Polygene control and trait dominance in death-feigning syndrome in the red flour beetle Tribolium castaneum

Death-feigning behavior is an anti-predator behavior in a wide range of animal taxa, and it often correlates with the movement (i.e. death-feigning syndrome). In the present study, we performed reciprocal crossing among strains with genetically longer (L strain) and shorter (S strain) duration of death feigning, and investigated related heritable factors in the F1 and F2 populations. We also investigated moving activity which negatively responded to artificial selection for death feigning in T. castaneum. Our results showed that death feigning occurred more frequently and for shorter periods in the F1 population. In the F2 population, death feigning and movement showed continuous segregation. The distribution of each trait value in the F2 generation was different from the distribution of trait values in the parental generation, and no individuals transgressing the distribution of trait values in the parental generation emerged in the F2 generation. Chi-square analysis of the observed death feigning and movement of F1 and F2 progenies rejected the hypothesis of mono-major gene inheritance. These results suggest that death-feigning syndrome is controlled in a polygenic manner. Our study indicated that reciprocal crossing experiments are useful in assessing the quantitative inheritance of behavioral traits.