PHYSICOCHEMICAL CHARACTERISTICS AND MELISSOPALYNOLOGICAL ANALYSIS OF COMMERCIAL BUCKWHEAT HONEYS FROM POLAND

Buckwheat honey is widely consumed by consumers due to its numerous health-promoting properties. Characteristically it is dark, tea-like in colour, sharp, tickly, and sweet in flavour, and has smelled of buckwheat flowers. In the current study, various commercial honey samples were examined to test the quality of buckwheat honey samples available in the market. The research materials were comprised of 15 samples of honeys from 4 voivodships, among these, 5 samples were collected from the Świętokrzyskie Voivodship, 4 from the Lesser Poland Voivodeship, 4 from the Lubelskie Voivodship, and reset 2 samples from the Podkarpackie Voivodship. Melissopalynological analyses of investigated honeys’ samples revealed that all samples had at least 45% of Fagopyrym pollen content, which means that researched honeys complied with the standards of the International Commission for Bee Botany (ICBB) for buckwheat honey. Honeys’ samples had an average water content of 15.3% (σ= 1.24), and electrical conductivity at 0.37 mS*cm-1. Therefore, all beekeepers correctly marked their honey type as buckwheat honey simply using the organoleptic properties of their honeys and observing their bees collecting pollen and honeydew

Ecological stoichiometry of the honeybee : Pollen diversity and adequate species composition are needed to mitigate limitations imposed on the growth and development of bees by pollen quality

The least understood aspects of the nutritional needs of bees are the elemental composition of pollen and the bees’ need for a stoichiometrically balanced diet containing the required proportions of nutrients. Reduced plant diversity has been proposed as an indirect factor responsible for the pollinator crisis. We suggest stoichiometric mismatch resulting from a nutritionally unbalanced diet as a potential direct factor. The concentrations and stoichiometric ratios of C, N, S, P, K, Na, Ca, Mg, Fe, Zn, Mn, and Cu were studied in the bodies of honeybees of various castes and sexes and in the nectar and pollen of various plant species. A literature review of the elemental composition of pollen was performed. We identified possible co-limitations of bee growth and development resulting mainly from the scarcity of Na, S, Cu, P and K, and possibly Zn and N, in pollen. Particular castes and sexes face specific limitations. Concentrations of potentially limiting elements in pollen revealed high taxonomic diversity. High floral diversity may be necessary to maintain populations of pollen eaters. Single-species crop plantations, even if these species are rich in nectar and pollen, might limit bee growth and development, not allowing for gathering nutrients in adequate proportions. However, particular plant species may play greater roles than others in balancing honeybee diets. Therefore, we suggest specific plant species that may (1) ensure optimal growth and production of individuals by producing pollen that is exceptionally well balanced stoichiometrically (e.g., clover) or (2) prevent growth and development of honeybees by producing pollen that is extremely unbalanced for bees (e.g., sunflower). Since pollen is generally poor in Na, this element must be supplemented using "dirty water". Nectar cannot supplement the diet with limiting elements. Stoichiometric mismatch should be considered in intervention strategies aimed at improving the nutritional base for bees

Botanical Characteristics of Polish Honeys from Natura 2000 Habitats

Eighteen samples of honeys which were harvested over several beekeeping seasons from apiaries located in the area of the “Kózki” Nature Reserve (central-eastern Poland) were the subject of the present study. The “Kózki” Nature Reserve is included in the European Ecological Network Natura 2000 program. A microscopic analysis of the pollen sediment in the honeys showed the presence of 61 pollen types from 32 botanical families in the investigated material. There were represented by nectariferous (72.1%) and nonnectariferous plants (27.9%) and both entomophilous and anemophilous ones. The total number of pollen taxa in individual samples ranged from 13 to 37. The main sources of nectar from trees and shrubs were: Frangula alnus, Prunus, Robinia pseudacacia, Rubus, Salix, Tilia. The main sources of nectar from herbaceous plants were: Anthriscus, Brassicaceae, Caryophyllaceae, Centaurea cyanus, Taraxacum, and Trifolium repens. Four unifloral honeys (three fruit tree honeys and one lime honey) and fourteen multifloral honeys, with a significant percentage of pollen from several nectariferous plant taxa, were distinguished in the studied material

Pollen sources in the Bojanów forest complex identified on honeybee pollen load by microscopic analysis

The aim of this study was to determine sources of pollen for the honeybee in the Bojanów forest complex, Nowa Dęba Forest District (southeastern Poland). Sampling of pollen loads from bees extended from the beginning of May until the end of September 2016 and was carried out at 7-day intervals using pollen traps mounted at the entrance of beehives. A total of 73 pollen load samples were collected from the study area. Fifty-nine taxa from 31 plant families were identified in the analyzed material. From 4 to 21 taxa (average 9.5) were recorded in one sample. The pollen of Brassicaceae (“others”), Taraxacum type, Solidago type, and Rumex had the highest frequency in the pollen loads examined. Apart from these four taxa, pollen grains of Rubus type, Poaceae (“others”), Calluna, Fagopyrum, Trifolium repens s. l., Phacelia, Aster type, Melampyrum, Quercus, Cornus, and Veronica were recorded in the dominant pollen group. The forest habitat taxa that provided pollen rewards to honeybees in the Bojanów forest complex were the following: Rubus, Calluna, Prunus, Tilia, Frangula alnus, Pinus, Quercus, Cornus, Robinia pseudoacacia, Salix, and Vaccinium. Apart from forest vegetation, the species from meadows and wastelands adjacent to this forest complex, represented by Taraxacum, Rumex, Plantago, Poaceae, Trifolium repens, and Solidago, proved to be an important source of pollen. The study indicates that forest communities are a valuable source of pollen for pollinating insects from early spring through to late fall

Evaluation of Selected Ornamental Asteraceae as a Pollen Source for Urban Bees

Offering more floral resources for urban bees can be achieved by growing ornamental bee plants. The aim of the present study was to evaluate selected Asteraceae (Calendula officinalis ‘Persimmon Beauty’ and ‘Santana’, Centaurea macrocephala, Cosmos sulphureus, Dahlia pinnata, Tagetes patula, Tithonia rotundifolia, and Zinnia elegans) as pollen sources for pollinators. Under urban conditions in Lublin, SE Poland, the investigated plants flowered from late June to the end of October. The mass of pollen produced in florets and capitula was found to be species-related. The highest pollen amounts per 10 florets (10.1 mg) as well as per capitulum (249.7 mg) were found for C. macrocephala. The mass of pollen yielded by a single plant depended on both the pollen mass delivered per disk florets and the proportion of disk florets in capitulum, and the flowering abundance of the plants. A single plant of D. pinnata and a single plant of T. rotundifolia each produced the largest pollen mass. Mean pollen yield per 1m2 of a plot ranged from 6.2 g (Z. elegans) to 60.7 g (D. pinnata). Pollen grains are tricolporate, with echinate exine, medium or small in size. They can be categorised as oblatespherical, spherical, and prolatespherical. The principal visitors to C. macrocephala, C. sulphureus, and C. officinalis were honey bees, whereas bumble bees dominated on T. rotundifolia and D. pinnata. A magnet plant for butterflies was Z. elegans. Among the investigated species, D. pinnata, C. macrocephala, and T. rotundifolia were found to be the most valuable sources of pollen flow for managed and wild bees

Źródła pożytku pyłkowego kompleksu leśnego Bojanów na podstawie analizy mikroskopowej obnóży pyłkowych pszczoły miodnej

The aim of this study was to determine sources of pollen for the honeybee in the Bojanów forest complex, Nowa Dęba Forest District (southeastern Poland). Sampling of pollen loads from bees extended from the beginning of May until the end of September 2016 and was carried out at 7-day intervals using pollen traps mounted at the entrance of beehives. A total of 73 pollen load samples were collected from the study area. Fifty-nine taxa from 31 plant families were identified in the analyzed material. From 4 to 21 taxa (average 9.5) were recorded in one sample. The pollen of Brassicaceae (“others”), Taraxacum type, Solidago type, and Rumex had the highest frequency in the pollen loads examined. Apart from these four taxa, pollen grains of Rubus type, Poaceae (“others”), Calluna, Fagopyrum, Trifolium repens s. l., Phacelia, Aster type, Melampyrum, Quercus, Cornus, and Veronica were recorded in the dominant pollen group. The forest habitat taxa that provided pollen rewards to honeybees in the Bojanów forest complex were the following: Rubus, Calluna, Prunus, Tilia, Frangula alnus, Pinus, Quercus, Cornus, Robinia pseudoacacia, Salix, and Vaccinium. Apart from forest vegetation, the species from meadows and wastelands adjacent to this forest complex, represented by Taraxacum, Rumex, Plantago, Poaceae, Trifolium repens, and Solidago, proved to be an important source of pollen. The study indicates that forest communities are a valuable source of pollen for pollinating insects from early spring through to late fall.Celem pracy było określenie źródła pożytku pyłkowego pszczoły miodnej w kompleksie leśnym Bojanów, nadleśnictwo Nowa Dęba (południowo-wschodnia Polska). Pobieranie prób obnóży pyłkowych od pszczół trwało od początku maja do końca września 2016 roku. Materiał pobierano, w siedmiodniowych odstępach czasu, stosując na ulach wylotowy poławiacz pyłku. Ogółem z terenu badań pozyskano 73 próbki obnóży pyłkowych. Analizę mikroskopową obnóży wykonano przy użyciu mikroskopu świetlnego Nikon Eclipse E600 przy powiększeniu 40×15. W każdym preparacie liczono co najmniej 300 ziaren pyłku w dwóch powtórzeniach po 150 ziaren w każdym z nich. Na podstawie spektrum pyłkowego każdej próbki obliczano frekwencję i udział poszczególnych taksonów w całości materiału, a także w próbkach pozyskanych wiosną, latem i jesienią. W analizowanym materiale wyróżniono ziarna pyłku 59 taksonów z 31 rodzin botanicznych. W jednej próbce notowano od 4 do 21 taksonów (średnio 9.5). W badanych obnóżach pyłkowych najwyższą frekwencję osiągnął pyłek Brassicaceae (inne), typu Taraxacum, typu Solidago i Rumex. W grupie pyłku dominującego (udział powyżej 45% w próbce) poza wspomnianymi 4 taksonami notowano jeszcze pyłek typu Rubus, Poaceae (inne), Calluna, Fagopyrum, Trifolium repens s. l., Phacelia, typu Aster, Melampyrum, Quercus, Cornus i Veronica. Gatunkami siedlisk leśnych dostarczającymi pszczole miodnej pożytku pyłkowego w kompleksie leśnym Bojanów były: Rubus, Calluna, Prunus, Tilia, Frangula alnus, Pinus, Quercus, Cornus, Robinia pseudoacacia, Salix i Vaccinium. Poza roślinnością leśną istotnym źródłem pyłku okazały się gatunki graniczących z kompleksem leśnym łąk i nieużytków reprezentowane przez: Taraxacum, Rumex, Plantago, Poaceae, Trifolium repens i Solidago. Przeprowadzone badania dowodzą, że zbiorowiska leśne stanowią cenne źródło pożytku pyłkowego dla owadów zapylających. Pożytek ten jest dostępny od wczesnej wiosny do późnej jesieni

Flowering, Forage Value, and Insect Pollination in Borage (Borago Officinalis L.) Cultivated in Se Poland

The three-year study on borage was conducted in Lublin, SE Poland. The aims were to investigate the flowering pattern and abundance, and the attractiveness (in terms of nectar and pollen production) for flower-visiting insects, mainly bees. Insect visitation and the effect of pollinators on fruit set and seed set were assessed as well. Flowering of borage started in the latter half of June and lasted eight weeks. The mean number of flowers · m−2 of the crop was 4570 per season. A borage flower produced on average 4.0 mg of nectar with a mean sugar concentration of 31.5%. The mean total sugar amount secreted in nectar was 1.2 mg. The pollen amount · flower−1 was 1.1 mg. A borage plant can supply insects with 1.1 g of nectar sugars and 1.1 g of pollen. The estimated nectar sugar yield and pollen yield per 1 m2 of the crop were similar, i.e. 5.2 g. Bees accounted for 73.0% of all insect visits to the borage flowers. The presence of insect pollinators increased the fruit set by 43.3% and seed set by 26.8%

Unravelling the dependence of a wild bee on floral diversity and composition using a feeding experiment

We investigated nutrition as a potential mechanism underlying the link between floral diversity/composition and wild bee performance. The health, resilience, and fitness of bees may be limited by a lack of nutritionally balanced larval food (pollen), influencing the entire population, even if adults are not limited nutritionally by the availability and quality of their food (mainly nectar). We hypothesized that the nutritional quality of bee larval food is indirectly connected to the species diversity of pollen provisions and is directly driven by the pollen species composition. Therefore, the accessibility of specific, nutritionally desirable key plant species for larvae might promote bee populations. Using a fully controlled feeding experiment, we simulated different pollen resources that could be available to bees in various environments, reflecting potential changes in floral species diversity and composition that could be caused by landscape changes. Suboptimal concentrations of certain nutrients in pollen produced by specific plant species resulted in reduced bee fitness. The negative effects were alleviated when scarce nutrients were added to these pollen diets. The scarcity of specific nutrients was associated with certain plant species but not with plant diversity. Thus, one of the mechanisms underlying the decreased fitness of wild bees in homogenous landscapes may be nutritional imbalance, i.e., the scarcity of specific nutrients associated with the presence of certain plant species and not with species diversity in pollen provisions eaten by larvae. Accordingly, we provide a conceptual representation of how the floral species composition and diversity can impact bee populations by affecting fitness-related life history traits. Additionally, we suggest that mixes of ‘bee-friendly’ plants used to improve the nutritional base for wild bees should be composed considering the local flora to supplement bees with vital nutrients that are scarce in the considered environment

Average concentrations of elements in honeybee castes and sexes.

<p>Average concentrations of elements in honeybee castes and sexes.</p