Aquatic Hyphomycetes (Ingoldian fungi): Which statements describe their biology and ecological role in streams?

Introduction / Context:
Aquatic Hyphomycetes (Ingoldian fungi) are key decomposers in streams and rivers, initiating leaf litter breakdown and fueling detrital food webs.

Given Data / Assumptions:

• Conidia morphology is a diagnostic feature (tetraradiate, sigmoid).
• Colonized leaves become palatable and nutritious to shredding insects.
• We evaluate both a morphological and an ecological statement.

Concept / Approach:
These fungi produce distinctive, nonmotile conidia adapted to aquatic dispersal and attachment. By conditioning leaf litter (softening tissue, enriching proteins), they make detritus a preferred substrate for aquatic invertebrates, linking microbial decomposition to higher trophic levels.

Step-by-Step Solution:
Confirm tetraradiate conidia as a hallmark of many aquatic hyphomycetes. Recognize leaf-conditioning function that enhances insect feeding. Select both statements as correct.

Verification / Alternative check:
Microscopic surveys of stream foam and leaf packs reveal characteristic conidia; feeding trials show preference for fungus-conditioned leaves.

Why Other Options Are Wrong:

• Only one statement: incomplete; both are accurate.
• None: contradicts established freshwater mycology.

Common Pitfalls:
Assuming all fungal spores are motile in water; these conidia are nonmotile but morphologically adapted for capture.

Final Answer:
both (a) and (b)