9705366 Social Organization and Task Allocation in a Eusocial Mannal The naked mole-rat (Heterocephalus glaber) occupies a unique place among social vertebrates because of its behavioral similarities to cooperatively breeding birds and mammals on the one hand and eusocial insects on the other. Naked mole- rats are playing a pivotal role in attempts to unite occurrences of alloparental care in vertebrates invertebrates under a single theoretical and terminological umbrella, to understand the relative importance of extrinsic (i.e, ecological), intrinsic (kinship), and historical factors in the evolution of eusociality, and identify proximate and ultimate sources of conflict and cooperation in animal societies. However, comparative behavioral and evolutionary analyses are presently stalled by lack of information, or existence of conflicting results, on key details of intra-colonial social organization and task allocation. The P.I. s research will address this need by quantifying the behavior of mole-rats in 5 captive colonies (n=126 animals, presently) housed in transparent burrow systems. Four specific questions will investigated: (1) Is there a specialized dispersive morph, or are putative dispersers actually colony defenders instead?, (2) Are burrows excavated primarily by large individuals or small individuals, or do large and small individuals participate, but in different aspects of burrow excavation?, (3) Do particular colony members seek environmental heat sources and then transfer heat to nest mates (like living hot water bottles), thereby improving the work efficiency of the entire colony?, and (4) How accurate is the recently- discovered foraging recruitment system: do scouts that find new food sources lay polarized trails to them, and how precisely do the communicate information about food quantity, quality, distance, and divisibility to potential recruits? For each question, straightforward, non-invasive experiments and observations will y ield strong inference tests of alternative hypotheses. Overall, this research will deepen our understanding of individual and group-level adaptations in one of the most remarkably complex, cooperation mammalian societies on earth.
