diff --git a/models/default_ecolab_model.py b/models/default_ecolab_model.py
index 5506577..6c9ca88 100644
--- a/models/default_ecolab_model.py
+++ b/models/default_ecolab_model.py
@@ -26,7 +26,16 @@ def randomList(num, min, max):
 ecolab.migration(nsp*[1e-5])
                   
 from plot import plot, penPlot
-from GUI import gui, statusBar
+from GUI import gui, statusBar, windows
+
+from tkinter import Tk,ttk
+from weakref import ref
+from ecolab import ecolabHome
+connectionPlot=Tk()
+connectionPlot.eval('load '+ecolabHome()+'/lib/ecolab.so')
+connectionPlot.eval('image create cairoSurface connectionCanvas -surface ecolab_model ecolab.connectionPlot')
+ttk.Label(connectionPlot, image='connectionCanvas').pack()
+windows.append(ref(connectionPlot))
 
 def step():
     ecolab.generate()
@@ -36,7 +45,8 @@ def step():
     statusBar.configure(text=f't={ecolab.tstep()} nsp:{nsp}')
     plot('No. species',ecolab.tstep(),nsp)
     penPlot('Density',ecolab.tstep(),ecolab.density()._properties, ecolab.species()._properties)
-
+    ecolab.connectionPlot.requestRedraw()
+    
 gui(step)
 
 
diff --git a/models/ecolab_model.cc b/models/ecolab_model.cc
index 7e3a931..d72d9eb 100644
--- a/models/ecolab_model.cc
+++ b/models/ecolab_model.cc
@@ -21,6 +21,8 @@ using array_ns::pcoord;
 #include "ecolab_model.h"
 #include "pythonBuffer.h"
 #include "plot.h"
+
+#include "object.cd"
 #include "ecolab_model.cd"
 
 #include "ecolab_epilogue.h"
@@ -306,3 +308,64 @@ array<double> ecolab_model::lifetimes()
 }
 
 
+bool ConnectionPlot::redraw(int x0, int y0, int width, int height)
+{
+  if (!surface) return false;
+  const double scale=4;
+  int low_colour, high_colour;
+  auto& row=connections.row;
+  auto& col=connections.col;
+  ecolab::array<int> enum_clusters(connections.diag.size());
+  enum_clusters=1; 
+  enum_clusters=enumerate(enum_clusters);
+  for (unsigned i=0; i<row.size(); i++)
+    {
+      high_colour = enum_clusters[col[i]];
+      low_colour =  enum_clusters[row[i]];
+      
+      if (high_colour<low_colour) std::swap(high_colour,low_colour);
+      enum_clusters = merge( enum_clusters==high_colour, 
+			     low_colour, enum_clusters);
+    }
+      
+  /* for grouping species into their ecologies */
+  
+  ecolab::array<int> map(density.size()), mask;
+  map=-1;
+  for (int i=0; i<=max(enum_clusters); i++)
+    {
+      mask = enum_clusters==i;
+      map = merge(  mask, enumerate(mask)+max(map)+1, map);
+    }
+
+  auto cairo=surface->cairo();
+  for (unsigned i=0; i<row.size(); i++)
+    {
+      cairo_rectangle(cairo, map[row[i]]*scale, map[col[i]]*scale, scale, scale);
+      //cairo_stroke_preserve(cairo);
+      if (density[row[i]]==0||density[col[i]]==0)
+        cairo_set_source_rgb(cairo, 0xf5/256.0, 0xde/256.0, 0xb3/256.0); // wheat
+      else
+        {
+          auto& colour=palette[enum_clusters[row[i]]%paletteSz];
+          cairo_set_source_rgb(cairo,colour.r,colour.g,colour.b);
+        }
+      cairo_fill(cairo);
+    }
+
+  // diagonals
+  for (size_t i=0; i<density.size(); i++)
+    {
+      cairo_rectangle(cairo, map[i]*scale, map[i]*scale, scale,scale);
+      if (density[i]==0)
+        cairo_set_source_rgb(cairo, 0xf5/256.0, 0xde/256.0, 0xb3/256.0); // wheat
+      else
+        {
+          auto& colour=palette[enum_clusters[i]%paletteSz];
+          cairo_set_source_rgb(cairo,colour.r,colour.g,colour.b);
+        }
+      cairo_fill(cairo);
+    }
+  return true;
+}
+
diff --git a/models/ecolab_model.h b/models/ecolab_model.h
index e9de115..e1a62a1 100644
--- a/models/ecolab_model.h
+++ b/models/ecolab_model.h
@@ -7,7 +7,7 @@
 */
 
 #include <netcomplexity.h>
-
+#include <cairoSurfaceImage.h>
 using classdesc::Object;
 
 /* ecolab cell  */
@@ -53,6 +53,16 @@ struct model_data: public ecolab_point
   sparse_mat_graph foodweb;
 };
 
+struct ConnectionPlot: public Object<ConnectionPlot, CairoSurface>
+{
+  const array<int>& density;
+  const sparse_mat& connections;
+  ConnectionPlot(const array<int>& density, const sparse_mat& connections):
+    density(density), connections(connections) {}
+  bool redraw(int x0, int y0, int width, int height) override;
+  void requestRedraw() const {if (surface) surface->requestRedraw();}
+};
+
 class ecolab_model: public model_data
 {
   void mutate_model(array<int>); 
@@ -65,6 +75,8 @@ class ecolab_model: public model_data
   //mutation parameters
   float sp_sep, mut_max, repro_min, repro_max, odiag_min, odiag_max;
 
+  ConnectionPlot connectionPlot{density,interaction};
+  
   ecolab_model()     
   {repro_min=0; repro_max=1; mut_max=0; odiag_min=0; odiag_max=1;
   tstep=0; last_mut_tstep=0; last_mig_tstep=0;}