A biologist observes that a species of stick insects on a remote island has three different color traits, almost equally distributed among the population. One phenotype is dark green, a second is light green, and a third is light green with dark green stripes. Over a decade, the biologist observes that the dark green phenotype becomes the most abundant, making up nearly 70% of the population. Which statement is the best explanation for this phenomenon?
A.
None of the color characteristics are undergoing selection at the present time.
B.
A founder effect has resulted in an increase in the numbers of the dark green phenotype.
C.
The dark green phenotype benefits the insects’ survival, making them more likely to reproduce.
D.
The insects with the dark green color trait have developed an r-selection strategy for survival.