A research group led by Takegaki Takeshi, an associate professor at the Graduate School of Fisheries and Environmental Sciences, Nagasaki University, said that the "child-killing" behavior of male parents of fish is not for nutritional supplementation, but for resuming the courtship behavior of the next breeding. For the first time in the world, it proved to be an indispensable process.
The phenomenon of firial cannibalism, in which parents who are raising children eat their own children, is known in many animals.This phenomenon, once considered anomalous behavior, is now understood as a breeding strategy that enhances parental reproductive success, or as a parental nutritional benefit from eating offspring.However, there were cases in which this hypothesis could not explain the "whole egg-eating behavior" of male parents of fish.
Therefore, this time, in order to explore the meaning of whole egg-eating behavior by male parents of fish, the group conducted a field operation experiment to remove or add eggs from the small marine fish, androgen, and the presence of eggs in the nest. It was shown to be a key stimulus that regulates the male hormone (androgen).In other words, males cannot resume courtship without removing all eggs from their nests.More interestingly, it was also confirmed that the males spit out of the nest without eating the eggs.These results strongly suggest that it is an "infanticide" aimed at eliminating the presence of offspring rather than an egg diet that is expected to benefit from nutrition.
This result is an extremely valuable discovery that elucidated the egg-eating behavior of fish by a completely new approach from the endocrinological mechanism, and was published in the US scientific journal "Current Biology" on August 2018, 8.
Paper information:[Current Biology] Filial cannibalism by male fish as an infanticide to restart courtship by self-regulating androgen levels
