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Comparative sizes of standard ring and giant ring in

Arthrobotrys brochopaga

Interesting note:  on water agar standard rings can be very common but giant rings are never produced.  The nematodes often stay at the larval stage and reproduction is restricted because of limited nutrition.  However, when the nutrient level is increased (e.g using weak corn meal agar, a rich medium for fungi, bacteria and nematodes etc) giant rings will be produced by the fungus on the culture plates.

STUDENTS:  Put forward a reasoable explanation to account for this observation.