diff --git a/trunk/paradiseo-mo/src/acceptCrit/moBetterAcceptCrit.h b/trunk/paradiseo-mo/src/acceptCrit/moBetterAcceptCrit.h
index a9a79d511..13f2f867c 100644
--- a/trunk/paradiseo-mo/src/acceptCrit/moBetterAcceptCrit.h
+++ b/trunk/paradiseo-mo/src/acceptCrit/moBetterAcceptCrit.h
@@ -43,10 +43,21 @@ class moBetterAcceptCrit : public moAcceptanceCriterion<Neighbor>, public moDumm
 public:
     typedef typename Neighbor::EOT EOT;
 
+  /*
+    constructor with a specific comparator
+
+    @param _comparator the comparaison method of two solutions
+  */
     moBetterAcceptCrit(moSolComparator<EOT>& _comparator):comparator(_comparator) {}
 
+  /*
+    default constructor:
+    compare the fitness value: accept if the fitness is higher
+  */
+    moBetterAcceptCrit():comparator(defaultComparator) {}
+
     /**
-     * Accept if the new solution is better than previous one
+     * Accept if the new solution is better than previous one according to the comparator
      * @param _sol1 the previous solution
      * @param _sol2 the new solution after local search
      * @return true if the new solution is better than previous one
@@ -58,6 +69,8 @@ public:
 private:
     moSolComparator<EOT>& comparator;
 
+    moSolComparator<EOT> defaultComparator;
+
 };
 
 #endif