ROLE OF SEX AND BREEDING STATUS IN GROOMING AND TOTAL TICK LOAD OF IMPALA

The role of sex and breeding status constraints on grooming behavior a nd tick load in impala was examined among females, bachelor males (B m ales), and territorial males (T males) during the breeding season in Z imbabwe. T males orally groomed themselves much less than females or B males, whereas B males orally groomed themselves at a higher rate tha n, but not significantly different from, females. T males never engage d in allogrooming and B males allogroomed at a low rate that was not s ignificantly different from that of T males; all males allogroomed muc h less than females. There was no difference in any of the grooming me asures between T males with a breeding herd in residence, and solitary T males without a breeding herd on the territory. In conjunction with a management exercise, culled impala were examined for total tick bur den using the digestion method, by which all ticks (larvae, nymphs, ad ults) are removed and counted. For all developmental stages, females h arbored the fewest number of ticks and T males supported the most; tic k loads of B males were intermediate to those of females and T males. When body surface area was taken into account, T males harbored a high er density of ticks than females and B males. All sex-breeding status groups supported a higher density of ticks on the head/neck region (in accessible to self oral grooming) compared with accessible areas of th e body. The results support the programmed grooming hypothesis, which predicts that those individuals that groom most will harbor fewest tic ks, in contrast to the stimulus-driven model which predicts that those that groom most will harbor the most ticks. The lower grooming rates of males versus females can be attributed to competing behavioral dema nds on males for vigilance and rutting behavior during the breeding se ason, and/or to higher testosterone levels exerting a physiological su ppression of oral grooming. The higher number and density of ticks har bored by T males indicates that lowered grooming rate is a significant cost to reproductively active impala males during the breeding season .