Similarly, eusociality occurs in some crustaceans and other arthropods. On some tropical reefs, several species of minute "Synalpheus" pistol shrimp are eusocial. They depend on certain sponges for the survival of their colony, and have a single breeding female and a number of male defenders armed with large snapping claws. Again, there is a single shared domicile for the colony members, and the non-breeding members act to defend it.