Question

Given below are two statements:
Statement (I): 99% of the arthropod vectors are insect and 55% of these are aphids
Statement (II): Most of the insect vectors (95%) are beetle
In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both Statement (I) and Statement (II) are correct
• B. Both Statement (I) and Statement (II) are incorrect
• C. Statement (I) is correct but Statement (II) is incorrect
• D. Statement (I) is incorrect but Statement (II) is correct

Hint:

Hemipterans (specifically aphids) are the most common vectors of plant viruses due to their piercing-sucking mouthparts, which allow them to feed on vascular tissues without killing the cells.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Arthropods, particularly insects, serve as the primary vectors for transmitting plant viruses.
Among insect groups, those with piercing-sucking mouthparts (order Hemiptera) are the most common vectors.
Detailed Explanation:
- Analysis of Statement (I): Insects represent the vast majority (about 99%) of all arthropod vectors of plant viruses (with mites making up most of the remainder).
Within class Insecta, aphids (family Aphididae) are the most common vectors, transmitting approximately 55% of all insect-vectored plant viruses.
Therefore, Statement (I) is correct.
- Analysis of Statement (II): Beetles (order Coleoptera) have biting and chewing mouthparts.
While they do transmit some stable plant viruses (such as tymoviruses and comoviruses), they represent only a small fraction of insect vectors.
The majority of insect vectors (over 70%) belong to the order Hemiptera (aphids, whiteflies, leafhoppers, and planthoppers), not Coleoptera.
Therefore, Statement (II) is incorrect.

Step 2: Final Answer:
Statement (I) is correct but Statement (II) is incorrect, corresponding to option (3).