Nutritional plasticity of the black soldier fly (Hermetia illucens) in response to artificial diets varying in protein and carbohydrate concentrations

Abstract

Protein (P) and carbohydrate (C) concentrations present in food affect larval performance, larval body nutrient concentration, and fecundity of the black soldier fly (BSF). We substantially expanded the range of dietary P- and C-concentrations investigated thus far to assess the effects of nutritionally – unbalanced diets on BSF larval and adult life-history traits, and on larval body protein and lipid concentrations. Twenty five artificial diets varying in their P- and C-concentration and ratio were formulated. We tested five macronutrient (P+C) concentrations (5, 15, 25, 50 and 75%) and five P:C ratios (1:1, 1:2, 1:4, 2:1 and 4:1). BSF performance was affected by P+C-concentration rather than by P:C ratios. A P-concentration between 10 and 15% and a C-concentration between 10 and 60% supported high larval and adult performance. P-concentration is limiting for most of the performance variables, however, a P-concentration higher than 37% reduced larval survival. C-concentration affected egg production more strongly than P-concentration. Overall, at P+C values of 25 and 50%, and P:C ratios 1:2 and 1:4 resulted in the highest values of most of the larval and adult performance variables we measured. For the protein and carbohydrate sources tested, dietary macronutrient concentrations significantly affected larval and adult performance of BSF in different ways. These results show a remarkable degree of nutritional plasticity, and point to the relevance of differentiating the formulation of diets to achieve maximal larval yield, high body protein or high body lipid accumulation or high adult emergence and egg production.

Genotype-by-Diet Interactions for Larval Performance and Body Composition Traits in the Black Soldier Fly, Hermetia illucens

“…Lipids are assumed to serve as the sole energy resource for the pupal and adult stages and are, therefore, expected to inherently translate into reproductive output [ 127 ], as feed uptake of adult flies is negligible [ 128 ]. Presumed associations between larval nutritional physiology and investment in fitness upon BSFL maturation (e.g., [ 33 , 41 , 129 ]) have only recently been evaluated by experimentally manipulating nutrients of artificial diets [ 130 , 131 , 132 , 133 ], including evidence that key metabolic responses to dietary conditions involve altered transcription profiles in BSFL fat bodies with relevance for protein and lipid metabolism [ 134 ]. Accordingly, during the transition from the fifth to the sixth (prepupal) larval instar, considered to be the critical phase for lipid metabolism, synthesis, and accumulation [ 41 , 135 , 136 , 137 ], particular signalling cascades may be under nuanced genetic control.…”

Black soldier fly (Hermetia illucens L.) as a high-potential agent for bioconversion of municipal primary sewage sludge

“…According to Barragan-Fonseca et al ( 2020 ), high larval performance can be achieved on substrates with a protein concentration between 10 and 15% (dry matter basis) and with a carbohydrate concentration between 10 and 60% (dry matter basis) and a protein:carbohydrate ratio in the range between 1:2 and 1:4. In this respect, our mixtures had a high protein content, over the range.…”

“…Moisture, pH (Cammack and Tomberlin 2017 ; Ma et al 2018 ), macronutrient content (fats, proteins and carbohydrates), and the availability of a balanced amount of calories are important factors that influence larval development (Gobbi et al 2013 ; Dortmans et al 2017 ; Barragan-Fonseca et al 2018 ; Barragan-Fonseca et al 2019 ; Gold et al 2018 ; Lalander et al 2019 ). Among nutrients, protein content is considered the most important key parameter (Barragan-Fonseca et al 2018 ; 2019 ) together with protein:carbohydrate ratios, having both a large influence on larval development and process performance (Barragan-Fonseca et al 2020 ), while lipids inhibit the larval development only if provided in excess (Oonincx et al 2015 ). The pH even if seems not to be a key factor for the BSFL activity (Joly and Nikiema 2019 ), influences BSFL activity (Meneguz et al 2018 ; Ma et al 2018 ) and should be in the range of 5 and 8 considered as suitable for BSFL development (Lalander et al 2015 ; Rehman et al 2017b ).…”

Nutrigonometry I: using right-angle triangles to quantify nutritional trade-offs in multidimensional performance landscapes

“…Recent initiatives have been made but these are complex to navigate and therefore studies continue to be published with visual inspection or with inaccurate methods to quantify the strength of nutritional trade-offs in GF landscapes [e.g., (Polak et al 2017;Ng et al 2018Ng et al , 2019Kutz et al 2019;Ma et al 2020;Barragan-Fonseca et al 2021)]. Why is it so difficult to measure nutritional trade-offs in GF multidimensional fitness landscapes?…”