Question 54·Hard·Central Ideas and Details
In an observational study spanning five continents, ecologists recorded how urbanization affects flowering plants pollinated by nocturnal moths. The researchers found that in heavily lit city centers, moth visitation rates fell by 62%, yet overall pollination success in these areas declined by only 12%. The team attributes the discrepancy to the increased abundance of day-active pollinators, such as bees, that compensated for the moths’ absence. However, in suburbs where artificial light was sporadic rather than continuous, the decline in moth visits (41%) was matched by a nearly identical drop in pollination success. The scientists suggest that in these locations, daytime pollinator numbers remained unchanged, leaving no ecological backup when moths decreased.
Based on the text, which choice best describes the role of day-active pollinators in the city centers studied?
For “role” questions in Reading & Writing, first find the exact sentence or two that mention the thing in question (here, day-active pollinators in city centers). Paraphrase what the passage says they did, paying close attention to contrast words and any data given (such as the two different percentages). Then eliminate any choice that reverses, exaggerates, or adds causes/effects not stated in the text. The correct answer will closely match the passage’s description without introducing new ideas.
Hints
Find where the question is answered
Reread the part of the passage that talks about city centers, especially the sentence that mentions day-active pollinators like bees.
Compare the two percentages
Notice the numbers: moth visitation fell by 62%, but pollination success fell by only 12% in city centers. Ask yourself: what does this difference suggest about what the daytime pollinators are doing?
Focus on the word “compensated”
What does it mean that day-active pollinators “compensated for the moths’ absence”? Think about whether that would increase, decrease, or stabilize overall pollination success.
Eliminate answers that contradict the text
Check each answer against the details: Did daytime pollinators go up or down? Are they active at day or at night? Did they make pollination better, worse, or about the same as the moth decline would predict?
Step-by-step Explanation
Locate the key sentence about day-active pollinators
Go back to the part of the passage that talks about day-active pollinators in city centers: “The team attributes the discrepancy to the increased abundance of day-active pollinators, such as bees, that compensated for the moths’ absence.” This is the line that explains their role.
Understand the “discrepancy” the researchers explain
In city centers, moth visitation rates fell by 62%, but pollination success declined by only 12%. If moths were the only pollinators, you would expect pollination success to drop by a similar amount. The “discrepancy” is that pollination success did not drop as much as moth visits did.
Paraphrase what day-active pollinators did
The passage says there was an increased abundance of day-active pollinators and that they “compensated for the moths’ absence.” In simpler words, there were more daytime pollinators, and they made up for some of the work that the missing moths would have done, so pollination success didn’t fall as sharply.
Match that idea to the answer choice
The role of day-active pollinators is that their increased numbers made up for the reduction in moth visits, so pollination success did not fall in proportion to the moth decline. This is exactly expressed by the choice: “They prevented the decline in moth visits from leading to a proportional decline in pollination success.”