SUMMARY Simultaneous selection byindependent culling levelsof two correlated traits in all four combinations of directions was investigated withTriboliumin a replicated experiment extending over nine generations. In addition to the two primary traits, 13-day larval weight and pupal weight, four secondary traits (pupation time, adult emergence time, adult weight and larval number) were observed. The observed responses for both selected and unselected traits agreed with theoretical expectations after the latter were adjusted for changes which occurred in genetic and phenotypic parameters. Phenotypio variances for the selected traits were correlated positively with population means, yet genetic variances and heritabilities declined in all selected populations. No change was detected in the genetic correlation between selected traits even though the divergent two-trait selection was designed especially to ‘break’ the positive correlation of + 0·55 ± 0·12 present in the base population. Striking changes in growth and developmental patterns resulting from the divergent selection were discussed in terms of metamorphic limits and ‘stabilizing’ genetic correlations.
No takes yet. Share an insight, caveat, or question.
Bell et al. (1973) studied this question.
Synapse has enriched 3 closely related papers on similar clinical questions. Consider them for comparative context: