Well, oddly enough, I found a vine weevil grub in a pot I was clearing yesterday. I wasn't sure what it was until I googled 'vine weevil grub' and got a picture - creamy white legless grub, brown face - perfect likeness. So, all the soil from the pot has been thrown out and I will give the pot a thorough scrub before using it again.
The reason I suspected something in this pot of sedum is that the top growth was loose and came away without roots. So, something had been busy!

The adult weevil is black in colour and they are very slow to move creatures, they nibble out the corners of leaves this is a sure sign that they are alive and well in your pots or earth. You need to cruch these little devils, if you can find them!

On 19 October 2011 Ianplant asked the question "What are these little fellows" and illustrated it with a picture of vine weevil grubs. I am sure that I have also posted pictures of them on GoY but I can't find them now.

The grubs are quite small and C shaped. Often the first you know about their presence is that the plant wilts or falls over because they have eaten all the roots. When you repot in the Spring its useful to examine the old compost carefully just in case, and make sure you don't tip any with the grubs in it onto the garden. They seem to like pot plants especially and to have some favourites - cyclamen and heucheras for a start, but lots of others too.
there are several treatments you can buy including nematodes but some at least only work in warmer weather.