R. C. Stavisky, J. K. Ramsey, T. Meeker, K. Cummings, A. Cerqueda and M. M. Crane Yerkes NPRC Field Station , 2409 Taylor Lane, Lawrenceville, GA 30043, USA |
YNPRC introduces breeder males to the SPF rhesus colonies every three years to increase genetic variability, avoid inbreeding and decrease the sex ratio with the goal of moderating aggression within the group. Eleven multi-generational breeding groups, comprised of adults, juveniles and infants (N=20-150 individuals), were examined to determine if introduction of males had an effect on aggression and trauma levels within the group. Trauma data spanning the breeding season were collected. Instances of trauma were analyzed corresponding to the final year of male residence (year three in the rotation) for the established breeder male(s), introductory year and second year of residence for new males. While repeated measures analyses indicated a significant difference in levels of trauma between the 11 groups (F=25.8[1,10], p=0.000), likely attributed to the differences in group sizes, more noteworthy was the significant difference across the three years within the social groups (F[2,20]=10.1, p=0.001) which was seen in all groups. Overall mean trauma levels were identical in the final year of residence for the established male(s) and the second year for the new male(s) (Χ2=26.545); however, the mean number of trauma occurrences was almost twice as great as the introductory year (Χ2=47.727). These findings suggest that trauma increases with the introduction of new males to a breeding group. Over time, these levels decrease supporting that male social integration is critical to social stability. |