Chapter 14, Problem 2WIO

What type of reproductive barrier applies to each of these scenarios?

a.	Humans introduced apple trees to North America in 1800s. Insects called hawthorn flies, which feed and mate on hawthorn plants, quickly discovered the new fruits. Some flies preferred the taste of apples to their native host plants. Because these flies mate where they eat, this difference in food preference quickly led to a reproductive barrier.
b	Water buffalo and cattle can mate with each other, but the embryos die early in development.
c.	Scientists try to mate two species of dragonfly that inhabit the same pond at the same time of day. However, females never allow males of the other species to mate with them.
d	One species of reed warbler is active in the upper parts of the tree canopy while another species of reed warbler is active in the lower canopy. Both species are active during the day.
e.	Scientists mate two parrots from different populations to see if speciation has occurred. The parrots mate over and over again, but the male’s sperm never fertilizes the female egg.