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Pollination biology is the scientific study of this critical ecological interaction between flowering plants and pollinators. It was invigorated in the 1960s and 1970s by interest in coevolution, mutualism, community ecology, and foraging theory. During this period, pollination biology began to move rapidly beyond its roots as a mostly descriptive science. Place-based research, illustrated by studies of Ipomopsis aggregata, Delphinium nelsonii, Ipomopsis tenuituba, native bumblebees, hummingbirds, hawkmoths, and other species at the Rocky Mountain Biological Laboratory, has made major contributions to this progress of pollination biology research.
Current pollination research at the RMBL is in large part the legacy of a small group of graduate students who arrived in the 1970s to conduct their doctoral research on flower-visiting animals and communities of flowering plants. As they characterized the floral food resources available to hummingbirds and pollinating insects, and as they observed patterns of bloom and visitation in the wildflower-rich meadows around RMBL, these people laid the foundation for continuing discoveries about ecological and evolutionary interactions between plants and pollinators, plants and herbivores, and among plants. What follows are seven “mini-stories” that illustrate pollination research at RMBL.
1. Pollinators as Careful Shoppers

The meadow and forest habitats near RMBL contain many species of plants, and subsets of those plants produce flowers at the same time. Thus pollinators at the RMBL (and this is generally true of pollinators) have many choices of flowers to visit – it’s as if they are shopping in a “floral supermarket”. What determines which flowers pollinators choose? Scientists at RMBL have shown that many pollinators such as bumble bees and hummingbirds are “careful shoppers” – they quickly learn what nectar or other rewards different plant species offer, and whether they can reach these rewards (often concealed inside the flowers), and they tend to choose the flowers that will yield the best rewards per unit of time or energy cost.
Can you explain why a behavior of “careful shopping” might evolve in pollinating animals?
Read more about the “shopping habits” of pollinators:
- Gori, D. F. 1989. Floral color change in Lupinus argenteus (Fabaceae): Why should plants advertise the location of unrewarding flowers to pollinators? Evolution 43:870-881.
- Pleasants, J. M., and N. M. Waser. 1985. Bumblebee foraging at a “hummingbird” flower: Reward economics and floral choice. American Midland Naturalist 114:283-291. pdf
- Hodges, C. M. 1981. Optimal foraging in bumblebees: Hunting by expectation. Animal Behaviour 29:1166-1171.
2. Pollination Interactions as a Web of Nature
Draw a “web” of interactions between a few plants and pollinators, as you imagine it. Is this the only possible way in which plants and pollinators might interact – or can you draw some alternatives?
Read more about pollination interactions:
- L. A. Burkle and R. Alarcon. 2011. The future of plant-pollinator diversity: Understanding interaction networks across time, space, and global change. American Journal of Botany 98:528-538. pdf
3. Climate Change, Flowering Phenology and Pollination
Could changes in flowering phenology caused by climate change decouple plant-pollinator relationships?
Read more about climate change and phenology:
- Aldridge, G, Inouye D. W, Forrest J.R., Barr, W.A. and Miller-Rushing A.J. 2011. Emergence of a mid-season period of low floral resources in a montane meadow ecosystem associated with climate change. Journal of Ecology 99:905-913.
- Thomson, J.D. 2010. Flowering phenology, fruiting success and progressive deterioration of pollination in an early-flowering geophyte. Phil Trans. R. Soc. B 365, 3187-3199. pdf
- Memmott, J., P. G. Craze, N. M. Waser, and M. V. Price. 2007. Global warming and the disruption of plant-pollinator interactions. Ecology Letters 10:710-717. pdf
- Price, M. V. and N. M. Waser. 1998. Effects of experimental warming on plant reproductive phenology in a subalpine meadow. Ecology 79:1261-1271. pdf
4. Floral Larceny
Can you explain floral larceny in terms of the ideas outlined above about pollinators as careful shoppers?
Read more about floral larceny:
- Irwin, R. E., A. K. Brody, and N. M. Waser. 2001. The impact of floral larceny on plant individuals, populations, and communities. Oecologia 129:161-168. pdf
- Irwin R.E. and Brody A.K. 1998. Nectar robbing in Ipomopsis aggregata: effects on pollinator behavior and plant fitness. Oecologica 116: 519-527.
- Inouye D.W. 1980a. The terminology of floral larceny. Ecology 61: 1251-1253.
5. The Paradox of Being Eaten
Is it “good” or “bad” for plants to be eaten? Can you imagine any circumstance in which it could be “good”? (Hint: see Vail, cited and discussed in Pulliam and Waser).
Read more about the paradox of being eaten:
- Pulliam, H. R., and N. M. Waser. 2010. Ecological invariance and the search for generality in ecology. In The Ecology of Place: Contributions of Place-Based Research to Ecological Understanding, eds. I. Billick and M. V. Price, University of Chicago Press, pp. 69-92. pdf
- Sharaf K. and Price M.V. 2004. Does pollination limit tolerance to browsing in Ipomopsis aggregata? Oecologia 138: 396-404. pdf
- Bergelson, J., Crawley M.J. 1992b. Herbivory and Ipomopsis aggregata: the disadvantages of being eaten. The American Naturalist 139: 870-882.
6. Interactions Between Plants Visited by the Same Pollinators

Because pollinating animals are careful shoppers, they may go to flowers with the best rewards, leaving other flowers without pollination. This is one way in which plants may compete for pollination. This possibility was recognized a century ago, but RMBL scientists provided the first solid evidence. They found experimentally that scarlet gilia and dwarf larkspur (Delphinium nelsonii) compete for hummingbird pollination – each species produces fewer seeds when it blooms in the company of the other species. Likewise, RMBL scientists were the first to demonstrate that plants can facilitate each others pollination in some cases – each species producing more seeds when blooming with others.
Facilitation can occur if pollinators are attracted to dense flower patches – why might they be attracted this way?
Read more about how plants compete for the attention of pollinators:
- Caruso, C. M., and M. Alfaro. 2000. Interspecific pollen transfer as a mechanism of competition: Effect of Castilleja linariaefolia pollen on seed set of Ipomopsis aggregata. Canadian Journal of Botany 78:600-606.
- Mitchell, R. J., R. J. Flanagan, B. J. Brown, N. M. Waser, and J. D. Karron. 2009. New frontiers in competition for pollination. Annals of Botany 103:1403-1413. pdf
- Thompson, J.D. 1981. Spatial and temporal components of resource assessment by flower-feeding insects. The Journal of Animal Ecology 50: 49-59. pdf
- Waser, N.M. 1978. Competition for hummingbird pollination and sequential flowering in two Colorado wildflowers. Ecology 59: 934-944.
7. Hybridization and Speciation
How might research on a system such as Ipomopsis shed light on concerns about “escape” of engineered genes from genetically modified crop plants?
Read more about hybrids and speciation:
- Campbell, D. R., N. M. Waser, G. Aldridge, and C. A. Wu. 2008. Lifetime fitness in two generations of Ipomopsis hybrids. Evolution 62: 2616-2627. pdf
- Aldridge, G., Campbell, D.R. 2007. Variation in pollinator preference between two Ipomopsis contact sites that differ in hybridization rate. Evolution 61: 99-110.
- Campbell, D.R. 2004. Natural selection in Ipomopsis hybrid zones: implications for ecological speciation. New Phytologist 161: 83-90.
Next step – learn about the Ipomopsis Research Group at RMBL.
Additional References
Billick, I and M.V. Price, Eds. 2010. The Ecology of Place: Contributions of Place-based Research to Ecological Understanding. Chicago: University of Chicago Press.