Influence of larval density and dietary nutrient concentration on performance, body protein, and fat contents of black soldier fly larvae (Hermetia illucens)

Abstract

Performance and body composition of insect larvae depend on quality and quantity of their diet, and on biotic factors such as larval density. We investigated the effect of dietary nutrient concentration and larval rearing density on survival, development, growth, and protein and fat contents of larvae of the black soldier fly (BSF), Hermetia illucens L. (Diptera: Stratiomyidae). Neonate larvae were fed with a low (NC1), intermediate (NC2), or high nutrient concentration (NC3), and with four rearing densities (50, 100, 200, or 400 larvae per container). Two feeding regimes (FR) were tested: in FR1, the amount of diet added during the experiment was based on the visually estimated larval mass present, whereas in FR2, a fixed feeding ration of 0.6 g of food per larva was applied at the start. FR1 resulted in food limitation, resulting in significantly lower body crude protein content on diet NC1 than on NC2 at larval densities 100 and 200. Larval crude fat content was higher on diets with higher nutrient concentration and at lower larval densities. For FR2, development time was shorter on diets with higher nutrient concentration and at lower larval densities. Individual larval weight and total larval yield increased with higher nutrient concentration at all four larval densities. At lower nutrient concentration, higher larval density resulted in higher individual larval weight and total larval yield, revealing an interaction between larval density and dietary quality. Larval crude protein content was higher at lower densities and lower nutrient concentration. Larval crude fat was higher at higher larval densities and nutrient concentrations. This study indicates that larval protein content is regulated within narrow limits, whereas larval crude fat content is strongly affected by nutrient concentration and by larval density.

Effects of dietary protein and carbohydrate on life‐history traits and body protein and fat contents of the black soldier fly Hermetia illucens

“…Even though all P + C‐contents tested are suitable for the complete life cycle of this species, because diet P17:C55 (P:C = 1:3; P + C = 72) supports the highest larval and adult performance and results in a high body crude protein content (42.3%) and an intermediate crude fat content (27.6%) on the diets tested, this would be the intake target for the fly feeding on chicken feed‐based diets, which matches with the P + C content of those resources that this species colonizes in the wild. Additionally, we also confirm our previous findings concerning the regulation of larval protein content within narrow limits, whereas larval crude fat content is strongly affected by nutrient concentration (Barragan‐Fonseca et al , ).…”

Stable flies, Stomoxys calcitrans L. (Diptera: Muscidae), improve offspring fitness by avoiding oviposition substrates with competitors or parasites

“…This provides a functional basis for avoidance of substrates with conspecific or heterospecific larvae by gravid female S. calcitrans. The impact of larval density on fitness parameters has also been found in other Diptera including Hermetia illucens [52], B. oleae [53], D.…”

“…aegypti larvae decreased by almost 50% as larval density increased. In H. illucens, crude fat concentration is higher in larvae reared at low density than those reared at high density [52]. Other studies suggest that high larval mortality observed with increased larval density results from interference competition.…”

Flies are what they eat : Tailoring nutrition of Black Soldier Fly (Hermetia illucens L.) for larval biomass production and fitness

“…The diets were formulated by including a standard proportion of chicken feed (Opfokmeel Farmfood, Agruniek Rijnvallei Voer BV, Wageningen, The Netherlands) in the diet (63% of the total dry mass of the experimental diet, which contributed 10% protein and 31.5% carbohydrate to each treatment). This was used because it supports the full life cycle of BSF (K. Barragán-Fonseca, personal observation from BSF rearing and previous experiments (Barragan-Fonseca et al, 2018). The remaining 37% of the experimental diet was composed of the protein casein (Bio-connect, Huissen, NL), containing all the essential amino acids in high and for insects well-balanced proportions (Cohen, 2004), and the digestible carbohydrate starch (Duchefa Biochemie BV, Haarlem, NL), which served both as a nutrient and as a texturing agent.…”