'Insects as Food and Feed: If You Can't Beat Them, Eat Them!'-To the Magnificent Seven and Beyond

Insects as Source of Nutraceuticals with Antioxidant, Antihypertensive, and Antidiabetic Properties: Focus on the Species Approved in Europe up to 2024

Insects represent a traditional food in different parts of the world, where eating insects is not only related to nutrition, but also results from a variety of sociocultural customs. Insects' nutritional profiles typically vary by species. Nevertheless, in terms of nutrition, edible insects can be a rich source of protein, dietary fiber, healthy fatty acids, and micronutrients, including minerals and vitamins. Insects have a low carbon footprint and require fewer resources in terms of land, water, and food with respect to animal livestock. Interestingly, insects are a source of bioactive compounds with different pharmacological activities, including antioxidant, antimicrobial, antidiabetic, antiobesity, antihypertensive, and antilipidemic. Among the bioactive compounds, polyphenols, chitosan, and protein hydrolysates are the most important ones, with direct activity on ROS quenching and enzymatic inhibition. Glucosidase, DPP-IV, ACE, and lipases are directly inhibited by insects' bioactive peptides. Lipids and tocopherols reduce inflammation and lipid peroxidation by acting on LOX and COX-2 enzymes and on ROS quenching. The insects' nutrient composition, coupled with their easy and economical breeding, is the cause of the growing interest in edible insects. During the last 20 years, the study and development of novel insect-based products increased, with relevant effects on the market. This review focuses on the edible insects currently approved in Europe, namely, Acheta domesticus, Alphitobus diaperinus, Locusta migratoria, and Tenebrio molitor. The nutrient profile and the functional compounds are examined, with an eye on market trends and on the patent applications filed in the last decades.

Zophobas morio versus Tenebrio molitor: Diversity in gut microbiota of larvae fed with polymers

Plastics are common synthetic materials that have been abundantly present as pollutants in natural ecosystems for the past few decades. Thus scientists have investigated the capability of plastic digestion by insects. Here we compare the effectiveness of biodegradation of the specific polymers: expanded polystyrene (EPS), polyvinyl chloride (PVC), low-density polyethylene (LDPE) and polypropylene (PP) altogether with above variants of plastics with microelements and vitamins by the mealworm - the larval form of the beetle Tenebrio molitor - and larvae of the beetle Zophobas morio, known as superworms. Z. morio beetles on all diets were able to complete their life cycle from larvae through pupae and imago, gaining 19 % and 22 % in mass on LDPE and EPS; 8 % and 7 % on PVC and PP. Mealworms (T. molitor) reared on polymers had minimal weight gain, gaining 2 % on LDPE and EPS, and a slight reduction in mass was observed when reared on PP and PVC. Not all specimens of T. molitor were able to pupate and transform to the adult stage. The results suggest that larvae of Z. morio can eat and degrade some types of plastic compounds more effectively than T. molitor. The changes in microbial gut communities were compared between these two species. The highest mass gain for Z. morio is associated with higher diversity in gut microbia and it was more diverse than that of T. molitor. Citrobacter freundii, a bacterium recognized for its ability to degrade long-chain polymers, linear hydrocarbons and cyclic hydrocarbons, was found in the microflora of Z. morio. The results confirm that superworms can survive on polymer feed. Moreover, this diet supplemented with microelements and vitamins increases the number of bacterial species and the diversity in the microbial gut.

Understanding consumers attitude towards insects as food: Influence of insect species on liking, emotions, sensory perception and food pairing

Entomophagy studies mainly focused on insects as a generic category, rarely considering insect species. This study investigated the: i) affective response to specific edible insect species; ii) sensory properties characterizing the tested insects and their role in driving preferences and food paring. A sensory test (85 consumers, 56.5 % female, 19-73 years) was performed on seven dried whole edible insects at the adult (weaver ants, crickets, grasshoppers), larva (bamboo worms, morio worms, sago worms) and pupae stage (silkworms). For each species, consumers expressed their liking and, through three check-all-that-apply tests, described the perceived sensory properties, the perceived emotions, and their potential food pairings. Results showed a significant effect of the species on all variables. Bamboo worms, weaver ants and grasshoppers resulted the most accepted, followed by morio worms, crickets, and silkworms, while the sago worms were the most disliked. Numerous sensory attributes significantly discriminated among insect species and the drivers of liking and sensory attributes associated to the food pairings were identified. However, two clusters with different preferences and drivers of liking were observed. Moreover, a gender effect was found: i) males associated insects with emotions like calm and wild, while females with glad and pleased; ii) males and females would pair different foods with the insect species. In conclusion, this study provided new knowledge useful for researchers and food industry to develop future insect-based foods and dishes able to meet the expectations of different consumers segments.

Larval performance of Zophobas morio (F.) (Coleoptera: Tenebrionidae) on various diets enriched with post-distillation residues and essential oils of aromatic and medicinal plants

The increasing demands for resources driven by the global population necessitate exploring sustainable alternatives for affordable animal protein over the use of traditional protein sources. Insects, with their high protein content, offer a promising solution, especially when reared on agricultural post-distillation residues for enhanced sustainability and cost-effectiveness. We assessed the development of Zophobas morio (F.) (Coleoptera: Tenebrionidae) larvae on diets enriched with essential oils and post-distillation residues from Greek aromatic and medicinal plants. Two aromatic plant mixtures (A and B) were examined. Mixture A consisted of post-distillation residues, while Mixture B incorporated these residues along with essential oils. Insect rearing diets were enriched with different proportions (10, 20, and 30 %) of these mixtures, with wheat bran serving as the control. Enrichment positively influenced larval development without compromising survival. Larval weight remained unchanged with Mixture A, but improved with Mixture B. No adverse effects were detected in the case of the enriched diets, although higher concentrations of Mixture B prolonged development time.

A Model for Consumer Acceptance of Insect-Based Dog Foods among Adult UK Dog Owners

The use of alternative proteins is becoming more common in pet feed, and insect-based dog foods (IBDFs) are becoming more widely available. However, little research has been conducted to date in respect of the drivers for consumers' acceptance of IBDF. This study aimed to investigate the acceptance of IBDF among adult UK dog owners and the factors influencing the decision to try and buy such products. A theoretical model was developed following a review of the existing literature. An online survey of 280 participants was carried out and the results were analysed using structural equation modelling (SEM) to test the theoretical model. The following constructs all had a significant impact on attitudes towards IBDF and/or intentions to try and buy IBDF: food preferences for animal welfare, health and environment; attitudes towards uses of animals; beliefs about insect sentience; disgust; perceptions of benefits and risks; and social norms. Social norms had the strongest influence of any single construct. Consumer acceptance of IBDF is multi-faceted including social, cultural and ethical components, and it is likely that the better availability of information and opportunities for consumers to familiarise themselves with IBDF would help to drive consumer acceptance. In order to allow dog owners to make informed decisions in line with their ethical preferences, further research is needed to establish the overall health and welfare implications of IBDF on the animals involved in production, as well as the companion animals, who are the ultimate consumers.

Mating compatibility and offspring traits evaluation among different strains of Tenebrio molitor

The fast-growing sector of insects for food and feed stimulates researchers and the industry to explore uncharted territories, such as insect breeding, to improve economically important insect fitness traits. The yellow mealworm, Tenebrio molitor L., is one of the most thoroughly studied insect species as food and feed. However, data on mating compatibility and the effect of cross-breeding between different strains on the performance and fitness of the hybrids are scarce. In the present study, we comparatively evaluated the mating compatibility between two T. molitor inbred strains (Greek and Italian) and their outbred strains, i.e., Italian (♀)-Greek (♂) and Greek (♀)-Italian (♂), as well as the performance of their hybrid offspring. Based on the results, there is good mating compatibility among adults of the strains tested. Offspring performance, quantified as larval survival and final larval weight, followed a similar pattern among the crossings examined. Even though differences were insignificant, the outbreeding of females of the Italian strain resulted in a higher cumulative number of eggs and hatching rate and higher offspring weight. The present study sheds light on the mating compatibility of different T. molitor strains and their hybrids' economically important life table characteristics to take the mass production of insects one step further.

Metabolic Modeling of Hermetia illucens Larvae Resource Allocation for High-Value Fatty Acid Production

All plant and animal kingdom organisms use highly connected biochemical networks to facilitate sustaining, proliferation, and growth functions. While the biochemical network details are well known, the understanding of the intense regulation principles is still limited. We chose to investigate the Hermetia illucens fly at the larval stage because this stage is a crucial period for the successful accumulation and allocation of resources for the subsequent organism's developmental stages. We combined iterative wet lab experiments and innovative metabolic modeling design approaches to simulate and explain the H. illucens larval stage resource allocation processes and biotechnology potential. We performed time-based growth and high-value chemical compound accumulation wet lab chemical analysis experiments on larvae and the Gainesville diet composition. We built and validated the first H. illucens medium-size, stoichiometric metabolic model to predict the effects of diet-based alterations on fatty acid allocation potential. Using optimization methods such as flux balance and flux variability analysis on the novel insect metabolic model, we predicted that doubled essential amino acid consumption increased the growth rate by 32%, but pure glucose consumption had no positive impact on growth. In the case of doubled pure valine consumption, the model predicted a 2% higher growth rate. In this study, we describe a new framework for researching the impact of dietary alterations on the metabolism of multi-cellular organisms at different developmental stages for improved, sustainable, and directed high-value chemicals.

Evaluation of the susceptibility of Alphitobius diaperinus meal to infestations by major stored-product beetle species

The projections for the production of insects as food and feed show an enormous increase for insect production in the near future, which will subsequently lead to the increase of the stored quantities of insect meals and related products. However, information on the susceptibility of insect meals to infestations by stored-product insects is rather limited. To this end, the objective of the present study was to evaluate the potential of major storage insect species to grow and reproduce on insect meals that are based on larvae of the lesser mealworm, Alphitobius diaperinus. The progeny production of thirteen stored-product insects on A. diaperinus meal, as well as their instantaneous rate of increase, as a measure of population growth, was recorded for each species. Based on the results, six out of the thirteen examined insect species (A. diaperinus, Tenebrio molitor, Trogoderma granarium, Lasioderma serricorne, Tribolium confusum, and Tribolium castaneum) were able to infest pure A. diaperinus meal, as they grew well and developed progeny on the insect meal substrate. Tribolium confusum, T. castaneum, and especially T. granarium gave the highest progeny production numbers in the A. diaperinus meal with the latter giving an instantaneous rate of increase of 0.067. Expecting the upcoming increase in the production of insect-based products globally, further research in this field is needed for improved production and storage facilities, detection and estimation methods, and technologies to minimize insect infestations without causing negative effects to farmed insects.

Development of a DNA Metabarcoding Method for the Identification of Insects in Food

Insects have the potential to become an efficient and reliable food source for humans in the future and could contribute to solving problems with the current food chain. Analytical methods to verify the authenticity of foods are essential for consumer acceptance. We present a DNA metabarcoding method that enables the identification and differentiation of insects in food. The method, developed on Illumina platforms, is targeting a 200 bp mitochondrial 16S rDNA fragment, which we found to be suitable for distinguishing more than 1000 insect species. We designed a novel universal primer pair for a singleplex PCR assay. Individual DNA extracts from reference samples, DNA extracts from model foods and food products commercially available were investigated. In all of the samples investigated, the insect species were correctly identified. The developed DNA metabarcoding method has a high potential to identify and differentiate insect DNA in the context of food authentication in routine analysis.

Challenges in farmed insect welfare: Beyond the question of sentience

The global Insects as Food and Feed (IAFF) industry currently farms over a trillion individual insects a year and is growing rapidly. Intensive animal production systems are known to cause a range of negative affective states in livestock; given the potential scale of the IAFF industry, it is urgent to consider the welfare of the industry's insect livestock. The majority of the literature on farmed insect welfare has focused on: (i) establishing that insect welfare ought to be of concern; or (ii) extending vertebrate welfare frameworks to insects. However, there are many overlooked challenges to studying insect welfare and applying that knowledge in IAFF industry contexts. Here, we briefly review five of these challenges. We end with practical recommendations for the future study of insect welfare.

In Vitro Evaluation of Antimicrobial Peptides from the Black Soldier Fly (Hermetia Illucens) against a Selection of Human Pathogens

Antimicrobial peptides (AMPs) are being explored as alternatives to traditional antibiotics to combat the rising antimicrobial resistance. Insects have proven to be a valuable source of new, potent AMPs with large structural diversity. For example, the black soldier fly has one of the largest AMP repertoires ever recorded in insects. Currently, however, this AMP collection has not yet undergone antimicrobial evaluation or in-depth in vitro characterization. This study evaluated the activity of a library of 36 black soldier fly AMPs against a panel of human pathogens (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Aspergillus fumigatus) and a human cell line (MRC5-SV2). The activity profile of two cecropins (Hill-Cec1 and Hill-Cec10) with potent Gram-negative activity, was further explored by characterizing their hemolysis, time-to-kill kinetics, membrane-permeabilization properties, and anti-biofilm activity. Hill-Cec1 and Hill-Cec10 also showed high activity against other bacterial species, including Klebsiella pneumoniae and multi-drug resistant P. aeruginosa. Both AMPs are bactericidal and have a rapid onset of action with membrane-permeabilizing effects. Hill-Cec1 and Hill-Cec10 were also able to prevent P. aeruginosa biofilm formation, but no relevant effect was seen on biofilm eradication. Overall, Hill-Cec1 and Hill-Cec10 are promising leads for new antimicrobial development to treat critical infections caused by Gram-negative pathogens such as P. aeruginosa.

IMPORTANCE With the ever growing antimicrobial resistance, finding new candidates for antimicrobial drug development is indispensable. Antimicrobial peptides have steadily gained attention as alternatives for conventional antibiotics, due to some highly desirable characteristics, such as their low propensity for resistance development. With this article, we aim to upgrade the knowledge on the activity of black soldier fly antimicrobial peptides and their potential as future therapeutics. To achieve this, we have evaluated for the first time a library of 36 synthetically produced peptides from the black soldier fly against a range of human pathogens and a human cell line. Two selected peptides have undergone additional testing to characterize their antimicrobial profile against P. aeruginosa, a clinically important Gram-negative pathogen with a high established resistance. Overall, this research has contributed to the search for new peptide drug leads to combat the rising antimicrobial resistance.

Farm to Institution to Farm: Circular Food Systems With Native Entomoculture

Edible insects recycle food waste, which can help feed a hungrier planet by making food systems more circular and diversifying protein production. The potential for entomophagy (i.e., insect cuisine) to contribute to waste recycling and lower input food production is only beginning to be explored in the U.S., although insects have been consumed by people for millennia in a wide range of cultures. In this perspective piece, we consider as a case study the potential for university foodservice programs in New England to serve as incubators for circular entomophagous food systems. Students are likely early adopters of entomophagy because they increasingly demand sustainable non-meat protein options. University foodservices meanwhile purchase large amounts of food wholesale from local producers, utilize standardized pre-processing, and generate consistent waste streams which may be valuable feed for local insect farmers. Current Farm to Institution approaches strengthen regional food systems by connecting small farmers with university foodservices; we argue that a similar model (Farm to Institution to Farm) could support establishment of local insect farms, introduce edible insects to a relatively receptive base of university student customers, and provide a more sustainable mechanism for repurposing university food waste as insect feed. But to enable this type of food system, additional requirements include: (1) research on domestication of native insect species; (2) investment in processing capacity, ensuring new insect farmers have reliable markets for raw insect products; (3) infrastructure to recirculate waste streams within existing food systems; and (4) creation of recipes that entice new insect consumers.

Habitat-centric versus species-centric approaches to edible insects for food and feed

The current paradigm of the edible insects for food and feed industry uses a species-centric approach in which an insect species is chosen first and development of rearing practices follows. The goal is to optimize production to maximize the yield of that species in that facility. In contrast, the habitat-centric approach first chooses a habitat, either natural or artificial, then develops harvesting or rearing protocols within that habitat. The goal of this approach is to maximize the yield derived from that habitat. The habitat-centric approach eliminates potential threats from invasive species, and can repurpose local food and agricultural waste into protein derived from local insect species. This approach can increase food security by increasing the diversity of insects that are mass-produced. The species-centric and habitat-centric approaches address different issues and offer advantages in different situations. Further development of the edible insect industry will likely use a combination of both approaches.

Influence of Temperature, Relative Humidity and Protein Content on the Growth and Development of Larvae of the Lesser Mealworm, Alphitobius diaperinus (Panzer)

The human population is rapidly growing, subsequently leading to an increase in food and protein demand. Therefore, alternative protein sources have to be evaluated as food and feed. Among the most promising alternative protein sources with significant advantages are insects. Nevertheless, insect rearing conditions have to be optimized prior to insect mass production. In the present study, using laboratory bioassays, we evaluated the effect of several biotic and abiotic factors on the development of the larvae of the lesser mealworm, Alphitobius diaperinus (Panzer). In the first series of bioassays, we investigated A. diaperinus larval growth at three temperatures (25, 30 and 32 °C) and two relative humidity (r.h.) levels (55 and 75%). Furthermore, in the second series of bioassays, the larval growth was assessed on wheat bran-based substrates with different percentages of yeast, i.e., 0%, 10%, 17.5%, 25%, 32.5% and 40%. According to our results, the temperature was shown to be highly important for larval development, with A. diaperinus larvae performing better at the higher temperatures tested, i.e., 30 and 32 °C. In contrast, relative humidity did not have a significant effect on A. diaperinus growth, at least for the relative humidity levels tested. Finally, the increase in the percentage of yeast in the diet increased larval growth, development and survival. Our study aims to highlight the significance of several biotic and abiotic factors for the rearing of A. diaperinus larvae, providing parameters that can be further utilized in mass rearing protocols of this species.