By Konkers
United Kingdom 
Every year I grow flowers in 4 long flowertubs placed on a wall. I take them down late autumn but do not clean them out until spring, saving many that have not been killed off by frosts. When emptying the compost out I often find many small white grubs in them. They are similar to, but much smaller than fly maggots. I feed them to the birds. What are they? Photo shows several out of just 1 tub. Also, I often find tiny yellow or orange balls that squish if I squash them. What are they?
31 May, 2014
Answers
Good job you emptied out the old compost because these eat the roots of plants until there are none left.
31 May, 2014
the larvae pictured are vine weevil - as for the orange/yellow 'eggs' these are usually the remains of feed pellets, those things that look like a clump of birdseed originally.
31 May, 2014