Black soldier fly larvae (BSFL) are considered a commercially viable solution for global organic waste problems. The objective of this study was to assess the feasibility of rearing BSFL on a wide range of low-value waste streams and its potential to transform them into high-quality animal feed and fertilizer. Six waste streams of different origins were selected and each tested in triplicate. Several parameters were analysed: growth performance, waste reduction index (WRI), conversion efficiency (ECI) and larval composition. Frass composition was also analysed. Larvae reared on fast food waste (FFW) had the highest ECI and WRI and the lowest values when reared on pig manure slurry mixed with silage grass (PMLSG) and slaughter waste (SW). The highest protein content was found for larvae reared on mushroom stems (MS) although this substrate had the lowest protein content. Moreover, the frass nutritional profile was proportionally related to the substrate’s nutritional profile: the protein-rich substrate (SW) resulted in protein-rich frass and the low-protein substrate (MS) resulted in protein-poor frass. The same was true for the lipid content. In conclusion, this study showed that BSFL can be successfully reared on a wide range of waste streams that can affect the larval and frass chemical compositions.

Diet is one of the most important factors affecting the growth and lifecycle of Tenebrio molitor L. The chemical and nutritional properties of the diet of mealworms are well studied whereas its physical properties are almost neglected. This work aims to study the effects of four different particle sizes (0-0.8, 0.8-2, 2-3 and 3-4 mm) of four different feeds (wheat bran, chicken feed pellets, grounded corn kernels and alfalfa dried pellets). Four-week-old larvae were reared on the experimental substrates for four to six weeks depending on the feed. Our results indicate that particle size can significantly influence larval growth and that particles smaller than 2 mm improve larval growth on all feeds except alfalfa pellets. The maximum larval weight was slightly different for wheat bran (12%) when comparing particle sizes smaller than 2 mm with greater than 2 mm but increased up to 70% when corn kernels were used as feed. Significant differences were found between the different feeds for growth rate, larval weight and variability in larval weight. The larvae that reached an average weight of 100 mg the fastest were those reared on wheat bran followed by chicken feed and corn kernels. Larvae reared on alfalfa pellets did not reach an average weight of 60 mg. The variability in larval growth was lowest when fed wheat bran followed by chicken feed and alfalfa pellets, and the highest variability was recorded when fed corn kernels. In conclusion, both the type (wheat bran, chicken feed and corn kernels) and particle size (< 2 mm) of the feed were important determinants of larval growth.

Yellow mealworm is a grain infesting pest that is receiving attention nowadays as an alternative protein source for humans and animals. Its ability to convert low quality feed, like organic by-products, into high-quality food increases its production sustainability. The feeding diet is one of the most important factors in rearingTenebrio molitor Linnaeus (Coleoptera: Tenebrionidae), which affects its growth, longevity and nutritional composition. Many by-products have been tested on larvae, but studies are scarce on adults. This work aimed to compare the effect of chicken feed diet (C) and wheat bran (B) by-product, as well as integrating yeast (CY and BY), on the adults’ reproduction and larval growth. Experiment was set up in a complete productive cycle of mass-rearing. The evaluation was done on the reproductive stage of the adults and the development of the larvae until harvesting (appearance of the first pupa). Results showed that the bran-based diets significantly improved the adults’ survival; after 50 days, mean of 110 and 146 adults survived on B and BY diets respectively compared to mean of 23 adults when reared on both chicken feed diets. Besides, wheat bran supplemented with yeast improved the total number of larvae (6,448.2 larvae) compared to bran diet (4,016.7 larvae). Whereas the two chicken feed-based diets had significant positive effect on the average larval weight; the maximum weight reached was 116.3 mg and 145.8 mg for larvae read on C and CY diets respectively compared to 47.8 mg and 57.3 mg on B and BY diets. Nevertheless, in 50 days of reproduction, the total larval biomass was highest on bran supplemented with yeast (283.1 g). In conclusion, the increase of sustainability and efficiency in mass-rearing of mealworms is possible by using appropriate diets on respective stages; bran-based diets for reproduction and chicken feed-based diets for larval growth.

The information on the production and reproduction of Tenebrio molitor and Hermetia illucens is essential for researchers pursuing a career in insect farming for food, feed and non-food applications. Rather than requiring researchers to sift through numerous studies to develop effective rearing protocols to maintain a stock population for experimental purposes, the authors summarized insights from peer-reviewed research, while expanding it with their collective experience in rearing these species in both laboratory and pilot-scale settings. A similar approach was applied to both species, beginning with a detailed overview of their life cycle, which is used as a framework for various maintenance procedures. Followed by a description of the environmental conditions in which each species should be held and the minimal infrastructure needed to rear them. Feed recommendations are provided, along with good practices for each stage of the lifecycle, including egg production, instar rearing, and adult handling. The final section addresses potential risks and hazards associated with insect rearing. This includes concerns about the allergenicity of particles produced during rearing, as well as the possibility of contamination, disease outbreaks, or pest infestations. The risks associated with maintaining different insect strains, including cross-contamination and the potential for genetic drift or inbreeding depression, are also discussed.

This article of the BugBook provides guidance and addresses challenges towards conducting experiments that aim to optimize the production of insects for food and feed, focusing exclusively on Tenebrio molitor (yellow mealworm) and Hermetia illucens (black soldier fly). The goal is to improve the reliability, reproducibility, and efficiency of insect production experiments. This reduces the human and financial resources needed, improves quality, and ensure the broader implementation of the results. Importantly, these guidelines are based on both data from literature and from unpublished experiences of the authors. Most aspects of the experimental systems are discussed, starting with methods to ensure that the laboratory conditions correct, followed by the experimental design and setup, including a focus on the control group, scale, and number of replicates. Thereafter, information is provided on the different aspects that need to be monitored during the experiment and how to conclude or harvest an experiment. The latter includes a discussion on the various criteria for determining the optimal harvest time. Finally, common challenges in working on insect larvae are identified and guidelines towards relevant publication information are provided.

The artificial diet ofTenebrio molitor has been a focal point of many studies that aimed to design the best diet combination. Recently, studies are focusing on the use of by-products and their efficiency as diets for rearingT. molitor. The rearing was successful on a wide range of by-products-based diets. The feed has a profound impact on the lifespan, growth, productivity and nutritional composition ofT. molitor. Productivity is one of the traits highly influenced by the diet’s composition, especially macronutrients. This work aims to study the effect of eight different diets on the weight and productivity of females and their progeny weight: larval weight. Wheat bran, brewer’s yeast, spent grain and bread remains were used to compose the diets, based on different inclusion percentages of each by-product. The nutritional composition, mainly the macronutrients, of the diets had a narrow range of differences. The diets were designed in a way to avoid the effect of different nutritional compositions and study the effect of the by-products type only. Results showed that the female’s weight-change during the egg-laying period was not significant under different rearing diets. Moreover, the female’s productivity measured by the larval number showed no significant difference between the different diets. However, the total larval biomass (452.4 mg) was significantly higher for larvae reared on diet A composed of wheat bran and brewer’s yeast. Also, the total mean larval weight was significantly higher for larvae reared on diets A (3.1 mg) and G (3.2 mg) composed of wheat bran, brewer’s yeast and spent grain. The mentioned diets although composed of different by-products have similar amounts of protein and carbohydrates. These results prove that the type of by-products included in the experimental diets does not affect the reproductive performance ofT. molitor, while it can affect larval growth.