Based on current research the agglomerations are potentially desirable habitats for bumblebees. However, the relationship between the biodiversity of these bees and the green areas where they live is poorly understood. The aim of the study was to estimate the influence of green areas (ranging from 8 to 102 ha) of big cities on bumblebee species richness, composition, and the relative number of these insects. The studies were conducted within the administrative borders of the city of Wrocław (Poland) in 2011-2012 in 12 green areas such as parks, cemeteries and other places with trees and shrubs. Species richness and abundance of bumblebees was determined by direct observation during 30 min. The gathered materials were used to calculate how areas of urban green space affected qualitative and quantitative bumblebee community structure. In total, 13 species of bumblebees (Bombus Latr.) were recorded, of which 3 belonged to cuckoo bumblebees (Psithyrus subgenus). The share of the most similar groups was congregated in green areas not smaller than 30 ha. This was proved by analysis of qualitative structure (Sørensen index), quantitative structure (Renkonen index), and qualitative-quantitative structure (Cody's index). The number of bumblebee species in the surveyed green areas (r = 0.7497) was decisive for the arrangement of the mutual similarity of group structure. Green urban areas should be created in a size of at least 30 ha. Such sites provide conditions for the most diversified bumblebee species communities. Sites smaller than 30 ha can play an important role as refuges, and allow migration to all pollinators.

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A b s t r a c t Due to fewer bumblebees in rural areas these days, it is necessary to look for alternative habitats for the active protection of these very important pollinators. The research was carried out in The Botanical Garden of Medicinal Plants, in Wrocław, Poland. In the garden, approximately 2000 plant species were cultivated, of which 185 were visited by bumblebees. Amongst them, 57 plant species were deemed very attractive and were determined to be indicators for 7 bumblebee species. Indicator species for bumblebees ranged between 6 for Bombus pratorum to up to 20 for B. pascuorum. Monarda didyma was an indicator plant to 6 recorded bumblebee species. Other indicator plant species for at least 4 bumblebees species were: Origanum vulgare, Lavandula angustifolia, Rhododendron catawbiense, Phacelia tanacetifolia, and Agastache rugosa. Three bumblebee species were found to forage the most on 11 of the flowering plant species. The biggest group of plants were those which were mostly visited by 1-2 bumblebee species. Amongst all recorded indicator plants, 32% were native species.

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AbstractThe aim of the study is to present all distribution sites of Bombus semenoviellus in Poland reported between 1988 and 2019. The increase of species dispersion was concluded, especially in the central part of the country, as well as the occurrence in the high Karkonosze and Tatry mountains. This is likely the effect of progressing climate change, as well as the increase in climate continentalism in Europe. Differences between summer and winter temperatures favour the spread of this Siberian bumblebee species throughout the continent. Many specimens were found on plants originating from its central and west Asia. Those plants also occur in eastern and central Europe which could have helped this bumblebee spread west throughout Europe. B. semenoviellus will increase its range towards Western Europe. Based on observations so far, it is not possible to determine its invasive features and increased competitiveness for food and nesting places in relation to other bumblebee species.

The research enabled the optimal parameters of reed stalks Phragmites australis (Cav.) Trin. ex Steud, to be determined and then be used for rearing red mason bees (Osmia rufa L.). During research conducted in 2015 and 2016, 3,293 reed stalks were occupied by red mason bees, and 19,461 nest cells were counted in the stalks, of which there were 16,222 non-parasitized larvae. The mean weight of one cocoon was 0.085 g. The mean length of the reed stalk occupied by the red mason bee was 169.45 mm, its mean diameter was 6.11 mm and the mean number of cells in the reed was 5.47. The mean length of the first cell, the vestibulum, was 38.38 mm. The mean degree of parasitism was 0.16. The length of the reed stalk positively correlated with the number of cells in the reed nest (r=0.543), vestibulum length (r=0.392) and cocoon mass (r=0.362) The diameter of the reed positively correlated with the mass of the cocoon (r=0.536), the number of cells in the reed (r=0.406) and vestibulum length (r=0.254). Correlation between degree of parasitatism and length, and diameter of the reed was insignificant. Reed stalks with a length of 150 to 200 mm and a diameter of 5–7 mm are recommended for the choice of red mason bee nesting material.

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