The effect of color onbee pollinator visitation to artificial flowers

Laura Gabriel, Mari Pettibone,Rona Chong, Meagan Tokunaga

Question

• Do bees prefer certain colors, and if so which colors do they prefer?

Innate Preferences• Physiological factors shape innate preferences for certain colors• Bees can’t see 300-550 nm, unable to detect red in field conditions

(Cronk and Ojeda 2010, Forrest and Thomson 2009)• Relation to patterns of bird pollination (Cronk and Ojeda)

• strongest preferences for blue, violet (Chittka and Raine 2012)

Innate Preferences• Conflicting results on the visibility of white (Giura et al. 1996)

• Bees have trouble seeing white (Hertz 1938)• Bees prefer blue flowers over white (Raine and Chittka 2012)• No significant difference in bee pollination of blue and white flowers

(Sanderson et al. 2006)

Frequency-dependent Selection• Evidence that bees prefer the most prevalent flower color

within a habitat (Smithson and Macnair 1996).• Density of surrounding flowers affects bee visitation to a plant

(Makino et al. 2007)• How will this affect results in Bernard Field Station?

Hypothesis• Fewer pollinators on red flowers• Bees don’t see red wavelength (Cronk and Ojeda)

• Unsure of blue or white preference• Bees prefer blue flowers over white (Raine and Chittka 2007)• No significant difference in bee pollination between blue and

white flowers (Sanderson et al. 2006)

Methods and Materials• Color treatment: 3 artificial flowers of a color, held by a 250

mL Erlenmeyer flask• A treatment of each color was placed at each of 4 sample sites,

for a total of 4 replicates for each treatment• Treatments were placed on the ground, in a triangle formation

6 inches apart.

Methods and Materials• Experiment conducted 2:00-2:30 PM April 25, 2012, around

the BFS outdoor classroom.• Temperature ~28.33°C (83°F)• Weather cloudy but humid.

• Counts were added to find totals for each treatment of color over 30 min.

• Chi-square applied to find a significant preference in proportions of visits.

Site Locations

Common Observed SpeciesPeponapis pruinosa (squash bee) Anthophora sp. (anthorpine bee)

Anthophora urbana Centris (Paracentris)

Results• Significantly different proportions across all three colors

(p=.05)• Chi-square, X2=18.95, df=2, p<.0001

• Significant difference between blue and red (p=.05/3=.0167)• Chi-square, X2=14.7, df=1, p=.0001

• Significant difference between red and white• Chi-square, X2=17.46, df=1, p<.0001

• No significant difference in blue and white• Chi-square, X2=.08, df=1, p=.7773

Results• The accumulation of pollinators on artificial flowers of blue,

red and white color.

Discussion• Significant color preference• No significant difference between white and blue• White flowers are common at BFS• Within a species, bees could have adapted weaker preferences

for blue• Surrounding flowers could affect bee preferences (Makino et al

2007)• Did not prefer red

References• Cronk, Q., and I. Ojeda. "Bird-pollinated Flowers in an Evolutionary and

Molecular Context." Journal of Experimental Botany 59.4 (2008): 715-27. Web of Science. Web. 29 Apr. 2010.

• Forrest, Jessica (2009). "Background complexity affects colour preference in bumblebees". Die Naturwissenschaften (0028-1042), 96 (8), p. 921.

• Makino, T. T., K. Ohashi, and S. Sakai. "How Do Floral Display Size and the Density of Surrounding Flowers Influence the Likelihood of Bumble Bee Revisitation to a Plant?" Functional Ecology 21.1 (2007). Web of Science. Web. 29 Apr. 2012.

• Raine, Nigel E., and Lars Chittka. "The Adaptive Significance of Sensory Bias in a Foraging Context: Floral Colour Preferences in the Bumblebee Bombus Terrestris." Ed. Sean Rands. PLoS ONE 2.6 (2007): E556. Web of Science. Web. 29 Apr. 2012.

• Sanderson, Charlotte E., Benjamin S. Orozco, Peggy S. M. Hill, and Harrington Wells. "Honeybee (Apis Mellifera Ligustica) Response to Differences in Handling Time, Rewards and Flower Colours." Ethology 112.10 (2006): 937-46. Web of Science. Web. 29 Apr. 2012.

• Smithson, A., and M. R. Macnair. "Frequency-dependent Selection by Pollinators: Mechanisms and Consequences with Regard to Behaviour of Bumblebees Bombus Terrestris (L.) (Hymenoptera: Apidae)." Journal of Evolutionary Biology 9.5 (1996): 571-88. Web of Science. Web. 29 Apr. 2012.