Determinants of male mating success in the red bishop (Euplectes orix)

We studied sexual selection in the red bishop, Euplectes ortix, a colonial, polygynous weaverbird widely distributed over sub-Saharan Africa. Male rep roductive success measured in terms of the number of nests accepted by fema les and the number of eggs and nestlings in all the nests on a male's terri tory varied considerably. The standardized variance (valiance/mean(2)) in m ale reproductive success ranged from 0.505 to 1.737 in different years, ind icating a high potential for sexual selection in this species. An analysis of genetic parentage for 432 nestlings by non-radioactive, multilocus DNA f ingerprinting confirmed that male reproductive success (number of young sir ed on the territory) in this species can be reliably estimated by the measu res introduced above. In all 4 study years there was a strong positive corr elation between male mating success and the total number of nests that male s built in their territories. The number of nests built can be partitioned into the number of weeks a male held a territory and his nest-building perf ormance. Both factors exert a significant positive effect on male mating su ccess and in combination explained between 53.3 and 86.3% of the variation in male reproductive success. Male morphological characters were found to b e of no importance. Males that established a territory in the following sea son built more nests and held their territories for longer than males that did not establish a territory in the following season, suggesting that thes e measures might be indicators of male condition and quality. Male nest-bui lding performance (number of nests built per week) seems to be unrelated to male condition or quality.