Data Set #1. Student Data - Visitation Rates collected 31 August 2000

These data were collected within one two-hour period, and were used to stimulate questions that students followed up on in the next lab. Students can compare visitation rates of flowers of different sizes, colors, longevities, and shapes.



Student Data - Visitation Rates collected 31 August 2000
Species	# Flowers observed	Number of observation periods (10 min)	# Visits per Flower per Minute	Main visitor	Estimated floral lifespan	Floral color
Bellflower (Sun)	20	4	0.285	Sweatbees	4 days	Blue
Bellflower (shade)	34	4	0.379	Bumblebees	4 days	Blue
Sunflower (sun)	65	4	0.109	Sweatbees	7 hours	Yellow
Sunflower (Shade)	70	4	0.011	Beetles, Sweatbees	7 hours	Yellow
Thistle (interior)	1155	7	0.00054	Bees	10 hours	Purple
Thistle (edge)	4200	4	0.0024	Butterflies	10 hours	Purple
Boneset	360	3	0.0017	Butterflies, Wasps	7 hours	White
Bush Clover	2028	6	0.486	Butterflies	10 hours	White
Black-eyed Susan	156	5	0.0029	Bumblebees, Sweatbees	7 hours	Yellow / Brown

______________________________________________________________

Data Set #2. Student Data - Summer Flowering Phenology for Partridge Pea (Cassia fasciculata), Illinois, July-August 1997.

Sample data collection sheet for flowering phenology of Partridge Pea, used to determine the flowering pattern of individual plants. Similar data would be collected daily, or every other day. The number of flowers on each marked plant in each phenology class is shown (Table 2a, 2b, 2c, and Figure 2).

Key to Flowering Phases of Partridge Pea:

A = Enclosed in bud,
B = Stamens visible, not dehiscing,
C = Anthers dehiscing, pistil not apparent,
D = Pistil visible, some anthers still with pollen,
E = No pollen visible, petals intact,
F = Petals aged but present, ovary swollen,
G = Ovary swollen, no petals, fruit apparent.




Table 2a. Date 14 July 1997
Plant #	A	B	C	D	E	F	G
1	7	1	0	0	0	0	0
2	11	3	1	0	0	0	0
3	6	0	0	0	0	0	0
4	13	5	2	1	0	0	0
total	37	9	3	1	0	0	0





Table 2b. Date 29 July 1997
Plant #	A	B	C	D	E	F	G
1	0	0	2	1	3	2	0
2	2	3	4	3	3	0	0
3	0	0	1	2	2	1	0
4	1	3	6	5	3	2	1
total	3	6	13	11	11	5	1





Table 2c. Date 10 Aug 1997
	A	B	C	D	E	F	G
total	0	4	8	10	15	17	12



Figure 2a. Number of flowers of Partridge Pea in each phenology phase (A = bud, G = in fruit).



For individually marked flowers, data may be recorded daily (for species with flowers that last more than one day):



Table 2d. The phenology class for each flower on 5 marked Partridge Pea plants on 14 July 1997.
Plant #	Flower #1	Flower #2	Flower #3	Flower #4
1	B	A	B	C
2	A	C	B	B
3	B	B	B	D
4	B	A	A	A
5	A	A	--	--



Not only is it necessary to determine the seasonal time of flowering, but the diurnal time is often also important. For flowers that only last one day, such as many Asteraceae, data should be collected throughout the day. Some flowers, such as Convolvulus and Tradescantia species, open very early in the morning (0400), but most open after 0700. Sample data for a composite species, Daisy Fleabane (Erigeron annuus), are shown in Table 2e based on a qualitative Key to the Flowering Phases developed for this plant. However, for some species, it may be more appropriate to measure the width of the flower (e.g. for Lactuca and many other Liguliflorae), the length of the style, count the number of stamens that are shedding pollen, or some other quantitative measure to access flowering status.

Table 2e. Sample data for diurnal flowering of the Daisy Fleabane (Erigeron annuus), with flowers lasting only one day. Individual flowers on inflorescences should be marked with indelible ink.

Key to Flowering Phases of the Daisy Fleabane (Erigeron annuus):

A = Enclosed in bud,
B = Style emerging through collar of stamens,
C = Style emerged, but stigma not open,
D = Stigmas spread open, pollen visible on outside of style,
E = Pollen no longer visible, style shriveling.




Table 2e. Sample data for diurnal flowering of the Daisy Fleabane (Erigeron annuus), 14 June 1997, Plant #1.
Time	Flower #1	Flower #2	Flower #3	Flower #4
0700 h	A	A	A	A
0900 h	A	A	A	A
1100 h	B	B	B	A
1300 h	D	C	D	C
1500 h	E	D	E	D
1700 h	E	E	E	E




Population data could also be collected on the estimated number of flowers open and either shedding pollen or having receptive stigmas. Plot data and number of flowers open per plant could be combined to calculate average number of flowers open (Figure 2b). This requires population sampling using randomly selected one-meter squared plots.

Figure 2b. Number of flowers per square meter of Partridge Pea, Cassia fasciculata, at Rock Springs Center for Environmental Discovery in Macon County, Illinois.

______________________________________________________________

Data Set #3. Student Data - Visitation Rates.

Average visitation rates for each two-hour period during the day can be calculated and used to estimate the number of visits expected per flower per day (Table 3).



Table 3. The average number of visits per 10-minute observation period to Partridge Pea, Cassia fasciculata, in a plot containing 157 flowers.
Time of Day	# Visits by Flies	Bumble bees	Honey bees	Sweat bees	Butterflies	Total visits
0700-0900 h	0	5	1	0	0	6
0900-1100 h	3	10	2	7	0	22
1100-1300 h	6	3	7	15	1	32
1300-1500 h	7	1	5	4	2	19
1500-1700 h	1	0	0	0	0	1



Total visits expected per flower per day (V) for all visitors would be calculated using the following equation:

     V = Sum from i=1 to n ( v * b/p ) / F, where:

         i = each time interval in which there were observations, 2 hours in this example
         n = number of time intervals observed, 5 in this example (0700-0900, etc.)
         v = average number of visits observed during observation period (10 minutes)
         b = number of minutes in the time interval (120 per two hour interval)
         p = number of minutes in an observation period (10)
         F = total number of flowers observed (157 as counted)

For the example in Table 4:

     V = ( 6 * 120/10 ) / 157) + ( 22 * 120/10 ) / 157 + ( 32 * 120/10 ) / 157 + ( 19 * 120/10 ) / 157 + (1 * 120/10 ) / 157

     V = 0.459 + 1.682 + 2.446 + 1.452 + 0.076

     V = 6.115 visits per flower per day by all visitors

If visitors are too small to brush pollen against stigmas or do not move from one plant of a species to another, but only sit and eat pollen or drink nectar, it is unlikely that their visits will result in cross-pollination. Many visits may be essentially robbery of floral rewards. Observers must determine whether to consider a visit a possible pollination. As the data above show, the most frequent visitor is not necessarily the most effective pollinator. Flies and sweat bees are not very effective pollinators of Partridge Peas, partially because of their behavior and partially because of their size. Therefore, only about 37 of the observed visits are likely to affect pollination (Bumblebees + Honey bees + Butterflies). The expected number of effective visits per day (Ve) could be calculated using the same formula as for the total number of visits.

     Ve = Sum from i=1 to n ( ve * b/p ) / F, where ve = sum of visits by Bumblebees + Honey bees + Butterflies

         note: (120/10) / 157= 0.0764

         Ve = 6 * 0.0764 + 12 * 0.0764 + 11 * 0.0764 + 8 * 0.0764 + 0 * 0.0764

         Ve = 0.459 + 0.917 + 0.841 + 0.611 + 0

         Ve = 2.828 visits per flower per day by effective visitors

Figure 3a. Number of visits per observation period for 157 flowers of Partridge Pea by 5 different visitors: Fl - Flies, BB - Bumblebees, HB - Honeybees, SB - Sweat bees, and BF - Butterflies



Figure 3b. The timing of the visits over the day is different for different species of visitors. Bumblebees visit earlier in the day than do honeybees or butterflies.



Question: If a plot of 157 flowers can expect 19 visits by bumblebees during the time observed, how many visits by bumblebees (Vbb ) could each flower expect?

Using the same equation as above:

         Vbb = 5 * 0.0764 + 10 * 0.0764 + 3 * 0.0764 + 1 * 0.0764 + 0 * 0.0764

Answer: Vbb = 1.452 visits by bumblebees per flower per day