The following question is based on information from Frank M. Frey, "Opposing Natural Selection from Herbivores and Pathogens May
Maintain Floral-Color Variation in Claytonia virginica (Portulacaceae)," Evolution58(11), 2004: 2426-37. Claytonia virginica is a woodland spring herb with flowers that vary from white, to pale pink, to bright pink. Slugs prefer to eat pink-flowering over white-flowering plants (due to chemical differences between the two), and plants experiencing severe herbivory are more likely to die. The bees that pollinate this plant also prefer pink to white flowers, so that Claytoniawith pink flowers have greater relative fruit set than Claytoniawith white flowers. A researcher observes that the percentage of different flower colors remains stable in the study population from year to year. Given no other information, if the researcher removes all slugs from the study population, what do you expect to happen to the distribution of flower colors in the population over time?
a)the percentage of white flowers should increase over time
b)the distribution of flower colors should not change
c)the distribution of flower colors should randomly fluctuate over time.
d)the percentage of pink flowers should increase over time.
The correct answer is option d)"the percentage of pink flowers should increase over time".
Explanation:
In this study it is stated that two factors affect the flower coloration of <em>Claytonia virginica</em>: slugs preference of eating pink-flowering plants and bees preference of pollinating pink-flowering plants as well. If the researcher removes all slugs from the study population we can expect that the percentage of pink flowers should increase over time. The removal of the predator that prefers eating pink-flowering plants will favor the reproduction of this type of plants, which are also favored by bees pollination preference.
