The importance of honey adulteration detection has recently increased owing to the limited production levels in recent years and the relative high price of honey; therefore, this illegal practice has ...become more and more attractive to producers. Hence, the need has arisen for more effective analytical methods aiming at detecting honey adulteration. The present research presents an effective method to detect adulteration in honey falsified by intentional addition of different concentrations of commercial sugar syrups, using one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) coupled with multivariate statistical analysis. Sixty-three authentic and 63 adulterated honey samples were analyzed. To prepare adulterated honeys, seven different sugar syrups normally used for nutrition of bees were used. The best discriminant model was obtained by 1D spectra, and leave-one-out cross-validation showed a predictive capacity of 95.2%. 2D NMR also furnished acceptable results (cross-validation correct classification 90.5%), although the 1H NMR sequence is preferable because it is the simplest and fastest NMR technique.
There is growing evidence that pesticides may be among the causes of worldwide bee declines, which has resulted in repeated calls for their increased scrutiny in regulatory assessments. One recurring ...concern is that the current frameworks may be biased towards assessing risks to the honey bee. This paradigm requires extrapolating toxicity information across bee species. Most research effort has therefore focused on quantifying differences in sensitivity across species. However, our understanding of how responses to pesticides may vary within a species is still very poor. Here we take the first steps towards filling this knowledge gap by comparing acute, lethal hazards in sexes and castes of the eusocial bee Bombus terrestris and in sexes of the solitary bee Osmia bicornis after oral and contact exposure to the pesticides sulfoxaflor, Amistar (azoxystrobin) and glyphosate. We show that sensitivity towards pesticides varies significantly both within and across species. Bee weight was a meaningful predictor of pesticide susceptibility. However, weight could not fully explain the observed differences, which suggests the existence of unexplored mechanisms regulating pesticide sensitivity across bee sexes and castes. Our data show that intra-specific responses are an overlooked yet important aspect of the risk assessment of pesticides in bees.
With 2,000 species currently recorded in Europe, bees are a highly diversified and efficient group of pollinating insects. They obtain their nutrients from nectar and pollen of flowers. However, the ...chemical composition of these resources, especially of pollen (e.g., protein, lipid, amino acids, fatty acids, or sterol content), is highly variable among plant species. While it is well-known that bees show interspecific variation in their floral choices, there is a lack of information on the nutritional requirements of different bee species. We therefore developed original experiments in laboratory conditions to evaluate the interspecific variations in bee nutritional requirements. We analyzed the chemical content of eight pollen blends, different in terms of protein, lipid, amino acids, and sterols total concentration and profiles. Each pollen blend was provided to four different bee model species: honey bees (
Apis mellifera
), bumblebees (
Bombus terrestris
), mason bees (
Osmia bicornis
and
Osmia cornuta
). For each species, specific protocols were used to monitor their development (e.g., weight, timing, survival) and resource collection. Overall, we found that the nutritional requirements across those species are different, and that a low-quality diet for one species is not necessarily low-quality for another one. While honey bees are negatively impacted by diets with a high protein content (~40%), bumblebees and mason bees develop normally on these diets but struggle on diets with a low total amino acid and sterol content, specifically with low concentrations of 24-methylenecholesterol and β-sitosterol. Overall, our study supports the need of conserving and/or introducing plant diversity into managed ecosystems to meet the natural nutritional preferences of bees at species and community level.
The global range of the environmental quality issues we all face necessitates integrated action from all of the countries that suffer from a particular environmental issue. We must be able to obtain ...data on the presence of pollutants and their effects on biota from any territory, regardless of its environmental, infrastructural, social, and economic conditions. Biomonitoring utilizes organisms and natural materials to obtain this information. In particular, the honeybee is a ubiquitous, easy-to-breed organism with great mobility. Its body, which is covered with hairs, picks up materials and particulates that it encounters in the environment. Therefore, bees are highly effective accumulators of materials from the soil, vegetation, air, and water. These characteristics mean that the honeybee is both a bioindicator and a passive bioaccumulator organism, making it an ideal agent for easily monitoring vast areas inexpensively, even in regions where infrastructure is scarce. In this short review, we summarize the main targets of the honeybee-based monitoring campaigns that have been carried out to date, highlighting the results obtained in assessments of organic and inorganic pollution performed by coupling more modern technologies with this long-standing practice. It is hoped that this review will make scientists more aware of the incredible potential of these delicate organisms to provide data that could prove useful in the management of environmental issues.
Declines in insect pollinators have been linked to a range of causative factors such as disease, loss of habitats, the quality and availability of food, and exposure to pesticides. Here, we analysed ...an extensive dataset generated from pesticide screening of foraging insects, pollen-nectar stores/beebread, pollen and ingested nectar across three species of bees collected at 128 European sites set in two types of crop. In this paper, we aimed to (i) derive a new index to summarise key aspects of complex pesticide exposure data and (ii) understand the links between pesticide exposures depicted by the different matrices, bee species and apple orchards versus oilseed rape crops. We found that summary indices were highly correlated with the number of pesticides detected in the related matrix but not with which pesticides were present. Matrices collected from apple orchards generally contained a higher number of pesticides (7.6 pesticides per site) than matrices from sites collected from oilseed rape crops (3.5 pesticides), with fungicides being highly represented in apple crops. A greater number of pesticides were found in pollen-nectar stores/beebread and pollen matrices compared with nectar and bee body matrices. Our results show that for a complete assessment of pollinator pesticide exposure, it is necessary to consider several different exposure routes and multiple species of bees across different agricultural systems.
Display omitted
•We use new indices to summarise big datasets on pesticide exposure of three species of bees•Novel indices are calculated using Item Response Theory (IRT) models•The indices are linked to the number of pesticides rather than the active ingredients•Matrices collected from apple orchards are exposed to a higher number of pesticides compared to oilseed rape crop sites•Pollen related matrices contained more pesticides than were found in nectar and on the bees themselves
Accomplishing the Italian law to verify honey quality is onerous, because it requires measuring many chemical and physical parameters. On the contrary, bioluminescence-based analytical methods allow ...for rapid and inexpensive analysis. Bioluminescence has never been applied before to verify honey adulteration. The application of chemometrics to analytical methods based on bioluminescence has been here explored for this scope. Several honey samples were prepared, in which sugar syrup was added without exceeding legal limits: in this case, univariate analysis prescribed by the law cannot reveal the fraud. All samples were subjected to measurements of parameters prescribed by the law and also to bioluminescence analysis, executed using the
Vibrio fischeri
bacterium, one of the most common bioluminescent bacteria. Principal components analysis, linear discriminant analysis, and partial least square regression were applied to discriminate sugar-added honeys with respect to natural honeys, both by regulated physicochemical parameters and by bioluminescence ones. The feasibility of combining bioluminescence and multivariate analysis for a rapid screening of honey authenticity was demonstrated.
Beekeepers interested in converting their honey farms to organic management must replace old combs with organic foundations. The experiment described in this paper compares two methods of replacement ...of old combs, “fast” (5 combs per year) and “slow” (2 combs per year), by measuring the levels of acaricide residues in the newly built combs. Tested acaricides were coumaphos (Perizin and Asuntol), fluvalinate (Apistan), and chlorfenvinphos (Supona). Significant differences between the two replacement groups were observed only for the Apistan group in the third year, confirming high lipophilicity of fluvalinate. The residue levels in the new combs three years after beginning the conversion were significantly lower than initial levels for all products. Direct contamination of the combs was highest in Asuntol-treated hives and lowest in Perizin-treated hives. Residues in honey exceeding EU Maximum Residue Limit were found only in the case of Asuntol.
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