15. The passage states that which of the following was not affected by parasite infestation?
Answer: B
Likelihood of adult survival
The survival probability for adults was not affected by parasites, indicating that adult hosts maintain their survival rates despite parasite infestation. This finding highlights a key distinction between the impact of parasites on juvenile and adult hosts.
A) Host surface area
Host surface area was adjusted in the study to account for the number of parasites present on the hosts. The researchers noted that parasite abundance was higher on adults than on juveniles, but this was not indicative of density. Therefore, host surface area was indeed influenced as a factor in the analysis, making this option incorrect.
B) Likelihood of adult survival
The likelihood of adult survival was explicitly stated to be unaffected by parasites, as the study found that adult hosts did not experience a decrease in survival probability due to parasitism. This aligns directly with the findings of the research, confirming that this option is correct.
C) Foraging habits
The extract suggests that parasitized juveniles may forage for longer periods, which implies that their foraging habits could be affected by parasite infestation. Since the text does not mention any changes to adult foraging habits, this option is incorrect in relation to the effects observed in adults.
D) Vulnerability to predators
While the study discusses that parasitized juveniles may have increased exposure to predators due to lower survival rates, it does not provide evidence that adult vulnerability to predators was influenced by parasite infestation. Thus, this option does not relate to the findings regarding adult hosts.
E) The capacity to mount an immune response
The extract suggests that adults have a better ability to mount an immune response compared to juveniles, but it does not state that this capacity is affected by parasite infestation. Rather, the immune response appears to be an inherent trait of adults that operates independently of parasitism, making this option incorrect.
Conclusion
The likelihood of adult survival remains unchanged despite parasite infestation, which aligns with the study's findings. In contrast, host surface area, foraging habits, vulnerability to predators, and the capacity to mount an immune response were all discussed in relation to their effects on hosts, particularly juveniles, thereby confirming that option B is the only choice that accurately reflects the results presented in the passage.