Preliminary survey of the nutritional and palynological traits of honey bee-foraged pollen from Liguria (Italy)

It is known that the palynological features, and consequently the nutritional quality, of bee-foraged pollen vary according to several factors such as sampling site and period of year. In our two year study, carried out as part of the COLOSS CSI Pollen study between April and September in the eastern province of Genova (Italy), we explored the relationships between the palynological spectra and the protein content of corbicular pollen. We found that the differences are mainly driven by the collection season rather than by the site. This observation allowed us to employ the sample\u2019s palynological traits for the identification of foraging seasons characterized by different protein content in pollen. The outcome of our study provides a useful tool for beekeepers, helping them to cautiously program certain apiary management practices. This work also provides suggestions for future monitoring programs, regarding the advantages of studying the seasonal pattern not only of the floral origin of pollen but also of its nutritional traits

Variations in Nutritional Requirements Across Bee Species

peer reviewedWith 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

A new method to quantify paraffin in beeswax based on FT-microRaman spectroscopy and multivariate analysis

none8nononeLara, Nobili; Francesca, Corvucci; Dora, Melucci; Roberto, Colomba; Giorgia, Serra; Michela, Boi; Chiara, Ceci; Francesca-Vittoria, GrillenzoniLara, Nobili; Francesca, Corvucci; Dora, Melucci; Roberto, Colomba; Giorgia, Serra; Michela, Boi; Chiara, Ceci; Francesca-Vittoria, Grillenzon

Pollen load diversity and foraging niche overlap in a pollinator community of the rare Dictamnus albus L.

International audienc

Floral Diversity of Pollen Collected by Honey Bees (Apis mellifera L.) – Validation of the Chromatic Assessment Method

Pollen collected from flowers by forager bees is the only natural protein source for the hive. This nutritional compound is fundamental for the nurse bee and brood development, and for the queen activity. Pollen has a strong influence on colony health. It is also known that the pollen quality, in terms of the amino acid profile and total protein content, varies significantly according to the floral origin. For this reason, the palynological diversity assessed in corbicular pollen is a good measure of the quality of the environment the bees live in, in terms of available food