Question

Which acid is present in high quantities in most of the insect galls produced in plants?

• A. Oxalic acid
• B. Citric acid
• C. Tannic acid
• D. Tartaric acid

Hint:

Gall nuts and insect galls are rich natural sources of tannins, specifically tannic acid, which has been historically harvested for leather tanning and ink manufacturing.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Insect galls are abnormal vegetative growths or swellings induced on plants by the physiological action of insect feeding, oviposition, or chemical secretions.
These structures are rich in secondary metabolites synthesized by the host plant as a defense mechanism or induced by the gall-maker.

Step 2: Detailed Explanation:
Insect galls, particularly those produced on woody plants like oak trees by gall wasps, contain exceptionally high concentrations of polyphenolic compounds known as tannins, specifically Tannic acid.
When gall-inducing insects feed on or oviposit into plant tissues, they trigger a localized defense and wound-healing response in the host.
The host plant responds by accumulating high concentrations of tannins within the gall tissue.
These tannins serve an ecological role by deterring herbivores and preventing microbial decay of the gall, thereby protecting both the plant tissue and, indirectly, the developing insect larva inside.
Historically, insect galls (such as oak marble galls) have been harvested commercially as a primary source of tannic acid for dye-making, leather tanning, and ink production.
Other organic acids like oxalic, citric, and tartaric acids are not accumulated in such massive, dominant quantities in gall tissues.

Step 3: Final Answer
The correct option is (C).