Sex-biased dispersal in African wild dogs, Lycaon pictus

摘要

Sex differences in African wild dog dispersal behaviour have been described variously as strongly female biased to unbiased. Dispersal from natal home ranges to reproductive home ranges was recorded over 5 years from eight study packs in a free-ranging population of wild dogs in northern Botswana. Analysis of sex differences in natal dispersal was based on (1) age of natal dispersers, (2) dispersing group size, and (3) natal dispersal distance. Dispersal distance was measured by (ⅰ) the distance between arithmetic centres of range locations, (ⅱ) spatial association of reproductive and natal home ranges (contiguous versus disjunct), and (ⅲ) pair-wise comparison of dispersal distances between males and females establishing a reproductive home range together. Males in this population dispersed later, in larger groups and further than females. These results contrast with earlier reports for wild dogs and show that females are the more spatially philopatric sex. This pattern of sex-biased dispersal is evaluated in relation to two current, alternative but not mutually exclusive hypotheses: inbreeding avoidance and competition for mating opportunities. All wild dogs of both sexes emigrated when in the presence of their opposite sex parent. Despite frequent opportunities, no dogs mated with close relatives (r ≥ 0.5). The consequences of sex-biased dispersal in wild dogs are consistent with both hypotheses, but the competition for mating opportunities hypothesis is supported only within the context of dispersal behaviour indicative of close inbreeding avoidance.