Interesting:

Another sexual reproduction theory bites the dust.

According to behavioral ecologist Dr. Jakob Bro-Jørgensen, female topi (an African antelope) can become extreme aggressors when it comes to mating, a shift in status-quo reproductive theory in which males are relatively persistent and females are relatively resistent members of the mating duo.

Every 1.5 months, a female topi is fertile and therefore becomes extremely sexually promiscuous, successfully mating with an average of four males with each male mounting her anywhere between 2-36 times (called intromissions). Females seek out and attempt to mate with males that have acquired the most territory in a breeding area - the mark of a studly topi - but will mate relatively indiscriminately if given the opportunity. And if there isn’t an opportunity, a female will make one - above is an image from the author’s nice PNAS piece in which a female is revving up to head-butt a male who is attempting to mate with another female. Go get ‘em!

After all, for these females, a small window of fertility means that conception and pregnancy is serious business - if it doesnt’ happen then, it won’t again for a long while. Talk about upping the ante.

So, given that a female topi’s strategy is to mate with as many males as possible while fertile, how could male topis not be the happiest little antelopes to grace the savannah??

As it turns out, the female mating strategy of “persistence wins out” doesn’t benefit the male topi in the least. In fact, our most studly male topi, who mates inceccently during females’ most fertile periods, may be at the greatest disadvantage. Males have limited stores of sperm, which are quickly depleted with multiple matings. And, to ensure the greatest likelihood of his offsprings’ survival, male topi would prefer to practice more selective mating, in which sperm could be distributed in a more discriminative manner to the cutest female topi.

In other words, males would prefer more choice in the matter.

But, while males of other species can resist sexual advances more easily, the female topi is relentless. How? Simple: they push the males around!

Pre-mating aggression is 10x more likely in dominant females than subordinate females. It comes as no surprise, then, that dominant females mate more often than subordinate females. By being pushy, a female can prevent a male from resisting by making her presence very, very conspicuous (a nice head-butt to the side will do that for you). But, if a male counter-attacks, say “so long” - while males only do so 7% of the time, he typically refuses the female as a mating partner, a harsh consequence.

Wonder what a topi date would be like…

There’s also a nice writeup on other aspects of this article here.
Images: female topis fighting here; female topi attacking a mating pair here.
In case the pdf didn’t work, find the abstract here.