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 plant communities, invasive species, and climate. No matter the cause, pollinator decline is a serious problem with the potential to impact not only natural plant communities but also agriculture and horticulture.
Clemson Extension has developed the Clemson Apiculture and Pollinator Protection Program to provide education for beekeepers and encourage pollinator protection among the general public. Over the next few months, this program will debut websites and digital learning opportunities, offering an array of training for various audiences. To learn more about pollinators, follow the Clemson Pollinator Facebook page at https://www.facebook.com/ClemsonPollinator/.
While enjoying gardens, fields, and forests this spring, remember the insects and other pollinators that help to create and maintain South Carolina’s diverse plant communities and inherent natural beauty. Consider that conservation of South Carolina’s flora requires protections for its pollinators.
A parasitic fly (Tachinidae) feeding from a tickseed flower (Coreopsis sp.).
Ben Powell, ©2020, Clemson Extension
(Halictidae) collecting pollen from a Mexican Sunflower (Tithonia rotundifolia).
Ben Powell, ©2020, Clemson Extension
A mating couple of thread-waisted wasps (Sphecidae) on a swamp sunflower (Coreopsis angustifolia).
Ben Powell, ©2020, Clemson Extension
A flower fly (Syrphidae) refueling on a flower of a groundsel tree (Baccharis halimifolia).
Ben Powell, ©2020, Clemson Extension
Footnotes:
- National Research Council. 2007. Status of Pollinators in North America. Washington, DC: The National Academies Press https://doi.org/10.17226/11761
https://www.nap.edu/catalog/11761/status-of-pollinators-in-north-america - Shulz, C., L. Brown, E. Pelton, and E. Crone. 2017. Citizen science monitoring demonstrates dramatic declines of monarch butterflies in western North America. Biological conservation Vol. 214 pp. 343-346 https://www.sciencedirect.com/science/article/pii/S0006320717304809)
