Question

A tactile organ in cockroach is
A. Antenna
B. Ommatidia
C. Fenestrae
D. Anal cerci

Answer 1

Tactile organs are sensory organs responsible for sensing touch, pressure etc. they are important as they help in identifying pressure, pain, texture, touch and temperature.

Complete Answer:
Let’s analyse the options one by one.
Option A: Antenna of cockroach are sensory appendages which are responsible for the generation of tactile sense. Cockroaches have 2 antennas on their head and they play a key role in perceiving physical objects and obstacles. Mechanoreceptors on the tip of the antenna are responsible for this function and this is a very essential mechanism because cockroaches are mostly nocturnal. Therefore this is a correct option.

Option B: Ommatidia are compound eyes present in arthropods including cockroaches. They have clusters of photoreceptor cells inside them and these are the structures responsible for vision. Therefore this is an incorrect option.

Option C: Fenestrae is a pair of openings present on the head of cockroach. They are simple eyes or photoreceptors responsible for perceiving light conditions. . Therefore this is an incorrect option.

Option D: Anal cerci are a pair of appendages in cockroach which are responsible for wind and vibration sensing. Anal cerci arise from the 10th segment of cockroach. . Therefore this is an incorrect option.

Thus the correct option is A: Antenna.

Additional information: Cockroaches are associated with a well developed sensory system and nervous system. The nervous system of cockroaches consist of a series of fused ganglia that are segmentally arranged and joined by paired longitudinal connectives.

Note: The antennae of male cockroaches are smaller than that of the females. Ommatidia creates multiple images and the vision is known as mosaic vision. They have more sensitivity but less resolution. Fenestrae is only responsible for sensing light and it doesn’t form an image on the retina. They are also known as ocelli.