The developmental stages of the black soldier fly, Hermetia illucens, are widely studied because there are several ways in which this species can be utilized. In this context, the aim of the current study is to determine the loss of weight of larvae of different weights between the prepupal and reproductive adult stages and their effect on the egg clutch quality parameters. The Hermetia illucens prepupae were categorized in 3 body weight classes. The weight loss was evaluated by weighing individuals in the prepupal, pupal and adult stages. The weight and length of the individuals were positively correlated in the pupal stage and adult females. There were significant losses of weight (P = 0.000) in the prepupal, pupal and adult stages in all three weight classes. In each weight class the relationship between weights was significant (P = 0.000) for all development stages. The results clearly indicate that the largest larvae of Hermetia illucens produced the adults with the best clutch quality parameters and the existence of significant positive correlations between body weight and both weight loss and the egg clutch quality parameters.