Genetic structure of African buffalo herds based on variation at the mitochondrial D-loop and autosomal microsatellite loci: Evidence for male-biased gene flow

Sexual differences in herding behaviour ofAfrican buffalo (Syncerus caffer) werestudied by analysing at the herd levelmitochondrial D-loop hypervariable region I andfourteen autosomal microsatellites. Three herdsfrom Arusha National Park in Tanzania wereanalysed with mtDNA and five herds from KrugerNational Park in South Africa with mtDNA andmicrosatellites. Significant mtDNAdifferentiation was observed among herds inArusha NP (F_ST = 0.12, based on haplotypefrequencies). Assignment tests withmicrosatellite data from Kruger NP showed thatmost frequent migration between herds is bymales two years. This was confirmed bytests for herd differentiation and analyseswith Lynch and Ritland's relatedness estimator.Within a herd, males younger than two years andfemales showed a higher relationship through acommon father rather than a common mother,indicating that female herd members mate withonly a few dominant males. This in turnsuggests a female:male sex ratio larger than5:1. The migration rate per generation betweenherds was estimated to be 5–2% for femalesand close to 100% for males. Finally, theimplications for the management of buffalopopulations are being discussed.