diff --git a/gazebo/physics/World.cc b/gazebo/physics/World.cc
index 4bb2fedd50..b36a152f6e 100644
--- a/gazebo/physics/World.cc
+++ b/gazebo/physics/World.cc
@@ -3359,8 +3359,7 @@ bool World::PluginInfoService(const ignition::msgs::StringMsg &_req,
 }
 
 //////////////////////////////////////////////////
-bool World::ShadowCasterService(const ignition::msgs::StringMsg &_req,
-                                ignition::msgs::StringMsg &_res)
+bool World::ShadowCasterService(ignition::msgs::StringMsg &_res)
 {
   _res.set_data(this->dataPtr->shadowCasterMaterialName.c_str());
   return true;
diff --git a/gazebo/physics/World.hh b/gazebo/physics/World.hh
index 19a01c2192..1f5dacf1d5 100644
--- a/gazebo/physics/World.hh
+++ b/gazebo/physics/World.hh
@@ -652,11 +652,9 @@ namespace gazebo
           ignition::msgs::Plugin_V &_plugins);
 
       /// \brief Callback for "<this_name>/shadow_caster_material_name" service.
-      /// \param[in] _request Request containing plugin URI.
       /// \param[out] _response Message containing shadow caster material name
       /// \return True if the info was successfully obtained.
-      private: bool ShadowCasterService(const ignition::msgs::StringMsg &_request,
-          ignition::msgs::StringMsg &_response);
+      private: bool ShadowCasterService(ignition::msgs::StringMsg &_response);
 
       /// \internal
       /// \brief Private data pointer.
diff --git a/gazebo/rendering/Scene.cc b/gazebo/rendering/Scene.cc
index 1f732d2b57..71de854eca 100644
--- a/gazebo/rendering/Scene.cc
+++ b/gazebo/rendering/Scene.cc
@@ -209,13 +209,12 @@ Scene::Scene(const std::string &_name, const bool _enableVisualizations,
 
   // Get shadow caster material name from physics::World
   ignition::transport::Node node;
-  ignition::msgs::StringMsg req;
   ignition::msgs::StringMsg rep;
   const std::string serviceName = "/shadow_caster_material_name";
   bool result;
   unsigned int timeout = 5000;
   bool executed = node.Request(serviceName,
-      req, timeout, rep, result);
+      timeout, rep, result);
   if (executed)
   {
     if (result)