Imitation of death (pretending to be dead) is a behavior commonly found in mammals, fish, birds, amphibians, reptiles, crustaceans, mites, insects and animals, and has evolved to avoid predation by natural enemies. It's a defense strategy.It has been more than 2004 years since Fabre asked in "Insects" that imitation of death is a kind of asphyxia in which living things fall, and whether it has adaptive meaning.The research group has been a world leader in dying imitation research since it announced in XNUMX that dying imitation is adaptive.

The research group has more than 20 generations of red flour beetle, which is a world-famous pest of rice and wheat, that keeps pretending to be dead even if it is stimulated for a long time and that does not imitate death no matter how much it is stimulated. Breeding.Analysis using a next-generation sequencer (transcriptome analysis) was performed between these breeding lines.As a result, the existence of genes with different expression of 518 was found among the strains.The amount of dopamine expressed in the brain differed between the strains, and when dopamine was ingested or injected into the body, the time to imitate death was shortened.Furthermore, it was clarified that the expression of dopamine-related genes involved in the tyrosine metabolism system was significantly different between the strains.

This study also elucidated the difference in behaviors that imitate death and not, depending on the dopamine expressed in the brain, even at the genomic level.This finding also gives important implications for diseases related to human behavior.

Paper information:[Scientific Reports] Transcriptomics comparison between beetle strains selected for short and long durations of death feigning