Genetic parameters and pedigree–based selective breeding outcomes for productivity traits in industrial black soldier fly (hermetia illucens L.) production systems

Abstract Background Selective breeding in mass-reared insects has progressed rapidly in recent years, and the black soldier fly ( Hermetia illucens L. - Diptera: Stratiomyidae), the most widely cultivated insect species for animal feed, is emerging as a strong candidate for genetic improvement. Estimation of quantitative‑genetic parameters and implementation of pedigree‑based selection schemes are essential to increase genetic gain while controlling inbreeding under industrial rearing. Here, we report a pilot‑scale breeding experiment conducted under family group‑mating with partial pedigree uncertainty, designed to assess the genetic parameters of key growth and reproductive traits in H. illucens and to evaluate the feasibility of pedigree‑informed selection in an industrial context. Genetic parameters were estimated using multivariate REML animal models and breeding values were predicted using Best Linear Unbiased Prediction. The feasibility of systematic genetic improvement under industrial rearing conditions was assessed through seven generations of family selection. Results A total of 15 179 individuals from 266 full-sib isofamilies were phenotyped. Heritability estimates (± SE) were: larval weight at stage 1 (LW1, h 2 = 0.12 ± 0.08), stage 2 (LW2, h 2 = 0.13 ± 0.04), restricted-feed LW2 (LW2R, h 2 = 0.58 ± 0.03), female body weight at emergence (FEMBW, h 2 = 0.006 ± 0.005), pupal perimeter (PERIM, h 2 = 0.06 ± 0.09), oocyte number (OOCY, h 2 = 0.43 ± 0.09), and thorax size (THOR, h 2 = 0.40 ± 0.09). Several traits exhibited substantial environmental variance. Larval body-weight traits (LW1, LW2, LW2R) exhibited positive genetic correlations with thorax size and oocyte number, while female body weight at emergence was negatively correlated with larval body weight. In this pilot‑scale programme, seven generations of selection for larval body weight yielded indicative genetic improvement, tempered by design constraints and a detectable risk of inbreeding. Conclusions These multi-trait genetic parameter estimates indicate that several economically important traits in H. illucens are moderately to highly heritables. Although genetic correlations were generally trait-dependent and could be either positive or negative, supporting the potential for genetic improvement through appropriately designed multi-trait breeding strategies. Patterns observed for larval body weight are indicative of a genetic response under industrial conditions, although environmental contributions cannot be fully excluded in the absence of a control line. Together, these results suggest the potential for genetic improvement in H. illucens populations, provided that inbreeding is carefully managed through adequate selection nucleus size and pedigree organisation.