Question

In the Florida Everglades, Burmese pythons are an invasive species. They were introduced into southern Florida in 1992. These pythons feed on many of the native Florida species, establishing the pythons as the top predator in the environment. By the year 2000, their population had increased dramatically.
Figures 1 and 2 display data collected by ecologists studying the results of the Burmese python invasion. Figure 1 shows counts of animals collected from nighttime road surveys in southern Florida, which are used to estimate population size. Figure 2 shows data collected from mosquitoes captured from the wild. DNA sequencing was used to identify the species of blood that the mosquitoes had in their stomachs, identifying various hosts used by the mosquitoes.

In 1996, the native Culex cedecei mosquitoes in southern Florida preferentially took blood meals from white-tailed deer and raccoons. It was predicted that changes in host population size would alter these host preferences. Additionally, it is known that cotton rats are often infected by the Everglades virus, which normally exists in animals, but is capable of infecting humans. Ecologists predict that increased feeding on cotton rats by C. cedecei may significantly increase the tendency of this virus to infect humans.

Which of the following most accurately explains an impact of Burmese pythons on the Everglades community in southern Florida using the data provided?

A - Python parasitism has reduced the population of white-tailed deer and raccoons.
B - Python predation has caused a trophic cascade that changed the mosquitoes' niche.
C - Pythons have a mutual symbiosis with cotton rats, allowing their population to increase.
D - Intraspecific competition for food between white-tailed deer and raccoons has increased due to pythons.

Answer 1

Answer:

B - Python predation has caused a trophic cascade that changed the mosquitoes' niche.

Explanation:

The passage infers that the predation by the Burmese pythons has reduced the population of the animals in Southern Florida thus making the Culex cedecei mosquito to have a reduced number of options to feed from. This is stressed when the author notes that these mosquitoes are now feeding on cotton rats which harbor the Everglades virus that also have the potentials of being transmitted to humans.

Summarily, the passage is saying that the invasion by the Burmese python has changed the niche of most animals including the mosquitoes in the Southern Florida's wild.