General aims and suggestions for classroom use
This fact sheet for middle school to high school students is appropriate for several
topics, including plant reproduction, plant diversity, and plant-animal interactions.
Page one introduces flowers as adaptations to attract animal pollinators, and leads
students to make a prediction about plant and pollinator associations. Page two focuses
on the North American example of yucca plants and yucca moths to illustrate the key
biology concepts of coevolution, mutualism, and obligate mutualisms.
Suggestions for using this fact sheet in conjunction with plant reproduction and
- Provide students with a diagram of a typical flower and a variety of flowers
(some with petals united into a corolla and extended stamens, some open, some with
large lower petal, some with nectar spurs, etc.). Have students draw and label the
reproductive and nonreproductive parts of the flowers, and identify similarities and
differences among them.
- Use the colorful and fragrant petals as a chemistry connection in your biology
lesson. For example, the blues and purples and many reds come from anthocyanin pigments,
yellows to whites from anthoxanthin pigments. The “flowery” to fetid flower scents are
due mixtures of organic compounds.
- Ask your students to suggest some plants that have wind-pollinated and water-pollinated
flowers, and adaptations those flowers might have.
- Present students with representative images of angiosperms, gymnosperms, ferns, and
mosses that grow in your region. Have students design and complete a chart contrasting
patterns of species diversity (number of species) and reproduction (pollination system)
among those plant groups.
- Introduce students to the extraordinary diversity of the earliest animal pollinators –
beetles (~350,000 species worldwide, ~30,000 species in North America). Have students
research the link between angiosperm diversity and insect diversity.
Suggestions for using this fact sheet in conjunction with pollination ecology and
- Have students model the effectiveness of bird beaks (or insect proboscis) of
different lengths to reach a nectar reward from flowers varying in lengths of their
corollas (see, for example, Coevolution---A simulation and story http://biology.arizona.edu/sciconn/lessons2/Roxane/co_eval.htm). Building on
that experience, ask students to describe generalist and specialist pollination
- Once yucca moths reach adulthood, they do not eat and live only a few days. Have
students suggest benefits yucca moths might receive from pollinating yucca plants.
Use this discussion to present other pollination systems without an immediate food
reward; for example, some flies are lured into fetid-smelling flowers, such as the
skunk cabbage (Lysichiton americanus), where they lay their eggs but receive
no food reward. Many specialist pollination systems provide rewards related to successful
reproduction of the pollinator. Ask students to develop hypotheses to explain this
- Does the word pollen make your students think of allergies? Ask this question to
jumpstart a brainstorming session on differences between wind and animal pollination.
Then, have students suggest an experiment to determine that yucca (or any other
animal-pollinated plant) is not wind pollinated, and to identify its potential pollinators
over a 24-hour cycle.
- Focus on declining pollinator populations in a "science and society"
discussion. Farmers in America are particularly concerned about reduced numbers of the
honeybee, a European species introduced to pollinate 100s of food crops. Native pollinator
populations also are declining due to habitat destruction, pesticides, and introduced
species. Have students predict what would happen to the yucca moths if the yucca population
declined or died out, and visa versa. Then, have them predict what would happen in a
generalized pollination system.
The reproductive lives of many plants are intimately entwined with numerous animal
species. Consider using the following case studies of North American plant-animal mutualisms
(see sources below).
- Pinyon pine (Pinus edulis) and whitebark pine (Pinus albicaulis)
rely on pinyon jays (Gymnorhinus cyanocephalus) and Clark's nutcrackers
(Nucifraga columbiana) to disperse their wingless seeds.
- In the Organ Pipe Cactus National Monument, the organ pipe cactus (Stenocereus
thurberi) is pollinated primarily by the migrating lesser long-nosed bat
(Leptonycteris curasoae) but in Mexico hummingbirds and insects provide those
services. (This case study is particularly useful for introducing the fact that
pollinators may vary over space and time.)
Nonflying mammals pollinate plants many regions around the world: Central
and South America-primates, procyonids, marsupials, & rodents; Africa-primates,
rodents, & viverrids; Asia-primates, rodents, viverrids, & treeshrews; and
Plants and animals, mainly ants and mites in tropical regions, form positive
associations for protection against herbivory. In return, plants provide the ants or
mites a place to live and sometimes food.
Animals aren't the only players in positive interactions with plants (or plant-like
- Most vascular plants have mutualistic associations with fungus, which form special
structures on the plant roots called mycorrhizae
- The mutualistic association between fungi and green algae or cyanobacteria is so
close we recognize them as one dual organism, a lichen. Visit http://mgd.nacse.org/hyperSQL/lichenland/
or http://www.lichen.com/ to learn more.
Links to more pollination facts and fun
Yucca Pollination in Action - Otto Pellmyr’s lab website has a movie of yucca
pollination and more.
The Arizona-Sonora Desert Museum, Migratory Pollinators Program - The
Desert Museum has a broad plan to study and conserve migration corridors used by
North American birds, bats, and insects.
North American Pollinator Protection Campaign - Promoting stable
pollinator populations is the aim of the Coevolution Institute and the National
Fish & Wildlife Foundation’s collaboration.
Pollination - The Ecological Society of America and the Union of
Concerned Scientists provides fact sheets, case studies, and references in their
"Communicating Ecosystem Services Project."
Ecology and Evolution 12(3): 104-108.
Buchmann, S. L. and Nabhan, G. P. 1996. The Forgotten Pollinators. Island
Carthew, S. M. and Goldingay, R. L. 1997. Non-flying mammals as pollinators. Trends
Farrell, B. D. 1998. "Inordinate fondness" explained: Why are there so many
beetles? Science 281: 555-559.
Fleming, T. H. and Valiente-Banuet, A. (eds.) 2002. Columnar Cacti and Their
Mutualists: Evolution, ecology, and conservation. The University of Arizona
Herrera, C. M. and Pellmyr, O. (eds.) 2002. Plant-Animal Interactions: An
Evolutionary Approach. Oxford University Press.
Hess, W. J. and Robbins, R. L. 2003. Yucca. In: Flora of North America,
volume 26, pages 423-439, Oxford University Press.
Kearns, C. A., Inouye, D. W., and Waser, N. 1998. Endangered mutualisms: The
conservation of plant-pollinator interactions. Annual Review of Ecology and Systematics
Pellmyr, O. 2003. Yuccas, yucca moths, and coevolution: A review. Annals of Missouri
Botanical Garden 90: 35-55.
Raguso, R. A., Levin, R. A., Foose, S. E., Holmberg, M. W., and McDade, L. A. 2003.
Fragrance chemistry, nocturnal rhythms and pollination "syndromes" in
Nicotiana. Phytochemistry63: 265-284.
Vander Wall, S. B. 1990. Food Hoarding in Animals. University of Chicago