By Susan Milius
Among topi antelopes, it’s the males that need convincing.
Topis, medium-sized antelopes in Africa, reverse the standard roles in courtship, says Jakob Bro-Jørgensen of the Zoological Society of London. “When biologists talk about the battle of the sexes, normally it’s between persistent males and resistant females,” he says. Not so among topis, even though they live otherwise standard mammal lives with maternal care. A male topi stakes out his own small territory in a male cluster. Females visit during a frenzied 6-week mating season. Bro-Jørgensen says the desirable males find an abundance of mates. Each female becomes fertile for only 1 day per year, and Bro-Jørgensen reports females averaging 11 encounters with each of 4 males. It’s not unusual for several hundred females to visit a cluster of only a dozen males.
A male presented with two fertile females prefers the newest arrival or the one he has mated with less often. Females spurned as old news readily lower their horns and charge a mating pair. Those lunges tend to shift a male away from his preferred newcomer and back to the repeat partner, Bro-Jørgensen says in the Dec. 18 Current Biology.
