Search

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

In some governorates of Egypt, the African migratory locust L. migratoria migratorioides is in a gregarious phase. Swarm development was successfully prevented by biological control agents. In this work, the two entomopathogenic nematode species, Steinernema sp. (SII)and Heterorhabditis bacteriophora (HP88) were investigated as natural enemies against the fifth nymph and adult African locusts at various concentrations (300, 600, 900, 1200, and 1500 Infected juveniles/100 g. soil). To ascertain fatal activity at 25 °C, the nematode-inoculated sand method was used. The two nematode species were semi-field administered against fifth nymphs and adult stages at (25 ± 2 °C) and 55–60% relative humidity with concentrations (3000, 6000, 9000, 12000, and 15000 Infected juveniles/kg. soil). Protease, amylase, invertase, and trehalase levels in the digestive enzymes of both fifth nymphs and adults fed with LC50 of both nematodes significantly decreased, but lipase and chitinase levels significantly increased. Adult locusts treated with the LC50 of S. sp. SII had basophilic epithelial cells, severe lumen hemorrhage, and highly aberrant proliferating cytoplasm, whereas the LC50 of H. bacteriophora HP88 displayed necrosis in an epithelial cell with vacuoles, loss of nucleus, and loss of goblet cells. [ABSTRACT FROM AUTHOR]

Locusta migratoria is a serious agricultural pest in China. Beauveria bassiana is one of the most important pathogens of grasshoppers and locusts. The effects of ultraviolet light were evaluated on the B. bassiana strain BbZJ1. The results showed that 253.7 and 360 nm wavelength UV (Ultra Violet) did not affect the germination of B. bassiana after its recovery from UV treatments. Nevertheless, the virulence of B. bassiana BbZJ1 after its recovery from radiation of UV (253.7 nm) increased. The mortality rates were 85.00% for the BbZJ1 control, was 96.67% for BbZJ1 recovered from radiation of UV (253.7 nm) for 60 min. After treatment with 253.7 nm UV radiation for 60 min, the expression levels of stress-resistant genes BbAlg9 and Bbadh2 in BbZJ1 strain were 2.68 and 2.29 times higher than those in the control group, respectively. Meanwhile, the B. bassiana prepared in 5% groundnut oil showed highest tolerance levels to the ultraviolet radiation. The 5% groundnut oil was the most suitable potential UV-protectant for B. bassiana in terms of cost and availability. [ABSTRACT FROM AUTHOR]

This study aimed at exploring the possibility of substituting powdered milk (PM) with migratory locust powder (MLP) as a cheap and sustainable alternative protein source in peanut-based ready-to-use therapeutic foods used in treatment of malnutrition. The migratory locust is a wide spread and underutilised high protein edible insect. Peanut-based ready-to-use therapeutic foods (RUTFs) were formulated according to the MSF/UNICEF 2013 nutritional standards. Milk powder was substituted with MLP at 5–30% levels. RUTF containing 30% milk powder was used as the control. Nutritional, antioxidant and antinutrients composition of the insect-enriched RUTFs were compared with RUTF containing milk powder only and a standard. The protein content of the insect-enriched RUTFs ranged from 19.58–26.38% exceeding the MSF/UNICEF minimum standard for protein. RUTF with 10% PM and 20% MLP had the highest (p < 0.05) mineral contents. All formulations had more thiamine (vitamin B1) than the recommended level of 0.5 mg/100 g. Niacin (Vitamin B3) was the most abundant vitamin in the formulations with considerable amounts of vitamin D and E. All MLP-enriched RUTFs met the FAO 2011 standard requirements for amino acids for children aged six months to three years. Therapeutic food with 30% MLP had the highest radical scavenging ability against DPPH, and iron chelating activity. Levels of phytate and tannin were below the tolerable limits. Therefore, MLP can be used as a low-cost substitute for milk powder in producing ready-to-use therapeutic foods. [ABSTRACT FROM AUTHOR]

FK506 binding proteins (FKBPs) are a highly-conserved group of proteins known to bind to FK506, an immunosuppressive drug. They play different physiological roles, including transcription regulation, protein folding, signal transduction and immunosuppression. A number of FKBP genes have been identified in eukaryotes; however, very little information about these genes has been reported in Locusta migratoria. Here, we identified and characterized 10 FKBP genes from L. migratoria. Phylogenetic analysis and comparison of domain architectures indicated that the LmFKBP family can be divided into two subfamilies and five subclasses. Developmental and tissue expression pattern analysis revealed that all LmFKBPs transcripts, including LmFKBP46, LmFKBP12, LmFKBP47, LmFKBP79, LmFKBP16, LmFKBP24, LmFKBP44b, LmFKBP53, were periodically expressed during different developmental stages and mainly expressed in the fat body, hemolymph, testis, and ovary. In brief, our work depicts a outline but panoramic picture of LmFKBP family in L. migratoria, and provides a solid foundation to further investigate the molecular functions of LmFKBPs. [ABSTRACT FROM AUTHOR]

Rising population in the world causes reduction on present food resources. Investigators have been looking for sustainable, nutritional and alternative food-stocks. Insects have been consumed as snacks or as food supplement in many countries, but they are still not attractive food resource worldwide. In the current study, β-fructofuranosidase enzyme production by Galactomyces geotrichum TS61 (GenBank accession: MN749818) strain was investigated using an edible insect (Locusta migratoria) as substrate. β-fructofuranosidase is a valuable enzyme in food industry. Taguchi L16 design of experiment (DOE) was employed to achieve an effective statistical optimization process, including three factors (concentration of locust powder, concentration of sucrose and initial pH) with four levels. The optimized conditions were determined as 40 g/L locust powder, 30 g/L sucrose and 6.0 pH. The analysis of variance results showed that locust powder had more effect on the enzyme production than sucrose and pH. At the end of the optimization process, approximately 4-fold higher β-fructofuranosidase production (40.91 U/mL) was obtained when compared with unoptimized experimental run (9.91 U/mL). Consequently, powdered insects may serve as an effective supplement for valuable enzyme production in food industry. [ABSTRACT FROM AUTHOR]

Locusts (Locusta migratoria) have outstanding flying abilities, and most of their lift is provided by their hind wings. Insect aerodynamic performance is strongly affected by wing deformation during stroke, which is closely related to its functional morphology (particularly its mechanical properties). The cross-vein is one of the main morphologies in the hind wing of locusts. However, few studies on the mechanical properties of cross-veins have been conducted. This study evaluated the cross-veins of the locust hind wing using uniaxial tensile tester, scanning electron microscope, and finite element methods. Four cross-vein types were identified at different locations on the hind wing, including periodical semi- and full-ellipsoidal humps and periodical semi- and full-conical humps. The four cross-veins showed similar tensile stiffness but differed in bending compliance. We suggest that the mechanical properties of the four cross-veins can be attributed to their physiological functions. This study elucidates cross-veins of locust hind wing and contributes our understanding of the flapping flight mechanism in locusts. [ABSTRACT FROM AUTHOR]

The stability of symbiotic flora is an important indicator of the health of an organism. Symbiotic bacteria have been proven to be closely involved in the immune process of organisms. The pathogenicity of Beauveria bassiana was studied in relation to symbiotic bacteria on the surface and inside of the migratory locust (Locusta migratoria). The results showed that the surface disinfection of test locusts contributed to the pathogenicity of B. bassiana to locusts. Most of the surface bacteria of L. migratoria caused some inhibition of B. bassiana growth, and LM5-4 (Raoultella ornithinolytica), LM5-2 (Enterobacter aerogenes), and LM5-13 (Citrobacter freundii) showed the highest inhibitory effect on the growth of B. bassiana. The inoculation of locusts with additional surface symbiotic bacteria reduced the virulence of B. bassiana to L. migratoria. Infection by different strains of B. bassiana caused similar changes in the symbiotic flora of migratory locusts. The inoculation of locusts with additional intestinal symbiotic bacteria (Enterobacter sp.) reduced the virulence of B. bassiana to L. migratoria. These findings illustrate the effect of bacterial communities on fungal infections in L. migratoria when seen from the perspective of ecology in a microenvironment. The active antifungal substances of such bacteria and their mechanisms of action need further study. [ABSTRACT FROM AUTHOR]

Paranosema (Antonospora) locustae (Canning) is a microsporidium with an extensive host range including >100 reported insect hosts from the order Orthoptera. The susceptibility of two species of locusts (Orthoptera: Acrididae) – the migratory locust, Locusta migratoria subsp. migratorioides (Fairmaire & Reiche), and the desert locust, Schistocerca gregaria Forsskål – to P. locustae was compared under laboratory conditions at a decreased temperature of 27 °C to enhance susceptibility to infection. Locusta migratoria was found highly vulnerable as infection percentages exceeded 70% at 104, 105, and 106 spores per insect, and mortality increased with increasing dosage. Conversely, P. locustae spores were not found in S. gregaria throughout the experiment. Only at 107 spores per insect, as many as 20% of S. gregaria were infected. This suggests that the desert locust is resistant to P. locustae infection, as opposed to the migratory locust. The laboratory models of these parasite–host systems may be useful for elucidating mechanisms of insect immunity to microsporidia. [ABSTRACT FROM AUTHOR]

The mole cricket Gryllotalpa orientalis is an evolutionarily, medicinal, and agriculturally significant insect that inhabits underground environments and is distributed globally. This study measured genome size by flow cytometry and k-mer based on low-coverage sequencing, and nuclear repetitive elements were also identified. The haploid genome size estimate is 3.14 Gb by flow cytometry, 3.17 Gb, and 3.77 Gb-based two k-mer methods, respectively, which is well within the range previously reported for other species of the suborder Ensifera. 56% of repetitive elements were found in G. orientalis, similar to 56.83% in Locusta migratoria. However, the great size of repetitive sequences could not be annotated to specific repeat element families. For the repetitive elements that were annotated, Class I-LINE retrotransposon elements were the most common families and more abundant than satellite and Class I-LTR. These results based on the newly developed genome survey could be used in the taxonomic study and whole genome sequencing to improve the understanding of the biology of G. orientalis. [ABSTRACT FROM AUTHOR]

The phase transition from solitary to gregarious locusts is crucial in outbreaks of locust plague, which threaten agricultural yield and food security. Research on the regulatory mechanisms of phase transition in locusts has focused primarily on the transcriptional or posttranslational level. However, the translational regulation of phase transition is unexplored. Here, we show a phase-dependent pattern at the translation level, which exhibits different polysome profiles between gregarious and solitary locusts. The gregarious locusts exhibit significant increases in 60S and polyribosomes, while solitary locusts possess higher peaks of the monoribosome and a specific “halfmer.” The polysome profiles, a molecular phenotype, respond to changes in population density. In gregarious locusts, ten genes involved in the cytosolic ribosome pathway exhibited increased translational efficiency (TE). In solitary locusts, five genes from the mitochondrial ribosome pathway displayed increased TE. The high expression of large ribosomal protein 7 at the translational level promotes accumulation of the free 60S ribosomal subunit in gregarious locusts, while solitary locusts employ mitochondrial small ribosomal protein 18c to induce the assembly of mitochondrial ribosomes, causing divergence of the translational profiles and behavioral transition. This study reveals the translational regulatory mechanism of locust phase transition, in which the locusts employ divergent ribosome pathways to cope with changes in population density [ABSTRACT FROM AUTHOR]

Lower plant resistance to herbivores following domestication has been suggested as the main cause for higher feeding damage in crops than in wild progenitors. While herbivore compensatory feeding has also been proposed as a possible mechanism for raised damage in crops with low nutritional quality, predictions regarding the effects of plant domestication on nutritional quality for herbivores remain unclear. In particular, data on primary metabolites, even major macronutrients, measured in the organs consumed by herbivores, are scarce. In this study, we used a collection of 10 accessions of wild ancestors and 10 accessions of modern progenies of Triticum turgidum to examine whether feeding damage and selectivity by nymphs of Locusta migratoria primarily depended on five leaf traits related to structural resistance or nutrient profiles. Our results unexpectedly showed that locusts favored wild ancestors over domesticated accessions and that leaf toughness and nitrogen and soluble protein contents increased with the domestication process. Furthermore, the quantitative relationship between soluble protein and digestible carbohydrates was found to poorly meet the specific requirements of the herbivore, in all wheat accessions, both wild and modern. The increase in leaf structural resistance to herbivores in domesticated tetraploid wheat accessions suggested that resource allocation trade‐offs between growth and herbivory resistance may have been disrupted by domestication in the vegetative organs of this species. Since domestication did not result in a loss of nutritional quality in the leaves of the tetraploid wheat, our results rather provides evidence for a role of the content of plants in nonnutritive nitrogenous secondary compounds, possibly deterrent or toxic, at least for grasshopper herbivores. [ABSTRACT FROM AUTHOR]

Metarhizium anisopliae is a broad-spectrum entomopathogenic fungus attacking Locusta migratoria. However, the complex immune system of L. migratoria has limited the insecticidal efficiency of M. anisopliae. Although many antifungal immune genes have been reported, the part-time genes involved in antifungal immunity have yet to be revealed. In this study, an immune-related protein was identified and named Apolipophorin-D (ApoLp-D). The ApoLp-D gene was highly expressed in the hemolymph of L. migratoria. The recombinant protein (rApoLp-D) showed a strong agglutination activity against conidia of M. anisopliae. Furthermore, RNAi of ApoLp-D decreased the antifungal activity of plasma against M. anisopliae. These results indicated that ApoLp-D played an important role in immune response of L. migratoria. A recombinant M. anisopliae was genetically engineered to express a double-stranded RNA (dsApoLp-D) targeting ApoLp-D in L. migratoria. The transgenic M. anisopliae successfully secreted dsApoLp-D and suppressed the expression of ApoLp-D and exhibited higher virulence against L. migratoria. Specifically, the time leading to a 100% mortality of L. migratoria challenged by the transgenic M. anisopliae was reduced from 9 days to 7 days. Our results provided a proof-of-concept of using genetic engineering approaches to enhance the insecticidal virulence of entomopathogenic fungi by RNAi-mediated suppression of the immune-related genes in insect pests. [ABSTRACT FROM AUTHOR]

Insect Sf9 cells are widely used for producing recombinant proteins, including myosin. It is expected that the protein folding machinery in Sf9 cells can meet the requirement for the proper folding of exogenous myosin. Of interest is that not all class II myosins are expressed functionally in Sf9 cells. Among vertebrate class II myosins, non-muscle myosin and smooth muscle myosin, but not striated muscle myosin, are functionally expressed in Sf9 cells, presumably due to lacking vertebrate striated muscle myosin-specific chaperone Unc45b in Sf9 cells. Insects only express a generic myosin-specific chaperone Unc45, which is expected to be responsible for the folding of all insect myosins, including striated muscle myosin. This rationale promotes us to investigate the folding of recombinant insect striated muscle myosins in Sf9 cells. We expressed the heavy meromyosin version of the striated muscle myosins from three insect species (Locusta migratoria , Drosophila melanogaster and Plutella xylostella) in Sf9 cells. Similar to vertebrate smooth muscle myosin, but unlike vertebrate striated muscle myosin, the insect striated muscle myosin expressed in Sf9 cells are soluble. The purified recombinant insect striated muscle myosins display normal myosin functions, including ATP-dependent actin interaction, actin-activated ATPase activity, and in vitro actin-gliding activity, indicating that Sf9 cells are suitable for expressing insect striated muscle myosin. We therefore conclude that, unlike vertebrate striated muscle myosin requiring striated muscle-specific chaperones (such as Unc45b) for its folding, insect striated muscle myosin can be properly folded by the generic protein folding machinery in insect cells. • Insect striated muscle myosin expressed in insect Sf9 cells are soluble. • Sf9 cell-expressed insect striated muscle myosin has normal myosin functions. • Insect generic protein folding system can correctly fold its striated muscle myosin. • Sf9 cells are suitable for expressing insect striated muscle myosin. [ABSTRACT FROM AUTHOR]

Insects comprise more than a million species and many authors have attempted to explain this success by evolutionary innovations. A much overlooked evolutionary novelty of insects is the serosa, an extraembryonic epithelium around the yolk and embryo. We have shown previously that this epithelium provides innate immune protection to eggs of the beetle Tribolium castaneum. It remained elusive, however, whether this immune competence evolved in the Tribolium lineage or is ancestral to all insects. Here, we expand our studies to two hemimetabolous insects, the bug Oncopeltus fasciatus and the swarming grasshopper Locusta migratoria. For Oncopeltus, RNA sequencing reveals an extensive response upon infection, including the massive upregulation of antimicrobial peptides (AMPs). We demonstrate antimicrobial activity of these peptides using in vitro bacterial growth assays and describe two novel AMP families called Serosins and Ovicins. For both insects, quantitative polymerase chain reaction shows immune competence of the eggs when the serosa is present, and in situ hybridizations demonstrate that immune gene expression is localized in the serosa. This first evidence from hemimetabolous insect eggs suggests that immune competence is an ancestral property of the serosa. The evolutionary origin of the serosa with its immune function might have facilitated the spectacular radiation of the insects. This article is part of the theme issue 'Extraembryonic tissues: exploring concepts, definitions and functions across the animal kingdom'. [ABSTRACT FROM AUTHOR]

Clathrin heavy chain (Chc) is a constituent of clathrin‐coated vesicles and serves important functions in endocytosis and intracellular membrane trafficking but appears to have physiological roles also at the organismal level. Most of what we know about Chc functions originates from studies performed in fungal or vertebrate cells. However, the physiological functions of Chc in insects remain poorly understood. Here, we identified a Chc ortholog from a Locusta migratoria transcriptome database. RT‐qPCR revealed that LmChc was constitutively expressed in fifth‐instar nymphs. In this developmental stage, LmChc showed the highest expression in the ovary followed by hemolymph, testis, hindgut, midgut, and foregut. In isolated hemocytes, we detected the Chc protein in patches at the plasma membrane. To examine the role of LmChc in L. migratoria during development, RNA interference was performed by injecting dsRNA into the early fifth‐instar nymphs. Silencing of LmChc caused a lethal phenotype with molting defect from nymph to adult. In addition, silencing of LmChc resulted in abnormal development of the ovaries, the size of which was significantly smaller than that in controls. Taken together, our results suggest that LmChc is a vital gene in L. migratoria that plays an important role in growth, development, and reproduction. LmChc may be used as an efficient RNAi target gene for developing dsRNA‐based biological insecticides to manage insect pests. [ABSTRACT FROM AUTHOR]

Simple Summary: This paper focus on the role of chitinase 5-1 (LmCht5-1) and chitinase 5-2 (LmCht5-2) in the degradation of the serosal cuticle and pro-nymphal cuticle during locust embryonic development. Serosal cuticles degenerated from 7-day-old embryos (E7) to E13 with the degradation of fine chitin in the lower part and coarse chitin layer in upper part in sequence, while pro-nymphal cuticles degenerated from E12 to E14 with degradation of chitin in the procuticle layer. RNAi experiments in embryonic stages showed that during the serosal cuticle molting process, dsLmCht5-1 averted the loss of the coarse chitin layer in the upper part during early and late embryogenesis. Meanwhile, dsLmCht5-2 blocked the degradation of the lower fine chitin layer at the early stage and blocked the chitin degradation of loose coarse chitin in the late molting process. During pro-nymphal cuticle degradation stages, dsLmCht5-1 inhibited the degradation of chitin between layers, and dsLmCht5-2 inhibited the degradation of chitin into filaments within layers. This study advances the understanding of the degradation of cuticles in the locust embryonic stage and makes a contribution to molecular targets for agricultural pest control. The success of the degradation of the extraembryonic serosal cuticle and the second embryonic cuticle (pro-nymphal cuticle) is essential for the development and molting of nymph from egg in Orthoptera Locusta migratoria. Chitinase 5 is an important gene for chitin degradation in nymphs and in the egg stage. In this study, we investigated the important roles of chitinase 5-1 (LmCht5-1) and chitinase 5-2 (LmCht5-2) in the degradation of the serosal and pro-nymphal cuticles during locust embryonic development. The serosal cuticle degrades from 7-day-old embryos (E7) to E13, along with the degradation of the pro-nymphal cuticle, which begins at E12 to E14. The mRNA and protein of LmCht5-1 and LmCht5-2 are expressed during the degradation process of the serosal cuticle and the pro-nymphal cuticle. RNAi experiments at the embryonic stage show that both dsLmCht5-1 and dsLmCht5-2 contribute to the failure of development in early and late embryogenesis. Further, during the serosal cuticle molting process, ultra-structure analysis indicated that dsLmCht5-1 prevented the loss of the coarse chitin layer in the upper part in both early and late embryogenesis. Meanwhile, dsLmCht5-2 blocked the degradation of the lower fine chitin layer at the early stage and blocked the chitin degradation of loose coarse chitin in the late molting process. During the degradation of the pro-nymphal cuticle, dsLmCht5-1 suppresses chitin degradation between layers in the procuticle, while dsLmCht5-2 suppresses chitin degradation into filaments inside of the layer. In summary, our results suggest that both LmCht5-1 and LmCht5-2 contribute to the degradation of the serosal and pro-nymphal cuticles during the locust embryonic stage. [ABSTRACT FROM AUTHOR]

Grasshoppers can swarm in the millions and destroy crops over wide areas, posing a major economic threat to agriculture. A wide range of insect-related viruses has recently been reported in the metagenomics of grasshoppers. Here, we identified and isolated a novel reovirus from grasshoppers, named Acrididae reovirus (ARV). The complete genome of ARV was composed of nine dsRNA segments. Phylogenetic analysis revealed that ARV formed a monophyletic lineage with unclassified insect-associated reoviruses and was sufficiently distinct from known genera of Reoviridae. ARV could replicate in its host Locusta migratoria and result in host death. Lower-dose ARV infection affected ovary development and resulted in a significant reduction in fecundity. The identification and characterization of a novel pathogenic reovirus could potentially promote the development of new biological control agents. [ABSTRACT FROM AUTHOR]

The ovipositor comprises the external genitalia of female insects, which plays an important role in the mating and ovipositing process of insects. However, it remains rudimentary of regional gene expression and physiological function in the ovipositor during structural development. Here, we analysed the basic structure and characteristics of the ovipositor in the migratory locust Locusta migratoria. RNA‐seq analysis revealed the specialization of chitin metabolism, lipids synthesis and transport, tanning and cuticular protein genes in the ovipositor. Among them, two cuticle protein genes, LmCP8 and LmACP79, were identified, which are specifically expressed in the ovipositor. Functional analysis based on RNA interference showed that deficiency of LmCP8 affected the structural development of the ovipositor resulting in the retention of a large number of remaining unproduced oocysts in the ovary of the locusts. Our results provide a fundamental resource to investigate the structural development and physiological function of the ovipositor in L. migratoria. [ABSTRACT FROM AUTHOR]