diff --git a/creatur.cabal b/creatur.cabal
--- a/creatur.cabal
+++ b/creatur.cabal
@@ -1,5 +1,5 @@
 Name:              creatur
-Version:           5.3.2
+Version:           5.4.0
 Stability:         experimental
 Synopsis:          Framework for artificial life experiments.
 Description:       A software framework for automating experiments
diff --git a/src/ALife/Creatur/Daemon.hs b/src/ALife/Creatur/Daemon.hs
--- a/src/ALife/Creatur/Daemon.hs
+++ b/src/ALife/Creatur/Daemon.hs
@@ -22,7 +22,8 @@
 import Control.Concurrent (MVar, newMVar, readMVar, swapMVar, 
   threadDelay)
 import Control.Exception (SomeException, handle, catch)
-import Control.Monad.State (StateT, execStateT)
+import Control.Monad (when)
+import Control.Monad.State (StateT, runStateT)
 import System.IO (hPutStr, stderr)
 import System.IO.Unsafe (unsafePerformIO)
 import System.Posix.Daemonize (CreateDaemon(..), serviced, simpleDaemon)
@@ -39,9 +40,9 @@
   {
     onStartup :: s -> IO s,
     onShutdown :: s -> IO (),
-    onException :: s -> SomeException -> IO s,
+    onException :: s -> SomeException -> IO (Bool, s),
     -- | The agent task.
-    task :: StateT s IO (),
+    task :: StateT s IO Bool,
     username :: String,
     -- | Number of microseconds to sleep between agent tasks.
     sleepTime :: Int
@@ -75,13 +76,13 @@
 
 daemonMainLoop :: Daemon s -> s -> IO ()
 daemonMainLoop d s = do
-  threadDelay $ sleepTime d
-  timeToStop <- readMVar termReceived
-  if timeToStop 
-    then onShutdown d s
-    else do
-      s' <- handle (onException d s) $ execStateT (task d) s
+  stopRequested <- readMVar termReceived
+  when (not stopRequested) $ do
+    (continue, s') <- handle (onException d s) $ runStateT (task d) s
+    when continue $ do
+      threadDelay $ sleepTime d
       daemonMainLoop d s'
+  onShutdown d s
 
 wrap :: IO () -> IO ()
 wrap t = catch t
diff --git a/src/ALife/Creatur/Task.hs b/src/ALife/Creatur/Task.hs
--- a/src/ALife/Creatur/Task.hs
+++ b/src/ALife/Creatur/Task.hs
@@ -37,7 +37,6 @@
   withAgent, withAgents, incTime)
 import Control.Conditional (whenM)
 import Control.Exception (SomeException)
-import Control.Monad (when)
 import Control.Monad.State (StateT, execStateT)
 import Data.Serialize (Serialize)
 
@@ -60,18 +59,25 @@
   _ <- execStateT (writeToLog "Shutdown requested") u
   return ()
 
-exceptionHandler :: Universe u => u -> SomeException -> IO u
-exceptionHandler u x = execStateT (writeToLog ("WARNING: " ++ show x)) u
+exceptionHandler :: Universe u => u -> SomeException -> IO (Bool, u)
+exceptionHandler u x = do
+  u' <- execStateT (writeToLog ("WARNING: " ++ show x)) u
+  return (True, u')
 
 runNoninteractingAgents
   :: (Universe u, Serialize (Agent u))
-    => AgentProgram u -> SummaryProgram u -> StateT u IO ()
+    => AgentProgram u -> SummaryProgram u -> StateT u IO Bool
 runNoninteractingAgents agentProgram summaryProgram = do
   atEndOfRound summaryProgram
-  (a:_) <- lineup
-  markDone a
-    -- do that first in case the next line triggers an exception
-  withAgent agentProgram a
+  as <- lineup
+  if null as
+    then return False
+    else do
+      let a = head as
+      markDone a
+      -- do that first in case the next line triggers an exception
+      withAgent agentProgram a
+      return True
 
 --   The input parameter is a list of agents. The first agent in the
 --   list is the agent whose turn it is to use the CPU. The rest of
@@ -84,13 +90,21 @@
 
 runInteractingAgents
   :: (Universe u, Serialize (Agent u))
-    => AgentsProgram u -> SummaryProgram u -> StateT u IO ()
-runInteractingAgents agentsProgram summaryProgram = do
+    => AgentsProgram u -> Int -> SummaryProgram u -> StateT u IO Bool
+runInteractingAgents agentsProgram minAgents summaryProgram = do
   atEndOfRound summaryProgram
   as <- lineup
-  when (not $ null as) $ markDone (head as)
-    -- do that first in case the next line triggers an exception
-  withAgents agentsProgram as
+  if length (take minAgents as) < minAgents -- efficient way of checking length, I think
+    then do
+      writeToLog "Population too small"
+      summaryProgram
+      writeToLog "Requesting shutdown (population too small)"
+      return False
+    else do
+      markDone (head as)
+      -- do that first in case the next line triggers an exception
+      withAgents agentsProgram as
+      return True
 
 atEndOfRound
   :: Universe u