Question

A substance emitted by a non-living material that evokes a behavioural or physiological reaction that is adaptively favourable to receiver but detrimental to an organism of another species that may be found in or on non-living material is

• A. Apneumone
• B. Kairomone
• C. Synomone
• D. Allomone

Hint:

Think of the prefix "A-" in "Apneumone" as meaning "without" (non-living or inanimate origin, like "abiotic"). This root word helps distinguish it from other living-origin allelochemicals.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Semiochemicals are chemical messenger substances that convey information between organisms.
They are broadly divided into pheromones (intraspecific communication) and allelochemicals (interspecific communication).
Allelochemicals are classified based on which species benefits from the communication.

Step 2: Detailed Explanation:
Let us define the options to identify the correct semiochemical class:
- Apneumone:
An apneumone is an allelochemical emitted by a non-living source (such as decaying organic matter, dung, or oatmeal) that triggers a behavioral or physiological reaction in a receiving organism.
This reaction is adaptively favorable to the receiver, but harmful to other species living on or in that non-living material.
A classic example is when a parasitoid wasp is attracted to the smell of rotting meat, allowing it to find and parasitize the pest larvae feeding there.
The chemical cue benefits the receiver (the wasp) but is detrimental to the host larvae (another species found on the material).
- Kairomone:
An allelochemical emitted by a living organism that benefits the receiver of another species but disadvantages the emitter (e.g., a predator locating prey by its scent).
- Synomone:
An allelochemical that benefits both the emitter and the receiver of different species (e.g., floral scents attracting pollinators).
- Allomone:
An allelochemical that benefits the emitter but disadvantages the receiver of another species (e.g., chemical defense sprays of beetles).
Since the question specifies a substance emitted by non-living material, it is an apneumone.

Step 3: Final Answer:
An apneumone is the specific chemical category emitted by non-living substances.
Thus, the correct option is (A).