How do the insects that pollinate flowers distinguish individual flowers with nectar from empty flowers? One possibility is that they can detect the slightly higher humidity of the air—produced by evaporation—in flowers that contain nectar. von Arx et al. (2012) tested this idea by manipulating the humidity of air emitted from artificial flowers that were otherwise identical. The following graph summarizes the number of visits to the two types of flowers by hawk moths (Hyles lineata).

a. What type of graph is this?

b. What does the horizontal line in the center of each rectangle represent?

c. What do the top and bottom edges of each rectangle represent?

d. What are the vertical lines extending above and below each rectangle?

e. Is an association apparent between the variables plotted? Explain.

Transcribed Image Text:

Flower visits 20 15- 10 5- 0 Ambient Humidified Air emitted from flower