Is there a genetic correlation between movement and immobility in field populations of a beetle?

Abstract

Genetic correlations among behavioural traits are often controlled by pleiotropic genes. Many studies suggest the existence of genetic correlations among behavioural traits based on artificial selection experiments in the laboratory. However, few studies have examined whether behavioural correlations in the laboratory are maintained in the field, where natural selection works. Artificial selection experiments showed a behavioural correlation among death feigning, walking movement, and locomotor activity in the red flour beetle (Tribolium castaneum). This study investigated whether this behavioural correlation is observed in wild T. castaneum populations. We also collected beetles from various regions in Japan and investigated the geographic variation in these traits. There was geographic variation in the three behavioural traits. However, these behavioural traits were not correlated. The results suggest that the genetic correlations among behavioural traits are not maintained in the field. Therefore, the results derived from laboratory experiments may be overestimated. The same correlation between traits was not believed to arise in the field, as the indoor results may have been caused by unrealistic selection pressures. Further laboratory and field investigations are both needed.