Index: boost/ptr_container/ptr_map_adapter.hpp
===================================================================
--- boost/ptr_container/ptr_map_adapter.hpp	(revision 75289)
+++ boost/ptr_container/ptr_map_adapter.hpp	(working copy)
@@ -549,7 +549,7 @@
         
     public:
         
-        std::pair<iterator,bool> insert( key_type& key, mapped_type x )
+        std::pair<iterator,bool> insert( const key_type& key, mapped_type x )
         {
             return insert_impl( key, x );
         }