Male red-winged blackbirds have bright red patches on their shoulders (epaulets). Females prefer to mate with males with the largest epaulets. Researchers captured all of the male birds in a single population. They measured how many parasites each male had (#parasites/body mass, higher numbers indicate a higher parasite load) and the size of the male's epaulets (cm). They produced the following graph (the line shows the relationship between parasites and epaulet width): Parasite Load (#parasites/body mass) 0.5- 0.4- 0.3 0.2 0.1 2.0 2.5 3.0 Epaulet Width (cm) 3.5 4.0 Explain what these data reveal about the correlation between epaulet size and parasite load and what might explain the fact that females prefer to mate with males displaying large epaulets.