As we have mentioned on countless occasions, the darkling beetle species Tenebrio molitor, known as mealworm in its larval stage, is a sustainable alternative for the production of biomass for animal and human food. At CHEERS we will take advantage of its ability to feed on bagasse and brewer’s yeast mixed with wheat bran to obtain high biological quality proteins that will be the basis for the design of new beverages, thus consolidating this value chain according to the project guidelines.

To ensure the success of a Tenebrio molitor farm, it is essential to understand its life cycle and to properly manage the different stages of the rearing process. This insect goes through four well-defined stages (fig.1):

  1. Eggs: Deposited on the nutrient substrate by the female beetles after mating, and which will hatch 7-14 days later depending on the temperature and humidity to which they are exposed.
  2. Larvae: The stage of greatest interest, as they will be fattened, harvested and processed for protein extraction. Under optimal conditions, they grow for about 70-80 days before pupating.
  3. Pupa: During this transitional stage, which lasts 7-14 days, the insect remains immobile and non-feeding while metamorphosis into a beetle takes place.
  4. Beetle: As adults, males and females can mate with each other. Females will lay hundreds of eggs during their 2-3 months of life, ensuring the production of larval biomass.

Fig.1- Diet formula with beer bagasse and wheat bran (left) and Tenebrio molitor life cycle (right)

Efficient industrial rearing of Tenebrio molitor depends on a correct spatial separation of life stages to optimise production. Therefore, we differentiate between larval fattening trays, pupation trays and brood beetle trays (fig. 2). Indiscriminate mixing of the different life stages can lead to significant production losses due to cannibalism of eggs and pupae by larvae and adult beetles.

Every Tenebrio molitor farm starts with an initial colony of breeding beetles. To this end, 100 kilos of Tenebrio molitor larvae have been transferred to the newly built insect plant in Alovera (fig. 3) with the aim of forming a stable colony of breeding beetles to maintain the production of larval biomass.

Fig. 2 – Brood beetle tray (left) and larval fattening tray (right).

It is important to note that the greater the amount of initial biomass, the sooner the maximum production capacity of the plant will be reached. However, we must bear in mind that this also makes management more difficult, especially in view of the experimental trials that PROTEINSECTA wishes to carry out.

It is also important to consider genetic variability, as it has been shown that, in many insect species, continuous inbreeding can lead to low reproductive rates, malformations and damage to egg viability. Therefore, we consolidate the initial mass of broodstock from genetic lineages of different suppliers in order to reduce the likelihood of defects due to inbreeding.

Thus, our initial larval colony will be fed until it pupates and, consequently, transforms into an adult beetle. The brood trays, consisting of breeding beetles, will be sieved weekly to remove the beetles and leave the eggs that have been deposited. These, together with the sieved substrate, will receive a food supply based on the formulation designed for the project, becoming fattening trays for the hatching larvae. In this way, each week new fattening trays are generated for the production of larval biomass (fig. 3).

Fig. 3 – Industrial larval fattening trays

Finally, it is important to consider that a percentage of the fattening trays must be used for the renewal of the brood beetle trays, which will progressively die and need to be replaced in order to maintain a constant and stable flow in egg production and, consequently, in the production of larval biomass.

The industrial farming of Tenebrio molitor represents an opportunity for the development of sustainable food systems. With the right management and an efficient approach, it is possible to establish both industrially scalable and economically profitable production, contributing to the circular economy and global food sustainability.

We will give you more details on our progress soon… until then… CHEERS!!!

About Proteinsecta

PROTEINSECTA is a Spanish insect processing company founded in 2018. It has a farm and processing plant and lab in Spain. PROTE has the largest living-lab net with more than 7 farms in several insect species (Tenebrio Molitor, Hermetia illucens, and Alphitobius Diaperinus) for food and feed in Europe.

Proteinsecta will be in charge of the design of the demo unit for the insect platform and will lead the bioconversion of bagasse to insects (WP2). Learn more about the project partners here.