Question

Given below are two statements:
Statement (I): In non-persistent transmission, the ability to transmit is lost between molts.
Statement (II): In persistent transmission, the ability to transmit is retained between molts.
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:

Shedding of the cuticle during molting acts as a mechanical reset for stylet-borne (non-persistent) viruses, but has no effect on internally carried (persistent/circulative) viruses.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
When an insect molts, it sheds its outer cuticle, including the cuticular lining (intima) of the foregut, hindgut, and salivary canal.
This shedding has different effects on virus transmission depending on whether the virus is carried externally or internally.
Detailed Explanation:
- Analysis of Statement (I): Non-persistent (stylet-borne) viruses are attached to the cuticular surface of the insect's mouthparts (stylet).
When the nymph molts, this outer cuticular lining is shed.
As a result, the virus is discarded along with the old cuticle, and the insect loses its ability to transmit the virus until it feeds on an infected plant again.
Therefore, Statement (I) is correct.
- Analysis of Statement (II): Persistent (circulative) viruses enter the insect's body, cross the gut wall, and circulate within the hemolymph and salivary glands.
Because these viruses are stored internally, shedding the external cuticle during molting does not remove them.
The insect therefore retains the virus and remains infective after molting.
Therefore, Statement (II) is correct.

Step 2: Final Answer:
Both Statement (I) and Statement (II) are correct, corresponding to option (1).