oligolecty

The most likely explanation for oligolecty in bees is not different from the explanation of specificity of any organism to its habitat; in fact, oligolecty is a form of host specificity.

1954 June 21, Charles Duncan Michener, “Bees of Panamá”, in Bulletin of the American Museum of Natural History, volume 104, article 1, New York, N.Y.: American Museum of Natural History, →ISSN, →OCLC, page 6, column 2

In so far as now known, all of the species exhibit a high degree of oligolecty (or monolecty) being restricted in pollen collecting to a single genus of plants.

1955 October, E[arle] G[orton] Linsley, J[ohn] W[inslow] MacSwain, Ray F[red] Smith, “Observations on the Nesting Habits and Flower Relationships of Some Species of Melandrina (Hymenoptera: Andrenidae)”, in P. D. Hurd, Jr., editor, The Pan-Pacific Entomologist, volume XXXI, number 4, San Francisco, Calif.: Pacific Coast Entomological Society, →ISSN, →OCLC, page 175

An individual of a polylectic species that takes pollen from only a few kinds of plants is showing flower constancy rather than oligolecty.

1974, Charles Duncan Michener, “Glossary”, in The Social Behavior of the Bees, Cambridge, Mass.: The Belknap Press of Harvard University Press, →ISBN, page 373, column 1

Once oligolecty was documented, the following two summers were used for field study of widely separated populations of I. pandurata.

1978, Daniel F. Austin, “Morning Glory Bees and the Ipomoea pandurata Complex (Hymenoptera: Anthophoridae)”, in Manya B. Stoetzel, editor, Proceedings of the Entomological Society of Washington, volume 80, number 3, Washington, D.C.: Entomological Society of Washington, →ISSN, →OCLC, page 397

That oligolecty exists is indisputable, but its application to particular bee species engenders confusion and debate. […] We propose a definition of oligolecty that is sufficiently inclusive without diluting the intended meaning for undisputed cases: we define oligolecty as consistent and predictable reliance of a species on a few plant genera for their pollen needs.

2006, James H. Cane, Sedonia Sipes, “Characterizing Floral Specialization by Bees: Analytical Methods and a Revised Lexicon for Oligolecty”, in Nickolas M. Waser, Jeff Ollerton, editors, Plant–Pollinator Interactions: From Specialization to Generalization, Chicago, Ill.; London: University of Chicago Press, →ISBN, part II (The Ecology and Evolution of Specialized and Generalized Pollination), page 110