They do not. I use "Mantis Online" (free, google it, not the asset store) to do it, which produces pretty good results, and keeps the blend shapes intact. Houdini, I hear, is the best way to do LODs. Though I haven't tried it myself. Ultimately I stopped providing LODs because i realized that each project would be unique, so the exactly amount of reduction would really depend on the project. Providing LODs only limited some users who had never done anything likethat before, as they were still stuck using my LODs instead of whatever worked best for their project.