Selection on phenotypic variation of pupa weight in Tribolium castaneum

Abstract

Responses to selection for high and low intrafamily coefficients of variation of pupa weight in Tribolium castaneum were observed for 10 generations. A significant decrease of the coefficient of variation has been observed in the replicated lines selected downwards while no response occurred in the other lines. Mean pupa weights did not change significantly throughout the experiment while mean fertility decreased in all lines, probably as a consequence of inbreeding depression. Realized heritability of the coefficient of variation of pupa weight was 0.15 ± 0.04 and 0.03 ± 0.01% for the downwards and upwards lines, respectively. These results show that the manipulation of the phenotypic variability by direct selection is possible.Key words: Tribolium, phenotypic variance, coefficient of variation of pupa weight.