Search Results (70)

A method for configuration synthesis of a reconfigurable decoupled parallel mechanical leg is proposed. In addition, a configuration evaluation index is proposed to evaluate the synthesized configurations and select the optimal one. Kinematic analysis and performance optimization of the selected mechanism’s configuration are carried out, and the motion mode of the robot’s reconfigurable mechanical leg is selected according to the task requirements. Then, the robot’s gait in walking mode is planned. Firstly, based on bionic principles, the motion characteristics of a mechanical leg based on a mammalian model and an insect model were analyzed. The input and output characteristics of the mechanism were analyzed to obtain the reconfiguration principle of the mechanism. Using type synthesis theory for the decoupled parallel mechanism, the configuration synthesis of the chain was carried out, and the constraint mode of the mechanical leg was determined according to the constraint property of the chain and the motion characteristics of the moving platform. Secondly, an evaluation index for the complexity of the reconfigurable mechanical leg structure was developed, and the synthesized mechanism was further analyzed and evaluated to select the mechanical leg’s configuration. Thirdly, the inverse position equations were established for the mechanical leg in the two motion modes, and its Jacobian matrix was derived. The degrees of freedom of the mechanism are completely decoupled in the two motion modes. Then, the workspace and motion/force transmission performance of the mechanical leg in the two motion modes were analyzed. Based on the weighted standard deviation of the motion/force transmission performance, the global performance fluctuation index of the mechanical leg motion/force transmission is defined, and the structural size parameters of the mechanical leg are optimized with the performance index as the optimization objective function. Finally, with the reconfigurable mechanical leg in the insect mode, the robot’s gait in the walking operation mode is planned according to the static stability criterion. Full article

Scale insects, which belong to the superfamily Coccoidea within the order Hemiptera, encompass more than 8000 species worldwide. The adult females of these species are characterized by their immobility, and often lack wings and legs. Scale insects feed on plant tissues and can cause significant agricultural damage as pests. This study presents the sequencing of five coccoid mitogenomes, revealing detailed annotations and comparisons with other Hemiptera. The sequencing yielded between 73 million and over 121 million reads, allowing for the reconstruction of mitogenomes ranging from 12,821 to 14,446 nucleotides. Notably, a high A + T content was observed across the newly sequenced mitogenomes. Gene rearrangements were identified in all five newly sequenced mitogenomes, with the evolutionary rate analysis indicating that Coccoidea exhibit the highest Ka and Ka/Ks values among the hemipterans. In a phylogenetic context, the mitogenomes of representative species from Coccoidea and Aleyrodoidea exhibit more frequent mitochondrial gene rearrangements than those of other hemipteran groups. The analysis suggests that the frequent mitochondrial gene rearrangements observed in the coccoid species are associated with accelerated nucleotide substitution rates, supporting a connection between genetic evolution and structural variation in mitogenomes. Full article

Lipids play vital roles in insect physiology, functioning as energy reserves, membrane constituents, and cuticular protectants. However, few studies have examined the anatomical distribution of lipids in blood-feeding Diptera and compared the compositions of the cuticular and internal compartments. This study analyzes the qualitative and quantitative profiles of free fatty acids (FFAs) in the female Tabanus bovinus, a hematophagous horsefly species, across different anatomical regions, including the head, wings, legs, thorax, and abdomen. The surface and internal lipid fractions were isolated using petroleum ether/dichloromethane extraction followed by sonication. GC-MS revealed the presence of 21 FFAs, including 16 saturated (C7:0, C8:0, C9:0, C10:0, C11:0, C12:0, C13:0, C14:0, C15:0, C16:0, C17:0, C18:0, C19:0, C20:0, C22:0, C24:0) and five unsaturated (C16:1, C18:2, C18:1, C20:5, C20:4). The head and wings showed the highest concentrations of cuticular FFAs. At the same time, internal lipid stores were most prominent in the thorax and abdomen (but four times lower than in the head cuticle), reflecting their role in energy storage and reproduction. All cuticular and internal extracts were dominated by C16:0, C18:0, and C18:1. Notably, several FFAs were undetected in specific compartments: C10:0 from inside the head, C11:0 and C13:0 from inside all examined body parts, C19:0 was absent from inside the head, wings and legs, while C20:5 and C20:4 were absent from both the cuticular and internal lipid pools of the wings. Interestingly, our analysis of the cuticle on the thorax and abdomen together revealed that both C13:0 and C19:0 were present only on the dorsal side, i.e., absent from the ventral side. These absences suggest a selective lipid metabolism tailored to the functional and ecological demands of T. bovinus females. Our findings suggest that the absence of specific compounds from individual body parts may serve as an indicator of physiological specialization. This work provides new insights into lipid compartmentalization in Tabanidae and offers a framework for future comparative and ecological lipidomics studies in insects. Full article

Tiger beetles are a family of predatory beetles characterized by their large eyes, long legs, and often bright colors. While popular with researchers, insect collectors, and photographers, the distribution of species in Oklahoma remains relatively understudied. Recently, three species were added to the state list, bringing the total to 39 species, the third highest in the United States. Knowledge of a species’ distribution is often characterized at the county level in the United States, with Oklahoma having 77 counties. Using collection records and community science submissions, we increased the number of documented county records 68%, from 461 to 776. In addition to reporting the county-level distributions for each species in the state, we discuss the utility of community science platforms for documenting species distribution records. We also present habitats that are utilized by these species, the subspecific taxonomy of populations in Oklahoma, and how anthropogenic changes are differentially affecting species distributions. Substantial range expansions for many southern species into the state suggest potential for tiger beetles to serve as indicators of warming temperatures. Full article

Edible insects are a significant component of traditional diets in Madagascar, where food insecurity and malnutrition persist. This study examines the production parameters and nutritional composition of four laboratory-farmed edible grasshopper species commonly consumed by Malagasy people with the aim of upscaling their farming to mitigate malnutrition. The grasshopper species include: vlei grasshopper (Paracinema tricolor), rice grasshopper (Oxya hyla), emerald-legged grasshopper (Eyprepocnemis smaragdipes), and Madagascan slant-faced grasshopper (Acrida madecassa). The study involved the assessment of production parameters (survival rate, developmental time, feed consumed, feed conversion ratio, biomass yield, fecundity, and hatchability). The study also involved analysis of the nutritional content (moisture, protein, fat, ash, fibre, carbohydrates, minerals, amino acids, fatty acids, and vitamins) to evaluate the potential dietary contribution of these grasshoppers. The result show P. tricolor had superior survival, faster development, low feed intake, and higher fecundity and hatchability when compared to other species of grasshoppers. Acrida madecassa showed the highest biomass yield and feed conversion ratio followed by P. tricolor. The results further show that all four species are rich in protein, essential fatty acids, and key minerals, particularly calcium, phosphorus, iron, and zinc. P. tricolor exhibited the highest protein and fat content. Moreover, P. tricolor showed the highest ash content, suggesting a superior mineral profile. Acrida madecassa showed the highest fibre content, reflecting its richness in chitin. These findings provide valuable insights into the nutritional role of grasshoppers in Malagasy diets. Furthermore, they offer reference values for selecting and optimizing the nutrient composition of insect species that are safe and easy to rear, which could serve as a sustainable alternative to wild collection. Future research should explore the bioavailability of nutrients in these species and identify suitable practices to mass rear these species to improve food security in Madagascar. Full article

In eukaryotes, a lot of proteins are transported across the endoplasmic reticulum by the heterotrimeric Sec61 channel. And post-translational transport needs another Sec62/Sec63 complex. However, functions of these genes are poorly explored in insects. In this study, we first identified five Sec genes, named Sec61α, Sec61β, Sec61γ, Sec62 and Sec63, in Locusta migratoria. Quantitative reverse-transcription polymerase chain reaction (RT-qPCR) analysis showed that these five genes were expressed in muti-tissues, including wing pad, leg, foregut, midgut, gastric cecum, hindgut, and highly expressed in the integument. Knockdown of LmSec61α and LmSec61γ by RNA interference (RNAi) lead to the feeding cessation with a mortality rate of 100%. However, there is only 13.4% of dsLmSec61β-injected nymphs died before molting. All nymphs injected with dsLmSec61α and dsLmSec61γ died before molting with the gut atrophy. Furthermore, hematoxylin–eosin staining indicated that the cells of the midguts and gastric caecum were defective, and the microvilli and peritrophic matrix were destroyed seriously after silencing LmSec61α and LmSec61γ. Knockdown of LmSec62 and LmSec63 resulted in high mortality before and during molting. The hematoxylin–eosin (HE) staining and transmission electron microscopy (TEM) results showed that both the formation of the new cuticle and the degradation of the old cuticle were inhibited in dsLmSec63-injected insects compared to the controls. Especially, there was no obvious plaques on microvillar tips of the epidermal cells after silencing of LmSec63. These results revealed that Sec61s and Sec62/Sec63 genes are required in the gut and cuticle development of locusts. Therefore, these genes are potential targets for the control of locusts. Full article

Insect odorant-binding proteins (OBPs) are promising molecular targets for developing novel pest management strategies by modulating chemoreception-driven behaviors. The tea gray geometrid Ectropis grisescens (Lepidoptera, Geometridae) is a major pest in tea plantations, causing substantial economic losses in China. In this study, we identified 18 OBPs from E. grisescens antennal transcriptome. All of the encoded proteins possessed N-terminal signal peptides and conserved cysteine residues, behaviors which are characteristic of insect OBPs. Phylogenetic analysis categorized these proteins into plus-C, minus-C, and classic OBP subfamilies. MEME motif analysis identified conserved sequence features potentially involved in odor detection. Tissue- and sex-specific expression profiling showed that EgriGOBP1-2, OBP3, OBP8, and OBP13 were highly expressed in the antennae of both sexes, suggesting roles in olfactory communication. Among them, EgriGOBP1-2, OBP3, and OBP13 exhibited similar expression levels between males and females, while other EgriOBPs were predominantly expressed in the legs, wings, or other tissues, indicating additional physiological functions beyond chemoreception. To investigate functional specificity, we selected antenna-enriched EgriGOBP2 for ligand-binding analysis. Fluorescence binding assays demonstrated that EgriGOBP2 exhibited broad binding affinity toward 8 of 12 host volatiles and 11 of 12 plant essential oil-derived volatiles. These combined findings lay the foundation for mechanistic studies of chemical recognition in E. grisescens and provide insights into the development of ecologically friendly pest control alternatives. Full article

Four species representing four different families of the hemipteran insect suborder Auchenorrhyncha, Lepyronia coleoptrata (Aphrophoridae), Euricania ocellus (Ricaniidae), Kolla sp. (Cicadellidae) and Tricentrus sp. (Membracidae) were investigated using high-speed photography and scanning electron microscopy to identify hind leg structures that may influence jumping performance. The coxa–trochanteral joint, femur and tibia were found to have distinct structural adaptations that vary among these jumping insects. Froghoppers and planthoppers possess a coxal protrusion which is absent in leafhoppers and treehoppers, the latter featuring a more recessed coxal fossa. The medial coxae of these insects exhibit fields of microtrichia that vary in density and fine structure. Medial gears on the trochanters of Tricentrus sp. are implicated in the storage of energy prior to their jumps. These structural differences manifest in the insects’ jumping performance. The study demonstrated a correlation between the robustness of the microtrichia field interaction and the insect’s jumping capability. Specifically, leafhoppers, equipped with a pair of rivet-like structures connecting the hind coxae, were observed to achieve quicker and more stable take-offs. The study reveals that structural variations in the hind legs of Auchenorrhyncha species significantly influence their jumping performance, with implications for both efficiency and stability. Full article

Insecticide resistance in mosquitoes has become a severe impediment to global vector control and manifests as decreased insecticide effectiveness. The role of target site mutations and detoxification enzymes as resistance markers has been documented in mosquitoes; however, the emergence of complex resistant phenotypes suggest the occurrence of additional mechanisms. Cuticular proteins (CPs) are key constituents of the insect cuticle, and play critical roles in insect development and insecticide resistance. In this study, via electron microscopy we observed that the leg cuticle thickness in deltamethrin-resistant (DR) Anopheles sinensis mosquitoes was significantly greater than that measured in deltamethrin-susceptible (DS) An. sinensis. Transcription analysis revealed that cuticle proteins were enriched in the legs, including members of the CPR, CPAP, and CPF families. Further comparisons revealed the specific overexpression of four CP genes in the legs of DR An. sinensis; whose expression levels increased after treatment with deltamethrin. The RNAi-mediated silencing of one CP gene, AsCPF1, resulted in a significant decrease in the leg cuticle thickness of DR mosquitoes and significantly elevated the mortality rate when exposed to deltamethrin. These findings suggest that alterations in the An. sinensis leg cuticle contribute to the insecticide resistance phenotype. AsCPF1 is thereby a target study molecule for investigation of its mode of action, and broader attention should be paid to the role of mosquito legs in the development of insecticide resistance. Full article

Sustainable food resources, including cell-cultured meat and edible insect proteins, are emerging as key solutions to meet future protein demands. This study evaluated the effects of black soldier fly larvae hydrolysate (BLH) on primary cells isolated from broiler leg and breast muscle tissues, as well as abdominal fat tissues. Primary cells isolated from each tissue were characterized for their myogenic and adipogenic (stromal vascular fraction, SVF) properties. Cells were cultured in a basal medium with five percent FBS supplemented with BLH at concentrations ranging from 25 to 300 µg/mL. Leg and breast muscle cells showed significantly enhanced proliferation, as indicated by MTS assay results and cell counts, in the BLH100 group compared to the FBS5 and control groups (p < 0.05). Furthermore, the expression of myogenic markers, including PAX7, NCAM1, MYF5, and MYOD1, was upregulated in leg muscle cells treated with BLH (p < 0.05). For SVFs, BLH50 promoted cell proliferation; however, differentiation decreased as BLH concentration increased. These findings suggest that BLH can enhance the proliferation of primary broiler cells, highlighting its potential applicability in the edible insect and cultured meat industries. Full article

Flapping wing micro aerial vehicles (FWMAVs) are recognized for their significant potential in military and civilian applications, such as military reconnaissance, environmental monitoring, and disaster rescue. However, the lack of takeoff and landing capabilities, particularly in landing behavior, greatly limits their adaptability to the environment during tasks. In this paper, the purple stem beetle (Sagra femorata), a natural flying insect, was chosen as the bionic research object. The three-dimensional reconstruction models of the beetle’s three thoracic legs were established, and the adhesive mechanism of the thoracic leg was analyzed. Then, a series of bionic design elements were extracted. On this basis, a hook-pad cooperation bionic deployable landing mechanism was designed, and mechanism motion, mechanical performance, and vibration performance were studied. Finally, the bionic landing mechanism model can land stably on various contact surfaces. The results of this research guide the stable landing capability of FWMAVs in challenging environments. Full article

This research presents the development and evaluation of a miniature autonomous robot inspired by insect locomotion, capable of bidirectional movement. The robot incorporates two piezoelectric bimorph resonators, 3D-printed legs, an electronic power circuit, and a battery-operated microcontroller. Each piezoelectric motor features ceramic plates measuring 15 × 1.5 × 0.6 ${\mathrm{m}\mathrm{m}}^3$ and weighing 0.1 g, with an optimized electrode layout. The bimorphs vibrate at two flexural modes with resonant frequencies of approximately 70 and 100 kHz. The strategic placement of the 3D-printed legs converts out-of-plane motion into effective forward or backward propulsion, depending on the vibration mode. A differential drive configuration, using the two parallel piezoelectric motors and calibrated excitation signals from the microcontroller, allows for arbitrary path navigation. The fully assembled robot measures 29 × 17 × 18 ${\mathrm{m}\mathrm{m}}^3$ and weighs 7.4 g. The robot was tested on a glass surface, reaching a maximum speed of 70 mm/s and a rotational speed of up to 190 deg./s, with power consumption of 50 mW, a cost of transport of 10, and an estimated continuous operation time of approximately 6.7 h. The robot successfully followed pre-programmed paths, demonstrating its precise control and agility in navigating complex environments, marking a significant advancement in insect-scale autonomous robotics. Full article

Olfaction and gustation processes play key roles in the life cycle of insects, such as finding and accepting food sources, oviposition sites, and mates, among other fundamental aspects of insect development. In this context, chemosensory genes found in sensory organs (e.g., antennae and maxillary palps) are crucial for understanding insect behaviour, particularly the phytophagous behaviour of insect pests that attack economically important crops. An example is the scarab beetle Hylamorpha elegans, which feeds on the roots of several crops important for livestock in its larval stage. In this study, chemosensory gene candidates of H. elegans white grubs identified through the head transcriptome and phylogenetic and tissue-biased gene expression (antennae, head without antennae, and legs) have been reported. Overall, 47 chemosensory genes were identified (2 ORs, 1 GR, 11 IRs, 9 CSPs, and 24 OBPs). Gene expression analysis revealed the predominant presence of IRs in the legs, whereas ORs and the GR were present in the heads and/or antennae. Particularly, HeleOBP9 and HeleCSP2 were significantly expressed in the head but not in the antennae or legs; these and other genes are discussed as potential targets in the context of H. elegans management. Full article

The ability of many insects to adhere vertically or even upside down to smooth substrates is closely related to the morphology and distribution of the adhesive structures on their legs. During locomotion, the legs are in direct contact with different substrates, and it is hypothesized that the adhesive structures have been evolved as an adaption to smooth substrates in specific environments. To investigate whether there is a relationship between the presence of adhesive structures and the combined effects of different environments and mating behavior, we compared five species of tiger beetles belonging to two tribes living in arboreal and non-arboreal environments, respectively. In three non-arboreal species, we found a specific type of adhesive structure consisting of elongated spoon-like setae present on the protarsi of males but absent on the male meso- and metatarsi and on females. In Tricondyla pulchripes, an arboreal species living on stems, we found three types of adhesive setae on male protarsi, while only two types of setae were found on male meso- and metatarsi and on females. In Neocollyris linearis, an arboreal species living on leaves, we found three types of adhesive setae on male pro-, meso- and meta-tarsi but only two types of adhesive setae on females. The adaptive evolution of these adhesive structures was probably driven by the selective pressures of both mating behavior and the presence of smooth substrates in the respective environments. It is discussed that the adhesive structures in tiger beetles may be an adaptive evolutionary response to the plant surfaces and may play an important role in species differentiation. Full article

Tabanidae (horse flies and deer flies) are hematophagous insects that cause direct and indirect damage to animal production. The aims of this study were to determine the preferred site, time of day, and duration of tabanid feeding on beef cattle and identify factors related to infestation by tabanids. The population of tabanids was surveyed on certain body parts of the beef cattle (fore udder, tail, navel, leg, dewlap, body, and under) during the morning hours (9.00–10.30 a.m.), midday (12.00–13.30 a.m.), and afternoon (15.30–17.00 p.m.) every day for 10 days. The findings showed that two genera, Tabanus Linnaeus, 1758, and Chrysops Meigen, 1803, landed on the cows. The leg was statistically significantly the most frequent landing site for tabanids (15.067 ± 7.54) compared with other parts. The average feeding duration for each insect was 2.76 ± 1.77 min. The results showed that a significant number of tabanids were present during midday, as compared with the morning and afternoon. Temperature was found to be positively associated with fly abundance. A regression model was derived in this study (y = 4.23x − 116.09). This information is important for tabanid control and prevention in beef cattle. Full article