I have drilled a big hole in the lid and then covered the hole with fly proof mesh ( the same stuff that they use when building a frog vivarium )
Alternatively you could use any big container that you can stretch a J cloth over instead of a lid.
I put organic wheat grain in there, it costs a few quid for 1kg on ebay.
Then i add the grain weevils.
They will live on the wheat grain and lay eggs on the grains as well
Keep the whole thing warm and dry.
After a few weeks you will see weevils climbing up the sides of the container.
This is when you know if your lid is good enough ! Every weevil thinks that he is Harry Houdini and will escape if he can.
To harvest the weevils some people just scrunch up a piece of tissue paper and place it on top of the wheat grain, after a few minutes it will be crawling with weevils.
I use the cardboard tube from the inside of a toilet roll.
I cut each tube into three pieces and put them on top of the grains.
The weevils climb onto the cardboard and you just pick them up and knock them off of the tube into a container ready for dusting with vitamin powder.
This is the only problem i have with them. When i dust them with calcium i then strain them off through a plastic tea strainer. The little buggers will NOT let go of the tea strainer !
Sometimes i have to shake the culture a bit to wake the weevils up before they climb onto the cardboard tubes.
It really is the easiest live food to culture up.
Just keep it bone dry and warm and the weevils do the rest.
When i think that all of the wheat grains have been used up ( you can see a hole in each and every one of them and there will be a fine powder dropping to the bottom of the container ) i just split the contents into to two containers ( leaving behind as much of the fine powder as i can ) and add more wheat grain to each new culture. This way you will still be harvesting the weevils and won't have to wait for weeks for them to start breeding.