Bees & Insects

Genetic parameters and genotype-by-diet (G à— D) interactions for growth traits in Australian Black soldier fly larvae

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Abstract

Black soldier fly larvae (BSFL) efficiently bio-convert organic waste into high-value protein for livestock, pet, and aquaculture feed. The growth and bioconversion potential of BSFL can be further maximised through selective breeding, which requires an understanding of genetic parameters and genotype-by-diet (G × D) interactions that influence trait performance under different substrate conditions. However, such knowledge needed to inform breeding programs that achieve high genetic gains is limited in the Australian BSFL context. This study estimated heritabilities (h2) and genetic correlations (rg) for BSFL growth traits and quantified G × D interactions across different diets. Fifty-three egg clutches were collected in a single day from a mass-bred BSF colony established through crossbreeding of stocks sourced across Australia. Neonates were randomly assigned to one of three diets: soy-okara (SYK; ~25% crude protein), brewer's spent grain (BSG; ~19% crude protein), or fruit and vegetable waste (FVW; ~11% crude protein), and reared until the fifth instar. Phenotyping was performed on 2,092 larvae to record individual larval body weight (LBW), length (LL), and width (LW), and all larvae were genotyped on a custom-designed genome-wide 6K Allegro SNP panel. The least-squares means of LBW across diets were 176 ± 0.9 mg for SYK, 136 ±1 mg for BSG and 90 ±1 mg for FVW, with the differences attributed to the nutrient content of the diets. Heritabilities, genetic correlations and G × D interactions were estimated using the ASReml-R by fitting an animal model using the genomic relationship matrix (GRM). Heritability was moderate for LBW (0.21 ± 0.03) and low for LL (0.09 ± 0.02) and LW (0.08 ± 0.02). Genetic correlations were high among the growth traits (rg > 0.85), except between LW and LL (0.68), indicating that selection for LBW is feasible and could achieve genetic gain while also improving correlated traits. G x D interactions were substantial: LBW (0.17 ± 0.16 to 0.45 ± 0.14), LL (-0.07 ± 0.21 to 0.47 ± 0.20), and LW (0.15 ± 0.24 to 0.41 ± 0.28) across diets. The observed heritabilities suggest that substantial genetic gain can be achieved given the short generation interval of BSF (~38-45 days); however, G × D interactions must be considered when implementing selective breeding. To implement a single breeding program, data from all diets should be included, or diet-specific selection programs should be designed and implemented. In conclusion, this study developed fundamental knowledge required for designing and implementing selective breeding programs to improve BSFL production, supporting sustainable protein production and the development of Australian BSFL farming.

Keywords: 2026

How to Cite:

Bommalingegowda, K., Jerry, D., Jones, D., Septriani, S., Tedder, C. & Zenger, K., (2026) “Genetic parameters and genotype-by-diet (G à— D) interactions for growth traits in Australian Black soldier fly larvae”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2267950. doi: https://doi.org/10.31274/wcgalp.23398

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