Bi-Directional Selection for Larval Period and Its Consequence on Pre-Pupal Weight in the Housefly, Musca domestica L

A two-way selection for larval period and the corresponding pre-pupal weight in the housefy, Musca domestica L. was carried out for parental through F16 generations when the traits attained plateaued levels. The high (shorter larval duration) and low (longer larval duration) selection regimes for larval period showed gradual and effective response from the very beginning (130.9±1.62 hrs), reaching at 96.10±2.74 hrs and 153.40±1.48 hrs, respectively in the end. Divergence in selection response for the larval duration ranged between 0.20 and 3.40 for the high and 0.30 and 3.00 for the low line, while the estimated narrow-sense cumulative heritability (h2) values for the lines were 0.28 and 0.37, respectively. Pre-pupal weight in the parental generation was 304.8±2.59 mg that increased to 439.3±1.57 mg in the high and declined to 172.5±2.77 mg in the low regime during 16 generations of selection. The larval period in M. domestica was found to be negatively correlated with the pre-pupal weight. relevance of the findings to the adaptation of the insect has been discussed