Which of the following structures in mosquitoes help in perceiving vibrations?

Options

A. Johnston's organs present on last abdominal segment
B. Halters present on antennae
C. Johnston's organs present on antennae
D. Halters present on 2nd pair of wings

Answer

To solve the question "Which of the following structures in mosquitoes help in perceiving vibrations?", we will analyze the options provided and identify the correct structure responsible for vibration perception.

### Step-by-Step Solution:

1. **Understanding the Structures**:
- We need to identify the structures mentioned in the options: Johnston's organ and halters.

2. **Analyzing Johnston's Organ**:
- Johnston's organ is a collection of sensory cells located on the pedicel of the antenna in mosquitoes.
- Its primary function is to act as a mechanoreceptor, which means it can perceive mechanical stimuli such as vibrations.

3. **Analyzing Halters**:
- Halters are the second pair of wings found in some insects, including mosquitoes.
- Their main function is to aid in flight stability and maneuverability, not specifically in perceiving vibrations.

4. **Evaluating the Options**:
- **Option 1**: Johnston's organ present on the last abdominal segment - Incorrect, as it is not located there.
- **Option 2**: Halters present on antenna - Incorrect, as halters are not located on the antenna.
- **Option 3**: Johnston's organ present on antenna - Correct, as it is indeed located on the antenna and is responsible for perceiving vibrations.
- **Option 4**: Halters present on second pair of wings - Incorrect, as halters are the second pair of wings but do not perceive vibrations.

5. **Conclusion**:
- The correct answer is **Option 3: Johnston's organ present on antenna**. This structure is specifically designed for perceiving vibrations in mosquitoes.