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Alarm calls produced by basal prey have a well-known informative value. In multi-predator communities, mesopredators, when faced with top predators, may emit alarm calls that could inform basal prey about their lowered predation risk. To test this unexplored possibility, we conducted one field and one mesocosm experiment in which we simulated alarm and non-alarm calls from little owls (Athene noctua) as mesopredators and measured their effects on grasshoppers as prey of little owls but not of top predators. In the field experiment, we found that grasshopper species were significantly more abundant in patches where we simulated either the presence of scared little owls (alarm treatment) or no owls (control treatment) compared to patches where the presence of non-scared little owls (non-alarm treatment) was simulated. In the mesocosm experiment, locusts (Locusta migratoria) moved significantly more to exposed areas when we simulated the presence of scared little owls (alarm treatment) or of a granivorous bird (control treatment), while they moved to sheltered areas when we simulated the presence of non-scared owls (non-alarm treatment). These results show that prey could cue on predators' calls to assess their predation risk and make decisions, revealing unprecedented potential ecological consequences of alarm calls in invertebrate communities. [ABSTRACT FROM AUTHOR]

The entomopathogenic fungus (EPF) Metarhizium acridum is a typical filamentous fungus and has been used to control migratory locusts (Locusta migratoria manilensis). This study examines the impact of the Zn(II)2Cys6 transcription factor, MaAzaR, in the virulence of M. acridum. Disruption of MaAzaR (ΔMaAzaR) diminished the fungus's ability to penetrate the insect cuticle, thereby decreasing its virulence. The median lethal time (LT50) for the ΔMaAzaR strain increased by approximately 1.5 d compared to the wild-type (WT) strain when topically inoculated, simulating natural infection conditions. ΔMaAzaR compromises the formation, turgor pressure, and secretion of extracellular hydrolytic enzymes in appressoria. However, the growth ability of ΔMaAzaR within the hemolymph is not impaired; in fact, it grows better than the WT strain. Moreover, RNA-sequencing (RNA-Seq) analysis of ΔMaAzaR and WT strains grown for 20 h on locust hindwings revealed 87 upregulated and 37 downregulated differentially expressed genes (DEGs) in the mutant strain. Pathogen–host interaction database (PHI) analysis showed that about 40% of the total DEGs were associated with virulence, suggesting that MaAzaR is a crucial transcription factor that directly regulates the expression of downstream genes. This study identifies a new transcription factor involved in EPF cuticle penetration, providing theoretical support and genetic resources for the developing highly virulent strains. [ABSTRACT FROM AUTHOR]

Background: Anaphylaxis represents the most severe end of the spectrum of allergic reactions. Frequent elicitors of anaphylaxis are insects, foods, and drugs. This paper summarizes recent development with regard to emerging and novel elicitors of anaphylaxis. Summary: Food allergens on the rise include pulses (like pea, chickpea), seeds (hemp, chia), nuts (cashew), pseudograins (buckwheat, quinoa), fruits, and microalgae. Novel foods are foods that were not consumed to any significant extent in the European Union before May 1997, which includes four edible insects (mealworm, migratory locust, house cricket, and buffalo worm). Recent investigations have pointed out the risk of anaphylaxis associated with the consumption of yellow mealworm for people allergic to shellfish and house dust mites. In Europe, fire ants (mostly Solenopsis invicta) and Vespa velutina nigrithorax represent invasive species, which account for increasing numbers of anaphylactic reactions. Also, several new drugs, especially biologicals, have been associated with anaphylaxis. Key Messages: Elicitors of anaphylaxis are changing as a result of (i) increase in demand for plant-based food, (ii) introduction of novel foods, (iii) spreading of allergens by climate changes and globalization, or (iv) due to exposure to newly developed drugs. [ABSTRACT FROM AUTHOR]

Myosin light chain kinase (MLCK) is a dedicated kinase of myosin regulatory light chain (RLC), playing an essential role in the regulation of muscle contraction and cell motility. Much of the knowledge about MLCK comes from the study of vertebrate MLCK, and little is known about insect MLCK. Here, we identified the single MLCK gene in the locust Locusta migratoria, which spans over 1400 kb, includes 62 exons and accounts for at least five transcripts. We found that the five distinct transcripts of the locust MLCK gene are expressed in a tissue‐specific manner, including three muscle‐specific isoforms and two generic isoforms. To characterise the kinase activity of locust MLCK, we recombinantly expressed LmMLCK‐G, the smallest locust MLCK isoform, in insect Sf9 cells. We demonstrated that LmMLCK‐G is a Ca2+/calmodulin‐dependent kinase that specifically phosphorylates serine 50 of locust muscle myosin RLC (LmRLC). Additionally, we found that almost all LmRLC molecules in the flight muscle and the hindleg muscles of adult locusts are phosphorylated. [ABSTRACT FROM AUTHOR]

Edible insects are perceived as an incredible opportunity to mitigate the major challenge of sustainably producing healthy foods for a growing world population in the face of climate change uncertainties over the coming decade. In this study, we assessed the nutrient composition and sensory properties of Acheta domesticus, Apis mellifera, Gnathocera trivittata, Gryllotalpa africana, Imbrasia epimethea, Imbrasia oyemensis, Locusta migratoria, Macrotermes subhylanus, Nomadacris septemfasciata, Rhyncophorus phoenicis, Ruspolia differens and Rhynchophorus ferrugineus consumed in Eastern D. R. Congo. The investigated edible insects are highly appreciated and nutritious, with proteins (20.67–43.93 g/100 g) and fats (14.53–36.02 g/100 g) being the major macro-nutrients, proving their potential to improve diets through food enrichment. The high potassium (24–386.67 mg/100 g), sodium (152–257.82 mg/100 g), magnesium (32–64 mg/100 g), iron (5.3–16.13 mg/100 g), calcium (25–156.67 mg/100 g) and zinc (11–19.67 mg/100 g) content make the assessed edible insects a useful mineral-containing ingredient for preventing undernutrition in countries which are plagued by micronutrient deficiencies. A scatter plot of matrices and Pearson's correlations between sensory attributes and nutritional composition showed a negative correlation (r = − 0.45) between protein and appearance. While no strong correlation was observed between nutritional attributes and sensory acceptance, a positive correlation was observed between potassium and aroma (r = 0.50), after-taste (r = 0.50) and acceptability (r = 0.52). Principal component analysis results indicated that the two axes accounted for up to 97.4% of the observed variability in the nutrient composition and sensory attributes of commonly consumed edible insects in the Eastern D. R. Congo. Given the significant delicacy and nutritional potential of edible insects highlighted in this paper, households can rely on the latter to meet their nutritional needs rather than conventional livestock, thus contributing to environmental and financial security through local business opportunities. [ABSTRACT FROM AUTHOR]

The epidermal cells of insects are polarized epithelial cells that play a pivotal role in the insect's molting process. Sinuous, a pivotal structural protein involved in the formation of septate junctions among epithelial cells, is essential for its physiological function. In this study, to determine whether sinuous participates in the regulation of insect molting, we identified the sinuous gene, Lmsinu, in Locusta migratoria, which encodes a protein belonging to the claudin family and shares 62.6% identity with Drosophila's sinuous protein. Lmsinu is expressed in multiple tissues, and its expression level in the integument significantly increases prior to molting. Knockdown of Lmsinu in L. migratoria results in larval mortality during molting. Furthermore, hematoxylin and eosin and chitin staining demonstrate that the downregulation of Lmsinu led to a prolonged degradation process of the old cuticle during the molting process. Electron microscopy analysis further revealed that knockdown of Lmsinu disrupts the formation of septate junctions among epidermal cells, which are a monolayer of polarized epithelial cells, which may hinder the functionality of epidermal cells during the process of molting. In summary, these findings suggest that Lmsinu plays a role in nymph molting by regulating the formation of septate junctions among epidermal cells. [ABSTRACT FROM AUTHOR]

The field of animal behaviour has often relied on tracking and recording the behaviour of a single individual. For example, for decades, gregarious locust behaviour research has used a standard assay that tracks the path of an individual in a cell, including how much time it spends next to an adjacent cell containing a group of stimulus locusts. However, this process can be time-consuming and impractical in lab and field settings. Here, we validate a complementary approach that uses spatial distribution patterns of a group of locusts in a circular arena to characterize the level of gregarious behaviour. We examined temporal variations in nearest neighbour distances as a criterion of attraction–repulsion and the successive changes of position of the individuals as a criterion of activity level. We used 3rd instar juveniles of the Migratory Locust, Locusta migratoria migratorioides (Reiche and Fairmaire1849), reared in isolated or crowded conditions. Locusts exhibit density-dependent plasticity, and crowd-rearing induces gregarious behaviour. As predicted, we found a larger nearest-neighbour distance between isolated-reared hoppers (indicating repulsion) than mass reared hoppers, which showed attraction to their conspecifics. Mass reared locusts walked greater distances, marking higher activity levels, which is another characteristic of gregarious locusts. These results indicate that this is an efficient and effective method of quantifying gregarious behaviour. [ABSTRACT FROM AUTHOR]

Simple Summary: Our study reveals a density-dependent developmental pattern in locusts, which is associated with the classical ecdysone synthesis pathway. Additionally, analysis of the brain transcriptomic dataset uncovers varied metabolic, immune, and nutritional signals associated with density size. Specifically, Immunoglobulin (IG) emerges as a pivotal gene regulating density-dependent development. These regulatory molecules involved in density dependence present intriguing prospects for future investigation. Insect development is intricately governed by hormonal signaling pathways, yet the pivotal upstream regulator that potentiates hormone activation remains largely elusive. The migratory locust, Locusta migratoria, exhibits population density-dependent phenotypic plasticity, encompassing traits such as flight capability, body coloration, and behavior. In this study, we elucidated a negative correlation between population density and ontogenetic development during the nymphal stage of locusts. We found that the level of density influences the developmental trajectory by modulating transcript abundance within the ecdysone signaling pathway, with knockdown of the prothoracicotropic hormone (PTTH) resulting in developmental delay. Transcriptomic analysis of locust brains across solitary and gregarious phases revealed significant differential expression of genes involved in various pathways, including protein synthesis, energy metabolism, hormonal regulation, and immunity. Notably, knockdown experiments targeting two energy regulators, adipokinetic hormone (AKH) and insulin-like polypeptide 1 (ilp1), failed to elicit changes in the developmental process in solitary locusts. However, knockdown of immunoglobulin (IG) significantly shortened the developmental time in higher-density populations. Collectively, our findings underscore the regulatory role of population density in determining developmental duration and suggest that an immune-related gene contributes to the observed differences in developmental patterns. [ABSTRACT FROM AUTHOR]

Many theoretical treatments of foraging use energy as currency, with carbohydrates and lipids considered interchangeable as energy sources. However, herbivores must often synthesize lipids from carbohydrates since they are in short supply in plants, theoretically increasing the cost of growth. We tested whether a generalist insect herbivore (Locusta migratoria) can improve its growth efficiency by consuming lipids, and whether these locusts have a preferred caloric intake ratio of carbohydrate to lipid (C : L). Locusts fed pairs of isocaloric, isoprotein diets differing in C and L consistently selected a 2C : 1L target. Locusts reared on isocaloric, isoprotein 3C : 0L diets attained similar final body masses and lipid contents to locusts fed the 2C : 1L diet, but they ate more and had a ~12% higher metabolic rate, indicating an energetic cost for lipogenesis. These results demonstrate that some animals can selectively regulate carbohydrate-to-lipid intake and that consumption of dietary lipids can improve growth efficiency. [ABSTRACT FROM AUTHOR]

The prolonged state of hepatic inflammation can lead to liver damage, a critical driving force in the progression of liver-related diseases. Locusta migratoria (LM), an edible insect, is recognized for its protein richness and potential to produce a range of bioactive polypeptides, presenting a novel solution for liver disease. This study investigated the hepatoprotective effects of LM hydrolysates in human hepatoma G2 (Hep G2) cells challenged with lipopolysaccharide (LPS)/D-Galactosamine (D-Gal), a model of liver injury. Remarkably, LM hydrolysates significantly ameliorated cell damage, as evidenced by the inhibition of the LPS/D-Gal-induced decrease in cell viability and reduction in lactate dehydrogenase (LDH) release. Furthermore, LM hydrolysates alleviated the release of aspartate aminotransferase (AST) from cells exposed to LPS/D-Gal and lowered the secretion of inflammatory cytokines while suppressing the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), a key pathway in inflammation. In particular, LM-N hydrolysate mitigated hepatotoxicity by attenuation of inflammatory responses to reduce interleukin 6 (IL-6) levels, and NF-κB nuclear translocation. These findings suggest that LM hydrolysates could potentially offer hepatoprotective effects by mitigating the inflammatory responses induced by LPS/D-Gal. [ABSTRACT FROM AUTHOR]

Locust (Locusta migratoria) has a single striated muscle myosin heavy chain (Mhc) gene, which contains 5 clusters of alternative exclusive exons and 1 differently included penultimate exon. The alternative exons of Mhc gene encode 4 distinct regions in the myosin motor domain, that is, the N‐terminal SH3‐like domain, one lip of the nucleotide‐binding pocket, the relay, and the converter. Here, we investigated the role of the alternative regions on the motor function of locust muscle myosin. Using Sf9‐baculovirus protein expression system, we expressed and purified 5 isoforms of the locust muscle myosin heavy meromyosin (HMM), including the major isoform in the thorax dorsal longitudinal flight muscle (FL1) and 4 isoforms expressed in the abdominal intersegmental muscle (AB1 to AB4). Among these 5 HMMs, FL1‐HMM displayed the highest level of actin‐activated adenosine triphosphatase (ATPase) activity (hereafter referred as ATPase activity). To identify the alternative region(s) responsible for the elevated ATPase activity of FL1‐HMM, we produced a number of chimeras of FL1‐HMM and AB4‐HMM. Substitution with the relay of AB4‐HMM (encoded by exon‐14c) substantially decreased the ATPase activity of FL1‐HMM, and conversely, the relay of FL1‐HMM (encoded by exon‐14a) enhanced the ATPase activity of AB4‐HMM. Mutagenesis showed that the exon‐14a‐encoded residues Gly474 and Asn509 are responsible for the elevated ATPase activity of FL1‐HMM. Those results indicate that the alternative relay encoded by exon‐14a/c play a key role in regulating the ATPase activity of FL1‐HMM and AB4‐HMM. [ABSTRACT FROM AUTHOR]

This study investigated the influence of different linearly polarized spectrum lights on locusts polartactic response characteristics linearly polarized vector sensitivity mode and polartactic response) by using linearly polarized spectrum vector light module and experimental device. The objective was to clarify the vector sensitivity characteristics and functional effect of linearly polarized light spectrum intensity on locusts polartactic response, determine the influence specificity of linearly polarized spectrum illumination properties on locusts polarization-related behavior. When spectrum and illumination were constant, locusts polartactic response, presenting the response feature of sine and cosine function change specificity, was related to spectrum attribute. The visual acuity effect stimulated by violet spectrum was the best, whereas the optical distance modulation effect induced by orange spectrum was the strongest. When illumination was enhanced, locusts vector sensitivity mode shifted to present the specific sensitivity prompted by light intensity at long distance and inhibited by light intensity at short distance. Moreover, the regulating function of violet spectrum was the strongest, and the regulatory mutation effect of orange spectrum was the least significant. Simultaneously, locusts polartactic sensitivity to 300° vector at 100 lx, whereas to 240° vector at 1000 lx of linearly polarized violet light was the strongest. Locusts polartactic aggregation and visual tendency sensitivity to 90° vector at 100 lx, whereas to 270° vector at 1000 lx of linearly polarized violet light was the strongest. The heterogeneous regulation function of different linearly polarized spectrum couplings with light intensity led to significant variations in locusts vector sensitivity mode. This was derived from the antagonistic and specific tuning characteristics of locusts polartactic vision, reflecting the integrated output effect of locusts vector dependence regulated by linearly polarized spectrum intensity attribute. The findings were significant for the construction of pest polarization induction light sources and the investigation of the sensitive physiology pathway of locusts polarization vision. [ABSTRACT FROM AUTHOR]

Simple Summary: Fushi Tarazu Factor-1 (FTZ-F1) is a member of the nuclear receptor superfamily, which plays an important role in the molting process of insects. In this study, two FTZ-F1 transcripts (LmFTZ-F1-X1 and LmFTZ-F1-X2) were identified in Locusta migratoria, which were highly expressed in the cuticle. Then, the function of LmFTZ-F1-X1 and LmFTZ-F1-X2 in the molting process was explored using RNA interference. Silencing LmFTZ-F1-X1 and LmFTZ-F1-X2 separately did not affect the normal development of the nymph, but the simultaneous RNAi of LmFTZ-F1-X1 and LmFTZ-F1-X2 blocked the nymphal molting by regulating the genes involved in cuticle formation, chitin synthesis, and other key molting processes. Fushi-tarazu factor 1 (FTZ-F1) is a class of transcription factors belonging to the nuclear receptor superfamily and an important molting regulator in insects; however, its detailed function in the molting process of Locusta migratoria is still unclear. This study identified two FTZ-F1 transcripts (LmFTZ-F1-X1 and LmFTZ-F1-X2) in L. migratoria. The classical domains of FTZ-F1 were present in their protein sequences and distinguished based on their variable N-terminal domains. Reverse-transcription quantitative polymerase chain reaction analysis revealed that LmFTZ-F1-X1 and LmFTZ-F1-X2 were highly expressed in the integument. RNA interference (RNAi) was used to explore the function of LmFTZ-F1s in the molting of the third-instar nymph. Separate LmFTZ-F1-X1 or LmFTZ-F1-X2 silencing did not affect the normal development of third-instar nymphs; however, the simultaneous RNAi of LmFTZ-F1-X1 and LmFTZ-F1-X2 caused the nymphs to be trapped in the third instar stage and finally die. Furthermore, the hematoxylin-eosin and chitin staining of the cuticle showed that the new cuticles were thickened after silencing the LmFTZ-F1s compared to the controls. RNA-seq analysis showed that genes encoding four cuticle proteins, two chitin synthesis enzymes, and cytochrome P450 303a1 were differentially expressed between dsGFP- and dsLmFTZ-F1s-injected groups. Taken together, LmFTZ-F1-X1 and LmFTZ-F1-X2 are involved in the ecdysis of locusts, possibly by regulating the expression of genes involved in cuticle formation, chitin synthesis, and other key molting processes. [ABSTRACT FROM AUTHOR]

The Journal of Comparative Physiology lived up to its name in the last 100 years by including more than 1500 different taxa in almost 10,000 publications. Seventeen phyla of the animal kingdom were represented. The honeybee (Apis mellifera) is the taxon with most publications, followed by locust (Locusta migratoria), crayfishes (Cambarus spp.), and fruitfly (Drosophila melanogaster). The representation of species in this journal in the past, thus, differs much from the 13 model systems as named by the National Institutes of Health (USA). We mention major accomplishments of research on species with specific adaptations, specialist animals, for example, the quantitative description of the processes underlying the axon potential in squid (Loligo forbesii) and the isolation of the first receptor channel in the electric eel (Electrophorus electricus) and electric ray (Torpedo spp.). Future neuroethological work should make the recent genetic and technological developments available for specialist animals. There are many research questions left that may be answered with high yield in specialists and some questions that can only be answered in specialists. Moreover, the adaptations of animals that occupy specific ecological niches often lend themselves to biomimetic applications. We go into some depth in explaining our thoughts in the research of motion vision in insects, sound localization in barn owls, and electroreception in weakly electric fish. [ABSTRACT FROM AUTHOR]

There are complex temporal and spatial interactions between insects and microbes. Previously, the function of microbial virulence factors has been identified and characterized. However, the roles of disease-related microbial-derived metabolites in regulating host innate immunity and the composition of microbial community are not explored. Entomopathogenic fungi (EPF) are important biological control agents because together with their insect hosts provide an idea model system to analyze the interplay between microbial-derived metabolites and host innate immune activity in relation to gut microbial community composition. Here, we report that the entomopathogenic fungus Metarhizium anisopliae produces a variety of metabolites during growth in the locust hemolymph, and their injection into locusts modifies the expression of a wide range of host genes, which participate in cellular and humoral innate immune processes. However, upon injection of the fungal metabolites, the antimicrobial peptide diptericin is specifically expressed in the locust cuticle and midgut, suppressing the microbiota inhabiting the latter tissue. Also, three commonly identified metabolites (nicotinamide, nicotinate, and choline) can activate the expression of immune-related genes in the locust midgut. Our results further reveal that injection of fungal metabolites into locusts substantially suppresses the locust gut microbial composition. Our findings expose a fungal pathogen infection strategy that involves the release of metabolites for activating insect immune effectors in the cuticle and midgut, which may comprise an important factor to restrain the number of gut-inhabiting bacteria. This study highlights the important functions of entomopathogenic fungal-derived metabolites in manipulating the insect host innate immunity and gut microbiota composition. [ABSTRACT FROM AUTHOR]

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The migratory locust, Locusta migratoria (L.), a significant grasshopper species known for its ability to form large swarms and cause extensive damage to crops and vegetation, is subject to the influence of climate change. This research paper employs geographic information system (GIS) and MaxEnt ecological modelling techniques to assess the impact of climate change on the distribution patterns of L. migratoria. Occurrence data and environmental variables are collected and analysed to create predictive models for the current and future distribution of the species. The study highlights the crucial role of climate factors, particularly temperature and precipitation, in determining the locust's distribution. The MaxEnt models exhibit high-performance indicators, accurately predicting the potential habitat suitability of L. migratoria. Additionally, specific bioclimatic variables, such as mean temperature and annual precipitation, are identified as significant factors influencing the species' presence. The generated future maps indicate how this species will invade new regions especially in Europe. Such results predict the risk of this destructive species for many agriculture communities as a direct result of a warming world. The research provides valuable insights into the complex relationship between locust distribution and environmental factors, enabling the development of effective strategies for locust management and early warning systems to mitigate the impact on agriculture and ecosystems. [ABSTRACT FROM AUTHOR]

Mealworm, migratory locust, and house cricket have recently been recognized by the European Commission as novel foods, thus being suitable in different food applications. In this work, we tested their powders as meat extenders at 5% (w/w) inclusion in beef burgers, considering their ability to vehicle phenolic compounds during simulated in vitro static gastrointestinal digestion (INFOGEST). Insect powders were abundant in different phenolic classes, recording the highest values in locust (LP; 314.69 mg/kg), followed by cricket (CP; 113.3 mg/kg) and mealworm (MWP; 51.9 mg/kg). Following a pan-cooking process, LP burgers were confirmed as the best source of phenolics, with a marked abundance of flavonoids and phenolic acids. Interestingly, the insect powders were found to affect the in vitro gastrointestinal bioaccessibility of phenolic compounds when compared with the CTR burger, likely promoted by the interactions between the phenolic compounds and proteins characterizing the tested insect powders. Among the most discriminant phenolic metabolites at the gastrointestinal level, we found several phenolic acids (mainly hydroxycinnamics), recording the highest content for the digested CP-containing burgers. Finally, stilbenes showed significant correlation values at the intestinal level with both antioxidant and enzymatic activities, while total flavonoids were the most correlated with the inhibition of acetylcholinesterase. Taken together, our preliminary findings demonstrated that insect powders added to beef burgers can promote the bioaccessibility and potential bioavailability of phenolics in the distal tracts of the intestine. [ABSTRACT FROM AUTHOR]

Social learning is an evolutionarily important ability increasingly attributed also to invertebrate species. Interfacing robots with animals represents a promising strategy to investigate social learning. Herein, we studied if the gregarious form of Locusta migratoria, a particularly suited model to examine social learning, can use social information provided by robotic demonstrators to optimize their predator avoidance. Robotic demonstrators with different silhouettes and colours (biomimetic or neutral) were used to investigate if their rotation on a rod (e.g. hiding behaviour) elicited the same behaviour in neighbouring locusts. Locusts' responses were affected by different robotic demonstrators, observing a significant impact of the biomimetic silhouette in reducing the latency duration, and in promoting social learning (e.g. locusts displaying hiding behaviour after observing it in robotic demonstrators). A significant impact of colour patterns in triggering socially induced hiding behaviour was also recorded, especially when the biomimetic silhouette was coloured with the gregarious-like pattern. This research indicates gregarious locusts exploit social information in specific ecological contexts, providing basic knowledge on the complex behavioural ecology and social biology in invertebrates. The proposed animal-robot interaction paradigm shows the role of robots as carrier of social information to living organisms, suggesting social biorobotics as advanced and sustainable approach for socio-biology investigation, and environmental management. [ABSTRACT FROM AUTHOR]

Swarming locusts cause huge plagues across the world threatening food production. Before swarms form, locust populations exhibit a dramatic phase change from a solitary to a gregarious phase. The cause of this phase change is a complicated interplay of conspecific and environmental cues and is, especially for one of the major pests, the migratory locust Locusta migratoria, still not well understood. Here we study the behavior of both solitary and gregarious L. migratoria towards the headspace odors of conspecifics. As we do not find a general attraction of gregarious animals to the headspace of gregarious conspecifics, swarm formation does not seem to be mainly governed by olfactory aggregation cues. When testing for potential mating signals, we observe that the headspace of virgin gregarious females is highly attractive only towards virgin males of the same phase, while mated gregarious males and solitary males, regardless of their mating state, do not become attracted. Interestingly, this phase-specific attraction goes along with the finding, that mating behavior in experiments with inter-phasic pairings is extremely rare. Our data suggest that odor emissions in L. migratoria play a significant role in a mating context. [ABSTRACT FROM AUTHOR]

BACKGROUND: The fungal genera Metarhizium contain many important multiple species that are used as biocontrol agents and as model organisms for exploring insect–fungal interactions. Metarhizium spp. exhibit different traits of pathogenicity, suggesting that the pathogenesis can be quite distinctive. However, the underlying differences in their pathogenesis remain poorly understood. RESULTS: Pathogenicity analysis showed that Metarhizium anisopliae (strain CQMa421) displayed higher virulence against oriental migratory locusts, Locusta migratoria manilensis (Meyen), than the acridid‐specific specie Metarhizium acridum (strain CQMa102). Relative to M. acridum, M. anisopliae possessed a higher conidial hydrophobicity, increased ability to penetrate the host, accelerated growth under hypoxia and enhanced ability for the utilization of different carbon sources. Different distributions of carbohydrate epitopes at cell wall surface of M. anisopliae might also contribute to successful evasion of host immune defenses. Comparative genomics showed that M. anisopliae has 98 more virulence‐related secreted proteins (133) than M. acridum (35), which can be functionally classified as hydrolases, virulence effectors, cell wall degradation and stress tolerance‐related proteins, and helpful to the cuticle penetration and host internal environment adaption. In addition, differences in genomic clusters specifically related to secondary metabolites, including the clusters of Indole‐NRPS hybrid, T1PKS‐NRPS like hybrid, Betalactone, Fungal‐Ripp and NRPS‐Terpene hybrid, may lead to differences in core virulence‐related secondary metabolite genes in M. acridum (18) and M. anisopliae (36). CONCLUSION: The comparative study provided new insights into the different infection strategies between M. anisopliae and M. acridum, and further facilitate the identification of virulence‐related genes for the improvement of mycoinsecticides. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: The oriental migratory locust is a major crop pest across eastern and south‐eastern Asia. Metarhizium anisopliae is an effective biopesticide agent used for locust control, but its performance is temperature dependent, and thus can be more variable than chemical pesticide performance. To predict biopesticide performance for the control of the oriental migratory locust, we adapted a previous temperature‐dependent model and validated it using field trial data. To increase the applicability of this model, we explored the use of readily available temperature variables, as well as our own satellite‐derived canopy temperature variable, to run the model. RESULTS: Compared to collected in situ temperature data, our canopy temperature variable most accurately represented the ambient temperature experienced by the locust. When the biopesticide performance model was run using this canopy temperature and compared to field trials results, the model predictions were more accurate than when the model was run with the other temperature variables. The accuracy of the biopesticide performance model was impacted by vegetation cover, but across the areas most associated with locust oviposition, growth and migration, the model predictions were satisfactorily accurate to guide biopesticide operational use. CONCLUSION: We validated the model in six provinces in China, representing the three agro‐ecological zones largely representative of the oriental migratory locust problem areas in China, Thailand, Cambodia and Vietnam. Whilst further validation work is needed, this model could be used in these countries to assess, at a fine spatial scale, the appropriateness of M. anisopliae for controlling the oriental migratory locust. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Abstract Background The European Union (EU) approved the placement on European market of insect-based novel foods. Those foods were defined safe for the consumption for all European population, including children. Main body The nutrition committee of the Italian society of Paediatric Hepatology and Nutrition (SIGENP) performed literature research to understand benefits and risk of those use of those NF for Italian children. A special attention was reserved to the European Food Safety Agency (EFSA) reports upon which those novel insect-based were approved. Conclusions Based on the current knowledge, despite a possible ecological advantage, the group of expert suggests additional researches before pronouncing on a possible use for children diet, because of insufficient evidence on nutritional benefits and possible food allergies.

Biological control methods provide a sustainable approach for reducing agricultural losses caused by locust plagues. Space mutagenesis can generate high numbers of mutations using satellites and spacecrafts, including beneficial and stable mutants. Aspergillus oryzae XJ-1 was recently reported to show high virulence against locusts. We subjected this fungal pathogen to space mutagenesis to obtain more effective strains. Pathogen conidia powder was mutated in the China Space Station for 6 months. We obtained five mutants of A. oryzae XJ-1, TQ201, TQ238, TQ302, TQ549, and TQ555, and all mutants were identified as A. oryzae by molecular techniques. TQ549 showed the highest virulence against adult L. migratoria (LT50: 4.97 ± 0.21 days); the LT50 of A. oryzae XJ-1 was 5.67 ± 0.06 days. Both TQ549 and A. oryzae XJ-1 grew most rapidly at 33 °C on potato dextrose agar (PDA) plates. There was no significant difference in the growth rate of TQ549 and A. oryzae XJ-1 at 24 °C. The colony morphological characteristics of the five mutants on PDA plates differed from that of A. oryzae XJ-1. The space mutant TQ549, which showed high virulence against adult locusts, could be used as a biological control agent for the control of locust infestations. [ABSTRACT FROM AUTHOR]

Adults of the migratory locust Locusta migratoria (Linnaeus, 1758) were collected in the Japanese Archipelago, which extends from the Ryukyu subtropical region to the Hokkaido cool-temperate region, covering more than 2,500 km. A saw-toothed pattern was observed in body size along the latitudinal or annual mean temperature gradient, which is similar to Masaki's clines initially described for crickets. The latitudinal cline of locusts was also observed in the laboratory, suggesting that this cline was primarily due to genetic variation. In the northern univoltine zone, locust body size increased toward the south. The latitudinal size trend was reversed in the transitional zones where the voltinism shifted from univoltine to bivoltine and from bivoltine to trivoltine life cycles. These patterns may be explained by changes in the length of the growing season for development and reproduction. Body size varied with growth efficiency but not with the variable lengths of nymphal development. Larger females had more ovarioles and produced fatter egg pods containing more eggs per pod. The morphometric ratio, F/C (hind femur length/head width), tended to decrease with latitude, but this characteristic could be primarily due to phylogenetic differences between the northern and southern clades. It was confirmed that F/C ratio decreased when the locusts were reared in a group. The sexual size dimorphism, or SSD, tended to increase as the mean body sizes of populations increased, converse to Rensch's rule. The relative body size of females and males correlated with latitude and was greatly reduced when the insects were reared in a group. The smaller rate of increase at higher latitudes may be related to male-female associations and predation pressure. [ABSTRACT FROM AUTHOR]

Simple Summary: Short-horned grasshoppers (Orthoptera; Caelifera) in Anatolia inhabit diverse habitats, aligning with the topographical and climatological heterogeneity of the region. In addition to certain swarming species, attention must be given to the pest potential of several pullulating species within the Anatolian fauna. This study seeks to classify Anatolia's short-horned grasshoppers from a biogeographical perspective and integrate these data to comprehend the future pest potential of non-swarming species, especially in the context of climate change. Our results reveal the following: (i) Acrididae and Pamphagidae are the most diverse families in Anatolia; (ii) approximately 40% of Caelifera and 71% of Pamphagidae are endemic, marking Anatolia as a biodiversity hotspot; (iii) the phytogeographical order of four provinces based on Caelifera diversity is Irano-Anatolia, Euro-Siberia, Mediterranean, and Mesopotamia; and (iv) based on our ecological modelling and personal observations, Dociostaurus maroccanus, Locusta migratoria, Calliptamus italicus, Heteracris pterosticha, Notostaurus anatolicus, Oedipoda miniata, and O. schochii should be monitored due to their pest potential. Biogeographically, Anatolia harbours a rich diversity of short-horned grasshoppers (Orthoptera, Caelifera). The number of species recorded from Anatolia so far stands at 300. They inhabit diverse habitats ranging from arid Eremial to Euro-Siberian-like montane meadows, aligning with the topographical and climatological heterogeneity of Anatolia. Alongside some swarming species, the pest potential of several pullulating species needs attention. This is especially important concerning global warming, a scenario expected to be more severe in the Northern Mediterranean Basin in general and Anatolia specifically. A faunal list of biogeographic Anatolia, the area extending from the Aegean Sea in the west to the intermountain basin of the Caucasus in the northeast, the lowlands of Lake Urmia in the east, and Mesopotamia in the southeast, was developed. The recorded species were classified according to the phytogeographical provinces of Anatolia. Distributions of the species with the potential for pullulating were modelled using ecological-niche-modelling approaches for the present and future. The results have the potential to lead to the development of a concept that merges biogeography and the pest potential of certain Anatolian grasshopper species. Our results reveal the following: (i) Acrididae and Pamphagidae are the most diverse families represented in Anatolia; (ii) roughly 40% of Caelifera and 71% of Pamphagidae are endemics, suggesting Anatolia is a biodiversity hotspot; (iii) according to Caelifera diversity, the phytogeographical provinces of Anatolia follow an order of Irano-Anatolia, Euro-Siberia, Mediterranean, and Mesopotamia; and (iv) based on ecological modelling and personal observations, Dociostaurus maroccanus, Locusta migratoria, Calliptamus italicus, Heteracris pterosticha, Notostaurus anatolicus, Oedipoda miniata, and O. schochii should be monitored regarding their pest potential. [ABSTRACT FROM AUTHOR]

Background: The European Union (EU) approved the placement on European market of insect-based novel foods. Those foods were defined safe for the consumption for all European population, including children. Main body: The nutrition committee of the Italian society of Paediatric Hepatology and Nutrition (SIGENP) performed literature research to understand benefits and risk of those use of those NF for Italian children. A special attention was reserved to the European Food Safety Agency (EFSA) reports upon which those novel insect-based were approved. Conclusions: Based on the current knowledge, despite a possible ecological advantage, the group of expert suggests additional researches before pronouncing on a possible use for children diet, because of insufficient evidence on nutritional benefits and possible food allergies. [ABSTRACT FROM AUTHOR]

Irradiation of food is promising for control of pests to minimize postharvest losses of yields and thus improvement of food safety, shelf life of produce. It is a method of choice that induces a series of lethal biochemical and molecular changes culminating into the engagement of a downstream cascade to cause abnormalities in irradiated pests. In this study, the effects of iodine-131 (131I) isotope radiation on the male gonad development of the migratory locust, Locusta migratoria, were evaluated. Newly emerged adult male locusts, less than one-day-old, were divided into two groups, control and irradiated. Locusts in the control group (n = 20 insects) didn't drink irradiated water and were reared under normal environmental conditions for one week. Locusts in the irradiated group (n = 20 insects) were exposed to irradiated water at a dose of 30 mCi and they were subsequently observed until they drank the whole quantity. At the end of the experiment, scanning and electron microscopic examination of testes obtained from irradiated locusts revealed several major abnormalities, including malformed nuclei of spermatozoa, irregular plasma membranes, shrinkage of testicular follicles, vacuolated cytoplasm, disintegrated nebenkern and agglutinations of spermatids. Flow cytometry analysis revealed that 131I radiation induced both early and late apoptosis, but not necrosis, in testicular tissues. Testes of irradiated insects also exhibited a burst in reactive oxygen species (ROS), as indicated by significant elevation in amounts of malondialdehyde (MDA), a marker for peroxidation of lipids. In contrast, irradiation coincided with significant reductions in activities of enzymatic antioxidant biomarkers. Relative to controls, a three-fold upregulation of expression of mRNA of heat shock protein, Hsp90, was observed in testicular tissue of irradiated locusts. 131I-irradiated insects exhibited genotoxicity, as indicated by significant increases in various indicators of DNA damage by the comet assay, including tail length (7.80 ± 0.80 µm; p <.01), olive tail moment (40.37 ± 8.08; p <.01) and tail DNA intensity % (5.1 ± 0.51; p <.01), in testicular cells compared to the controls. This is the first report on elucidation of I131-irradiation-mediated histopathological, biochemical and molecular mechanisms in gonads of male L. migratoria. Herein, the findings underscore the utility of 131I radiation as an eco-friendly postharvest strategy for management of insect pests and in particular for control of populations of L. migratoria. [ABSTRACT FROM AUTHOR]

Aimed at addressing the problems of the existing straw choppers on combine harvesters, such as a large cutting resistance and poor cutting effect, combined with bionic engineering technology and biological characteristics, a bionic model was used to extract the characteristics of the cutting blades of locusta migratoria manilensis's upper jaw. A 3D point cloud reconstruction and machine vision methods were used to fit the polynomial curve of the blade edge using Matlab 2016. A straw-cutting process was simulated using the discrete element method, and the cutting effect of the bionic blade was verified. Cutting experiments with rice straws were conducted using a physical property tester, and the cutting resistance of straw to bionic blades and general blades was compared. On the whole, the average cutting force of the bionic blades was lower than that of the general blades. The average cutting force of the bionic blade was 18.74~38.23% lower than that of a smooth blade and 1.63~25.23% lower than that of a serrated blade. Similarly, the maximum instantaneous cutting force of the bionic blade was reduced by 2.30~2.89% compared with the general blade, which had a significant drag reduction effect. By comparing the time–force curves of different blades' cutting processes, it was determined that the drag-reducing effect of the bionic blade lies in shortening the straw rupture time. The larger the contact area between the blade and the straw, the more uniform the cutting morphology of the straw after cutting. Field experiment results indicate that the average power consumption of a straw chopper partially installed with bionic blades was 5.48% lower than one with smooth blades, measured using a wireless torque analysis module. In this research study, the structure of the straw chopper of an existing combine harvester was improved based on the bionic principle, which reduced resistance when cutting crop straw, thus reducing the power consumption required by the straw chopper and improving the effectiveness and stability of the blades. [ABSTRACT FROM AUTHOR]

This study is based on the fatty acid and amino acid profiles of seven edible insect species: Acheta domesticus, Alphitobius diaperinus, Blaptica dubia, Galleria mellonella, Locusta migratoria, Tenebrio molitor, and Zophobas morio. The aim of the present study is to provide new data on the fatty acid distributions among lipid classes as well as the species-specific protein conversion factor (Kp) of a wide range of insects in order to further improve the nutritional characterisation of insects as food. Oleic acid was the predominant fatty acid in all insects except for A. domesticus, in which a significantly higher percentage of linoleic acid was found. The majority of the lipids were neutral lipids. A significant amount of α-linolenic acid in the phospholipid fraction of L. migratoria was shown, while in T. molitor, phospholipids were the only fraction in which a measurable amount of docosahexaenoic acid was found. Overall, in most insects, the phospholipid fraction had the highest polyunsaturated fatty acid content compared to the other classes, which may be protective in terms of auto-oxidative stability. Kp values in the range of 4.17 to 6.43 were obtained. Within the nutritional quality indices, all insects showed healthy fatty acids and high-quality amino acid profiles. [ABSTRACT FROM AUTHOR]

Simple Summary: Four species of plague locust, namely the brown locust, the African migratory locust, the red locust, and the southern African desert locust, have threatened agricultural production in South Africa for centuries. The history of the plague invasions of the red locust and African migratory locust into South Africa are described, as well as the rare local outbreaks of the southern African desert locust in the Kalahari Desert region. The dynamics of the locally produced outbreaks of the African migratory locust in the cereal crop environment on the Highveld are discussed in detail. However, the brown locust is by far the most economically important locust species in South Africa, with a very high frequency of outbreaks occurring in the semi-arid Karoo region. After synthetic insecticides became available in 1945, most of the outbreaks were contained within the Karoo following vigorous control campaigns with only short-lived escapes of swarms into grain production areas outside the Karoo and into surrounding countries. However, the large-scale plague eruptions of the brown locust are almost impossible to stop with the resources currently available to the South African locust control organization, and the threat that the brown locust poses to food security in southern Africa is very real. The current paper provides a detailed review of the historical outbreaks of each of the four plague locust species found in South Africa, namely the brown locust, the African migratory locust, the red locust, and the southern African desert locust. The history and dynamics of the plague infestations and the major local outbreaks are summarized. The typical patterns of the outbreaks of the different species are described, and the threat of these locusts to agriculture in South Africa is defined. The brown locust produces regular outbreaks in the semi-arid Karoo, with large-scale eruptions of plague proportions occurring about once per decade. Patterns of outbreaks often repeat themselves, but the sheer size of the plague outbreaks is almost impossible to stop, and the brown locust has the potential to threaten food security throughout southern Africa. The African migratory locust produces outbreaks in some of the main maize and wheat cropping areas where it is difficult to control. This locust has taken advantage of the man-made crop environment to produce an extra generation per year that was not previously possible in the original grasslands. The coastal area of KwaZulu Natal Province in South Africa was a prime reception and breeding area for plague invasions of the red locust in the past, and the country, therefore, relies on the successful control of outbreaks in east and central Africa to prevent the recurrence of the plague invasions. The southern African desert locust occurs in the Kalahari Desert area, and outbreaks requiring chemical control are rare. [ABSTRACT FROM AUTHOR]

Insect development is intricately governed by hormonal signaling pathways, yet the pivotal upstream regulator that potentiates hormone activation remains largely elusive. The migratory locust, Locusta migratoria, exhibits population density-dependent phenotypic plasticity, encompassing traits such as flight capability, body coloration, and behavior. In this study, we elucidated a negative correlation between population density and ontogenetic development during the nymphal stage of locusts. We found that the level of density influences the developmental trajectory by modulating transcript abundance within the ecdysone signaling pathway, with knockdown of the prothoracicotropic hormone (PTTH) resulting in developmental delay. Transcriptomic analysis of locust brains across solitary and gregarious phases revealed significant differential expression of genes involved in various pathways, including protein synthesis, energy metabolism, hormonal regulation, and immunity. Notably, knockdown experiments targeting two energy regulators, adipokinetic hormone (AKH) and insulin-like polypeptide 1 (ilp1), failed to elicit changes in the developmental process in solitary locusts. However, knockdown of immunoglobulin (IG) significantly shortened the developmental time in higher-density populations. Collectively, our findings underscore the regulatory role of population density in determining developmental duration and suggest that an immune-related gene contributes to the observed differences in developmental patterns.

The Sahara Desert is one of the major ecological barriers of the Palearctic‐Africa bird migration system. We analysed the behaviour of GPS‐tagged booted eagles (Aquila pennata) breeding in Spain and wintering in Tropical Africa, focusing on the Sahara crossing. We searched for anomalous track segments recorded during the desert crossing, finding that non‐directional and/or slow movements occur in 35% of the migratory journeys and last up to 31 days (average: 5.9). The analyses show that this behaviour is not triggered by adverse weather conditions, and is shown especially by females during spring. The length of the stopping periods affects the arrival date to the breeding grounds only in males, which means that females buffer the potential delay with an earlier migration start, suggesting that this behaviour is followed deliberately. These wandering movements occur in hyper‐arid areas without vegetation cover. A similar behaviour has not been previously recorded in any other trans‐Saharan raptor and is probably related to the ability of booted eagles to take advantage of food resources unexploited by other predators, such as migratory songbirds stopping in the desert during the day, and migratory locusts. If confirmed by further research involving higher resolution tracking and field observations, our findings may show a new way of combining foraging and migration, without a well‐defined directed trajectory, nor stopping in a restricted spot, but instead wandering over wide areas. [ABSTRACT FROM AUTHOR]

(1) Background: Few studies have been carried out to appraise abamectin toxicity toward Locusta migratoria nymphs. (2) Methods: This study aimed to evaluate the cytotoxic effect of abamectin as an insecticide through examining the changes and damage caused by this drug, in both neurosecretory cells and midgut, using L. migratoria nymphs as a model of the cytotoxic effect. Histopathological change in the brain was examined in both normal and abamectin-treated fifth-instar nymphs. Neurosecretory cells (NSCs) were also examined where there were loosely disintegrated cells or vacuolated cytoplasm. (3) Results: The results showed distinct histological changes in the gastrointestinal tract of L. migratoria nymphs treated with abamectin, with significant cellular damage and disorganization, i.e., characteristic symptoms of cell necrosis, a destroyed epithelium, enlarged cells, and reduced nuclei. The observed biochemical changes included an elevation in all measured oxidative stress parameters compared to untreated controls. The malondialdehyde activities (MDAs) of the treated nymphs had a five- to six-fold increase, with a ten-fold increase in superoxide dismutase (SOD), nine-fold increase in glutathione-S-transferase (GST), and four-fold increase in nitric oxide (NO). (4) Conclusions: To further investigate the theoretical method of action, a molecular docking simulation was performed, examining the possibility that abamectin is an inhibitor of the fatty acid-binding protein Lm-FABP (2FLJ) and that it binds with two successive electrostatic hydrogen bonds. [ABSTRACT FROM AUTHOR]

BACKGROUND: Locusts and grasshoppers are pests of many agricultural crops, and their frequent outbreaks worldwide threaten food security. Microbial control agents are currently used to suppress the early (nymphal) stages of pests, but they are often less effective against adults, which are primarily responsible for locust plagues. The fungal pathogen Aspergillus oryzae XJ‐1 has high pathogenicity in locust nymphs. To assess its potential for controlling locust adults, we evaluated the virulence of A. oryzae XJ‐1 (i.e., locust Aspergillus, LAsp) in locust adults using laboratory, field‐cage experiments, and a field trial. RESULTS: The lethal concentration of LAsp in adult Locusta migratoria was 3.58 ± 0.09 × 105 conidia mL−1 15 days after inoculation in the laboratory. A field‐cage experiment showed that the mortalities of adult L. migratoria were 92.0 ± 4.6% and 90.1 ± 3.2% 15 days after inoculation with 3 × 105 and 3 × 103 conidia m−2 of LAsp, respectively. A large‐scale field trial of 666.6 ha was conducted, in which a LAsp water suspension was applied at a concentration of 2 × 108 conidia mL−1 in 15 L ha−1 by aerial spraying via drones. The densities of mixed populations of L. migratoria and Epacromius spp. were significantly reduced by 85.4 ± 7.9%–94.9 ± 5.1%. In addition, the infection rates of surviving locusts collected from the treated plots were 79.6% and 78.3% on the 17th and 31st day after treatment, respectively. CONCLUSION: These results indicate that A. oryzae XJ‐1 is highly virulent in adult locusts and that it has high potential for the control of locusts. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Chemical signals from conspecifics are essential in insect group formation and maintenance. Migratory locusts use the aggregation pheromone 4-vinylanisole (4VA), specifically released by gregarious locusts, to attract and recruit conspecific individuals, leading to the formation of large-scale swarms. However, how 4VA contributes to the transition from solitary phase to gregarious phase remains unclear. We investigated the occurrence of locust behavioral phase changes in the presence and absence of 4VA perception. The findings indicated that solitary locusts require crowding for 48 and 72 h to adopt partial and analogous gregarious behavior. However, exposure to increased concentrations of 4VA enabled solitary locusts to display behavioral changes within 24 h of crowding. Crowded solitary locusts with RNAi knockdown of Or35, the specific olfactory receptor for 4VA, failed to exhibit gregarious behaviors. Conversely, the knockdown of Or35 in gregarious locusts resulted in the appearance of solitary behavior. Additionally, a multi-individual behavioral assay system was developed to evaluate the interactions among locust individuals, and four behavioral parameters representing the inclination and conduct of social interactions were positively correlated with the process of crowding. Our data indicated that exposure to 4VA accelerated the behavioral transition from solitary phase to gregarious phase by enhancing the propensity toward proximity and body contact among conspecific individuals. These results highlight the crucial roles of 4VA in the behavioral phase transition of locusts. Furthermore, this study offers valuable insights into the mechanisms of behavioral plasticity that promote the formation of locust swarms and suggests the potential for 4VA application in locust control. [ABSTRACT FROM AUTHOR]

Microsporidia are a group of eukaryotic intracellular parasitic organisms that infect almost all vertebrates and invertebrates. Paranosema locustae are specialized parasites of Orthoptera that are often used as biological controls of locusts, with slow effects of action. In this study, we found that after infection with P. locustae, changes in energy metabolism in male and female Locusta migratoria as were consistent, with no gender differences. During the first 8 days of infection, L. migratoria used sugar as a source of energy. After 8 days, lipids and proteins were consumed to provide energy when the spore load was considerably heavy, and energy supply was insufficient. With increasing infection concentration and time, energy conversion from sugar, fats, and proteins was improved, which may explain why high mortality did not occur until about 15 days after P. locustae infection. The tandem mass tag-based quantitative proteomics analysis revealed that most altered metabolism-related proteins were upregulated (27 of 29 in the metabolic pathway). This result suggests that P. locustae infection accelerated metabolism in L. migratoria , which facilitated the pathogen's life cycle, inhibiting the growth and development of the locusts and eventually killing them. Our findings will be useful to better understand of the chronic pathogenic mechanisms of P. locustae and inform on applications of P. locustae to control locusts. [ABSTRACT FROM AUTHOR]

[Objectives] To investigate the effects of tea saponin on detoxification and protective enzyme activity of Locusta migratoria. [Methods] The effects of different concentrations of tea saponin on the activity of glutathione-S-transferase (GST), carboxylatetasse (CarE), cytochrome P450 (CYP450), peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) were compared by injecting low, medium and high concentrations of tea saponin solution into the abdomen of adult L. migratoria and monitoring changes in detoxification and protective enzyme activity after 0, 12, 24 and 48 h. [Results] The activity of the three detoxification enzymes increased rapidly in the low concentration treatment group, but GST activity was subsequently inhibited, and CarE activity was highest in the medium concentration treatment group. The activity of CYP450 increased with tea saponin dosage. CarE and CYP450 activity increased significantly after 12 h, and the activity of GST increased significantly after 24 h. POD and CAT had the highest activity in the low-concentration treatment group, whereas SOD activity increased significantly in the medium concentration treatment group. Protective enzyme activity began to increase significantly after 24 h in the low concentration treatment group. POD and SOD activity continued to increase, but CAT activity decreased, after 48 h. [Conclusion] Tea saponin can affect the activity of both detoxifying and protective enzyme in Locusta migratoria. [ABSTRACT FROM AUTHOR]

The species composition of fungal pathogens among three of the most harmful locust species (Asian migratory locust, Moroccan locust and Italian locust) in the southern Russian Federation was studied. Insects were sampled in 20 locations of seven federal subjects of the Russian Federation (Republic of Dagestan, Republic of Kalmykia; Krasnodar and Stavropol Krai; Astrakhan, Volgograd and Rostov Regions). Forty-five isolates belonging to the fungal genus Beauveria were collected, particularly isolates of B. bassiana and B. pseudobassiana. B. bassiana was the most prevalent, constituting 98% of the samples, and could be differentiated into three clades, as evidenced by the TEF gene and intergenic spacer Bloc. Clade 1, represented by the reference isolate ARSEF 2040, was most abundant (61%), and Clade 2, represented by ARSEF 1811, had lower abundance (27%). The remaining isolates either belonged to the genetically distinct Clade 3, represented by ARSEF 1564, or were found to fall outside the major lineages. The frequency of infection in locust populations was variable and tended to increase under conditions unfavorable for the insects. The vast majority of Beauveria isolates from locusts were highly virulent in this insect group. [ABSTRACT FROM AUTHOR]

(1) Locusts are important agricultural pests. Identifying harmful substances and avoiding them is important for locusts' survival; their abilities to do so remain to be clarified. (2) We examined the electrophysiological (electroantennogram (EAG) and single sensillum recording (SSR)) and behavioral responses (preference behavior in a T-maze) of locusts to 18 different compounds; (3) Of these 18 compounds, 9 elicited strong EAG responses, and 3 elicited SSR responses of neurons expressing locust odorant receptor 3 (LmigOR3). The 11 chemicals that elicited stronger EAG or SSR responses were selected for evaluation of the behavioral responses of locusts. Only 2-heptanone induced significant attraction responses in locusts at the tested concentration. RNA interference (RNAi) of LmigOR3 and SSR experiments revealed that LmigOR3 could detect 2-heptanone and 3-octanone. However, in behavioral experiments, RNAi of LmigOR3 did not alter 2-heptanone-induced attraction but increased attraction by 3-octanone. (4) Our results suggest that the broadly tuned receptor expressed in a heterologous expression system exhibits a narrow electrophysiological response spectrum, and the aversive response of locusts to 3-octanone, an odorant from fungal pathogens, natural enemies, and non-host plants, is mediated by LmigOR3. These findings enhance our understanding of the complex olfactory recognition mechanism in insects. [ABSTRACT FROM AUTHOR]

ABSTRAK Belalang kembara merupakan hama yang sangat merugikan pertanian pada beberapa kabupaten di NTT setiap tahunnya. Pengendalian belalang melalui pemanfaatan potensi pangan serangga ini dapat menjadi solusi ekonomis bagi masyarakat. Belalang diketahui merupakan salah satu sumber pangan kaya protein. Konsumsi belalang dalam bentuk produk olahan seperti nugget dapat menjadi introduksi awal pemanfaatan belalang. Penelitian pengembangan nugget dilakukan dengan 5 perlakuan, yaitu A1 (100% daging ayam), A2 (75%daging ayam, da:25% tepung belalang, tb), A3 (67.5% da:32.5% tb), A4 (50% da:50% tb), dan A5 (100% tb) dalam rancangan acak lengkap dengan 3 ulangan untuk dipelajari sifat fisiko-kimia dan organoleptiknya. Nugget perlakuan A2 memiliki prospek yang baik, terlihat dari respon panelis suka (skor 4) untuk semua sifat organoleptik, dengan kandungan gizi yang setara dengan nugget 100% daging ayam (A1), serta sifat fisik berupa warna dan tekstur yang baik. Peningkatan proporsi tepung belalang meningkatkan kandungan gizi terutama protein dari nugget, namun menurunkan skor kesukaan panelis dan warna internal nugget semakin gelap. Kata kunci: Belalang kembara, Gizi nugget, Kesukaan, Tekstur , Warna ABSTRACT Migratory locust is a major agricultural pest in several regencies at East Nusa Tenggara. The control of this locust through the utilization of its nutritional potency could be an economic solution for farmers. Locust is known as a source of protein. Consuming locusts in the form of processed products such as nuggets may be the first way of its utilization. Study on nugget development has been conducted within 5 treatments, i.e. A1 (100% chicken meat), A2 (75% chicken meat:25% locust flour), A3 (67.5% chicken meat:32.5% locust flour), A4 (50% chicken meat:50% locust flour), and A5 (100% locust flour) in a Completed Randomized Design with 3 replications to study their physicochemical and organoleptic properties. Nugget A2 has a good prospect with a four score (like) of organoleptic responses of panelists, good nutritional content, color, and texture. Increasing the proportion of locust flour increases the nutrition value of nuggets, but reduces their organoleptic scores, and the internal nugget turns darker. Keywords: Color, likeness, Migratory locust, Nugget nutrition, Texture

Mealworm, migratory locust, and house cricket have recently been recognized by the European Commission as novel foods, thus being suitable in different food applications. In this work, we tested their powders as meat extenders at 5% (w/w) inclusion in beef burgers, considering their ability to vehicle phenolic compounds during simulated in vitro static gastrointestinal digestion (INFOGEST). Insect powders were abundant in different phenolic classes, recording the highest values in locust (LP; 314.69 mg/kg), followed by cricket (CP; 113.3 mg/kg) and mealworm (MWP; 51.9 mg/kg). Following a pan-cooking process, LP burgers were confirmed as the best source of phenolics, with a marked abundance of flavonoids and phenolic acids. Interestingly, the insect powders were found to affect the in vitro gastrointestinal bioaccessibility of phenolic compounds when compared with the CTR burger, likely promoted by the interactions between the phenolic compounds and proteins characterizing the tested insect powders. Among the most discriminant phenolic metabolites at the gastrointestinal level, we found several phenolic acids (mainly hydroxycinnamics), recording the highest content for the digested CP-containing burgers. Finally, stilbenes showed significant correlation values at the intestinal level with both antioxidant and enzymatic activities, while total flavonoids were the most correlated with the inhibition of acetylcholinesterase. Taken together, our preliminary findings demonstrated that insect powders added to beef burgers can promote the bioaccessibility and potential bioavailability of phenolics in the distal tracts of the intestine.

The TRP channel superfamily was widely found in multiple species. They were involved in many extrasensory perceptions and were important for adapting to the environment. The migratory locust was one of the worldwide agricultural pests due to huge damage. In this study, we identified 13 TRP superfamily genes in the locust genome. The number of LmTRP superfamily genes was consistent with most insects. The phylogenetic tree showed that LmTRP superfamily genes could be divided into seven subfamilies. The conserved motifs and domains analysis documented that LmTRP superfamily genes contained unique characteristics of the TRP superfamily. The expression profiles in different organs identified LmTRP superfamily genes in the head and antennae, which were involved in sensory function. The expression pattern of different life phases also demonstrated that LmTRP superfamily genes were mainly expressed in third-instar nymphs and male adults. Our findings could contribute to a better understanding of the TRP channel superfamily gene and provide potential targets for insect control. [ABSTRACT FROM AUTHOR]

The Clustered Regularly Interspaced Short Palindromic Repeats‐associated (CRISPR‐Cas) system has been used as a powerful diagnostic tool because of its trans‐cleavage ability to accurately recognize and cleave specific nucleic acid targets. However, its application in insect pest detection has rarely been reported. The aim of the current study was to develop a new molecular identification method for insect based on CRISPR‐Cas13a system. In this study, we have developed a highly specific and sensitive detection system that combines polymerase chain reaction, CRISPR‐Cas13a system and lateral flow dipstick (PCR‐Cas13a‐LFD) to rapidly detect the presence of Locusta migratoria manilensis (Orthoptera: Acrididae) DNA and discriminate it from other species, by using material from different stages of development. A pair of specific primers and crRNA were designed based on the Gene DEAD‐box DDX10 mRNA sequence. For visual readout, a FAM‐RNA‐biotin reporter was used for detection. The CRISPR‐Cas13a‐based detection method utilizes the visual identification of L. migratoria manilensis at different developmental stages or with the use of incomplete samples. The test results could be distinguished within 2 h. The sensitivity of the PCR‐Cas13a‐LFD detection system reached 0.1 ng/μL, a 10‐fold increase compared with that of the PCR with electrophoresis. The LFD coupled with CRISPR‐Cas13a (Cas13a‐LFD) is promising for the portable, onsite and fast identification of insect pests. This study provides a reference for the development of a new method for insect identification. [ABSTRACT FROM AUTHOR]

Background: It has been reported previously that AV water-solubility was enhanced great by solid dispersion in PEG6k carrier. Materials and Methods: In this study, AV water-solubility was improved primarily by addition of PLX188 into PEG6k carrier, and further by addition of a deep eutectic solvent of CBU (choline chloride, betaine and urea) in the combinatory carrier of PEG6k and PLX188. Results: The result showed that the water-solubility of AV-PEG6k-PLX188 solid dispersion was 10.8 times of AV-PEG6k solid dispersion, and the cumulative dissolution rate (within 60 min) of AV-PEG6k-PLX188 solid dispersion was 3.3 times of AV-PEG6k solid dispersions. With the further addition of CBU in the AV-PEG6k-PLX188 system, the water-solubility of AV-PEG6k-PLX188-CBU solid dispersion was increased by 3.4 times, and the cumulative dissolution rate (within 60 min) was increased by 1.6 times. The X-ray powder diffraction measurement indicated that AV existed in the AV-PEG6k-PLX188-CBU solid dispersion as a non-crystalline state. Further, the in vitro toxicity against 3rd instar Asiatic migratory locust was measured, which showed that the LC50 of the AV-PEG6k-PLX188-CBU solid dispersion (0.88 mg/L) was a third of that of AV emulsifiable concentrate (2.64 mg/L), suggesting a higher bioavailability. Conclusion: The finding of this work showed that AV-PEG6k-PLX188-CBU solid dispersion was more effective than AV emulsifiable concentrate, in suppressing or killing locusts. [ABSTRACT FROM AUTHOR]

Hypoxia challenges aerobic organisms in numerous environments, and hypoxic conditions may become more severe under future climate‐change scenarios. The impact of hypoxia on the development of terrestrial insect embryos is not well understood. Here, to address this gap, embryonic life‐history traits of migratory locust Locusta migratoria from low‐altitude and high‐altitude regions were compared under 2 oxygen levels: normoxia (i.e., 21 kPa oxygen partial pressure and mild hypoxia (i.e., 10 kPa oxygen partial pressure). Our results demonstrated that, whether reared under normoxia or mild hypoxia, L. migratoria from high‐altitude populations had longer developmental times, reduced weight, and lower mean relative growth rate as compared with those from low‐altitude populations. When transferred from normoxia to mild hypoxia, nearly all the tested life‐history traits presented significant negative changes in the low‐altitude populations, but not in the high‐altitude populations. The factor 'strain' alone explained 18.26%–54.59% of the total variation for traits, suggesting that the phenotypic differences between L. migratoria populations from the 2 altitudes could be driven by genetic variation. Significant genetic correlations were found between life‐history traits, and most of these showed differentiation between the 2 altitudinal gradients. G‐matrix comparisons showed significant structural differences between L. migratoria from the 2 regions, as well as several negative covariances (i.e., trade‐offs) between traits in the low‐altitude populations. Overall, our study provides clear evidence that evolutionary divergence of embryonic traits between L. migratoria populations from different altitudes has occurred. [ABSTRACT FROM AUTHOR]

[Objectives] This study was conducted to investigate the effects of dietary straw content on the growth and development of oriental migratory locusts (Locusta migratoria), as well as the eefects of temperature and substrate on their egg hatching. [Methods] The eggs of oriental migratory locusts were hatched at 15, 20, 25, 30, 35, and 40 °C in sawdust, soil and sawdust r soil conditions, respectively, to determine suitable environmental conditions for artificial hatching of oriental migratory locusts. Rice straw was added at 0%, 20%, 40%, 60%, 80% and 100% to the basic diet, and the obtained diets was feed to oriental migratory locusts at the 4th instar to investigate the effects on their growth and development. [Results] The eggs of oriental migratory locusts had a good hatching rate at 25 - 30 °C, and sawdust was the best choice for their hatching substrate. Adding 40% of rice straw to the diet could ensure the normal growth and development of oriental migratory locusts while consuming as much rice straw as possible. % Conclusions] This study explored a technical solution for efficiently producing insect protein from discarded crop straw (treating waste with insects' and turning waste into treasure) ' providing support for breeding of oriental migratory locusts and locust disaster prevention. [ABSTRACT FROM AUTHOR]

Many animals engage in cannibalism to supplement their diets. Among dense populations of migratory locusts, cannibalism is prevalent. We show that under crowded conditions, locusts produce an anticannibalistic pheromone called phenylacetonitrile. Both the degree of cannibalism and the production of phenylacetonitrile are density dependent and covary. We identified the olfactory receptor that detects phenylacetonitrile and used genome editing to make this receptor nonfunctional, thereby abolishing the negative behavioral response. We also inactivated the gene underlying phenylacetonitrile production and show that locusts that lack this compound lose its protection and are more frequently exposed to intraspecific predation. Thus, we reveal an anticannibalistic feature built on a specifically produced odor. The system is very likely to be of major importance in locust population ecology, and our results might therefore provide opportunities in locust management. [ABSTRACT FROM AUTHOR]

Locust and grasshopper plagues pose a serious threat to crop production in many areas worldwide. However, there is a lack of effective, quick-acting methods to control such outbreaks. Methods exploiting the phototactic response of these insects are receiving increasing attention. The current study investigated the effect of linearly polarized and unpolarized light on locust phototactic and polarotactic responses, in particular the function of their dorsal rim area (DRA) and non-DRA visual fields. The results showed that the polarotactic function weight of DRA vision was stimulated by linearly polarized ultraviolet (UV) and violet light, the phototactic function weight was induced by blue, green, and orange light, and under linearly polarized light, the functional effect of DRA vision was strongest in response to linearly polarized violet light. Moreover, the locust visual response effect was related to spectral light attributes, with the linear polarization effect intensifying in response to the short-range vision sensitivity of non-DRA visual fields, whereas DRA vision regulated the short-range sensitivity of compound eye vision. When illumination increased, the synergistic enhancement effects of linearly polarized ultraviolet and violet light were significant, whereas the visual sensitivity was restricted significantly by linearly polarized blue, green, or orange light. Thus, non-DRA vision determined, while DRA vision enhanced, the phototactic response sensitivity, whereas, in linearly polarized UV or violet light, non-DRA vision determined, while DRA vision enhanced, the visual trend and polarotaxic aggregation sensitivity, with opposite effects in linearly polarized blue, green, or orange light. When illumination increased, there was a driving effect caused by linearly polarized violet light on non-DRA vision, whereas at short-wave lengths, the control effect induced by linearly polarized orange light was optimal; however, the photo-induced effect of linearly polarized violet light and the visual distance control effect of linearly polarized orange light were optimal. These results provide theoretical support for the photo-induced mechanism of the locust visual response effect and for the development of linearly polarized light sources for the environmentally friendly prevention and control of locust populations. [ABSTRACT FROM AUTHOR]

Selecting palatable plants matters for insect herbivores' survival, especially for food-restricted oligophagous and monophagous species. However, the definite selection strategy to distinguish host plants from nonhost plants, as well as the underlying sensory basis, remains controversial. Here, we investigated the olfactory recognition of host plants in oligophagous migratory locusts. By establishing one novel behavioral paradigm that allowed the free-moving locusts to make olfactory choices in short-distance, we demonstrated that palps were required to differentiate host plants apart from nonhost counterparts sensitively. Specifically, the characteristic odors between the host plant and nonhost plant defined the behavioral differentiation of food sources, and this process required intact palps. Further, single nonhost odor suppressed the behavioral potency to host plant extraction, while single host odor attenuated the behavioral repulsion to nonhost plant. We also identified the palps odorant receptors (ORs) repertoire that modulated the short-range recognition of key volatiles from host plants and nonhost and demonstrated that combinatorial olfactory signaling controls food choice. Our results support a "pull–push" model in which olfactory signaling on locust palps acts as a key tuning modulator in host plant recognition, expanding the knowledge of insect chemosensation. [ABSTRACT FROM AUTHOR]