Imagine a male dragonfly is flying around in an aggressive pattern to find an appropriate mate in a wetland with many species of dragonflies and damselflies. Finally, he spots a female dragonfly that appears to be of the same species, based on her flight behavior and color, and the two mate. The sperm of the male, however, are unable to fertilize the eggs of the female when she lays them because her egg cell membrane proteins and carbohydrates do not recognize and bind to the male's sperm. This is an example of: