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Insects Jun 2024The abundance of insects in Burmese amber illustrates a highly diverse insect community from the mid-Cretaceous period; yet, records of crickets (Grylloidea) are notably...
The abundance of insects in Burmese amber illustrates a highly diverse insect community from the mid-Cretaceous period; yet, records of crickets (Grylloidea) are notably scarce. In this study, we describe two new genera with three new species, gen. et sp. nov., sp. nov., and gen. et sp. nov., based on three specimens collected in north Myanmar. These new species can be placed within the Trigonidiidae (Orthoptera: Grylloidea) by their triangular head, compound eyes that protrude in dorsal view, and a body entirely covered with robust setae, particularly noticeable in the head and pronotum; however, subfamily assignments are not possible. Another known species, , Xu et al., 2020, from Myanmar amber is redescribed based on a new specimen and a recheck of the holotype.
PubMed: 38921157
DOI: 10.3390/insects15060442 -
Insects Jun 2024Currently, the subfamily Meconematinae encompasses 1029 species, but whole-mitochondrial-genome assemblies have only been made available for 13. In this study, the whole...
Currently, the subfamily Meconematinae encompasses 1029 species, but whole-mitochondrial-genome assemblies have only been made available for 13. In this study, the whole mitochondrial genomes (mitogenomes) of nine additional species in the subfamily Meconematinae were sequenced. The size ranged from 15,627 bp to 17,461 bp, indicating double-stranded circular structures. The length of the control region was the main cause of the difference in mitochondrial genome length among the nine species. All the mitogenomes including 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes (rRNAs) and a control region (CR). The majority strand encoded 23 genes, and the minority strand encoded 14 genes. A phylogenetic analysis reaffirmed the monophyletic status of each subfamily, but the monophysitism of , and was not supported.
PubMed: 38921128
DOI: 10.3390/insects15060413 -
Journal of the Royal Society, Interface Jun 2024Many animals employ a second frequency filter beyond the initial filtering of the eardrum (or tympanal membrane). In the field cricket ear, both the filtering mechanism...
Coupled membranes: a mechanism of frequency filtering and transmission in the field cricket ear evidenced by micro-computed tomography, laser Doppler vibrometry and finite element analysis.
Many animals employ a second frequency filter beyond the initial filtering of the eardrum (or tympanal membrane). In the field cricket ear, both the filtering mechanism and the transmission path from the posterior tympanal membrane (PTM) have remained unclear. A mismatch between PTM vibrations and sensilla tuning has prompted speculations of a second filter. PTM coupling to the tracheal branches is suggested to support a transmission pathway. Here, we present three independent lines of evidence converging on the same conclusion: the existence of a series of linked membranes with distinct resonant frequencies serving both filtering and transmission functions. Micro-computed tomography (µ-CT) highlighted the 'dividing membrane (DivM)', separating the tracheal branches and connected to the PTM via the dorsal membrane of the posterior tracheal branch (DM-PTB). Thickness analysis showed the DivM to share significant thinness similarity with the PTM. Laser Doppler vibrometry indicated the first of two PTM vibrational peaks, at 6 and 14 kHz, originates not from the PTM but from the coupled DM-PTB. This result was corroborated by µ-CT-based finite element analysis. These findings clarify further the biophysical source of neuroethological pathways in what is an important model of behavioural neuroscience. Tuned microscale coupled membranes may also hold biomimetic relevance.
Topics: Animals; Gryllidae; X-Ray Microtomography; Finite Element Analysis; Tympanic Membrane; Vibration
PubMed: 38903010
DOI: 10.1098/rsif.2023.0779 -
Pesticide Biochemistry and Physiology Jun 2024Syntaxin5 (Syx5) belongs to SNAREs family, which play important roles in fusion of vesicles to target membranes. Most of what we know about functions of Syx5 originates...
Syntaxin5 (Syx5) belongs to SNAREs family, which play important roles in fusion of vesicles to target membranes. Most of what we know about functions of Syx5 originates from studies in fungal or vertebrate cells, how Syx5 operates during the development of insects is poorly understood. In this study, we investigated the role of LmSyx5 in the gut development of the hemimetabolous insect Locusta migratoria. LmSyx5 was expressed in many tissues, with higher levels in the gut. Knockdown of LmSyx5 by RNA interference (RNAi) considerably suppressed feeding in both nymphs and adults. The dsLmSyx5-injected locusts lost body weight and finally died at a mortality of 100%. Furthermore, hematoxylin-eosin staining indicated that the midgut is deformed in dsLmSyx5-treated nymphs and the brush border in midgut epithelial cells is severely damaged, suggesting that LmSyx5 is involved in morphogenesis of the midgut. TEM further showed that the endoplasmic reticulum of midgut cells have a bloated appearance. Taken together, these results suggest that LmSyx5 is essential for midgut epithelial homeostsis that affects growth and development of L. migratoria. Thus, Syx5 is a promising RNAi target for controlling L. migratoria, and even other pests.
Topics: Locusta migratoria; Qa-SNARE Proteins; Intestinal Mucosa; Insect Proteins; Feeding Behavior; Gene Knockdown Techniques; Sequence Homology, Amino Acid; Tissue Distribution; Body Weight; Gene Expression Regulation, Developmental
PubMed: 38879326
DOI: 10.1016/j.pestbp.2024.105934 -
Food Research International (Ottawa,... Aug 2024Edible insects are recognized as promising food sources due to their nutritional composition. Some species, such as Gryllus assimilis, contain proteins, lipids, and...
Edible insects are recognized as promising food sources due to their nutritional composition. Some species, such as Gryllus assimilis, contain proteins, lipids, and carbohydrates of high biological value, which regulate several metabolic functions, including the Renin-Angiotensin System (RAS). In this context, the present study aimed to assess the effects of dietary supplementation with whole Gryllus assimilis powder on the metabolism of malnourished mice. Thirty-two male Swiss mice were used and divided into four treatment groups. The groups were identified as (AIN93-M); AIN93-M + Gryllus assimilis diet (AIN93-M + GA); AIN93-M + Renutrition diet (AIN93-M + REN) and AIN93-M + Renutrition diet + Gryllus assimilis (AIN93-M + REN + GA). The results showed that whole Gryllus assimilis powder inclusion promotes recovery from protein-energy malnutrition, reduces adiposity, and improves glucose tolerance and insulin sensitivity. It also reduces total cholesterol, triglycerides, VLDL, and adipocyte area. We also observed a significant increase in the expression of RAS-related genes, such as ACE2 and MasR, followed by a reduction in Angiotensinogen and ACE. The main findings of the present study suggest the use of black cricket as a viable strategy for the prevention and treatment of protein-energy malnutrition, as well as the reduction of adiposity, and improvement of lipid and glycemic parameters, with antihypertensive potential.
Topics: Animals; Renin-Angiotensin System; Male; Dietary Supplements; Mice; Gryllidae; Protein-Energy Malnutrition; Adipose Tissue; Adiposity; Insulin Resistance
PubMed: 38876598
DOI: 10.1016/j.foodres.2024.114570 -
Nature Communications Jun 2024Theory predicts that compensatory genetic changes reduce negative indirect effects of selected variants during adaptive evolution, but evidence is scarce. Here, we test...
Theory predicts that compensatory genetic changes reduce negative indirect effects of selected variants during adaptive evolution, but evidence is scarce. Here, we test this in a wild population of Hawaiian crickets using temporal genomics and a high-quality chromosome-level cricket genome. In this population, a mutation, flatwing, silences males and rapidly spread due to an acoustically-orienting parasitoid. Our sampling spanned a social transition during which flatwing fixed and the population went silent. We find long-range linkage disequilibrium around the putative flatwing locus was maintained over time, and hitchhiking genes had functions related to negative flatwing-associated effects. We develop a combinatorial enrichment approach using transcriptome data to test for compensatory, intragenomic coevolution. Temporal changes in genomic selection were distributed genome-wide and functionally associated with the population's transition to silence, particularly behavioural responses to silent environments. Our results demonstrate how 'adaptation begets adaptation'; changes to the sociogenetic environment accompanying rapid trait evolution can generate selection provoking further, compensatory adaptation.
Topics: Animals; Gryllidae; Male; Genomics; Hawaii; Adaptation, Physiological; Linkage Disequilibrium; Genome, Insect; Biological Evolution; Female; Mutation; Selection, Genetic; Evolution, Molecular; Transcriptome
PubMed: 38866741
DOI: 10.1038/s41467-024-49344-4 -
Frontiers in Immunology 2024This study investigates immune priming effects associated with granulocytes in crickets through a comprehensive analysis. Kaplan-Meier survival analysis reveals a...
This study investigates immune priming effects associated with granulocytes in crickets through a comprehensive analysis. Kaplan-Meier survival analysis reveals a significant contrast in survival rates, with the heat-killed ()-primed group exhibiting an impressive ~80% survival rate compared to the PBS buffer-primed group with only ~10% survival 60 hours post live infection. Hemocyte analysis underscores elevated hemocyte counts, particularly in granulocytes of the killed -primed group, suggesting a correlation between the heat-killed priming and heightened immune activation. Microscopy techniques further explore granulocyte morphology, unveiling distinctive immune responses in the killed -primed group characterized by prolonged immune activation, heightened granulocyte activity, phagocytosis, and extracellular trap formation, contributing to enhanced survival rates. In particular, after 24 hours of injecting live , most granulocytes in the PBS buffer-primed group exhibited extracellular DNA trap cell death (ETosis), while in the killed -primed group, the majority of granulocytes were observed to maintain highly activated extracellular traps, sustaining the immune response. Gene expression analysis supports these findings, revealing differential regulation of immune-related genes such as antibacterial humoral response, detection of bacterial lipopeptides, and cellular response to bacteria lipopeptides. Additionally, the heat-killed -primed group, the heat-killed -primed group, and the PBS-primed group were re-injected with live 2 and 9 days post priming. Two days later, only the PBS-primed group displayed low survival rates. After injecting live 9 days later, the heat-killed -primed group surprisingly showed a similarly low survival rate, while the heat-killed -primed group exhibited a high survival rate of ~60% after 60 hours, with actively moving and healthy crickets. In conclusion, this research provides valuable insights into both short-term and long-term immune priming effects in crickets, contributing to our understanding of invertebrate immunity with potential applications in public health.
Topics: Animals; Granulocytes; Gryllidae; Bacillus thuringiensis; Phagocytosis; Hemocytes; Extracellular Traps
PubMed: 38827743
DOI: 10.3389/fimmu.2024.1383498 -
BMC Biology May 2024The female locust is equipped with unique digging tools, namely two pairs of valves-a dorsal and a ventral-utilized for excavating an underground hole in which she lays...
BACKGROUND
The female locust is equipped with unique digging tools, namely two pairs of valves-a dorsal and a ventral-utilized for excavating an underground hole in which she lays her eggs. This apparatus ensures that the eggs are protected from potential predators and provides optimal conditions for successful hatching. The dorsal and the ventral valves are assigned distinct roles in the digging process. Specifically, the ventral valves primarily function as anchors during propagation, while the dorsal valves displace soil and shape the underground tunnel.
RESULTS
In this study, we investigated the noticeable asymmetry and distinct shapes of the valves, using a geometrical model and a finite element method. Our analysis revealed that although the two pairs of valves share morphological similarities, they exhibit different 3D characteristics in terms of absolute size and structure. We introduced a structural characteristic, the skew of the valve cross-section, to quantify the differences between the two pairs of valves. Our findings indicate that these structural variations do not significantly contribute to the valves' load-bearing capabilities under external forces.
CONCLUSIONS
The evolutionary development of the form of the female locust digging valves is more aligned with fitting their respective functions rather than solely responding to biomechanical support needs. By understanding the intricate features of these locust valves, and using our geometrical model, valuable insights can be obtained for creating more efficient and specialized tools for various digging applications.
Topics: Animals; Female; Grasshoppers; Biomechanical Phenomena; Finite Element Analysis
PubMed: 38822347
DOI: 10.1186/s12915-024-01930-0 -
ELife May 2024To navigate their environment, insects need to keep track of their orientation. Previous work has shown that insects encode their head direction as a sinusoidal activity...
To navigate their environment, insects need to keep track of their orientation. Previous work has shown that insects encode their head direction as a sinusoidal activity pattern around a ring of neurons arranged in an eight-column structure. However, it is unclear whether this sinusoidal encoding of head direction is just an evolutionary coincidence or if it offers a particular functional advantage. To address this question, we establish the basic mathematical requirements for direction encoding and show that it can be performed by many circuits, all with different activity patterns. Among these activity patterns, we prove that the sinusoidal one is the most noise-resilient, but only when coupled with a sinusoidal connectivity pattern between the encoding neurons. We compare this predicted optimal connectivity pattern with anatomical data from the head direction circuits of the locust and the fruit fly, finding that our theory agrees with experimental evidence. Furthermore, we demonstrate that our predicted circuit can emerge using Hebbian plasticity, implying that the neural connectivity does not need to be explicitly encoded in the genetic program of the insect but rather can emerge during development. Finally, we illustrate that in our theory, the consistent presence of the eight-column organisation of head direction circuits across multiple insect species is not a chance artefact but instead can be explained by basic evolutionary principles.
Topics: Animals; Head; Grasshoppers; Neurons; Insecta; Models, Neurological; Drosophila melanogaster
PubMed: 38814703
DOI: 10.7554/eLife.91533 -
Proceedings. Biological Sciences May 2024Many theoretical treatments of foraging use energy as currency, with carbohydrates and lipids considered interchangeable as energy sources. However, herbivores must...
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 () 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.
Topics: Animals; Dietary Carbohydrates; Grasshoppers; Dietary Fats; Diet; Energy Metabolism; Lipid Metabolism; Energy Intake; Herbivory
PubMed: 38807520
DOI: 10.1098/rspb.2024.0424