Locked up tighter than a nuns knickers

It's so dry the trees are bribing the dogs

Gave it a lick and a promise (they did a poor job)

Amputate your timber (go away)

Beat the devil around the stump (to avoid responsibility)

Brick in his hat (he's drunk)

Didn't have a tail feather left (being broke)

Hard row to hoe (tough job)

Actually the answer to the second question depends on the species of ant, some will fight other colonies of the same species, some will merge with them.