The Outline of an Experiment Aiming to Identify the Relationships between Certain Plants in the Groton Area and their Pollinators
Anna Steim
Alexander Littauer
Advanced Eology
5/28/05
Purpose: To attempt to identify the patterns of pollination in wildflowers in the Groton area. In essence, we hoped to pinpoint strategies employed by certain species of plants to attract specific pollinators.
Plant Information:
Bluet / Dandelion / Mint / Crab Apple / Lyre-Leaved Sage / Garlic MustardPlot / Gym / Gym,
Dining Hall / Gym / Oates / Dining Hall / Dining Hall
Color / White fading to purple / Yellow / Purple / White / Purple / White
Height (in.) / 2-8 / 2-18 / 2-8 / Tree / 12-24 / 1-3
Diameter of Flower (in.) / .5 / 1.5 / .5 / 1 / 1 / .5
# Petals / 4 / 100-200 ray flowers / 5 / 5 / 2 / 4
# Flowers/
Stem / 1 / 1 / Multiple / Multiple / 3-10 / Multiple
Abundance of Plant in plot / Only one / Few / Abundant / Abundant / Abundant / Few
Strength of Odor / None / Mild / Mild / Strong / Medium / Medium
Sex Organs / 4 Stamen, 2 Stigma / Unknown / 4 Stamen,
1 Stigma / Unknown / 2 Stamen, 1 Stigma / 6 Stamen, 1 Stigma
Pollinator Information:
Bumblebee / Gym / Mint / 5 / 5/20/05
Gym / Mint / 5 / 5/22/05
Honeybee / Oates / Crab Apple / 12 / 5/20/05
Methods:
· Three plots of 1 meter square in different areas of the campus
o Gym—the hill behind the hockey rink
o Oates—the small circle of Crab Apple trees around the water fountain just above the Oates Field Hockey Field
o Dining Hall—in that small garden of flowers next to the parking lot at the back of the dining hall and chapel, close to Farmer’s Row
· Identify plants and pollinators through observation and collection
· Observe plots at different periods of the day, record any activity between plant and pollinator, movement, and frequency of visits, and notice developing patterns in pollinator preference between species.
Data Recorded:
· May 20
o Observation
o Captured 3 Honeybees
· May 21 (Rain)
o No movement/activity
· May 22
o Observation
As is exhibited by May 21, the bad weather caused no movement in pollinators the remainder of the study period.
Originally, the purpose of this lab was to identify the species each plant used to pollinate them. The weather, unfortunately, hindered our data collection. We had hoped to be able to use the information we collected through observation of the pollinators present in an attempt to understand the relationship between a plant and its pollinators, especially those relationships where there is a specific, preferred pollinator for each plant. This dynamic is much like the idea of a beaver OFS: each plant, like the beaver, has a specific, preferred goal in mind. In this case, some certain plants cater to the needs of certain pollinators in order to woo them. They will utilize other pollinators if necessary, but this one is optimal, much the way a certain tree species of a certain size at a certain distance is best for beavers, though not absolutely necessary. We had hoped to be able to look at the data and tell what it was about each plant that attracted each pollinator, and to discuss the success each of these plants met with.
There are certain strategies each plant employs in order to attract certain pollinators, manifested in visual and olfactory cues: color, size, shape, and odor. The two pollinators we encountered on the two days we collected data were the Bumblebee and the Honeybee. Bees’ vision is centered on the blue end of our visible spectrum, so they do not see reds, thus focusing on blue or violet, as well as white and yellow plants. However, their vision allows them to see some UV light. Many plants use UV patterns and signals on their petals, so in certain cases, bees will land on what we see as reddish plants, but in fact exhibit these UV patterns. The actual physical size of a plant matters very little in fact, for the ultimate goal, the pollen, is relatively uniformly sized. The reason a large flower will attract a greater number of pollinators is not for its breadth, but for its color display: the larger the flower, the larger the amount of petal to cover in flamboyant color in an effort to draw in pollinators. Shape is the single largest factor used by plants to discriminate against certain pollinators. A flower must be of a shape to accommodate the desired pollinators, but also that it not lose nectar and thus pollen to undesired ones. For example, flowers that are pollinated by hummingbirds face down because these animals do not need a place to perch as they take the nectar the way bees do. So, this is an effective strategy to keep hummingbirds, its optimal pollinator, in and bees out. For some pollinators, the fragrance of the flower guides them to it. Flowers produce this odor in a gradient, that the smell grows stronger as the pollinator comes closer. Certain species are especially attracted to certain odors: for example, fly-pollinated plants give of the smell of manure because flies, their preferred pollinators, respond to this smell more than any other species.
Studies have proven that bumblebees and honeybees have their own preferences concerning the flower’s presentation. A British study from 1970 proved that honeybees are determinedly more attracted to star shaped or lobed form flowers than circle shaped flowers. Both the honeybee and the bumblebee are most attracted to flowers with blue, purple, white and yellow colors, and sometimes what appear to be white flowers are attractive not because they are white but in reality UV (the flower looks white to the human eye because we can’t see UV). Bees, because of their size and weight, are most attracted to flowers that have perches or something to cling to while collecting the pollen and nectar. The little data that we collected, generally, reflects these preferences. The bumblebees were most attracted to the purple colored mint flowers. These flowers also offered, after the crab apple flower, the most support for the bee (perch and size of stem). The honeybees were most attracted to crab apple flowers. These flowers have a lobed form and are white—thus our data reflects and confirms that of established studies. Also, the fact that each plant had a specific pollinator tentatively shows that the plants observed were adapted that they might utilize their preferred pollinator. If there had been more time for data collection and observation, we might have been able to compare traits in plants that share pollinators and thus get a better grasp on which characteristics are particularly attractive to certain pollinators and which plants are particularly successful in their pursuit of the optimal pollinator.
The reason our Independent Project was such a failure was the weather. Pollinating insects, like bees, are not active in bad weather. In fact, even if the flowers are wet from a rain that occurred hours before most pollinators are still not present. There were only two days in which it did not rain and we were able to collect constructive data. Thus drawing any sort of formative conclusion was impossible—and there is not a strong argument to disprove the null hypothesis of no relationship between the variables studied. There really was no inherent flaw in the lab design, research question, or groups studied, rather the conditions were limiting. If we had had better weather the outcome of project would have been much more successful. Advice we would give to future students attempting to do this study project would be to set up the plots earlier in the season in order to both obtain data pertaining to a diverse assortment of plant species and also to utilize the number of good, sunny days for observation.
Literature Cited
Fulcher, Bob. The Meaning of Flowers. www.state.tn.us/environment/tn_consv/archive/flowers.htm
Kilmas, John E. and James A. Cunningham. 1981. Wildflowers of Eastern America. Galahad Books. New York.
http://koning.ecsu.ctstateu.edu/Plant_Biology/pollination.html
Marinelli, Janet. 2000. Bumblebees—The essential, Indefatigable Pollinators. www.bbg.org/gar2/topics/wildlife/2000su_bumblebees.html
Moore, Professor David M., ed.. 1988.The Marshall Cavendish Illustrated Encyclopedia of Plants and Earth Sciences. Marshall Cavendish. New York.
Zomlefer, Wendy B. 1994. Guide to Flowering Plant Families. The University of North Carolina Press. Chapel Hill.
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