The bumble and cuckooo bees (Hymenoptera: Apidae: Bombini; Bombus spp. and Psithyrus spp., respectively) are important plant pollinators and any decline in numbers or species constitutes a significant threat both to biological diversity and to whole economies. The distribution, status and factors threatening all 60 known taxa (species and subspecies) of Bombini of 11 countries of Western and Central Europe (Belgium, the Netherlands, Luxembourg, Denmark, Germany, Switzerland, Austria, Czech Republic, Slovakia, Hungary, Poland) were assessed from the beginning of the 20th century. The analysis was based on a literature review, unpublished data, personal communications, our own observations, and an expert review. The IUCN Red List categories were used for assessing the threat of extinction. Eighty per cent of taxa were threatened in at least one country of the region, and 30% of taxa were threatened throughout their range in the countries considered. More species went extinct per country in the second than in the first half of the 20th century, and four taxa went extinct in all 11 countries during 1951–2000. Amongst the factors adversely affecting the Bombini anthropogenic factors (particularly those associated with large-scale farming schemes) appear to be of greater importance than natural factors. To halt population declines and species extinctions it will be necessary to preserve aspects of traditional farming practices and for all Bombini to be afforded legal protection in all countries of the region. The implementation of the European Union's Common Agricultural Policy is likely to have the greatest single impact upon pollinators in the near future.

Pollinating insect populations, essential for maintaining wild plant diversity and agricultural productivity, rely on (semi)natural habitats. An increasing human population is encroaching upon and deteriorating pollinator habitats. Thus the population persistence of pollinating insects and their associated ecosystem services may depend upon on man-made novel habitats; however, their importance for ecosystem services is barely understood. We tested if man-made infrastructure (railway embankments) in an agricultural landscape establishes novel habitats that support large populations of pollinators (bees, butterflies, hoverflies) when compared to typical habitats for these insects, i.e., semi-natural grasslands. We also identified key environmental factors affecting the species richness and abundance of pollinators on embankments. Species richness and abundance of bees and butterflies were higher for railway embankments than for grasslands. The occurrence of bare (non-vegetated) ground on embankments positively affected bee species richness and abundance, but negatively affected butterfly populations. Species richness and abundance of butterflies positively depended on species richness of native plants on embankments, whereas bee species richness was positively affected by species richness of non-native flowering plants. The density of shrubs on embankments negatively affected the number of bee species and their abundance. Bee and hoverfly species richness were positively related to wood cover in a landscape surrounding embankments. This is the first study showing that railway embankments constitute valuable habitat for the conservation of pollinators in farmland. Specific conservation strategies involving embankments should focus on preventing habitat deterioration due to encroachment of dense shrubs and maintaining grassland vegetation with patches of bare ground.

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AimLandscape composition and spatial configuration of habitat patches are important determinants of biodiversity in fragmented semi‐natural habitats spread across agricultural landscapes. However, little attention has been paid to man‐made structures that can moderate spatial processes affecting pollinator communities. In a large‐scale study, we explored the importance of railway embankments for the turnover of pollinator species in agricultural landscapes. Because species differ in vulnerability to landscape composition and patch configuration, we also accounted for body size as well as food specialization of pollinators.LocationKraków area, Poland.MethodsWe sampled pollinating insects (bees, butterflies and hoverflies), at 25 study sites located along railway lines in the region of Kraków, Poland. Control grasslands for the embankments included 19 patches, located among crop fields, in which pollinators were sampled. We assessed the relationships between dissimilarity and distance for bee, butterfly and hoverfly trait groups on embankments and grasslands using Moran's Eigenvector Maps.ResultsThe dissimilarity for food‐non‐specialized bees on embankments was spatially structured: sites that were closer together were also less dissimilar in their community composition than more distant ones. Dissimilarity was also spatially aligned for large‐bodied butterflies and hoverflies on embankments. The species dissimilarity of pollinators divided into trait‐based groups was not spatially structured on grasslands.Main conclusionOur study highlights the potential function of railway embankments as corridors for at least some pollinator populations. Landscape managers should include railways in green networks to improve spatial processes linked with the distribution and turnover of pollinator species in agricultural landscapes. Thus, railway embankments and their correct management may be a good example of man‐made alterations in the environment that meet the demands of both civilization and biodiversity conservation.

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Abstract. Current distribution of bumblebee species in Cracow was studied in [2000][2001][2002][2003] in 23 atlas squares. The results were compared with historical data available for last 150 years, including published materials and museum collections. A total 28 bumblebee species were recorded throughout that period. Among them, 11 species are currently threatened in the study area. There were stated three tendencies among the studied bumblebee species. After 1850, 10 species were strongly regressing (withdrew from the Cracow area altogether or range contraction); further 11 species were more or less stable in their area; the next 6 species were strongly expanding in Cracow. 6 species were stated as a new for Cracow, including 2 species recorded between 1901-1972 and 4 between 1973-2003. Negative population tendencies by the Bombini in the Cracow area were the result of both natural and anthropogenic factors. Species protection and conservation of the most valuable areas as nature reserves are expected to prevent further decrease of bumblebees in the Cracow area.Résumé. Changements à long terme de la composition spécifi que et de la distribution des Bombini (Apidae) de Cracovie depuis 1850. La distribution actuelle des espèces de bourdons de Cracovie a été étudiée en 2000-2003, dans 23 carrés cartographiques. Les résultats on tété comparés avec les données historiques des dernières 150 années, y compris les données publiées et celles des collections de musées. Au total, 28 espèces de bourdons ont été observées durant l'ensemble de la période. Parmi ces espèces, onze sont menacées dans l'aire d'étude. On a établi trois tendances parmi les espèces de bourdons. Après 1850, 10 espèces ont fortement régressé (éteintes de Cracovie tandis que leur aire se contractait), 11 autres espèces ont été plus ou moins stables dans leur distribution ; 6 espèces se sont fortement étendues dans la région. 6 espèces ont été nouvellement observées : 2 nouvelles espèces durant la période 1901-1972 et 4 durant la période 1973-2003. Les tendances négatives des Bombini de Cracovie ont été le résultat à la fois de facteurs naturels et anthropiques. On espère que les mesures de protection d'espèces et les mises en réserves naturelles des zones les plus intéressantes arrêtent le déclin des bourdons de la région de Cracovie.

There are several possible causes of aggregated nesting in solitary Aculeata, one being joint defense against parasites. We tested whether females prefer nesting in aggregations, even if they consist of heterospecifics. We compared the colonization and nesting parasitism of trap-nests with and without a red mason bee aggregation. The results did not support our hypothesis that females prefer nesting in aggregations. The numbers of wild Aculeata nests did not differ between trap-nests with and without an aggregation. Unexpectedly, parasitism rates were higher in trap-nests with aggregations. When analyzing only nests of wild insects (mostly wasps), the differences in parasitism disappeared. Natural nesting sites may be such a limited resource that females nested in the first trap-nest they encountered and did not discriminate between our treatments, or wasps might share too few parasites species with bees to benefit from joint nest defense.