 Complete the following phrase:  Sebuku, along with Sebesi, has been noted as a stepping stone for butterfly migration between Sumatra and Krakatoa. There are numerous butterfly species from both Java and Sumatra on Sebuku. Four species of ants have been found on Sebuku, fewer than Sebesi and Krakatoa. These included ants not found on Krakatoa, thought to be descended from fauna that survived the 