An entomologist uses DNA barcoding to identify pollinators. Out of 180 insect samples, 105 carry pollen from apple trees, 95 from cherry trees, and 40 carry pollen from both. How many samples carry pollen from only one type of tree? - Parker Core Knowledge

Understanding the Context

Traditional identification of pollen-laden insects relies on visual inspection, which can be time-consuming and prone to error. DNA barcoding revolutionizes this process by using short, standardized gene sequences—typically from the mitochondrial COI gene—to precisely identify species. This technique enables researchers to determine precisely which plants pollen-carrying insects have visited, even when grains are fragmented or mixed.

In a recent study analyzing 180 insect specimens, scientists discovered that a significant portion actively participates in pollination. Of these, 105 carried apple tree pollen, 95 carried cherry tree pollen, and 40 transported pollen from both tree species.

Determining Pollinators with Specialized Pollen Carriers

To uncover how many insects pollinate only one type of tree—crucial data for targeting conservation efforts—researchers applied basic set logic:

Key Insights

Let:

• A = insects carrying apple pollen (105)
  
• C = insects carrying cherry pollen (95)
  
• A ∩ C = insects carrying pollen from both (40)

The number carrying pollen from only one tree species is:

• Only apple pollen: A − (A ∩ C) = 105 − 40 = 65
  
• Only cherry pollen: C − (A ∩ C) = 95 − 40 = 55

Adding these gives the total number of pollinators visiting only one tree type:
65 + 55 = 120

Implications for Agriculture and Ecology

Final Thoughts

The discovery that 120 insect samples carry pollen from just one fruit tree underscores the importance of habitat diversity. Insects visiting only apples or only cherries may rely heavily on monocultures, increasing their vulnerability to environmental changes. This data helps guide conservation strategies, such as planting diverse flowering species to support generalist pollinators and reduce dependency on single crops.

Moreover, leveraging DNA barcoding enables faster, more scalable monitoring of pollinator networks—proving essential in combating pollinator declines worldwide.

Conclusion

By identifying pollinators through DNA barcoding, entomologists gain a clearer picture of insect-plant interactions. In this study, 105 insects carried apple pollen, 95 carried cherry pollen, and 40 overlapped, leaving 120 pollinators associated with only one tree type. This insight not only advances our understanding of pollination ecology but also supports targeted efforts to protect vital pollinators across agricultural landscapes.

Keywords: entomologist, DNA barcoding, pollinators, apple tree pollen, cherry tree pollen, insect identification, conservation, agricultural ecology, pollination networks, genetic analysis.