Oligolege

Oligolectic pollinators are often called oligoleges or simply specialist pollinators, and this behavior is especially common in the bee families Andrenidae and Halictidae, though there are thousands of species in hundreds of genera, in essentially all known bee families; in certain areas of the world, such as deserts, oligoleges may represent half or more of all the resident bee species. Attempts have been made to determine whether a narrow host preference is due to an inability of the bee larvae to digest and develop on a variety of pollen types, or a limitation of the adult bee's learning and perception (i.e., they simply do not recognize other flowers as potential food sources), and most of the available evidence suggests the latter. However, a few plants whose pollen contains toxic substances (e.g., Toxicoscordion and related genera in the Melanthieae) are visited by oligolectic bees, and these may fall into the former category. The evidence from large-scale phylogenetic analyses of bee evolution suggests that, for most groups of bees, oligolecty is the ancestral condition and polylectic lineages arose from among those ancestral specialists.