|SREL Reprint #2193|
DO BLACK-TAILED PRAIRIE DOGS MINIMIZE
F. STEPHEN DOBSON,1 RONALD K. CHESSER,2,3 JOHN L. HOOGLAND,4 DERRICK W. SUGG,5 AND DAVID W. FOLTZ6
1Department of Zoology and Wildlife Science, and Alabama Agricultural Experimental
Station, Auburn University, Auburn, Alabama 36849
Abstract.-Considerable controversy surrounds the importance of inbreeding in
natural populations. The rate of natural inbreeding and the influences of
behavioral mechanisms that serve to promote or minimize inbreeding (e.g.,
philopatry vs. dispersal) are poorly understood. We studied inbreeding and
social structuring of a population of black-tailed prairie dogs (Cynomys
ludovicianus) to assess the influence of dispersal and mating behavior on patterns
of genetic variation. We examined 15 years of data on prairie dogs, including
survival and reproduction, social behavior, pedigrees, and allozyme alleles.
Pedigrees revealed mean inbreeding coefficients (F) of 1-2%. A breeding-group
model that incorporated details of prairie dog behavior and demography was
used to estimate values of fixation indices (F-statistics). Model predictions were
consistent with the minimization of inbreeding within breeding groups ("coteries,"
asymptotic FIL = -0.18) and random mating within the subpopulation ("colony,"
asymptotic FIS = 0.00). Estimates from pedigrees (mean FIL = -0.23, mean FLS
= 0.00) and allozyme data (mean FIL = -0.21, mean FIS = -0.01) were
consistent with predictions of the model. The breeding-group model, pedigrees,
and allozyme data showed remarkably congruent results, and indicated strong
genetic structuring within the colony (FLS = 0. 16, 0.19, and 0. 17, respectively).
We concluded that although inbreeding occurred in the colony, the rate of
inbreeding was strongly minimized at the level of breeding groups, but not at the
subpopulation level. The behavioral mechanisms most important to the
minimization of inbreeding appeared to be patterns of male-biased dispersal of
both subadults and adults, associated with strong philopatry of females. Incest
avoidance also occurred, associated with recognition of close kin via direct
social learning within the breeding groups.
SREL Reprint #2193
Dobson, F.S., R.K. Chesser, J.L. Hoogland, D.W. Sugg, and D.W. Foltz.
1997. Do black-tailed prairie dogs minimize inbreeding? Evolution 51:970-978.