Three-generation simultaneous selection in two quantitative traits of <i>Tenebrio molitor</i> (Coleoptera: Tenebrionidae) and seasonal effects on phenotype expression

Tenebrio molitor L. (Coleoptera Tenebrionidae) is 1 of the 3 most important species of industrialized insects worldwide. Its potential as a substitute for fish meal in animal feed formulations and as a source of protein and lipid for human consumption has increased over the years. Improving the characteristics of the stock commercial colonies of T. molitor to increase biomass productivity is one of the current questions of interest for the industry. Despite their high degree of plasticity, the quantitative traits development time and pupal weight have been proven to possess sufficient levels of heritability to be impacted by selection. The objective of this study was to determine if significant differences in these 2 traits could be observed in selected populations after 3 generations of selection. Starting from a single cohort from the stock colony, mealworms were grouped in 4 selection groups (F0): completing larval development within 16, 18, 20, and 22 wk and with pupal weight ranges of 180 to 199, 200 to 219, 220 to 239, and 240 to 259 mg, respectively. Groups were selected for 3 generations to conform with the ranges established and at the end of selection, fecundity and egg viability were evaluated for F3 adults of each of the selection classes. Significant changes in development time and pupal weight were observed in the F3 in all the selected classes. The F3 also showed significant differences in fecundity, egg viability, and immature survival at the end of the F3.