EXTREME STREAMLINING. “At the other extreme of social parasitism are the inquilines, species of ant that spend their entire life cycle in the nest of the host. The inquilines’ dependence on the host is typically so absolute that the loss of social functions is associated with the loss of the parasite’s bodily organs.”
http://www.jstor.org/stable/29774232?seq=1#page_scan_tab_contents