Flower size and color as factors influencing bee visitation

Bee Behavior

Bees are flying insects that perform an important role in pollination of plants, as well as the production of honey and beeswax. There are over 20,000 species of bees in nine families, but classified as Anthophila. Bees are found in every continent except Antarctica, and have adapted for the feeding on nectar and pollen as a high-level energy source, with pollen being used as food for larvae in the developing honeycomb (Savage, 2008). In each specific environment, there are different types of flowers that appear seasonally with varying colors and sizes. Since bees have adapted to nearly every contemporary environment, it is important to understand what evolutionary mechanisms are used by flowers to attract bees. This is both a learning issue and evolutionary adaptation, since the more certain flowers are pollinated, the more that specific color and adaptation will have in seeding and promulgating. For this study, we will ask if the size or color of a flower will influence bee visitation and theoretically pollination.

Background

Bees have a long tongue (proboscis) that is complex and flexible, adapting to seeking nectar from many different types of plants. Bees, like ants, are a specialized form of wasps, and typically live in eusocial groups (honeybees, bumblebees, etc.). There is a clear hierarchy and division of labor in the bee colony, with the honeybee among the most complex. Eggs are laid singly in a wax honeycomb and fed with royal jelly or honey and pollen; a larvae solely fed by royal jelly develops into a queen. Young worker bees clean the hive and feed the larvae; worker bees cooperate to find food and use a "dance" to communicate the location of new flowers. Swarms -- or a mated queen and a contingent of worker bees establish Colonies. Male bees, or drones, die right after mating (Engle & Grimaldi, 2005)

Hypothesis

A -- Color -- With equal concentrations of sugar and the same size floral cut out with different colors, most bees will visit one color of flower over the others.

B -- Size -- With equal concentrations of sugar in the nectar and the same color of a floral cut-out, the number of visits by the bee will be the same, despite changes in flower-cut-out size.

Thus -- color is a primary motivator and attractor for bees while size of flower is not.

Methodology

The experiment breaks down as follows:

1. Four identical floral cuts outs were prepared using poster board and measured 6" in diameter. They were painted yellow, red, blue or left white.

Example:

2. Four bowls using a nectar solution of 2:2 ratio of cups of sugar with tepid water were placed in four identical clear bowls that were slightly smaller than the floral cut out.

3. Tape floral cut out to bowl, and place 25' from a known flower bed/apiary source.

4. Place "feeders" one day in advance of data collection to allow bees to become familiar with the unit.

5. Visit field site in early afternoon, from noon-3pm, sitting close enough to observe usage and far enough to remain partially hidden. Record data for 2 minutes each hour for a total of 3 records.

6. Repeat experiment using different size flowers but a singular color based on data collected Steps 1-4 (e.g. yellow was most visited, so 4 different sized yellow flowers were used in Part B of the experiment).

7. Collect the data and average the number of visits per color and size.

Results

Part A - COLOR

Yellow

Red

Blue

White

Trial 1

5

1

3

4

Trial 2

9

2

2

5

Trial 3

8

1

4

5

Total

22

4

9

14

Average

7.3

1.3

3

4.7

Part B -- SIZE

3"

4.5"

6"

7"

Trial 1

4

5

9

8

Trial 2

8

6

5

6

Trial 3

7

8

6

4

Total

19

19

20

18

Average

6.3

6.3

6.7

6.0

Discussion

The experiment showed that bees had a clear preference for yellow or white flowers. The bees preferred the yellow flowers 44% of the time, the white 29%. The bees did not seem to have a preference on size, the differences showed no statistical correlation. It is likely that the flowers that are in this biome are mostly yellow and white, at least at this season, and form the crux of the bees' preference. There is also a possibility that the bee prefers the yellow color because it reflects well in the sunlight, is easy to see and navigate to, and invites a presumption of freshness. There are few blue flowers of this hue, so that tone might have been confusing; and a red or orange tone in color might imply Fall or end of the season, and thus less pollen. The hypothesis was proven correct -- bees do prefer one color over others, but size seems immaterial.

Potential changes in experiment -- Color combinations, Hue variance, and shape variance, different levels of nectar/sugar solution, finding colors that match more of the environment, multiple apiaries or hive performance.

Sources