Representative image showing a fish.
Credit: Pixabay Photo
In the fish world, few win the crown for being the best dads. Most are ‘absentee’ fathers, who disappear after mating and leave the burden of parenting to the females. Cichlids, a family of freshwater fish found in parts of Africa, South and Central America and Asia, including India, are no different. After the males fertilize the eggs, the females carry them around in their mouths to keep them safe from predators. This behaviour, called mouthbrooding, prevents the fish from feeding until the eggs hatch and the little fish emerge.
A new study reveals that this parenting tale—and the gene involved in the behaviour—has an unexpected twist. The researchers, studying a species of African cichlids called Astatotilapia burtoni, observed that when two specific genes related to detecting female pheromones in the males mutate, the absentee cichlid fathers turn into doting dads, carrying the eggs in their mouth just like the females do. In the males, two genes—Or113a and cnga2b—act like a switch in turning the nurturing behaviour on and off. When the males sense fertile female pheromones, the neural circuit responsible for mouthbrooding is switched off, and males become hands-off dads after mating. However, small mutations in these genes can keep this neural circuit on, turning them into doting dads.
The parenting tricks of cichlids don’t end there. In another study on Neolamprologus savoryi, also a cichlid species native to Lake Tanganyika in Africa, researchers found that the parents ‘spank’ their kids when they don’t help with chores. N. savoryi is a cooperative breeding species, where the young fish stay with their parents for a long time, and the elder ones help parents raise younger broods by helping with parenting chores. However, when the elder kids slack, the parents attack them as punishment, triggering them to participate in their family duties. Fish brains, after all, deserve more credit than we give them.