Cricket Gryllus Bimaculatus Research Articles

Blanching pre-treatment on quality characteristics of cricket powder

Cricket powder (CP) is a valuable cricket-based product that has recently been developed and applied in many food products. Postharvest insect processing has a significant impact on CP quality. In this study, the effects of blanching pre-treatment at different temperatures (80, 90, and 100°C) and times (5, 10, and 15 mins) were investigated on the physicochemical and microbiological properties of two edible crickets (Gryllus bimaculatus and Acheta domesticus) powders. CP preparation without blanching treatment served as the control. CP obtained from blanching at 80°C for 10 mins increased protein and fiber content but decreased fat content compared to unblanched CP in both species. CP contained histamine at lower than 4 µg/g. Blanching at 80°C for 10 mins gave the highest total phenolic content (TPC) (150.0 and 258.4 mg GAE/g for G. bimaculatus and A. domesticus, respectively) and the highest antioxidant activities in all assays (DPPH, ABTS•+, and FRAP). Compared to unblanched CP, blanching crickets also reduced the total microbial load in both CPs. Results suggested that blanching as a pre-treatment improved the safety, functional properties, antioxidant activity of cricket powder.

Correction: Polyandry works as bet-hedging in the field cricket Gryllus bimaculatus, even after eliminating females in poor condition that cannot accept remating

Correction: Polyandry works as bet-hedging in the field cricket Gryllus bimaculatus, even after eliminating females in poor condition that cannot accept remating

The white gene as a transgenesis marker for the cricket Gryllus bimaculatus.

The cricket Gryllus bimaculatus is an emerging model insect of the order Orthoptera that is used in a wide variety of biological research themes. This hemimetabolous species appears highly complementary to Drosophila and other well-established holometabolous models. To improve transgenesis applications in G. bimaculatus, we have designed a transformation marker gene inspired from the widespread Drosophila mini-white+. Using CRISPR/Cas9, we first generated a loss-of-function mutant allele of the Gb-white gene (Gb-w), which exhibits a white eye coloration at all developmental stages. We then demonstrate that transgenic insertions of a piggyBac vector containing a 3xP3-Gb-w+ cassette rescue eye pigmentation. As an application, we used this vector to generate G. bimaculatus lines expressing a centromeric histone H3 variant (CenH3.1) fused to EGFP and validated EGFP-CenH3.1 detection at cricket centromeres. Finally, we demonstrate that Minos-based germline transformation and site-specific plasmid insertion with the ΦC31 integrase system function in G. bimaculatus.

Damage to the host cadaver, simulating the effects of scavenging, differentially affects fitness of entomopathogenic nematode species

Insect cadavers infected by entomopathogenic nematodes (EPN) are defended against scavengers by chemical and other means. Despite these defences, the cadaver may be bitten before being rejected. In this study, we investigated the effect of damage to the cadaver cuticle on the fitness of nematodes (Heterorhabditis downesi or Steinernema feltiae) developing inside. We first quantified the severity of scavenger damage to EPN-infected Galleria mellonella Linnaeus cadavers in the field, and separately, with crickets (Gryllus bimaculatus De Geer) in the laboratory. In field and laboratory, EPN-infected cadavers suffered less damage than freeze-killed controls, and damage consisted mainly of small lesions to the cuticle. In further experiments, scavenging damage was simulated shortly after death of infected cadavers by piercing the cuticle 0, 1, 3 or 5 times and incubating in moist (100% relative humidity (RH)) or dry (60-70% RH) conditions. The greater the level of damage, the greater the loss of moisture from the cadaver (estimated by weight loss), and this was exacerbated in dry conditions. The number of Infective Juveniles (IJs) emerging from H. downesi-infected cadavers was significantly reduced by damage, especially in dry conditions. In addition, emerging IJs were progressively smaller with increasing damage. For this species, number of IJs was negatively correlated with moisture loss, indicated that the reduction in fitness was mediated by desiccation. For S. feltiae, damage impacted IJ number to a lesser extent and size was not affected. The reduction in numbers was not explained by moisture loss, indicating that for S. feltiae, some factor other than desiccation (perhaps competition with opportunistic microbes) impacts the nematodes when the cuticle is damaged. The greater vulnerability of H. downesi than S. feltiae to scavenger damage to the host cadaver may be due to its longer developmental time in the host resulting in longer exposure to damaging conditions. In conclusion, damage simulating biting by scavengers impacts the fitness of EPN, with the effect depending on nematode species, environmental conditions and the extent of damage. These findings have implications for the success of field application of EPN in infected cadavers.

Independent operations of appetitive and aversive conditioning systems lead to simultaneous production of conflicting memories in an insect.

Pavlovian conditioning is a ubiquitous form of associative learning that enables animals to remember appetitive and aversive experiences. Animals possess appetitive and aversive conditioning systems that memorize and retrieve appetitive and aversive experiences. Here, we addressed a question of whether integration of competing appetitive and aversive information takes place during the encoding of the experience or during memory retrieval. We developed novel experimental procedures to address this question using crickets (Gryllus bimaculatus), which allowed selective blockade of the expression of appetitive and aversive memories by injecting octopamine and dopamine receptor antagonists. We conditioned an odour (conditioned stimulus 1, CS1) with water and then with sodium chloride solution. At 24 h after conditioning, crickets retained both appetitive and aversive memories, and the memories were integrated to produce a conditioned response (CR). Importantly, when a visual pattern (CS2) was conditioned with CS1, appetitive and aversive memories formed simultaneously. This indicates that appetitive and aversive second-order conditionings are achieved at the same time. The memories were integrated for producing a conditioned response. We conclude that appetitive and aversive conditioning systems operate independently to form parallel appetitive and aversive memories, which compete to produce learned behaviour in crickets.

Field Cricket (Gryllus bimaculatus) and Spirulina (Arthrospira platensis) Powders as Environmentally Friendly Protein Enrichment Ingredients in Corn Snacks.

Unconventional protein sources are currently extensively studied as food ingredients. This study aimed to evaluate the effect of 1.5% and 3% field cricket powder (GB) and 2-8% of its mixture (1:1) with spirulina powder (S) on the nutritional value, physicochemical properties, and sensory characteristics of corn extrudates. Additionally, 2% baking powder (BP) was added to assess its impact on the properties of the enriched extrudates. The results showed that both GB and GB + S improved nutritional value, with protein content increasing by up to 46% and higher levels of essential amino acids, particularly leucine and valine. However, these ingredients decreased the expansion ratio (by up to 15%), colour lightness (by up to 30%), and yellowness (by up to 47%) and increased the hardness (by up to 25%) of the corn extrudates. The S addition positively influenced product storage stability but decreased its sensory acceptance, especially aroma and taste. The BP addition mitigated the negative effects of higher GB and GB + S concentrations, particularly on sensory characteristics. In conclusion, incorporating up to 6% of the GB + S mixture provides a higher protein content with only minor changes to the product's characteristics compared to GB. Ratings exceeding 4.2 points indicate the good acceptability of these snacks.

Unraveling mate choice evolution through indirect genetic effects

Abstract Attractiveness is not solely determined by a single sexual trait but rather by a combination of traits. Because the response of the chooser is based on the combination of sexual traits in the courter, variation in the chooser’s responses that are attributable to the opposite-sex courter genotypes (i.e., the indirect genetic effects [IGEs] on chooser response) can reflect genetic variation in overall attractiveness. This genetic variation can be associated with the genetic basis of other traits in both the chooser and the courter. Investigating this complex genetic architecture, including IGEs, can enhance our understanding of the evolution of mate choice. In the present study on the field cricket Gryllus bimaculatus, we estimated (1) genetic variation in overall attractiveness and (2) genetic correlations between overall attractiveness and other pre- and postcopulatory traits (e.g., male latency to sing, female latency to mount, male guarding intensity, male and female body mass, male mandible size, and testis size) within and between sexes. We revealed a genetic basis for attractiveness in both males and females. Furthermore, a genetic variance associated with female attractiveness was correlated with a genetic variance underlying larger male testes. Our findings imply that males that mate with attractive females can produce offspring that are successful in terms of precopulatory sexual selection (daughters who are attractive) and postcopulatory sexual selection (sons with an advantage in sperm competition), potentially leading to runaway sexual selection. Our study exemplifies how the incorporation of the IGE framework provides novel insights into the evolution of mate choice.

Bacterial and fungal microbes associated with cricket rearing systems in the tropics

Abstract House crickets (Acheta domesticus) and field crickets (Gryllus bimaculatus) are among the commonly reared insects for human and animal consumption. However, the potential contamination of rearing facilities with microbes poses a serious threat to sustainability of production of these insects, especially in poorer regions of the world where strategies for ensuring microbe-free environments are lacking in most cases. In this study, bacterial and fungal communities associated with cricket-rearing facility under partially controlled conditions were isolated and examined using morphological and molecular marker-based approaches. BLAST analysis of amplified 16S rRNA sequences revealed similarities to the bacterial genera Rickettsiella, Enterobacter, Bacillus, Levilactobacillus, and Aeromonas, while analysis of the ITS sequences revealed similarities to the fungi Pithomyces spp., Fusarium spp., Aspergillus spp. and Tetrapisispora spp. Increased mortality and reduced nutritional contents of crickets exposed to the bacterial and fungal microbes were evident. Of notable concern is the contamination of the crickets with spore-forming bacteria and toxin-forming bacteria as well as fungi. Although the levels of mycotoxin were relatively low compared to the threshold set by many countries in sub-Saharan Africa, the detection of aflatoxin in both species of crickets is of great concern as any dosage can pose serious health risks to consumers. Strategies to minimize contamination of crickets by entomopathogenic microbes are outlined, and future areas of research are suggested.

Reciprocal Coupling of Circadian Clocks in the Compound Eye and Optic Lobe in the Cricket Gryllus bimaculatus.

The circadian system comprises multiple clocks, including central and peripheral clocks. The central clock generally governs peripheral clocks to synchronize circadian rhythms throughout the animal body. However, whether the peripheral clock influences the central clock is unclear. This issue can be addressed through a system comprising a peripheral clock (compound eye clock [CE clock]) and central clock (the optic lobe [OL] clock) in the cricket Gryllus bimaculatus. We previously found that the compound eye regulates the free-running period (τ) and the stability of locomotor rhythms driven by the OL clock, as measured by the daily deviation of τ at 30°C. However, the role of the CE clock in this regulation remains unexplored. In this study, we investigated the importance of the CE clock in this regulation using RNA interference (RNAi) of the period (per) gene localized to the compound eye (perCE-RNAi). The perCE-RNAi abolished the compound eye rhythms of the electroretinogram (ERG) amplitude and clock gene expression but the locomotor rhythm driven by the OL clock was maintained. The locomotor rhythm of the tested crickets showed a significantly longer τ and greater daily variation of τ than those of control crickets treated with dsDsRed2. The variation of τ was comparable with that of crickets with the optic nerve severed. The τ was considerably longer but was comparable with that of crickets with the optic nerve severed. These results suggest that the CE clock regulates the OL clock to maintain and stabilize τ.

Feeding Concentrate and Market Waste on the Performance of Collared Crickets (Gryllus bimaculatus)

In Indonesia, crickets (Gryllus sp.) are used as feed for pet animals, especially insectivorous animals, one of which is the kalung/collared cricket. Collared crickets have a short life cycle, high egg hatchability, fast growth, low feed conversion, and have softer body skin that is preferred by birds and other insectivorous animals. Feed is very important in intensive cricket rearing, especially in hatching crickets. The feed given to crickets is generally in the form of concentrates and leaves. This study aims to determine the effect of giving concentrates and market waste (kale, cabbage, cassava leaves) on the performance of collared crickets (Gryllus bimaculatus). This research was conducted at the Livestock Biology Laboratory, Department of Animal Science, Faculty of Agriculture, Universitas Sumatera Utara, from March to April 2020. This research was conducted experimentally using a completely randomised design (CRD) consisting of 4 treatments and 5 replications. The treatments consisted of P0 = 100% market waste, P1 = 75% market waste + 25% concentrate, P2 = 50% market waste + 50% concentrate, P3 = 25% market waste + 75% concentrate. The results of this study showed that the provision of concentrate and market waste (kale, cabbage, and cassava leaves) had no significant effect on the performance of collared crickets. The average mortality in this study was 6.4%, the feed consumption value was 8.74 g/head/day, the average body weight gain was 0.43 g/head/day, and the average feed conversion was 20.71 g/head. In conclusion as there is no difference between each treatment on cricket performance, the 100% market waste treatment can be used for collared cricket feed.

Amino acid composition and chemical properties of protein noodles incorporated with cricket (Gryllus bimaculatus De Geer) powder

Crickets (Gryllus bimaculatus De Geer) are considered a primary meat-alternative protein source. The insects comprise of 58 - 63% high-quality protein rich in essential amino acids. Nowadays, noodles are regularly consumed. Cricket powder-based protein noodles (PNCP) could be a choice for individuals with gluten allergies. In the present work, PNCP 0%, PNCP 15%, and PNCP 30% were assessed. PNCP 30% yielded the optimal nutritional quality in terms of moisture, ash, crude protein, crude fat, and crude fibre contents. It also contained the highest levels of 18 amino acids. Results also revealed that the noodles incorporated with cricket powder had double aspartic acid content, and increased proline content (3 - 7%) compared to control samples. Statistical analysis demonstrated a direct correlation between increased nutritional quality and the cricket powder amount added. Nevertheless, increasing cricket powder amount affected the colour of the resultant noodles. PNCP 30% yielded the darkest hue amongst the samples with an L* value of 38.21 ± 1.93%. Conversely, PNCP 0% and 15% samples yielded 56.18 ± 0.75 and 45.06 ± 1.66% L* values, respectively. Texture profile analysis also revealed the effects on the tensile strength values of enhancing the cricket powder content. Panellists scored the PNCP samples on a 9-point hedonic scale in a five-dimensional sensory evaluation. PNCP 15% recorded the ideal combination of palatability, appearance, and characteristics. Overall, the present work demonstrated that whilst utilising cricket powder as the alternative protein source in noodles is feasible, an accompanying sensory evaluation is critical to ensure that its incorporation does not compromise consumer acceptance of the final product.

Impact of temperature on the bionomics and geographical range margins of the two-spotted field cricket Gryllus bimaculatus in the world: Implications for its mass farming.

Gryllus bimaculatus (Orthoptera: Gryllidae) is widely considered an excellent nutrient source for food and feed. Despite its economic importance, there is limited information on the impact of temperature on the bionomics of this cricket to guide its effective and sustainable mass production in its geographical range. The biological parameters of G. bimaculatus were investigated at eight different temperatures ranging from 20-40˚C. The Insect Life-Cycle Modelling (ILCYM) program was used to fit linear and non-linear functions to the data to describe the influence of temperature on life history parameters and its farmability under the current and projected climate for 2050. Our results revealed that G. bimaculatus was able to complete its lifecycle in the temperature range of 20°C to 37°C with a maximum finite rate of population increase (= 1.14) at 35°C. The developmental time of G. bimaculatus decreased with increasing temperature. The least developmental time and mortality were attained at 32°C. The highest wet length and mass of G. bimaculatus occurred at 32°C. The lowest temperature threshold for G. bimaculatus egg and nymph development was approximated using linear regression functions to be at 15.9°C and 16.2°C with a temperature constant of 108.7 and 555.6 degree days. The maximum fecundity (2301.98 eggs per female), net reproductive rate (988.42 daughters/ generation), and intrinsic rate of natural increase (0.134 days) were recorded at 32°C and the shortest doubling of 5.2 days was observed at 35°C. Based on our findings G. bimaculatus can be farmed in countries with temperatures ranging between 20 and 37°C around the globe. These findings will help the cricket farmers understand and project the cricket population dynamics around the world as influenced by temperature, and as such, will contribute to more efficient farming.

Mandible microwear texture analysis of crickets raised on diets of different abrasiveness reveals universality of diet-induced wear.

Animals have evolved diverse comminuting tools. While vertebrates possess mineralized teeth, insect mandibles often bear metal-inclusion-hardened serrated cusps. Microscopic dental enamel wear (microwear) is known to be caused by contact with ingesta. To test if insect mandible microwear is also diet-dependent, we kept newly moulted adult two-spotted crickets (Gryllus bimaculatus) for four weeks on alfalfa-based rodent pellets with and without added mineral abrasives (loess, quartz, volcanic ash). Six crickets per diet were examined after 1, 3, 7, 14, 21 and 28 days. All diets induced progressive mandible wear, affecting specific locations along the distal tooth cusps differently. The depth of furrows increased on most abrasive-containing diets until day 21, while wear mark complexity increased from day 1 to 3 and 14 to 21. After 28 days, these parameter values for large volcanic ash and large quartz diets significantly exceeded those for the control diet. These results are comparable to observations from guinea pig feeding experiments with the same diets. Cricket mandible wear was affected by all abrasives. Notably, large volcanic ash and large quartz induced the deepest, most complex lesions, akin to observations in guinea pigs. This suggests a universal wear process, supporting that microwear analyses are suitable for inferring invertebrate diets.

Heatwaves inflict reproductive but not survival costs to male insects.

Climate change is having a dramatic effect on the environment, with rising global temperatures and more frequent extreme climatic events, such as heatwaves, that can hamper organisms' biological functions. Although it is clear that sudden and extreme temperatures can damage reproductive processes, there is limited understanding of the effects of heatwaves on male mating behaviour and reproductive success. We tested for the effects of heat stress induced by ecologically relevant heatwaves (33°C and 39°C for five consecutive days) on the mating behaviour, reproductive success, body mass and survival of male field crickets Gryllus bimaculatus, paired with untreated females. We predicted life-history and reproductive costs would increase with increasing heatwave intensity. Consistent with our expectations, males exposed to the highest heatwave temperature produced the fewest offspring, while having to increase courtship effort to successfully mate. Males also gained relatively more weight following heatwave exposure. Given that we found no difference in lifetime survival, our results suggest a potential trade-off in resource allocation between somatic maintenance and reproductive investment. Taken together, our findings indicate that sublethal effects of heatwaves could reduce the growth and persistence of animal populations by negatively impacting reproductive rates. These findings highlight the need for considering thermal ecologies, life history and behaviour to better understand the consequences of extreme climatic events on individuals and populations.

Palatability of Cuscus (Spilocuscus maculatus) to the Combinations of Pellet Feed Based on Organic Value

Cuscus (Spilocuscus maculatus) in captivity that were given a dominant fruit diet needed additional feed from their natural habitat because of the higher nutritional potential and fiber components. This study aims to determine the palatability of cuscus to the feed based on organic value. An experimental method was used, consisting of 4 treatment groups: 100% banana (Musa paradisiaca) as control, 70% banana mixed with 30% matoa (Pometia pinnata) leaves, 70% banana mixed with 30% ironwood (Pongamia pinnata) leaves, and 70% banana mixed with 30% crickets (Gryllus bimaculatus). The results showed that banana was the most preferred feed ingredient, either alone or as a supplementary feed mixture. In terms of quantity, its mixture with matoa leaves had a higher consumption level than ironwood leaves and crickets. The consumption level of organic matter was higher in the treatment with 100% banana than in other treatments. This information will help support ex-situ and in-situ conservation programs formulated by the government and other parties, including the community. Keywords: cuscus, feed, organic matter, palatability, Spilocuscus maculatus

Monoaminergic Systems in Flight-Induced Potentiation of Phonotactic Behavior in Female Crickets Gryllus bimaculatus.

We have recently shown that experience of flight remarkably enhanced subsequent terrestrial phonotaxis in females in response to the male calling song. Here, we elucidated the possible roles of octopamine and serotonin in the enhancing effect of flying on phonotactic behavior. Octopamine is known to be released into the hemolymph during flight in insects; however, the octopamine receptor antagonist epinastine did not abolish the effects of flight in our study. On the contrary, the drug significantly potentiated the influence of flying on phonotactic behavior. The octopamine receptor agonist chlordimeform, at a concentration of 2 mM, which was previously found to activate aggression in crickets, dramatically reduced the phonotactic response. However, at a 10-times-lower dose, chlordimeform produced a light but significant decrease in the time that females took to reach the source of the calling song. A similar effect was produced by octopamine itself, which hardly passes the blood-brain barrier in insects. The effect of flight was completely abolished in female crickets treated with alpha-methyl tryptophan (AMTP). AMPT suppresses the synthesis of serotonin, decreasing its content in the nervous systems of insects, including crickets. An activation of the serotonin synthesis with 5-hydroxytryptophan mimicked the effect of flight by increasing the number of visits to and the time spent in the zone near the source of the calling song. The 5-HT content in the third thoracic ganglion was significantly higher in flyers compared to the control group. In contrast, no changes in the octopamine level were observed in the third thoracic ganglion, which is known to play a crucial role in decision-making involved in intraspecific interactions. Therefore, the results suggest that although octopamine is known to be released into the hemolymph during flight, it is likely to inhibit rather than activate the central mechanisms related to phonotaxis. The weak facilitating effect of a low dose of chlordimeform can be attributed to the activation of peripheral octopaminergic receptors. Our results suggest that the serotoninergic system may contribute to the facilitation of female phonotactic behavior by flying. We suggest that both flying and serotonin enhance sexual motivation in females and, by these means, impact their behavioral response to the male calling song.

Critical roles of nicotinic acetylcholine receptors in olfactory memory formation and retrieval in crickets.

Acetylcholine (ACh) is a major excitatory neurotransmitter in the insect central nervous system, and insect neurons express several types of ACh receptors (AChRs). AChRs are classified into two subgroups, muscarinic AChRs and nicotinic AChRs (nAChRs). nAChRs are also divided into two subgroups by sensitivity to α-bungarotoxin (α-BGT). The cricket Gryllus bimaculatus is one of the useful insects for studying the molecular mechanisms in olfactory learning and memory. However, the roles of nAChRs in olfactory learning and memory of the cricket are still unknown. In the present study, to investigate whether nAChRs are involved in cricket olfactory learning and memory, we tested the effects of two different AChR antagonists on long-term memory (LTM) formation and retrieval in a behavioral assay. The two AChR antagonists that we used are mecamylamine (MEC), an α-BGT-insensitive nAChR antagonist, and methyllycaconitine (MLA), an α-BGT-sensitive nAChR antagonist. In crickets, multiple-trial olfactory conditioning induced 1-day memory (LTM), whereas single-trial olfactory conditioning induced 1-h memory (mid-term memory, MTM) but not 1-day memory. Crickets injected with MEC 20min before the retention test at 1day after the multiple-trial conditioning exhibited no memory retrieval. This indicates that α-BGT-insensitive nAChRs participate in memory retrieval. In addition, crickets injected with MLA before the multiple-trial conditioning exhibited MTM but not LTM, indicating that α-BGT-sensitive nAChRs participate in the formation of LTM. Moreover, injection of nicotine (an nAChR agonist) before the single-trial conditioning induced LTM. Finally, the nitric oxide (NO)-cGMP signaling pathway is known to participate in the formation of LTM in crickets, and we conducted co-injection experiments with an agonist or inhibitor of the nAChR and an activator or inhibitor of the NO-cGMP signaling pathway. The results suggest that nAChR works upstream of the NO-cGMP signaling system in the LTM formation process.

Effects of temperature variation on yield and quality of field crickets (<i>Gryllus bimaculatus</i>) and black soldier flies (<i>Hermetia illucens</i>)

Insect rearing provides an affordable alternative source of animal nutrition for most small-scale farmers. However, current rearing technology with uncontrolled environmental conditions suppresses insect yields, leading to low adoption of insect production. The objective of this study was to assess the effect of temperature variation, using an adaptive control structure, on the yield of field crickets (Gryllus bimaculatus) and black soldier fly larvae (Hermetia illucens). Temperature values of 25°C, 27°C, and 30°C constant relative humidity of 50%, and constant air speed of 3 m/s were adopted for the study. Throughout the study, weighing of the insect wet yield was done on a daily basis for larvae and after three days for cricket pinheads. Black soldier fly larvae and adult crickets were harvested at the ages of two weeks and six weeks, respectively, and oven dried at 105°C for 24 hours for subsequent analysis of proteins. Results indicated that black soldier fly larvae reared at 25°C, 27°C, and 30°C had a maximum mean wet yield of 0.216 ± 0.022 g, 0.234 ± 0.019 g, and 0.248 ± 0.016 g, respectively, at the age of two weeks. Similarly, crickets reared at 25°C, 27°C, and 30°C had a mean yield of 0.807 ± 0.167 g, 0.933 ± 0.102 g, and 1.306 ± 0.254 g at the age of six weeks. Dried cricket reared at 25°C, 27°C, and 30°C had 25.566 ± 0.012%, 46.811 ± 0.647%, and 58.216 ± 1.510% protein, respectively. Contrary to this, black soldier flies reared at 25°C, 27°C, and 30°C yielded 42.655 ± 1.732%, 47.121 ± 0.015%, and 62.536 ± 0.014%, respectively. Larval yield recorded significant different yields (f = 4.935, p = 0.03), whereas crickets failed to record significant different yields (f = 0.777, p = 0.388) under different temperature levels. A higher temperature regime yielded higher body mass and protein turnover. The findings of this study boost the future prospects of insects as food and feed for enhancing food and nutrition security.

A convolutional neural network with image and numerical data to improve farming of edible crickets as a source of food-A decision support system.

Crickets (Gryllus bimaculatus) produce sounds as a natural means to communicate and convey various behaviors and activities, including mating, feeding, aggression, distress, and more. These vocalizations are intricately linked to prevailing environmental conditions such as temperature and humidity. By accurately monitoring, identifying, and appropriately addressing these behaviors and activities, the farming and production of crickets can be enhanced. This research implemented a decision support system that leverages machine learning (ML) algorithms to decode and classify cricket songs, along with their associated key weather variables (temperature and humidity). Videos capturing cricket behavior and weather variables were recorded. From these videos, sound signals were extracted and classified such as calling, aggression, and courtship. Numerical and image features were extracted from the sound signals and combined with the weather variables. The extracted numerical features, i.e., Mel-Frequency Cepstral Coefficients (MFCC), Linear Frequency Cepstral Coefficients, and chroma, were used to train shallow (support vector machine, k-nearest neighbors, and random forest (RF)) ML algorithms. While image features, i.e., spectrograms, were used to train different state-of-the-art deep ML models, i,e., convolutional neural network architectures (ResNet152V2, VGG16, and EfficientNetB4). In the deep ML category, ResNet152V2 had the best accuracy of 99.42%. The RF algorithm had the best accuracy of 95.63% in the shallow ML category when trained with a combination of MFCC+chroma and after feature selection. In descending order of importance, the top 6 ranked features in the RF algorithm were, namely humidity, temperature, C#, mfcc11, mfcc10, and D. From the selected features, it is notable that temperature and humidity are necessary for growth and metabolic activities in insects. Moreover, the songs produced by certain cricket species naturally align to musical tones such as C# and D as ranked by the algorithm. Using this knowledge, a decision support system was built to guide farmers about the optimal temperature and humidity ranges and interpret the songs (calling, aggression, and courtship) in relation to weather variables. With this information, farmers can put in place suitable measures such as temperature regulation, humidity control, addressing aggressors, and other relevant interventions to minimize or eliminate losses and enhance cricket production.

Chemical and Nutritional Fat Profile of Acheta domesticus, Gryllus bimaculatus, Tenebrio molitor and Rhynchophorus ferrugineus.

The use of edible insects in the human diet is gaining importance because they are characterized by high nutritional value, and their cultivation is much more environmentally friendly than traditional livestock farming. The objective of this study was to determine the chemical and nutritional fat profile of selected edible insects as follows: house cricket (Acheta domesticus adult), field cricket (Gryllus bimaculatus adult), mealworm (Tenebrio molitor larvae), and palm weevil (Rhynchophorus ferrugineus larvae) which are now commercially available worldwide. Additionally, the degree of implementation of nutrition standards for selected nutrients by these insects was assessed. Freeze-dried insects were studied using infrared-attenuated total reflectance mid-infrared spectroscopy for basic differentiation. The content of fat and fatty acids was determined, and dietary indicators were calculated. The spectroscopic findings align with biochemical data, revealing that Rhynchophorus ferrugineus larvae contain the highest fat content and the least protein. Unsaturated fatty acids (UFAs) predominated in the fat of the assessed insects. The highest content of saturated fatty acids (SFAs), along with the lowest content of polyunsaturated fatty acids (PUFAs), was observed in the larvae of the Rhynchophorus ferrugineus species. From a nutritional standpoint, Tenebrio molitor larvae exhibit the most favorable indicators, characterized by minimal athero- and thrombogenic effects, along with an optimal balance of hypo- and hypercholesterolemic acids. Knowledge of the composition and quantities of fats in different insect species is valuable for planning and preparing meals with accurate nutritional profiles, among other applications.