Mouth-brooding female cichlids (family Cichlidae) are in control of both pre- and post-mating sexual selection.
In this highly specialized mating system, females gather up their extruded eggs and brood them in their mouths while soliciting sperm donations from select males.
It’s like having several males ejaculate into your mouth in quick succession so that the most competitive sperm fertilizes the eggs.
It’s worth noting that this kind of mouth-brooding strategy is markedly different from most other fish that spawn into nests on the ocean floor. In the latter case, the female is not in control of which sperms are contributed for fertilization.
Indeed, in many of these systems there are both dominant and sneaker males that have their own strategies for being reproductively successful irrespective of a female’s desires.
Subsequent to spawning, female mouth-brooding cichlids continue to solicit sperm donations, including from males that were not present when the eggs were first spawned. This sets the scene for intense sperm competition inside her mouth.
She’s effectively “sperm shopping” in order to induce the highest level of competition; clutches can have up to four sires (eggs within a given clutch may be fertilized by different sperms).
In addition to sperm shopping and mixing, females prefer scpecific phenotypic characteristics of males, such as those with elongated pelvic fins and large body length, so in this example it can be seen that females are in direct control of both pre-and post-copulatory sexual selection.
This post is an adapted excerpt from my book “Wild Sex: The Science Behind Mating in the Animal Kingdom“