A friend of mine converted to Buddhisn a few years ago.

Part if his training involved a trip to Tailand and a stay with monks.

One of the monks was faced with a trail of large, aggressive ants
invading his limited space.

The monk got a bottle of extremely toxic insecticide, made in China
   and doubtless containing many very toxic impurities, and made
   a large circle on the ground, defining his (the monk's) territory.

As the ants walked over the line and fell immediately into convulsions
   and died, my friend asked how the monk could justify the use of
   such tactics in light of his devotion to Buddhism.

The monk replied "It was their choice. They could have walked around".