Why are flowers so pretty? It is of little benefit to a wild plant to be admired. Why have plants put so much energy into the structure
of flowers and production of nectar and other rewards? Of course, the flower’s purpose is to result in sexual reproduction.
Berenbaum (1995) states that “Sexual reproduction is just as important for plants as it is for animals when it comes to generating
genetic variation, but plants have a singular disadvantage compared to animals when it comes to sex: they can't just get up and find
themselves a mate. " Plants must rely on pollen vectors, from wind to insects to birds, to transport their pollen to another individual.
Those visitors must be attracted to the same species repeatedly to bring about pollination. Visitors must cause pollen transfer for flowers
to be successful. Usually this means that the visitor must be attracted, collect pollen accidentally by brushing floral parts, or purposefully
collect pollen to take back to a nest, and then visit another flower of the same species and brush up against the stigma, effecting
pollination. Flowers can attract pollinators by providing ample nectar of the right composition, and by advertising this nectar by deep
shape and recognizable floral patterns, by providing excess pollen as food, or by providing shelter or a place to raise (and feed) young -
or by at least looking as if they do (Faegri and van der Pijl 1971). We human observers have tastes that are somewhat similar to those
of the birds and bees when it comes to floral attractiveness (although we vary from carrion beetles and flies, as we do NOT consider the
smell of rotting meat attractive). Our perception of color differs from that of non-vertebrate pollinators. Bees don’t see colors at the red
end of what we consider the visible light spectrum, but they do see colors of ultraviolet. Many flowers have ultraviolet markings that act
as nectar guides that cue insects on where to find floral rewards (Barth 1991, Buchmann and Nabhan 1996, Proctor et al 1996).
In some cases, there are many species of plants, or many flowers of the same species, open at the same time, resulting in a shortage of
possible pollinators and competition among the plants for visits (Mosquin 1971, Waser 1983, Caruso 2000). This may result in differences in
flowering time to reduce competition for pollinators (Frankie 1975, Anderson and Schelfhout 1980) or in changes in floral structure (Waser
1983, Fishman and Wyatt 1999, Medel et al 2003). In other cases, pollinators must compete with each other, as the floral rewards are in
short supply (Pleasants 1981, Pyke 1982, Thomson 2004).
Natural selection has favored those flowering plants that are most attractive to pollinators, and those pollinators best able to get floral
rewards. Millions of years of coevolution between flowering plants and their pollinators, with each participating species population acting
as a selective agent on the other, have resulted in overwhelming biodiversity of both insects and flowering plants (Stebbins 1983). “The
shapes and colors of the flowers, their scent, their location on the stalks, the season and daily schedule of their pollen and nectar offerings,
as well as other qualities we admire but seldom understand, are adjusted precisely to attract particular species of insects; and those
specialists in turn, whether beetles, butterflies, bees, or some other group, are genetically adapted to respond to certain kinds of flowers”
(Wilson 1999). The mutualistic relationships that develop between a flowering plant , which benefits by cross-fertilization and its most
effective pollinator, which benefits from an enhanced food source, are also influenced by other species populations. There may be herbivores
and nectar thieves that visit flowers to acquire rewards, but do not disperse pollen (Irwin and Brody 1999, Maloof and Inouye 2000). We
see the results of reciprocal selective pressures, with adaptations of the flower to restrict nectar acquisition to a visitor with the ability to
move its pollen effectively, and adaptations of the insect to acquire nectar in long, curved tubes. Other organisms that interact with both
flower and pollinator may complicate the system, resulting in apparent or real maladaptations (Thompson et al 2002).
The most frequent visitor to a flowering plant is not necessarily the one that is the most effective pollinator. Natural selection will result in
the flower adapting to the pollinator that is most likely to bring about effective pollen transfer for fertilization. Floral color, shape, placement,
timing, and reward will be selected, with the most attractive flower getting the most effective visits, producing more viable seed, and leaving
more offspring in future gene pools. The most likely pollinator can often be deduced from floral characteristics, with flowers that attract the
same type of pollinator converging in morphology into what we call pollination syndromes (Table 1, Key 2) but it usually takes careful
observation to sort out specific pollination relationships. Most flowers attract several different kinds of pollinators, with several different
attractants which may not be consistent with the “syndrome”.
Materials and Methods:
Outdoors, anywhere there are plants in flower - ranging from spring beauties in the lawn, to flower beds on campus, to insect
pollinated trees like crabapple or buckeye.
Overview of Data Collection and Analysis Methods.
Example Assignment - Natural History Observations.
The class might be divided into three groups, one to estimate visitation rates, one to determine the phenology (seasonal and/or
daily timing of flowering) of the flowering species (Ohio buckeye in this case), and one to collect visitors and determine how
much and what kind of pollen is carried. Alternatively, any one part could be used. Once you have these kinds of data about
the most likely flowering plants and visitors for the time of your class, you may want to provide students with these data and go
straight to the student-generated questions. Many of the techniques are described in Kearns and Inouye (1993).
Group 1 - Visitation Rates
- stopwatches or watches with second hand,
- marking tape or flags,
- “eyeball ID”,
- hand lenses,
- data sheets,
- tape recorder or partner to record visits so observer’s eyes can remain on flowers.
- Each person in the group should find a branch (buckeye) or a plot (spring beauties) with receptive flowers (pollen is being shed, and/or
stigmatic surface is visible and sticky). Mark the branch or plot with marking tape (buckeye) or flags (spring beauties).
- Carefully examine the flowers. Use the key to pollination syndromes (sets of traits of flowers thought to attract and/or accommodate
pollen vectors, and sets of traits of animals that allow them to exploit flowers with those traits) to predict visitors by floral morphology.
- Count the number of individual OPEN flowers on the branch to be observed, or in the marked plot. Count only the flowers you will
observe - and record visits on only the flowers selected or in the plot.
- Observe the marked branch or plot for three observation periods of exactly 10 minutes, counting the number of visits by each category
of visitor (categories include honeybees, bumblebees, small bees, flies, butterflies, beetles, and birds).
- Note the ambient air temperature in oC.
- Return to the same branch or plot and make three ten-minute observations at additional assigned time (later in the day, or earlier on
another day - assigned times will cover two hour blocks - 0800 to 1000, 1000 to 1200, 1200 to 1400, 1400 to 1600, and 1600 to 1800 hr),
- Note the temperature in oC
- Calculate the average number of visits per category of visitor per flower per observation period.,
- Is the most frequent visitor the one you expected from the pollination syndrome key? If not, why might there be a difference in what
the flower appears to attract and what actually visits most frequently?
- What were each of the visitors doing at the flower? Does that activity promote pollen transfer?
- Turn in your observations to your instructor so that they may be compiled. Pick up the compiled observations from all groups,
- Estimate the number of visits that can be expected per flower at each observation time.
Report Form: Visitation Rates - Group 1, In-class Observation
Time of Day ______________ Temperature ___________ (oC)
Number of flowers observed_____________ Number of minutes observed _______________
|Category||observation #1||observation #2
Report Form: Visitation Rates - Group 1, Additional Assigned Observation
Time of Day ______________ Temperature ___________ (oC)
Number of flowers observed_____________ Number of minutes observed _______________
|Category||observation #1||observation #2
|Key 1 - Major Insect Visitors to Flowers (based on Central Illinois)|
||Wings not visible, or hard wing covers concealing wings....
||No wings, narrow area between thorax and abdomen....
||Hard wing covers conceal flight wings, form line down middle of back, chewing mouthparts....
||One set of filamentous wings, eyes large and obvious (careful - some Syrphid flies mimic bees)....
||Two sets of wings....
||Both sets of wings often colorful, covered with scales....
||Antennae with knob-like ends, wings usually folded when at rest....
||Antennae with feathered ends, no knob, wings often open at rest....
||Wings membranous, usually clear....
||Thorax and abdomen joined by narrow “waist,” abdomen often pointed....
||“Waist” not as marked, body usually hairy....
||Pollen carried on “belly”....
||Pollen carried mainly on leg....
||Usually small (~5-10mm), black or metallic green, short tongued....
||Long tongue, usually over 12 mm....
||Spur on hind leg, abdomen often appears striped....
||No spur, body robust, usually over 20mm, yellow and black, eyes not hairy....
||No spur, golden brown color, 12-15mm, hairy eyeballs(!)....
|Key 2 - Dichotomous key to pollination syndromes|
||Flowers small, inconspicuous and usually green or dull in color, petals reduced or absent....
||Flowers conspicuous, usually with white or colored petals....
||Flowers regular in shape, radially symmetrical....
||Flowers purple-brown or greenish in color, often with strong odor of rotting fruit or meat, little floral depth....
||Flowers purple-brown, sometimes with a “light window”....
||Odor day or night, dull color....
||Flowers with little odor, or sweet odor....
||Flowers with deep corolla tube....
||Flowers red, open in day, little or no odor, no nectar guide, nectar plentiful....
||Flowers not pure red, usually sweet odor....
||Flowers yellow, blue, or purple, corolla tube not narrow, but sometimes needing
forced opening, often with nectar guides....
||Long tongued bees|
||Flowers red, purple or white, corolla tube or spur narrow, usually lack nectar guide....
||Flowers purple or pink, diurnal, upright, with landing area....
||Flowers white or pale, pendant, open or producing odor at night....
||Flowers more dish-shaped, reward accessible, yellow, or with abundant pollen....
||Flowers irregular in shape, bilaterally symmetrical....
||Flowers red, little or no odor....
||Flowers with odor, usually with nectar guides....
|Table 1. Pollination Syndromes: Characteristics of flowers and the animal vectors that shape them.|
||Characteristics of Flower
||Characteristics of Vector|
||* Inconspicuous, green or dull in color, petals reduced or absent, abundant and in canopy
||* Dull colors, dark red, strong, spicy odor, or odor of rotting flesh, flat shape
* May have light window (flies)
|* Good sense of smell|
* Some lay eggs in rotting flesh
||* Often blue or yellow, with landing platform
* Often have markings that act as nectar guides, sometimes in UV spectrum
* Reduced numbers of floral parts
* Often irregular in shape
* May have deep tube or spur for nectar
|* Good sense of vision, smell|
* Often have body hairs
* Can perceive depth, “count” petals
* Do not see true red - see UV
||* Open at dusk or night, emit sweet odor at night
* Often dull or white
* Long corolla, no landing platform
|* Most active at night|
* Strong sense of smell
* Have long proboscis for nectar acquisition
||* Open in day, emit some odor in day
* Landing platform
* Long corolla tube, narrow
* May be blue, purple, red, yellow
* May have nectar guide
|* Active in day|
* Have long, thin proboscis for nectar acquisition
* Can see red
* Alight on blossoms
||* Red, large flowers with deep nectar tube and abundant nectar
* Little or no fragrance
* Open in day
* No landing platform
* No nectar guide
|* Vision much like human - see red|
* Long bill and tongue, large body
* Little sense of smell
* Intelligent - remember and return to flowers with abundant reward
* Active in day
* Approach flower and hover
Group 2 - Phenology
- colored bell wire, embroidery floss,
- flags to mark plot,
- hand lenses,
- aluminum tags, or colored plastic toothpicks,
- permanent marker,
- field guide to flowering plants.
- Carefully examine flowers. Determine if some are shedding pollen, with stigmatic surfaces not receptive (functionally male),
or if pollen is all shed, but stigmatic surfaces are open and sticky (functionally female), or if both stamens and pistils are functional,
or if both are finished. Note presence of a scent or nectar. Note color patterns, and presence of nectar guides.
- Mark at least 15 individual flowers with numbered small tags, with colored floss, or with colored toothpicks. Note the phase or
phenological state of each. The group should decide on criteria to describe each phase (see examples for spring beauty
and partridge pea).
- If population size estimates are required, randomly select at least 10 one-meter squared plots and count number of individual plants
of the target species that are in flower.
- Return to collect data on phenological phase of marked flowers and population in flower at four additional assigned times or days.
Observations of class members should continue for at least 5 days, or at 4 times of day on one day if the flowers are short-lived.
- Turn in observations to your instructor so that they may be compiled. Make sure to pick up compiled data.
- Determine the sequence of each phase of floral function, the average longevity of each phase, and how long the flower
is open for visitation.
Phase Key must be designed or modified depending upon what species of flowering plant is the target.
For Spring Beauty: Key to Phases: (from closed bud to flower finished)
A - Flower enclosed in bud,
B - Flower open, streaked pink, stamens very pink and erect,
C - At least 2 stamens appear less pink, pistil obvious,
D - Stamens folded back against petals, style clearly splits into 3 stigmas,
E - Ovary swollen, petals wilting.
|Date and Time of Observations:|
|Phase at Each Observation|
Group 3 - Visitors
Equipment Needed to Collect Insects:
- aerial nets,
- kill jars with ethyl acetate, OR freezer,
- insect pins and boxes,
- “Eyeball ID” for insects,
- field guide to insects.
Equipment Needed to Collect Pollen:
- basic fuchsin gelatin (recipe below),
- dissecting needle,
- microscope slides, coverslips,
- candle and matches, lighter, or black paper and warm sunshine,
- marking pen,
- microscope with 100x.
- Individuals with allergic reactions to bee stings should not participate in this portion.
- Keep the basic fuchsin gelatin out of the sun, in a small ice chest. If phenol was added, do not touch the gel.
- In an area away from where the visitation observations are underway, collect as many visitors to flowers as you can with an insect net.
- Use ethyl acetate to kill or stun insects.
- Use a dissecting needle to cut a 0.5 x 0.5 cm cube of glycerin fuchsin jelly. Holding the cube of jelly on the dissecting needle,
wipe pollen from the body of the visitor. Make separate slides for jelly wiped on mouthparts, abdomen, and legs of the insect
(or other body parts as observed). Carefully remove all visible pollen from the body section. If the specimen is a bee with a
pollen load, crush the load so that pollen grains are identifiable.
- Place the cube on a glass slide, put on a coverslip, and gently melt over a candle or lighter, or place on dark surface in the sun.
- Label the slide with a Sharpee - date, time, type of visitor, body part.
- Make a reference slide from the flowering species for comparison. Wipe a cube of the jelly on an anther that is shedding pollen. Label it
with date, time, species, and phase of flower.
- Examine your slides under a microscope at 100X. Count the number of pollen grains of the target species (buckeye or spring beauty) AND
the number of non-target species pollen grains. Identify non-target species if possible. Start at one corner of the coverslip
and systematically move the slide back and forth so that the field of view covers the slide the same way that an eraser
would erase a blackboard.
- If pollen grains are too numerous for a complete count, sample the slide by counting 10 fields of view. Estimate how many fields of
view there are (this will differ depending on the magnification you are using). Then, multiply the average number
of pollen grains of both target and non-target species counted in your 10 fields by the number of fields to estimate
the number of pollen grains on the slide.
- Calculate the proportion of target species pollen in the pollen load or jelly wipe that is from each part of the body. If non-target pollen
is identified, calculate the proportion of each species pollen on the slide.
|Group 3, Visitor - Target Flower Species:|
Legs - Target
Legs - Nontarget
Body - Target
Body - Nontarget
Mouth - Target
Additional Instructions for All 3 Groups:
Turn in the report form from your section of the investigation. Pick up the compiled data from all groups and answer the following questions.
After examining the data, develop five questions the data raise and testable hypotheses for each of those questions.
In addition, you may be asked to choose one of those hypotheses to to design and carry out an experiment to test.
If so, use the Format for Written Research Report below to write your lab report.
Format for Research Report - should include the following sections:
- One sentence summary of the paper - should be concise and informative. Include the appropriate taxonomic information about the organism.
- State the purpose of the study and enough background material to demonstrate the significance of the study.
- This is where your hypothesis and predictions go.
- You should also refer to relevant published articles that pertain to your study (what have other researchers learned in investigating
similar topics or processes?). Start with general background and work to your specific project.
- Citation of sources should take place within the body of the paper, right after the information cited from that source. In science,
it is important to know WHO said it and WHEN it was said, so put the author and year in parentheses (Parrish 2004). At least
three non-textbook, published and peer-reviewed sources are required for the report.
* METHODS AND MATERIALS
- Summary of setting of study (date, time in military format - 1400, not 2:00 p.m., cloud cover, temperature, environment of room, etc.),
equipment and materials used, information about the organism(s) studied, experimental design and procedures used, and statistical methods.
- This section should allow other researchers to repeat your experiment.
- All data and statistics. Do not include raw, unsummarized data in this section. Raw data should be placed in an appendix. Data
should be summarized and analyzed (means, standard deviation, etc.) and presented as visually as possible. Well constructed
graphs are clearer than tables for most data.
- Graphs and drawings are figures, and are numbered consecutively.
- Tables are also numbered consecutively (separately from figures).
- Refer to the figures and tables within a narrative, describing the trends. In other words, walk the reader through your results. The
opening paragraph should state the overall trends found in the data - but do not say SIGNIFICANT difference unless you did the
statistics to test for significance. The following paragraphs should give the specific findings that support the overall trend. Do not
say “See tables for results” or “Figure one shows that...” or (See Figure 1). Say “There were more herbivores than primary producers (Fig. 1).”
- The tables and figures should have headings which are clear and complete enough that they can stand alone and the reader can
extract the meaning without reading the text.
- Any explanation, interpretation, or BECAUSE statements should not appear in the results, but in the discussion.
- This is the meat of the report. You should interpret your results, place them in context, and provide supporting references.
- Compare your results to your hypothesis. Avoid statements not supported by your data.
- You should also write about possible errors in the design and implementation of the study. Alternative explanations for the results
should also be considered here, as well as alternate hypotheses.
- Compare your results to those of other scientists, and cite their work. Start with the specific (your work) and then go to the general, big picture.
- The final paragraph should be your conclusions from the study. What are the main points you want the reader to understand?
Your conclusions should be forceful and memorable.
* LITERATURE CITED
- Every article cited in the body of the paper - and none that are not cited - should appear in this section.
- Citations are by alphabetical order of the last name of the first author listed in each paper, then by date if you cite more than one
article by the same author.
- Different journals use different formats for the literature citations, as are shown in McMillan. To be consistent, we will use journals
such as Ecology for format direction,
Juenger, T., and J. Bergelson. 1997. Pollen and resource limitation of compensation to
herbivory in scarlet gilia, Ipomopsis aggregata. Ecology 78: 1684-1695.
You should have at least three references. Textbooks and encyclopedias DO NOT COUNT!!!! (but do cite them if you use them). Web articles
may count ONLY if they have an author - and ONLY ONE of your three required sources may be from the web. Use current journal
articles as much as possible. The quality of your introduction and discussion depends upon good use of literature.
IN ADDITION: PROOFREAD AND USE SPELL CHECK!!!!!
- Points will be deducted for errors in grammar, spelling, punctuation, and format.
Preparation of Basic Fuchsin Gelatin and Pollen Slides.
A jelly containing stain to make a semi-permanent microscope slide of pollen, as suggested by Beattie, A. J. 1971. Pan-Pacific Entomologist 47: 82.
Use the following ingredients:
* distilled water, 175 ml,
* glycerin, 150 ml,
* gelatin, 50 g,
* crystalline basic fuchsin as desired - enough to make solution the “color of a fine claret,”
* crystalline phenol, 5 g - important in humid environments, may be left out if gelatin can be refrigerated. Don’t touch gelatin if phenol is used.
Procedure to Make the Fuchsin Gelatin:
- add the gelatin to the distilled water in a beaker and heat until the gelatin dissolves,
- add the glycerin,
- add phenol, if desired,
- add basic fuchsin crystals a few at a time until the solution is the color desired. Too light will not stain the pollen, but too
dark may mask details of the pollen,
- filter the solution through glass wool or cheesecloth,
- pour into sterile containers such as petri plates that can be covered. If phenol is not used, refrigerate the plates and slides.
They will keep about a month without refrigeration.
Preparation of Pollen Slides
- keep the prepared slides, and the unused jelly, out of the sun, and cool enough not to melt,
- with a dissecting needle, cut a small cube of the jelly out of the petri plate,
- brush the cube of jelly against an anther containing pollen, or on the insect body part,
- place the cube containing the pollen sample on a glass slide,
- place a coverslip on top of the cube of jelly,
- gently heat the slide over a candle flame until the jelly melts. Do not overheat, or scorch the slide. If it is warm and sunny,
the jelly may be melted by placing the slide on a dark surface in the sun instead of using the candle flame. This will make a
semi-permanent, stained specimen,
- using a permanent marker, label the glass slide (date, species sample was collected on).
Questions for Further Thought and Discussion:
- Describe the phenology of the target species. Are there color changes in floral display? If so, can you think of any advantage to the flower
for the change? To the pollinator?
- Draw a graph to display the average visitation rate by all categories of visitors over daily time. Are flowers more likely to be visited at
certain times of day?
- Draw another graph to display the average visitation rate by all categories of visitor at different temperatures. How does this graph compare
to the time of day graph?
- Calculate the probability of visit to each flower by any possible pollinator. You will need data from the phenology group to know how long the
flowers are open for visitation, as well as average visitation rates, or rates for specific time periods.
- Which visitors carry the most pollen? Is that pollen likely to be transferred to another flower of the same species? If more than one species of
pollen is present, is it in the same place on the visitor’s body?
- Which visitors are likely to be the most effective pollinators? Why? Which visitors are probably not pollinators?
- What attributes of the plant population (e.g. density, patch size, identity of neighbors) might raise or lower the predicted visitation rate?
*** Note: Answers to many of these questions and numerous other comments by the contributing author can be found in the
"NOTES TO FACULTY" page.
References and Links:
Anderson, R. C, and S. Schelfhout. 1980. Phenological patterns among tallgrass prairie plants and their implications for pollinator competition.
American Midland Naturalist 104: 253-263.
Barth, F. G. 1991. Insects and Flowers: The Biology of a Partnership. Princeton University Press, New Jersey. 408 pp.
Berenbaum, M. 1995. Bugs in the system: Insects and their impact on human affairs. Helix Books, Addison Wesley Publishing Company.
Bronstein, J. L., P. H. Gouyon, C. Gliddon, G. Kjellberg, and G. Michaloud. 1990. The ecological consequences of flowering asynchrony in
monoecious figs: a simulation study. Ecology 71: 2145-2156.
Buchmann, S. L., and G. P. Nabhan. 1996. The Forgotten Pollinators. Island Press, Washington, D.C. 292 pp.
Caruso, C. M. 2000. Competition for pollination influences selection on floral traits of Ipomopsis aggregata. Evolution 54: 1546-1557
Faegri, K., and L. Van der Pijl. 1971. The Principles of Pollination Biology. Pergamon Press, New York. 281 pp.
Fenster, C. B., W. S. Armbruster, P. Wilson, M. R. Dudash, J. D. Thomson. 2004. Pollination Syndromes and Floral Specialization
Annual Review of Ecology, Evolution, and Systematics 35 (in press, expected 12/04)
Feinsinger, P., L. Margutti, and R. D. Oviedo. 1997. School yards and nature trails: ecology education outside the university. TREE 12: 115-120.
Fishman, L., and R. Wyatt. 1999. Pollinator-mediated competition, reproductive character displacement, and the evolution of selfing in
Arenaria uniflora (Caryophyllaceae). Evolution 53: 1723-33.
Frankie, G. W. 1975. Tropical forest phenology and pollinator plant coevolution. Pages 192-209 in L. E. Gilbert and P. H. Raven, eds,
Coevolution of Animals and Plants. University of Texas Press, Austin, Texas, U.S.A.
Irwin, R. E., and A. K. Brody. 1999. Nectar-robbing bumblebees reduce the fitness of Ipomopsis aggregata (Polemoniaceae).
Kearns, C. A., and D. W. Inouye. 1993. Techniques for Pollination Biologists. University Press of Colorado, Niwat, CO. 571 pp.
Maloof, J. E., and D. W. Inouye. 2000. Are nectar robbers cheaters or mutualists? Ecology 81: 2651-2661.
McMillan, V. E. 2001. Writing papers in the biological sciences. Bedford/St. Martin’s Press, Boston, MA.
Medel, R., C. Botto-Mahan, and M. Kalin-Arroyo. 2003. Pollinator-mediated selection on the nectar guide phenotype in the Andean monkey
flower, Mimulus luteus. Ecology 84: 1721-1732.
Mustajarvi, K., P. Siikamaki, and S. Rytkonen. 2001. Consequences of plant population size and density for plant-pollinator interactions and
plant performance. Journal of Ecology 89: 80-87.
Pleasants, J. M. 1981. Bumblebee response to variation in nectar availability. Ecology 62: 1648-1661.
Proctor, M., P. Yeo, and A. Lack. 1996. The Pollination of Flowers. Timber Press, Portland, OR. 479 pp.
Pyke, G. H. 1982. Local geographic distributions of bumblebees near Crested Butte, Colorado: competition and community structure.
Ecology 63: 555-573.
Stanton, M. L. 1994. Male-male competition during pollination in plant populations. American Naturalist 144: S40-S68.
Stebbins, G. L. 1983. Why are there so many species of flowering plants? BioScience 31: 573-577.
Thompson, J. N., S. L. Nuismer, and R. Gomulkiewicz. 2002. Coevolution and maladaptation. Integrative and Comparative Biology 42: 381-387.
Thomson, D. 2004. Competitive interactions between the invasive European honey bee and native bumble bees. Ecology 85: 458-470.
Waser. N. M. 1979. Effective mutualism between mutually sequentially flowering plant species. Nature 281: 670-672.
Waser, N. M. 1983. Competition for pollination and floral character differences among sympatric plant species: a review of evidence.
Pages 277-293 in C. E. Jones and R. J. Little (eds.) Handbook of Experimental Pollination Biology. Van Nostrand Reinhold, New York.
Waser, N. M., L. Chittka, M. V. Price, N. M.Williams, and J. Ollerton. 1996. Generalization in pollination systems, and why it matters.
Ecology 77: 1043-1060.
Willson, M. F. 1983. Plant Reproductive Ecology. New York: John Wiley and Sons.
Wilson, E. O. 1999. Diversity of Life. W.W. Norton and Company, New York. 424 pp.
Pictures and descriptions of flowers adapted for various types of pollination (wind, beetles, flies, bees, birds)
see also bioimages.cas.vanderbilt.edu/
Dichotomous key to most likely pollinator
Images of 96 flowers and descriptions of their pollination
Descriptions of pollination syndromes, and images
Test of the predictability of pollination syndromes
Source references to Pollination biology: means of attraction, coevolution, and diversification
Descriptions and comparisons of Proteaceae that are pollinated by different vectors - wind, birds, rodents, and insects
Introduction to pollination biology, pollination syndromes. Laboratory instructions for three session investigation and presentations.
Tools for Assessment of Student Learning Outcomes:
Guidelines for Assessment:
Each student's grade will be based on 15% from the answers to pre-lab questions, 15% for group data collected, 10% for answers to
questions for further thought, and 10% for questions and testable hypotheses generated. The other 50% will be from the
individual research-style papers submitted (Ten points for each section - Introduction, Methods and Materials, Results, Discussion,
and Literature Cited). A practical exam will test knowledge of flower parts and species of flowering plants and insect visitors.
|Formal Report Scoring Sheet:|
|Methods - repeatable, clear
| Tables and/or figures properly drawn & labeled
DATA PRESENTED ONCE
Pertinent results presented
| Narrative - describes trends
| No explanation (only in discussion)
| Results compared to hypothesis
| Explanations, alternative explanations
| Literature used correctly
| Demonstrated understanding of coevolution
| Strong conclusion
| At least 3 primary sources
| Proper format
Tools for Formative Evaluation of this Experiment:
An extensive discussion on Evaluation appears in the Teaching section of this site.