It no longer lives in its largest habitat ; Lord Howe Island , and has been called `` the rarest insect in the world '' , because there are less than 30 living today on the small islet of Ball 's Pyramid . It is extinct in its largest habitat , Lord Howe Island , and has been called `` the rarest insect in the world '' , as the rediscovered population consisted of fewer than 30 individuals living on the small islet of Ball 's Pyramid .