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

Death-feigning behavior is an anti-predatory technique used in several animal taxa and often correlates with inhibited movements (i.e., death-feigning syndrome). We performed a reciprocal crossing among strains exhibiting a genetically longer (L-strain) and shorter (S-strain) duration of death feigning. Then, we investigated related heritable factors in F 1 and F 2 populations. We also evaluated movement activities, which negatively responded to artificial selection for death feigning in T. castaneum . Our results indicated that death feigning occurred more frequently and for shorter periods in the F 1 population. However, in the F 2 population, death feigning and movement exhibited continuous segregation. Although the distribution of each trait value in the F 2 generation differed from that of the parental generation, no individuals transgressing the distribution of trait values in the parental generation emerged from the F 2 generation. Besides, chi-square analysis of the observed death feigning and movement of F 1 and F 2 progenies rejected the hypothesis of mono-major gene inheritance. These results suggested that the death-feigning syndrome was polygenically controlled, indicating the usefulness of reciprocal crossing experiments in assessing the quantitative inheritance of behavioral traits.