TEMPORAL CHANGES IN THE SOCIAL-STRUCTURE OF A CAPTIVE COLONY OF THE DAMARALAND MOLE-RAT, CRYPTOMYS DAMARENSIS - THE RELATIONSHIP OF SEX ANDAGE TO DOMINANCE AND BURROW-MAINTENANCE ACTIVITY
A. Gaylard et al., TEMPORAL CHANGES IN THE SOCIAL-STRUCTURE OF A CAPTIVE COLONY OF THE DAMARALAND MOLE-RAT, CRYPTOMYS DAMARENSIS - THE RELATIONSHIP OF SEX ANDAGE TO DOMINANCE AND BURROW-MAINTENANCE ACTIVITY, Journal of zoology, 244, 1998, pp. 313-321
Crytomys damarensis is a eusocial subterranean rodent occurring in col
onies in which a sole reproductive female and one to two males are inv
olved in procreation; the remaining colony members are nonreproductive
. Within each sex the reproductive animals are usually the largest and
most dominant animals. The dominance hierarchy of a young colony cons
isting of a founding reproductive pair of genetically unrelated animal
s and the first three successive litters, comprising 12 offspring, fro
m this pair had a nonlinear dominance hierarchy, h = 0.32. Dominance w
as found to be correlated positively to body mass as well as to the ag
e of the animal. A subsequent study, which followed the incorporation
of two subsequent litters and growth of the first three litters, and c
omprised 15 offspring, revealed that the dominance hierarchy had attai
ned linearity, h = 0.9. Dominance was again positively correlated with
the age and body mass of respective colony members. In both studies t
here was no clear relationship between dominance and sex within the co
lony. The relationship between body mass and burrow-maintenance activi
ty revealed that frequent workers in the colony had a greater mean bod
y mass than infrequent workers. It is suggested that in establishing c
olonies, the older, stronger and hence larger animals may constitute t
he initial workforce. In addition the colony exhibits frequency-relate
d work determination into frequent and infrequent workers. Gender was
found to play no role in the frequency of work associated with burrow
maintenance. The social organization and temporal changes with recruit
ment are discussed in the light of events occurring in the field.