The term oligolecty is used in pollination ecology to refer to bees that exhibit a narrow, specialized preference for pollen sources, typically to a single family or genus of flowering plants.
When the choice is very narrow, the term monolecty is sometimes used, originally meaning a single plant species but recently broadened to include examples where the host plants are related members of a single genus.
[2] 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.
[2] There are some cases where oligoleges collect their host plant's pollen as larval food but, for various reasons, rarely or never actually pollinate the flowers.