Cyclopropane Hydrocarbons from the Springtail Vertagopus sarekensis─A New Class of Cuticular Lipids from Arthropods.

The epicuticle of insects is usually coated with a complex mixture of hydrocarbons, primarily straight-chain and methyl-branched alkanes and alkenes. We were interested in whether springtails (Collembola), a sister class of the insects, also use such compounds. We focused here on Vertagopus sarekensis, an abundant Isotomidae species in European high alpine regions, exhibiting coordinated group behavior and migration. This coordination, suggesting chemical communication, made the species interesting for our study on epicuticular hydrocarbons in springtails with different degrees of group behavior. We isolated a single hydrocarbon from its surface, which is the major epicuticular lipid. The structure was deduced by NMR analysis and GC/MS including derivatization. Total synthesis confirmed the structure as cis,cis-3,4,13,14-bismethylene-24-methyldotriacontane (4, sarekensane). The GC/MS analyses of some other cyclopropane hydrocarbons also synthesized showed the close similarity of both mass spectra and gas chromatographic retention indices of alkenes and cyclopropanes. Therefore, analyses of cuticular alkenes must be performed with appropriate derivatization to distinguish these two types of cuticular hydrocarbons. Sarekensane (4) is the first nonterpenoid cuticular hydrocarbon from Collembola that is biosynthesized via the fatty acid pathway, as are insect hydrocarbons, and contains unprecedented cyclopropane rings in the chain, not previously reported from arthropods.

Bioactive Peptides Derived from Edible Insects: Effects on Human Health and Possible Applications in Dentistry.

Novel foods, including edible insects, are emerging because of their nutritional characteristics and low environmental impacts and could represent a valid alternative source of food in a more sustainable way. Edible insects have been shown to have beneficial effects on human health. Insect-derived bioactive peptides exert antihypertensive, antioxidant, anti-inflammatory, and antimicrobial properties and have protective effects against common metabolic conditions. In this review, the roles of edible insects in human health are reported, and the possible applications of these peptides in clinical practice are discussed. A special mention is given to the role of antimicrobial peptides and their potential applications in controlling infections in orthodontic procedures. In this context, insects' antimicrobial peptides might represent a potential tool to face the onset of infective endocarditis, with a low chance to develop resistances, and could be manipulated and optimized to replace common antibiotics used in clinical practice so far. Although some safety concerns must be taken into consideration, and the isolation and production of insect-derived proteins are far from easy, edible insects represent an interesting source of peptides, with beneficial effects that may be, in the future, integrated into clinical and orthodontic practice.

Review: Recent advances in insect-based feeds: from animal farming to the acceptance of consumers and stakeholders.

The search for new, alternative and sustainable feeding sources, including insects, has become an important challenge on the feed market. In 2017, the European Union (EU) started to allow the use of insect meals as feeds for fish. In addition, in 2021, the EU also authorised the use of insect meal for pig and poultry farming. However, the adoption of insect meal by the European aquaculture sector is still limited, and this is mostly due to the lack of availability of insects and their higher costs than conventional feed ingredients. Thus, the insect-based feed industry is still in its infancy, and its successful development and integration in the food value chain depend on several factors. Among these, the technical feasibility and production of quality products, and acceptance by European consumers and farmers are relevant factors. To address these points, this narrative review describes the state of the art of the potential role of insect-based feeds. The stakeholders' and consumers' perspectives are investigated, along with the effects of insect-based feeds on the production and nutritional values of fish, poultry (meat and eggs), and pork. Indeed, matching the nutritional values of insect products with conventional feeds is one of the future challenges of the insect sector, as their nutritional composition is highly dependent on the rearing substrates, and thus, their use in animal feeding needs to be investigated carefully. Feeding animals with insect-based diets affects their growth performances and the chemical composition of the derived products (fish fillets, meat, and eggs). Whether these effects can be considered positive or negative seems to depend to a great extent on the percentage of insects included in their diets and the chemical composition of the ingredients. The use of insect-based feeds has also shown a potential to improve the nutritional features and values of animal products and even to add new ones. Finally, many of the acceptance studies on the use of insects in feeds have focused mostly on the consumers' perception rather than on industry stakeholders (e.g., farmers). Future research should focus more on the farmers' perceptions on and market analyses of these innovative feeds. Even though it is likely that the upscaling of the insect sector will lead to a decrease in prices and an increase in market availability, it is still critical to understand the potential barriers and drivers for the implementation of insects as feeds from a production point of view.

Simultaneous Detection and Distribution of Five Juvenile Hormones in 58 Insect Species and the Absolute Configuration in 32 Insect Species.

Juvenile hormone (JH) plays an important role in regulating various insect physiological processes. Herein, a novel method (chiral and achiral) for the simultaneous detection of five JHs was established by processing a whole insect without complicated hemolymph extraction. The proposed method was used to determine the distribution of JHs in 58 insect species and the absolute configuration of JHs in 32 species. The results showed that JHSB3 was uniquely synthesized in Hemiptera, JHB3 was unique to Diptera, and JH I and JH II were unique to Lepidoptera. JH III was present in most insect species surveyed, with social insects having generally higher JH III titers. Interestingly, JHSB3 and JHB3, both double epoxidation JHs, were found in insects with sucking mouthparts. The absolute conformation of JH III and the 10C of the detected JHs were all R stereoisomers.

An Assassin's Secret: Multifunctional Cytotoxic Compounds in the Predation Venom of the Assassin Bug Psytalla horrida (Reduviidae, Hemiptera).

Predatory assassin bugs produce venomous saliva that enables them to overwhelm, kill, and pre-digest large prey animals. Venom from the posterior main gland (PMG) of the African assassin bug Psytalla horrida has strong cytotoxic effects, but the responsible compounds are yet unknown. Using cation-exchange chromatography, we fractionated PMG extracts from P. horrida and screened the fractions for toxicity. Two venom fractions strongly affected insect cell viability, bacterial growth, erythrocyte integrity, and intracellular calcium levels in Drosophila melanogaster olfactory sensory neurons. LC-MS/MS analysis revealed that both fractions contained gelsolin, redulysins, S1 family peptidases, and proteins from the uncharacterized venom protein family 2. Synthetic peptides representing the putative lytic domain of redulysins had strong antimicrobial activity against Escherichia coli and/or Bacillus subtilis but only weak toxicity towards insect or mammalian cells, indicating a primary role in preventing the intake of microbial pathogens. In contrast, a recombinant venom protein family 2 protein significantly reduced insect cell viability but exhibited no antibacterial or hemolytic activity, suggesting that it plays a role in prey overwhelming and killing. The results of our study show that P. horrida secretes multiple cytotoxic compounds targeting different organisms to facilitate predation and antimicrobial defense.

Edible Insects an Alternative Nutritional Source of Bioactive Compounds: A Review.

Edible insects have the potential to become one of the major future foods. In fact, they can be considered cheap, highly nutritious, and healthy food sources. International agencies, such as the Food and Agriculture Organization (FAO), have focused their attention on the consumption of edible insects, in particular, regarding their nutritional value and possible biological, toxicological, and allergenic risks, wishing the development of analytical methods to verify the authenticity, quality, and safety of insect-based products. Edible insects are rich in proteins, fats, fiber, vitamins, and minerals but also seem to contain large amounts of polyphenols able to have a key role in specific bioactivities. Therefore, this review is an overview of the potential of edible insects as a source of bioactive compounds, such as polyphenols, that can be a function of diet but also related to insect chemical defense. Currently, insect phenolic compounds have mostly been assayed for their antioxidant bioactivity; however, they also exert other activities, such as anti-inflammatory and anticancer activity, antityrosinase, antigenotoxic, and pancreatic lipase inhibitory activities.

Alternative protein sources of plant, algal, fungal and insect origins for dietary diversification in search of nutrition and health.

This review aimed to compare alternative protein sources in terms of nutritional composition and health benefits with the purpose of disseminating up-to-date knowledge and contribute for diversification of the food marked and consumers decision-making. Plant-based is the most well-established category of alternative proteins, but there is still room for diversification. Less conventional species such as chia seeds are prominent sources of ω-3 (∼60% total lipids), while hempseed and quinoa are notable sources of ω-6 (up to 58% and 61%, respectively). Edible insects and microalgae are alternative foods rich in protein (up to 70%), fibers (∼30%), as well as peptides and polysaccharides with antimicrobial, antioxidant, anti-hypertensive, antidiabetic, antidepressant, antitumor, and immunomodulatory activities. Additionally, lipid contents in insect larvae can be as high as 50%, on a dry weight basis, containing fatty acids with anti-inflammatory and antitumor properties. In contrast, edible fungi have low lipid contents (∼2%), but are rich in carbohydrates (up to 79%) and have balanced amino acid profiles. The results suggest that food formulations combining different alternative protein sources can meet dietary requirements. Further studies on flavoring and texturing processes will help to create meat and dairy analogs, thus helping to broaden acceptance and applicability of alternative protein sources.

New Eco-Sustainable Feed in Aquaculture: Influence of Insect-Based Diets on the Content of Potentially Toxic Elements in the Experimental Model Zebrafish (Danio rerio).

According to the concept of circular economy, insects represent good candidates as aquafeed ingredients. Nevertheless, there are some potential chemical risks linked with insect consumption. In this study, we reared the teleost Danio rerio, used as an experimental model, with five experimental diets characterized by increasing levels (0%, 25%, 50%, 75%, and 100%) of full-fat Hermetia illucens (Hi) prepupae, substituting for fish meal (FM) and fish oil (FO). We investigated the presence of potentially toxic elements (PTEs) Cd, Pb, Ni, As, and Hg in larval (20 days), juvenile (2 months), and adult (6 months) fish. Quantitative determinations of Cd, Pb, Ni, and As were made with an atomic absorption spectrometer; the total mercury content was determined by a direct mercury analyzer. The substitution of FM and FO with Hermetia illucens meal led to a reduction in the content of some PTEs, such as Pb, As, and Ni, in fishfeed, leading to concentrations below the legal limit of undesirable substances in animal feed. By increasing the Hi meal dietary content, we observed in the Danio rerio specimens an increase in Cd, Pb, and Ni content and a reduction in As content for all life stages. Moreover, a general increase in the content of Cd, Pb, Hg, and Ni from larvae to juvenile was measured, while the shift of Danio rerio from the juvenile to the adult stage involved a significant increase in the content of Pb, Hg, and Ni. Larvae had a reduced ability to bioaccumulate metal(loid)s compared to juveniles and adults. In conclusion, the content of PTEs in Danio rerio is influenced both by the type of diet administered and by the life stage of the animal itself. This research demonstrates the possibility of using Hi prepupae as an aquafeed ingredient without exposing fish to a chemical risk and, in perspective, allows applying these eco-sustainable diets for the breeding of edible fish species, without endangering human health.

Potential health benefits of edible insects.

Animal-based foods have traditionally been viewed as dietary staples because they provide many essential nutrients; however, edible insects have the potential to serve as healthy, sustainable alternatives to these because of their nutrient contents. Edible insects may have superior health benefits due to their high levels of vitamin B12, iron, zinc, fiber, essential amino acids, omega-3 and omega-6 fatty acids, and antioxidants. The addition of edible insects such as crickets to the human diet could offer a myriad of environmental and nutritional benefits including an overall reduction in greenhouse gas emissions, decreased agricultural use of land and water, improved prevention and management of chronic diseases like diabetes, cancer, and cardiovascular disease, and enhanced immune function. Future research should aim to understand the beneficial effects of whole insects or insect isolates in comparison to traditional animal- and plant-based foodstuffs. Ultimately, insects have the potential to be used as meat substitutes or dietary supplements, resulting in human health and environmental benefits. The purpose of this review is to provide additional insight on the nutrient composition of edible insects, their potential use as meat substitutes or dietary supplements, the associated health and wellness benefits, and their potential role in exercise performance.

How to extract and analyze pollen from internal organs and exoskeletons of fossil insects?

This protocol explains how to extract pollen from fossil insects with subsequent descriptions of pollen treatment. We also describe how to document morphological and ultrastructural features with light-microscopy and electron microscopy. It enables a taxonomic assignment of pollen that can be used to interpret flower-insect interactions, foraging and feeding behavior of insects, and the paleoenvironment. The protocol is limited by the state of the fossil, the presence/absence of pollen on fossil specimens, and the availability of extant pollen for comparison. For complete details on the use and execution of this protocol, please refer to Wappler et al. (2015), Ulrich and Grímsson (2020), and Wedmann et al. (2021).

Enantioselective sensing of insect pheromones in water.

An arrayed combination of water-soluble deep cavitands and cationic dyes has been shown to optically sense insect pheromones at micromolar concentration in water. Machine learning approaches were used to optimize the most effective array components, which allows differentiation between small structural differences in targets, including between different diastereomers, even though the pheromones have no innate chromophore. When combined with chiral additives, enantiodiscrimination is possible, dependent on the size and shape of the pheromone.

Volatilome and Essential Oil of Ulomoides dermestoides: A Broad-Spectrum Medical Insect.

Ulomoides dermestoides are used as a broad-spectrum medical insect in the alternative treatment of various diseases. Preliminary volatilome studies carried out to date have shown, as the main components, methyl-1,4-benzoquinone, ethyl-1,4-benzoquinone, 1-tridecene, 1-pentadecene, and limonene. This work focused on the production of metabolites and their metabolic variations in U. dermestoides under stress conditions to provide additional valuable information to help better understand the broad-spectrum medical uses. To this end, VOCs were characterized by HS-SPME with PEG and CAR/PDMS fibers, and the first reported insect essential oils were obtained. In HS-SMPE, we found 17 terpenes, six quinones, five alkenes, and four aromatic compounds; in the essential oils, 53 terpenes, 54 carboxylic acids and derivatives, three alkynes, 12 alkenes (1-Pentadecene, EOT1: 77.6% and EOT2: 57.9%), 28 alkanes, nine alkyl disulfides, three aromatic compounds, 19 alcohols, three quinones, and 12 aldehydes were identified. Between both study approaches, a total of 171 secondary metabolites were identified with no previous report for U. dermestoides. A considerable number of the identified metabolites showed previous studies of the activity of pharmacological interest. Therefore, considering the wide variety of activities reported for these metabolites, this work allows a broader vision of the therapeutic potential of U. dermestoides in traditional medicine.

Naturally-derived targeted therapy for wound healing: Beyond classical strategies.

This review summarizes the four processes of wound healing in the human body (hemostasis, inflammatory, proliferation, and remodeling) and the most current research on the most important factors affecting cutaneous wound healing and the underlying cellular and/or molecular pathways. Local factors, including temperature, oxygenation, and infection, and systemic factors, such as age, diabetes, sex hormones, genetic components, autoimmune diseases, psychological stress, smoking and obesity are also addressed. A better understanding of the role of these factors in wound repair could result in the development of therapeutics that promote wound healing and resolve affected wounds. Additionally, natural products obtained from plants and animals are critical targets for the discovery of novel biologically significant pharmacophores, such as medicines and agrochemicals. This review outlines the most recent advances in naturally derived targeted treatment for wound healing. These are plant-derived natural products, insect-derived natural products, marine-derived natural products, nanomaterial-based wound-healing therapeutics (metal- and non-metal-based nanoparticles), and natural product-based nanomedicine to improve the future direction of wound healing. Natural products extracted from plants and animals have advanced significantly, particularly in the treatment of wound healing. As a result, the isolation and extraction of bioactive compounds from a variety of sources can continue to advance our understanding of wound healing. Undescribed bioactive compounds or unexplored formulations that could have a role in today's medicinal arsenal may be contained in the abundance of natural products and natural product derivatives.

Parvaxanthines D-F and Asponguanosines C and D, Racemic Natural Hybrids from the Insect Cyclopelta parva.

Five new compounds including three pairs of enantiomeric xanthine analogues, parvaxanthines D-F (1-3), two new guanosine derivatives, asponguanosines C and D (6 and 7), along with two known adenine derivatives were isolated from the insect Cyclopelta parva. Racemic 1-3 were further separated by chiral HPLC. Their absolute configurations were assigned by spectroscopic and computational methods. It is interesting that all of these isolates are natural product hybrids. Antiviral, immunosuppressive, antitumor and anti-inflammatory properties of all the isolates were evaluated.

Triple Stiffness: A Bioinspired Strategy to Combine Load-Bearing, Durability, and Impact-Resistance.

Structures with variable stiffness have received increasing attention in the fields of robotics, aerospace, structural, and biomedical engineering. This is because they not only adapt to applied loads, but can also combine mutually exclusive properties. Here inspired by insect wings, the concept of "triple stiffness" is introduced and applied to engineering systems that exhibit three distinct deformability regimes. By implementing "flexible joints," "mechanical stoppers," and "buckling zones," structures are engineered to be not only load-bearing and durable, but also impact-resistant. To practice the performance of the design concept in real-life applications, the developed structures are integrated into 3D printed airplane wing models that withstood collisions without failure. The concept developed here opens new avenues for the development of structural elements that are load-bearing, durable, and impact-resistant at the same time.

Nutritional Qualities and Enhancement of Edible Insects.

Over the last decade, the urgency to find alternative and sustainable protein sources has prompted an exponential increase in the interest in insects as a human food source. Edible insects contribute suitable amounts of energy and protein, fatty acids, and micronutrients to the human diet. Nutritional values of insects can be manipulated to meet specific needs. Edible insects in food-insecure countries can contribute to improving diets and preventing undernutrition. Bioactive compounds in insects may reduce health risks. Food safety risks are low and mainly relate to those of allergenicity. Strategies to overcome barriers to the consumption of insect products include emphasizing their sustainability, increasing their tastiness, and developing the ability to disguise insects in familiar products. A new sector of insects as food and feed is emerging. Major challenges include legislation, lowering prices by automation and cheap substrates, developing insect products that appeal to consumers, and exploring the health benefits.

An insect isoscape of UK and Ireland.

RATIONALE: The study of insect migration is problematic due to the small size of insects. Stable isotope analysis can be used to elucidate movement, either by geographic assignment of location of a species, or by simply distinguishing migrant from resident populations. There are few isoscapes of any kind in the UK/Ireland available for interrogation. Thus, I have measured stable isotope ratios (of H, C, N and S) of 299 individuals of the non-migratory Brimstone moth (Opisthograptis luteolata) collected from 93 locations around the UK and Ireland by citizen scientists. METHODS: After removing lipids, stable isotope ratios were measured by continuous flow isotope ratio mass spectrometry, using either a conventional elemental analyser (C, N and S) or a high-temperature, thermal conversion elemental analyser in reductive mode. RESULTS: Maps (isoscapes) were constructed that illustrate the stable isotope spatial distribution of this insect. These are the first isoscapes of H, C, N and S of biological samples covering both UK and Ireland. CONCLUSIONS: The insect isoscape patterns can be explained from what we know of moth diet, climate and geology. Sulfur isotopes may be of particular use for distinguishing individuals from areas of unique geology. Isoscape patterns may (with care) predict isotope compositions of other, herbivorous, non-aquatic, chitinous taxa. Such isoscapes, when extended beyond the UK and Ireland, would provide a useful tool to elucidate insect migration.

Chemical host-seeking cues of entomopathogenic nematodes.

Entomopathogenic nematodes (EPNs) are obligate parasites that infect a broad range of insect species. Host-seeking is a crucial step for EPN infection success and survival. Yet, the identity and ecological functions of chemicals involved in host-seeking by EPNs remain overlooked. In this review, we report known CO2, plant-derived and insect-derived cues shaping EPN host-seeking and recognition. Despite species-specific response to environmental cues, we highlight a hierarchical integration of chemicals by EPNs. We further emphasize the impact of EPN selection pressure, age, and experience on their responsiveness to infochemicals. Finally, we feature that EPN chemical ecology can translate into powerful sustainable strategies to control insect herbivores in agriculture.

Genetic basis of chemical communication in eusocial insects.

Social behavior is one of the most fascinating and complex behaviors in humans and animals. A fundamental process of social behavior is communication among individuals. It relies on the capability of the nervous system to sense, process, and interpret various signals (e.g., pheromones) and respond with appropriate decisions and actions. Eusocial insects, including ants, some bees, some wasps, and termites, display intriguing cooperative social behavior. Recent advances in genetic and genomic studies have revealed key genes that are involved in pheromone synthesis, chemosensory perception, and physiological and behavioral responses to varied pheromones. In this review, we highlight the genes and pathways that regulate queen pheromone-mediated social communication, discuss the evolutionary changes in genetic systems, and outline prospects of functional studies in sociobiology.

Effect of policosanol from insect wax on amyloid ß-peptide-induced toxicity in a transgenic Caenorhabditis elegans model of Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD), an age-related neurodegenerative disorder and a serious public health concern, is mainly caused by ß-amyloid (Aß)-induced toxicity. Currently, a limited number of drugs are effective against AD, and only a few are used for its treatment. According to traditional Chinese medicine, white wax is mainly composed of policosanol, hexacosanol, and octacosanol. Policosanol has been shown to reduce lipid levels in blood and alleviate the symptoms associated with diabetic complications and neurodegenerative disorders, such as Parkinson's disease and AD. However, the efficacy of policosanol depends on the purity and composition of the preparation, and the therapeutic efficacy of policosanol derived from insect wax (PIW) in AD is unknown. METHODS: Here, we identified the main components of PIW and investigated the effects of PIW on Aß-induced toxicity and life-span in a transgenic Caenorhabditis elegans model of AD, CL4176. Furthermore, we estimated the expression of amyloid precursor-like protein (apl-1) and the genes involved in various pathways associated with longevity and alleviation of AD-related symptoms in PIW-fed CL4176. RESULTS: PIW mainly consists of tetracosanol, hexacosanol, octacosanol, and triacontanol; it could decrease the Aß-induced paralysis rate from 86.87 to 66.97% (P < 0.01) and extend the life-span from 6.2 d to 7.8 d (P < 0.001) in CL4176 worms. Furthermore, PIW downregulated apl-1, a gene known to be associated with the levels of Aß deposits in C. elegans. Additionally, our results showed that PIW modulated the expression of genes associated with longevity-related pathways such as heat shock response, anti-oxidative stress, and glutamine cysteine synthetase. CONCLUSION: Our findings suggest that PIW may be a potential therapeutic agent for the prevention and treatment of AD. However, its effects on murine models and patients with AD need to be explored further.