I started with two hermit crabs, and they would run through the normal hermit crab cycle of not being out much during the day and being more active at night. Recently one of my hermit crabs died and as unfortunate as that is I have begun to see a lot more activity in my other crab. I'm not so concerned, I'm just wondering why this spike of activity has happened directly after my first crab's death. Is he lonely, or is he maybe looking for my other crab?
Hermit crabs are known to fight so this might be a result of it feeling safer now when the other one is gone.
Lots of crustaceans have problems living close to each other,one can see this in crabs-crayfish-lobsters they will fight and hurt each other.
So your hermit crab do probably feel safer now and this is why it is more active now.