Psychology professor Justin Rhodes and graduate student Ross DeAngelis discovered two molecules in the brains of clown fish fathers that control how nurturing a parent they will be. Clownfish are also called anemonefish and like the cartoon versions featured in the Disney movie Finding Nemo, they have very involved fathers. Males will care for the eggs by cleaning them with their mouths and fanning them will freshwater to provide oxygen. When predators approach, however, they will become aggressive and try to fight and chase the would-be attacker away.
The new study published in Hormones and Behavior showed that blocking the effects of a molecule in the brain called arginine vasotocin, anemonefish fathers became less aggressive and provided even more paternal care. In contrast, by blocking the effects of a molecule called isotocin (the fish version of oxytocin), fathers became less involved in caring for their eggs and displayed more aggression.
This work shows how brain signaling molecules can create a balancing effect that allows parents to adaptively respond to the needs of their offspring. By being able to switch between either caring for or fighting for their eggs, anemonefish fathers are able to answer the demands of their environment and increase the chances of survival for their young. You can read more about this study at the Illinois News Bureau.