VARIATION IN LEKKING COSTS IN BLACKBUCK (ANTILOPE CERVICAPRA): RELATIONSHIP TO LEK-TERRITORY LOCATION AND FEMALE MATING PATTERNS

Abstract

AbstractWe studied variation in lekking costs in an Indian antelope, the blackbuck Antilope cervicapra, in relation to female mating patterns. We tested the hypothesis that central males had a higher mating success and faced higher costs than peripheral males. We used continuous focal animal sampling to estimate time-activity budgets of individually identified central and peripheral lekking males and bachelor males. Scan sampling was used to estimate the time spent on the lek by central and peripheral males and to monitor female visits to the lek. We mapped lek-territories and monitored territory additions, territory turnover, and the location of matings. We found that central males faced higher costs than peripheral males. Central males foraged less, spent more time on the lek and tended to have higher fighting rates than peripheral males. Corresponding to this difference in costs, mating benefits were also greater for central males. Our results suggest that lek-territory location may be an important cue in female choice. Male mating success was skewed and 90% of matings observed occurred in the lek-centre. Furthermore, three of the five most successful males previously held territories in the lek-periphery where they were not observed to mate. Territory turnover was higher in the centre than in the periphery and males tended to move towards the centre while shifting territories. Based on these findings, we suggest that central and peripheral males follow two different strategies in response to a female preference for central territories: while central males may try to maximise encounters with oestrous females by investing heavily in lekking, peripheral males seem to attempt to maximise their chances of gaining central territories by not compromising on foraging time and investing less in lekking. Since we did not directly measure male phenotype, its role in explaining the patterns we found remains to be studied.