Question

What is the correct general scheme of the fungal succession on herbivore dung:
A. Basidiomycetes
B. Discomycetes
C. Phycomycetes
D. Pyrenomycetes
Choose the correct answer from the options given below:

• A. A, B, C, D
• B. A, C, B, D
• C. B, A, D, C
• D. C, B, D, A

Hint:

Think of fungal succession on dung as a race for food. The fastest sprinters (\textbf{P}hycomycetes) eat the easy food (sugars) first. Then come the marathon runners (\textbf{A}scomycetes) that can digest tougher food (cellulose). Finally, the ultra-marathoners (\textbf{B}asidiomycetes) arrive to break down the hardest food (lignin).

Answer 1

The Correct Option is D

Step 1: Concept Summary:
The question concerns the typical order of fungal groups colonizing herbivore dung. This succession is based on the fungi's ability to decompose compounds of varying complexity.
Step 2: Detailed Explanation:
The succession of coprophilous fungi follows this general pattern:

First Stage - Phycomycetes (C): (Often classified as Zygomycetes). Pioneers such as {Mucor} and {Pilobolus} rapidly utilize simple sugars and carbohydrates, appearing within days.

Second Stage - Ascomycetes (B and D): After simple sugars are depleted, Ascomycetes appear. Their cellulases break down complex carbohydrates like cellulose. This includes Discomycetes (cup fungi, e.g., {Ascobolus}) and Pyrenomycetes (flask fungi, e.g., {Sordaria}). They appear after Phycomycetes, with the order of Discomycetes (B) and Pyrenomycetes (D) sometimes varying.

Third Stage - Basidiomycetes (A): These are late colonizers, appearing after weeks. Fungi like {Coprinus} (mushroom) use ligninases to decompose resistant components like lignin and complex cellulose.

The succession progresses from simple sugar consumers to cellulose decomposers to lignin decomposers.
Step 3: Conclusion:
The correct order is C (Phycomycetes) \(\rightarrow\) B (Discomycetes) \(\rightarrow\) D (Pyrenomycetes) \(\rightarrow\) A (Basidiomycetes), corresponding to option (D).