glabrata the most sensitive yeast (70% methanol). Microorganisms most sensitive to propolis extracts were L. monocytogenes, A. fumigatus (70% ethanol) and G. candidum (70% methanol). Most sensitive to beeswax extracts were E. coli, A. niger and C. tropicalis.

The Effect of Various Storage Methods on Organoleptic Quality of Bee Pollen Loads

The Effect of Various Storage Methods on Organoleptic Quality of Bee Pollen LoadsThe aim of this research was to evaluate the effect of storing frozen pollen loads in controlled and/or air atmosphere, on organoleptic properties of the product. Collected pollen loads were cleared of mechanical impurities and preserved as follows: frozen and stored in air atmosphere; frozen and stored in an artificial atmosphere of a carbon dioxide and nitrogen mixture (30% CO2, 70% N2); frozen and stored in pure nitrogen (100% N2); frozen and stored using a vacuum system; dried out at ca. 40°C and stored in air atmosphere.In an organoleptic study, all tested pollen samples, irrespective of their storage method, were evaluated positively. The studied storage factors did not affect the shape, specific identity or aroma of pollen loads. The average point scores obtained for these features were similar in all groups. Storage conditions did influence the color and flavor of stored pollen loads. The experiment revealed significant differences in the perception of taste and aroma of tested pollen samples depending in the sex of the testing person. The taste and aroma of pollen loads were more appealing to men than to women testers.

Native Bees, Honeybees, and Pollination in Oregon Cranberries

Cultivated cranberry (Vaccinium macrocarpon Aiton) relies on insect pollination for berry production. Honeybees (Apis mellifera L.) have historically provided this service, but their recent decline has underscored the need for additional pollinators. The objective of this study was to determine the richness and abundance of native bees in the cranberry-growing area of southern coastal Oregon and compare foraging behaviors of honeybees and native bees. In a 2-year study, we collected over 27 native bee species in traps set out during and after bloom (mid-May to mid-June). During 67 2-min observations, honeybees (68.1%) and three species of bumble bees (Bombus spp.; 31.6%) comprised 99.7% of foragers. The dominant bumble bee was Bombus vosnesenskii Radoszkowski (56.0%). Multivariate regression of temperature and wind speed data indicated that both were significantly predictive of honeybee and bumble bee foragers (P < 0.001). The interquartile range for foraging was 18.3 to 22.2 °C for bumble bees and 21.1 to 26.7 °C for honeybees. Over 75% of honeybees were seen foraging above the average observed temperature (19.5 °C). Bumble bee pollen loads had a greater dry mass (6.8 ± 12.9 mg) than those of honeybees (2.0 ± 3.6 mg; P < 0.001), and the latter were observed collecting nectar but no pollen more often (during 37.2% of visits) than bumble bees (11.3% of visits). Based on our results, bumble bees in general, and B. vosnesenskii in particular, may be providing significant pollination services for Oregon cranberry farms. However, to maintain current native bumble bee populations, conservation efforts are recommended.

Bee pollen loads and their use in indicating flowering in the Caatinga region of Brazil

The study presents a map of pollen samples collected by Apis mellifera L. in an area of Caatinga (dryland) vegetation in Canudos, Bahia State, Brazil. A total of 62 bee pollen samples obtained from pollen-traps between March/2004 and February/2006 were examined. The pollen loads were acetolyzed and the pollen types identified and counted by sampling using an optical microscope. Thirty-six plant families were found to contribute to the composition of the pollen spectrum of the samples, with 85 different pollen types. Fabaceae was the most represented family (21 pollen types), and Mimosa filipes was the single most frequently observed pollen type (37 samples). The predominant pollen class included 14 pollen types; the secondary class, 18 types; important minor class, 37 types; minor class, 38 types; and 37 “present” pollen types (<1%). Plant species characteristic of the Caatinga region that have apicultural potential, such as Croton spp., Spondias tuberosa Arruda and Ziziphus joazeiro Mart., were well represented in the pollen spectrum. The pollen map was found to be useful for indicating the flowering periods of certain Caatinga species if long and continuous observations were made.

Botanical origin ofApispollen loads using colour, weight and pollen morphology data

Samples of commercially available bee pollen loads or pellets, denoted by common names and presenting several colours, were examined using pollen analysis in order to obtain their botanical and regional origin. Two grammes of each of the nineteen well-mixed samples, comprising of ca. 300 pellets, were used. Each sample was grouped into subsamples considering the colour of the loads that were weighed again. Pollen slides were prepared without the use of acetolysis. Thirteen samples presented a dominant pollen type of equal or more than the half of the sample’s weight. The dominant pollen loads may be monochromatic or polychromatic, and the identified pollen types were of Arecaceae, Baccharis , Brassicaceae, Crotalaria , Eupatorium , Myrcia , Mimosa scabrella and Piper . These taxa indicated that the samples proceeded from the South and Southeast regions in Brazil. The common names agreed with the scientific names only in three samples. In other samples they did not agree with the dominant pollen type. Pollen analysis, therefore, is a very useful technique for the exact identification of floral and regional pollen origin.

Initial data on the specific heterogeneity found in the bee pollen loads produced in the Pontevedra region (north‐west Spain)

Heterogeneous pollen load frequency from a beehive located in the Morcón (Pontevedra, north‐west Spain) was recorded. Samples of pollen loads were obtained weekly between May and July using pollen traps, and the accumulated pollen was removed at different times. Of the total analysed pollen loads an average heterogeneity percentage of approximately 5% was recorded. The pollen load heterogeneity consisted of mixed pellets with pollen of several species, but usually with one species (Erica umbellata L., Lythrum salicaria L., Lotus corniculatus L., Cytisus scoparius‐type, Castanea sativa Miller, Echium plantagineum L., Reseda media Lag., Erica cinerea L., Trifolium arvense L., Lonicera peryclimenum L., Scandix pecten‐veneris L., Calystegia sepium (L.) Br., Crepis capillaris (L.) Wallr., Eucalyptus globulus Labill., Plantago lanceolata L., ‐Raphanus raphanistrum L., Rubus ulmifolius‐ type or Poaceae) having higher values than others. It appears that mixed loads are not the result of flower deception but related to a decrease in pollen availability from plants the bees are currently foraging on that result in mixed foraging behaviour on other taxa.

Initial data on the specific heterogeneity found in the bee pollen loads produced in the “Baixa Limia-Serra do Xurés” nature reserve

A study has been made on the heterogeneous pollen loads frequency from a beehive located in the “Baixa Limia-Serra do Xurés” Nature Reserve. An analysis was made on several samples, obtained from the hive once a week, at different times of the day, from March to May. Of the total analysed pollen loads an average heterogeneity percentage of approximately 5% was obtained. The pollen loads heterogeneity consisted in the appearance of pollen loads of one pollen as most abundant (Cytisus scoparius type, Erica umbellata, Halimium alyssoides, Reseda media, Crataegus monogyna, Sedum acre and Lotus corniculatus) with other pollens.

Composition of Pollen Loads of Megachile rotundata in Relation to Flower Diversity (Hymenoptera: Megachilidae)

Abstract We examined the composition of pollen loads of female alfalfa leafcutting bees (Megachile rotundata) at a location where a variety of flowering plants were available, but where alfalfa (Medicago sativa) provided the vast majority of flowers. All females carried alfalfa pollen. Based on counts of pollen grains, pollen loads were greater than 90% alfalfa on three-quarters of the females collected in July and on nearly two-thirds of those collected in August. A single non-alfalfa pollen made up the majority of the loads on just 6% of females. The most common alternative pollen sources were yellow sweetclover (Melilotus officinalis), and Brassicaceae and Chenopodaceae whose pollens we could not distinguish at the species level. In both July and August, the diversity of pollen types on females was positively correlated with flower diversity within 50 m of shelters. This and other studies indicate that M. rotundata is an opportunist capable of exploiting a variety of plant taxa and flowers of different...

Melissopalynology in Brazil: a review of pollen analysis of honeys, propolis and pollen loads of bees

This paper reviews current knowledge on the occurrence of several types of pollen grains in the sediments of honey samples, propolis and bee loads of Apiinae and Meliponinae in Brazil. After a short historical introduction about research activities in Melissopalynology using Brazilian samples, bee products were analyzed in respect to the greater Brazilian regions (South, Southeast, Northeast and North), emphasizing monofloral honeys and the green propolis. Numerous bibliographic references and a short glossary of the technical terms used is presented.

Fatty acid composition and palynological analysis of bee (Apis) pollen loads in the states of São Paulo and Minas Gerais, Brazil

SUMMARYThe fatty-acid composition and botanical origin of 14 honey bee (Apis mellifera) pollen load samples acquired in shops and apiaries in Minas Gerais and São Paulo states, Brazil, were determined. The fatty acids presented a variable composition among these samples. All samples contained oleic, linoleic and arachidic acid. Only one sample did not contain palmitic acid. The unsaturated fatty-acid level varied from 18.6% to 55.9% of the total fatty-acid composition, suggesting that pollen is a good source of unsaturated fatty acids to the diet. Several pollen types were identified. Eucalyptus (Myrtaceae) and Eupatorium (Asteraceae) pollen types were the most common among those sampled. These data might help the regulatory agencies establish quality parameters for pollen produced in Brazil. There are no additional data available on Brazilian pollen fatty acid composition.

Flower constancy of honeybees (Apis mellifera L.) to blooming pear plantations

Studies were made on the composition of pollen loads of honeybees captured at the flowers of blooming pear trees in pear plantations. Also the foraging behaviour of honeybees was observed. Overwhelming majority of honeybees visiting the flowers of 13 pear cultivars in 1996 were pollen gatherers (95.6 per cent). Proportion of pure nectar gatherers was as low as some 3.7 per cent and no more than 0.7 per cent performed mixed behaviour. The analysis of pollen loads of bees collected at pear flowers in blooming pear plantations showed that fidelity was as high as 89-90 per cent towards pear, higher than for another fruit species in other studies. Even those plant species that are regarded to be strong competitors of blooming fruit trees in the literature (Taraxacum officinale, Stellaria media, Lamium purpureum) were scarcely represented in the loads. Accordingly, honeybees can be much more important and more effective pollinating agents of pear cultivars than generally believed.&#x0D;

Anthophilous Fly Distribution Across an Elevation Gradient

-Flower-visiting Diptera are abundant in montane and Arctic areas. This research, conducted on the western slope of the Colorado Rocky Mountains: (1) characterizes the predominant anthophilous fly taxa in comparison with other high-elevation and highlatitude sites; (2) examines changes in fly abundance with elevation, and (3) examines the potential of flies as pollinators by examining quality and quantity of pollen loads. Flies collected from 66 flowering species were identified to species to produce a data base containing taxonomic information, elevation and floral records. Malaise trap censuses were conducted in three elevational zones. Pollen carried by flies and pollen in their guts were quantified and examined to determine the number of plant species represented. Proportional representation of dipteran families changed in a similar manner in different mountain systems and the Arctic. The predominance of flies on flowers at high elevations appears to be due to a decrease in representation of other orders of insects. Most fly taxa fed at multiple plant species, but gut contents indicated that individual flies fed largely on a single pollen type. Total pollen loads of flies and solitary bees were similar although flies collected on Linum lewisii carried less pollen than bees.

An Analysis of Honey Bee Pollen Loads from Banthra, Lucknow, India

Abstract The botanical composition of bee pollen loads, collected between January and April, 1970, is presented, and discussed in relation to seasonal preferences.

An Analysis of Pollen Loads of Honey Bees from Kangra, India

Abstract Thirty-nine bee pollen loads collected in Kangra, were analyzed, during a period of three months. Eight loads were found to be mixed and the rest unifloral. In all, twenty pollen types were recognised in the loads, which included some of the anemophilous types, namely, Gramineae, Cyperaceae, Palmae, Chenopodiaceae and Urticaceae.

Additional Techniques for Studying the behavior of wild bees

This supplement to a paper byLinsleyet al. (1952) describes techniques for the study of socialHalictidae as well as other bees. Methods used to judge relative ages of bees include study of mandibular wear and wing wear. Marking of individuals with quick drying paints is described. Marked bees may be returned to their nest through a glass tube. Paints often wear off; more permanent marking may be achieved by staining wings with an alcohol or acetone solution of methyl or ethyl eosin. Methods are described for delaying bees as they enter or leave their nest, so that color markings can be more easily seen. Small wire screen cones placed over nest entrances often serve this purpose. Methods of obtaining data from nests which are very close together are described, as well as methods of making population estimates of bees by means of the Lincoln Index. The following observations on each bee are recommended to learn as much as possible of habits and caste differences: (1) size of ovaries, (2) number of enlarged ovarioles, (3) number and size of largest oocytes, (4) presence of sperm cells in spermatheca, (5) presence of pollen in gut, (6) length of wing or some other index of size, (7) amount of wing and mandibular wear. The pollen loads of bees entering a nest can be marked with powder of different colors. Subsequent examination of cell provisions shows how many foragers cooperated in provisioning a cell. Replacement of a part of a nest with a glass tube provides opportunities for study of activities inside of the nest.

A STUDY IN THE RELATIVE CONSTANCY OF HIVE BEES AND WILD BEES IN POLLEN GATHERING

The chief purpose of the investigations described in this paper was to determine the relative pollen constancy of the various insect pollinators of the apple. In addition to the hive bee, these proved to be solitary bees belonging to the genera Halictus and Andrena, with Bremidae and various Diptera playing a minor role. It is pointed out that apparent flower constancy depends a great deal upon availability and that almost any result may be obtained by choosing certain periods in which to make tests. The results, based on analyses of the pollen loads of bees captured in apple blossoms, place the hive bee first as regards the number of pure loads, followed by Halictus, with Andrena a poor third. Taking into consideration the results of the entire season, and the analyses of bees from different sources of pollen, Halictus came first in these particular tests, but the difference is not considered significant. The supposed superiority of the hive bee from the standpoint of constancy does not appear to have been proved. Both Halictus and the hive bee, however, evidenced a significant superiority over the Andrena species studied.