Question

Sensillae present on 1st, 2nd and 3rd tarsomeres of leg of cockroach are

• A. Olfactory sensillae
• B. Thermoreceptor sensillae
• C. Gustatory sensillae
• D. Chemoreceptor sensillae

Hint:

{Thermoreceptors} help the cockroach select suitable microhabitats. {Anal Cerci} bear phonoreceptors (sound/vibration).

Answer 1

The Correct Option is B

Step 1: Locate the Sensillae:
Cockroaches have various sensory receptors (sensillae) distributed over their body:

• Antennae: Tactile, Olfactory, Thermal.
• Maxillary/Labial Palps: Gustatory (Taste), Olfactory.
• Legs (Tarsus): The tarsus is divided into 5 segments (tarsomeres). The soft pads (plantulae) on the underside of the first, second, and third tarsomeres contain specialized thermoreceptor sensillae, allowing the cockroach to detect surface temperature.

Step 2: Final Answer:
The correct option is Thermoreceptor sensillae.