Oligolectic bee species in Northern Europe (Hymenoptera, Apoidea)

Abstract

Evolution of flower specialization in bees, the concepts of poly-, oligo- andmonolecty are reviewed. About 60 species recorded in the area of Finland and Sweden are regarded as oligolectic. The proportions of oligoleges among all pollen-collecting bee species are about 30 percent in alarge area of central and Northern Europe. The proportion is about 15 percent in the northern boreal area of Finland and Sweden, where the percentage of polylectic bumblebees is much greater than in more southern areas. Of the solitary bee species recorded in Finland and Sweden, 25 arc regarded as narrow oligoleges, of which 6 species collect pollen from Campanula and 5 from Salix. Eusocial Bombus consobrinus is regarded as a facultative narrow oligolege of Aconitum septentrionale and, apparently, this bee species is the only oligolege in northern Europe, whose distribution completely covers that of the pollen plant. The distribution limits of some narrow oligoleges (e.9. Eucera longicornis and Andrena hattorfiana) approximately follow certain frequencies of their principal pollen plants (lathyrus pratensis and Knautia, respectively). Of the oligolectic bee species in Finland, 32 occur on the lists of threatened species of England, southwestern Germany or Poland. Records of E. longicornis and A. hattorfiana from various periods are given as examples of the decline of oligolectic bees in Finland during recent decades.

High‐elevation range limit of an annual herb is neither caused nor reinforced by declining pollinator service

“…How often does pollination failure impose plant range limits? Pauw & Bond () proposed that pollinator declines might commonly limit plant distributions directly, but highly specialized pollination systems like those they studied (see also Pekkarinen ) are the extreme of a continuum. Most are more generalized, such that loss of one pollinator species may not strongly reduce reproduction (Waser et al .…”

Selectivity in the exploitation of floral resources by hoverflies (Diptera: Syrphinae)

“…Oligolectic species have a short tongue like most other Syrphinae; as for bees (Pekkarinen 1998), specialization is essentially an ethological character that does not necessarily require any visible morphological qualification. Oligolectic species have a short tongue like most other Syrphinae; as for bees (Pekkarinen 1998), specialization is essentially an ethological character that does not necessarily require any visible morphological qualification.…”

“…Proboscis size suggests that most Syrphinae are generalist consumers of pollen and do not display any evidence of diet specialization corresponding to our guild typology. Oligolectic species have a short tongue like most other Syrphinae; as for bees (Pekkarinen 1998), specialization is essentially an ethological character that does not necessarily require any visible morphological qualification. However, some morphometric traits seem to be linked with polyphagy and the ability of hoverflies to colonize open habitats.…”

Phylogenetic relationships and host‐plant evolution within the basal clade of Halictidae (Hymenoptera, Apoidea)

“…Abundant and widespread plants [e.g., Larrea (Zygophyllaceae); Minckley et al, 1999) are known to support many specialist pollinators. Arid regions with highly seasonal rainfall patterns (Minckley et al, 1999) and Mediterranean climate regions (Pekkarinen, 1997) also host large proportions of oligolectic species.…”