The Buzz About Pollinators

Red maples, lavender henbit, and yellow dandelions are blooming, all early signs that spring’s explosion of color is merely one month away. Why is spring so colorful? What mysterious force drives plants to develop so many different flower sizes, shapes, colors, and fragrances? The primary answer is their pollinators.

While many plants rely on wind and water to carry pollen, most of the “showy” flowering plants are pollinated by animals. These plants must ensure that the pollinator visits flowers of the same species of plant. If the plant cannot create fidelity between the pollinator and its flowers, then the pollen is lost as the pollinator visits unrelated species. This creates strong selective pressure for each species of plant to evolve unique flowers to attract specific pollinators that visit flowers of a certain color, size, shape, or fragrance. In turn, pollinators diversify and adapt to the unique attractants each flower type provides. This co-evolution between flowering plants and pollinators, mostly insects, has driven diversification in both plants and pollinators; thus, pollinator fidelity is a primary reason for why both plants and pollinators are so diverse.

A 2007 report by the National Research Council reviewed the status of pollinators across North America. The review identified numerous species in decline and indicated an array of causes for the declines1. For example, the western monarch population has declined by 97% since the 1980s, and the suspected cause is the loss of host plants (milkweeds) along their migration path2. Habitat loss, parasites, and diseases in wild and managed bees and pesticides are considered significant factors in pollinator decline. Contributing factors also include changes in