A research group at Kagawa University and Okayama University investigated the relationship between the mandible size of a male insect called the red flour beetle and the pretending to be dead. For the first time in the world, we have revealed what we will do.

 Male weapon traits such as elephant seals, deer, and stag beetles are used in male-male struggles over mating with females, and it is said that larger weapon sizes make it easier to win.However, large weapon traits are also considered to increase the risk of death because they stand out from natural enemies.Therefore, prominent males with large weapon sizes were expected to have some strategy to avoid predation from natural enemies, but no studies have validated this.

 Red flour beetle is known as a rice and wheat storage pest.It is about 4 mm long and can be easily bred with flour, so you can observe its behavior using many individuals.The research group used this insect to investigate the relationship between male weapon size and dead pretending behavior.

 When an external stimulus imitating an attack from a predator was given, the relationship between mandibular size and the frequency of dead pretending behavior showed a positive correlation.Also, when I met a natural enemy, the jumping spider, it turned out that the male pretending to be dead survived and the male not pretending to be dead died.These results suggest that males with large weapon sizes have tactics that reduce the risk of death by pretending to be dead when encountering natural enemies.

 This time, the relationship between the weapons used in the struggle and predation avoidance behavior was clarified for the first time.It is expected that the ingenuity of living things that has come to have a large weapon that can be said to be a cost for survival will be a hint when considering the survival strategy of living things.

Paper information:[Biology Letters] Anti-predator behavior depends on male weapon size

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