Expert: Florence M Rollwagen - 8/26/2008

Question
Karl von Frisch studied the interactions between bees and flowers. He wanted to know how bees select which flower to go to, and in particular whether the bees could see different flower colors, and therefore select flowers based on their color. In his first experiment, von Frisch put out pieces of red- and blue-colored paper, each of which had a bowl on top. In the bowl on the blue paper he put sugar water; he left the bowl on the red paper empty. Bees discovered the sugar water in the bowl on the blue paper and ate it, returning again and again with other bees to get more.
After a while, von Frisch took away the papers and bowls. He replaced them with two new bowls with colored paper, identical to the first pair except that both bowls were empty this time. He found that bees swarmed around the bowl on the blue paper, ignoring the bowl on the red paper.

Note that von Frisch already knew that bees like sugar water; this issue is not being tested in this experiment.

Question:   What was von Frisch’s hypothesis?

***My answer: I thought that the hypothesis was if bees are attracted to the flower by its color, then the bees select which flower to go to. *then bees have color vision*

But i am so confused!! it does not sound right to me.

Answer
Hi Blaine:  Thanks for your question.  von Frisch was essentially "training" the bees to associate food with the blue color.  After he took away the sugar water, the bees still went to the blue paper because they remembered that's where the food was.  After a while, they would stop going there because there was no reinforcement.

These experiments were carried out in the early 1900s.  von Frisch actually won the Nobel Prize in 1973, in part from his work on bee vision.

So the question: "Do bees have color vision" was answered in part by von Frisch's experiments, but later elaborated into ultraviolet vision.  

Bees actually see different colors than humans, they see in the ultraviolet.  Here is a reference:

http://www.sewanee.edu/Chem/Chem&Art/Detail_Pages/ColorProjects_2003/Crone/index...

Here is an approximation of what bees actually see:
http://www.monash.edu.au/news/monashmemo/stories/20070523/bee.html

Note the "red" center of the flower visible to the bee, but invisible to us.  

I hope this answer has helped you.  Please write back if you have more questions.

FM Rollwagen, PhD