Hives were bases for the Vahki order enforcers in Metru Nui. Each hive contained an energy cradle through which Vahki could be recharged. When the Metru Nui power plant was destroyed, the resulting energy surge wrecked the hives as well.1
Notes
Dwelling in hives in the six metru, the Vahki swarmed out when there was trouble, chased down the offending Matoran, and made sure they fell back into line.2