Question

Adult Culex and Anopheles can be distinguished with the help of

• A. mouth parts/colour
• B. sitting posture
• C. antennae/wings
• D. feeding habits.

Answer 1

The Correct Option is B

In this question, we need to identify the distinguishing feature between adult Culex and Anopheles mosquitoes. These two genera of mosquitoes are most commonly recognized for their roles in transmitting diseases like malaria (Anopheles) and various forms of viral diseases, such as West Nile virus (Culex).

The correct answer is sitting posture. Let's explore why this is the case and rule out the other options:

• Mouth parts/colour: While there might be differences in mouthparts between different genera due to their feeding habits, these features are not typically used for quick visual identification in field studies. Colour differences are also not typically significant for quick differentiation.
• Sitting posture: This is the most prominent distinguishing feature.
  • Anopheles: When at rest, Anopheles mosquitoes are known to have a characteristic sitting posture where their body is at a steep angle (approximately 45-degree) relative to the surface.
  • Culex: In contrast, Culex mosquitoes rest with their bodies parallel to the surface they are sitting on.
  This distinct difference in posture is a reliable visual cue for differentiating between these two types of mosquitoes.
• Antennae/wings: Differences in antennae and wings can exist but require closer inspection and are not as immediately apparent as posture differences.
• Feeding habits: Both genera are blood-feeders, but their feeding time (e.g., nocturnal versus diurnal) may differ. This is not a distinguishing feature that can be observed during a casual visual inspection.

Therefore, the correct and most efficient way to distinguish between adult Culex and Anopheles mosquitoes in a field setting, based on the options given, is indeed their sitting posture.