Everybody mulches, and it is encouraged here in Florida both for erosion control and moisture retention. A lot of the mulch used is aromatic wood chip such as eucalyptus or melaleuca (which is the tree that they make tea tree oil from). Both those aromatics repel insect activity including termites.http://polkmastergardener.ifas.ufl.edu/Articles/Mulch%20as%20published%20Pat.pdf I've never heard of mosquitoes breeding in mulch.
I also have lots of bromeliads and many hold water in the 'cups' but I sprinkle my used coffee grounds into them consistently, and that seems to do the trick. I never see mosquito larvae in them any more. Trees with large leaves certainly can breed mosquitoes in the leaf litter, though. I rake up the leaves under my mango tree, or spread coffee grounds around under there.
If I treat my standing water (pot saucers and other collectors plus the nearby ditches) regularly with Mosquito Dunks I have very little problem with mosquitoes.
