Search Results (74)

Triatoma pallidipennis, the main vector of Chagas disease in central Mexico, hosts a diverse and complex gut bacterial community shaped by environmental and physiological factors. To gain insight into these microbes’ dynamics, we characterised the gut bacterial communities of wild and insectary insects under different feeding and Trypanosoma cruzi infection conditions, using 16S rRNA gene sequencing. We identified 91 bacterial genera across 8 phyla, with Proteobacteria dominating most samples. Wild insects showed greater bacterial diversity, led by Acinetobacter and Pseudomonas, while insectary insects exhibited lower diversity and were dominated by Arsenophonus. The origin of the insects, whether they were reared in the insectary (laboratory) or collected from wild populations, was the principal factor structuring the gut microbiota, followed by feeding and T. cruzi infection. A stable core microbiota of 12 bacterial genera was present across all conditions, suggesting key functional roles in host physiology. Co-occurrence and functional enrichment analyses revealed that feeding and infection induced condition-specific microbial interactions and metabolic pathways. Our findings highlight the ecological plasticity of the triatomine gut microbiota and its potential role in modulating vector competence, providing a foundation for future microbiota-based control strategies. Full article

Recent advances in microbiome studies have deepened our understanding of endosymbionts and gut-associated microbiota in host biology. Of those, lepidopteran systems in particular harbor a complex and diverse microbiome with various microbial taxa that are stable and transmitted between larval and adult stages, and others that are transient and context-dependent. We highlight key microorganisms—including Bacillus, Lactobacillus, Escherichia coli, Pseudomonas, Rhizobium, Fusarium, Aspergillus, Saccharomyces, Bifidobacterium, and Wolbachia—that play critical roles in microbial ecology, biotechnology, and microbiome studies. The fitness implications of these microbial communities can be variable; some microbes improve host performance, while others neither positively nor negatively impact host fitness, or their impact is undetectable. This review examines the central position played by the gut microbiota in interactions of insects with plants, highlighting the functions of the microbiota in the manipulation of the behavior of herbivorous pests, modulating plant physiology, and regulating higher trophic levels in natural food webs. It also bridges microbiome ecology and applied pest management, emphasizing S. frugiperda as a model for symbiont-based intervention. As gut microbiota are central to the life history of herbivorous pests, we consider how these interactions can be exploited to drive the development of new, environmentally sound biocontrol strategies. Novel biotechnological strategies, including symbiont-based RNA interference (RNAi) and paratransgenesis, represent promising but still immature technologies with major obstacles to overcome in their practical application. However, microbiota-mediated pest control is an attractive strategy to move towards sustainable agriculture. Significantly, the gut microbiota of S. frugiperda is essential for S. frugiperda to adapt to a wide spectrum of host plants and different ecological niches. Studies have revealed that the microbiome of S. frugiperda has a close positive relationship with the fitness and susceptibility to entomopathogenic fungi; therefore, targeting the S. frugiperda microbiome may have good potential for innovative biocontrol strategies in the future. Full article

Stag beetles are saproxylic insects, essential for decomposing rotten wood and maintaining the carbon cycle. Their gut bacteria contribute significantly to nutrient digestion and energy acquisition, making them crucial for understanding host-microbe interactions. Despite the fungivorous behavior of stag beetle larvae, research on how diet influences gut bacterial diversity remains scarce. Therefore, this study was conducted to compare the diversity and metabolic functions of gut bacteria in Dorcus hopei larvae fed on fungus (Pleurotus geesteranus) and rotten wood diets using high-throughput sequencing technology. Significant differences (p < 0.05) were observed in gut bacterial community composition between two diets, highlighting diet as a key factor shaping bacterial diversity. Additionally, gut bacterial communities varied across larval developmental stages (p < 0.05), indicating the influence of host age. Dominant bacterial phyla included Firmicutes, Bacteroidetes, and Proteobacteria. Bacteroidetes were more abundant in rotten-wood-fed larvae (7.61%) than fungus-fed larvae (0.15%), while Proteobacteria were more abundant in fungus-fed larvae. Functional analysis revealed that rotten-wood-fed larvae were primarily related to carbohydrate and amino acid metabolism, whereas fungus-fed larvae exhibited enhanced membrane transport function. This study enhances the understanding of gut bacterial diversity and functions in stag beetles, providing a theoretical foundation for their conservation and sustainable utilization. Full article

Plants are naturally subjected to various types of biotic stresses, including pathogenic microorganisms and herbivory by insects, which trigger different signaling pathways and related defense mechanisms. Inoculation with microorganisms, such as plant growth-promoting rhizobacteria (PGPR), can be seen as a form of stress because it triggers a systemic resistance response in plants similar to that caused by insect herbivory. However, these interactions have typically been studied independently, which has limited the understanding of their combined effects. This study examines the effects of Bacillus amyloliquefaciens GB03 inoculation and Spodoptera frugiperda herbivory on the total phenolic contents of Ocimum basilicum. We also analyze the levels of endogenous phytohormones and the activity of phenylalanine ammonia-lyase (PAL), a crucial enzyme involved in the biosynthesis of phenolic defense-related metabolites. The results indicate that the total phenolic content significantly increased only in plants that were both inoculated by GB03 and damaged by larvae. Additionally, PAL activity showed an increase in plants that were damaged by larvae and in those subjected to the combined treatment of larval damage and inoculation with GB03. Regarding phytohormones, in plants damaged by insects, the levels of salicylic acid (SA) increased, regardless of whether they were inoculated or not, while the levels of jasmonic acid–isoleucine (JA-ile) rose in all treatments compared to the control. This study highlights the intricate relationships among beneficial microbes, herbivores, and plant defense mechanisms, emphasizing their potential impact on improving plant resilience and the production of secondary metabolites. Furthermore, understanding the independent effects of PGPR inoculation, beyond its interaction with herbivory, could provide valuable insights into its role as a sustainable alternative for enhancing plant defense responses and promoting crop productivity. Full article

The annual bluegrass weevil (Listronotus maculicollis Kirby) is a devastating insect pest of annual bluegrass (Poa annua L.) and, to a lesser extent, creeping bentgrass (Agrostis stolonifera L.) on golf courses. Listronotus maculicollis-reared A. stolonifera, a comparatively tolerant host, incurs fitness costs, including longer developmental periods and reduced larval survivorship. This study sought to characterize microbiota diversity in L. maculicollis adults and larvae reared on P. annua and A. stolonifera cultivars (Penncross & A4) to explore whether intrinsic factors, such as microbial community composition, vary across host plants and developmental stages, potentially influencing host suitability. Alpha diversity analyses showed adults feeding on A4 exhibited higher bacterial species richness than their offspring reared on the same cultivar. Beta diversity analysis revealed significant dissimilarities between L. maculicollis adults and offspring regardless of host. Pseudomonas sp. was consistently abundant in larvae across all turfgrasses, indicating a potential association with larval development. Elevated levels of Wolbachia sp., known for insect reproductive manipulation, were observed in adults, but appear to be unrelated to host plant effects. The most prevalent bacterium detected was Candidatus Nardonella, a conserved endosymbiont essential for cuticular hardening in weevils. Given the role of cuticular integrity in insecticide resistance, further investigations into insect–microbe–plant interactions could guide the development of targeted pest management strategies, reducing resistance and improving control measures for L. maculicollis. Full article

Intestinal microbes are known to impact the growth and development of insects. However, there are few reports on the intestinal microbiota of silkworms (Bombyx mori). The present study used Illumina 16S rRNA gene sequencing to investigate the changes over time in the intestinal bacteriome of fifth-instar silkworms fed mulberry leaf (MB) or artificial diet (AD). The results showed that the intestinal microbiota richness was significantly higher, before the 4th day of the fifth instar, in the silkworms fed AD rather than MB, while the richness was consistent between the AD and MB groups directly before cocooning. Proteobacteria was the most dominant phylum in MBs, AD, and the silkworm intestinal bacteriome, regardless of sex, feed type, or date, except that Firmicutes was the most dominant phylum for females on the 6th day of the fifth instar. Acinetobacter was the dominant genus in silkworms fed MB, while Enterococcus was the dominant genus in silkworms fed AD. Only 3.62% of the intestinal microbiota of silkworms fed MB was derived from MB, while 13.71% of the intestinal microbiota of silkworms fed AD was derived from AD. Thus, both bacterial communities were dominated by bacteria of unknown origin (non-feed sources). In the correlation network analysis, the silkworms fed AD appeared to have more complex interactions than the silkworms fed MB. Proteobacteria was the phylum most closely related to silkworm cocoon quality and feeding efficiency. Pantoea was the genera most closely related to cocoon quality and silkworm feeding efficiency in silkworms fed MB. AD had a significant impact on the predicted functions of the intestinal microbiota. There were significant differences in all six KEGG level 1 functions and all BugBase (except for Gram_Positive) phenotypes between silkworms fed AD or MB. The BugBase “Aerobic” phenotype was significantly higher in females compared to males, in both the AD and MB groups, while the “Oxidative_Stress_Tolerant” phenotype was the opposite. Overall, the findings suggest that the diversity, community structure, and predicted functions of intestinal bacteria in silkworms were significantly influenced by feed type. The study provides insights into the complex silkworm intestinal bacterial diversity and a foundation for probiotic screening. Full article

Accurate postmortem interval (PMI) estimation is critical for forensic investigations, aiding case classification and providing vital trial evidence. Early postmortem signs, such as body temperature and rigor mortis, are reliable for estimating PMI shortly after death. However, these indicators become less useful as decomposition progresses, making late-stage PMI estimation a significant challenge. Decomposition involves predictable microbial activity, which may serve as an objective criterion for PMI estimation. During decomposition, anaerobic microbes metabolize body tissues, producing gases and organic acids, leading to significant changes in skin and soil microbial communities. These shifts, especially the transition from anaerobic to aerobic microbiomes, can objectively segment decomposition into pre- and post-rupture stages according to rupture point. Microbial communities change markedly after death, with anaerobic bacteria dominating early stages and aerobic bacteria prevalent post-rupture. Different organs exhibit distinct microbial successions, providing valuable PMI insights. Alongside microbial changes, metabolic and volatile organic compound (VOC) profiles also shift, reflecting the body’s biochemical environment. Due to insufficient information, unimodal models could not comprehensively reflect the PMI, so a muti-modal model should be used to estimate the PMI. Machine learning (ML) offers promising methods for integrating these multimodal data sources, enabling more accurate PMI predictions. Despite challenges such as data quality and ethical considerations, developing human-specific multimodal databases and exploring microbial–insect interactions can significantly enhance PMI estimation accuracy, advancing forensic science. Full article

The Nearctic leafhopper Scaphoideus titanus (Hemiptera: Cicadellidae) is the primary vector of ‘Candidatus Phytoplasma vitis’, the causative agent of Flavescence doreé in Europe. Although microorganisms play an important role in the ecology and behavior of insects, knowledge about the interaction between S. titanus and microbes is limited. In this study, we employed an amplicon metabarcoding approach for profiling the V4 region of the 16S rRNA gene to characterize the bacterial communities of S. titanus across several populations from four European localities. Additionally, we investigated changes in bacterial communities between nymphal and adult stages. In total, we identified 7,472 amplicon sequence variants (ASVs) in adults from the European populations. At the genus level, ‘Candidatus Karelsulcia’ and ‘Candidatus Cardinium’ were the most abundant genera, with both being present in every individual. While we found significant changes in the microbial composition of S. titanus across different European populations, no significant differences were observed between nymphal and adult stages. Our study reveals new insights into the microbial composition of S. titanus and highlights the role of geography in influencing its bacterial community. Full article

The brown planthopper (Nilaparvata lugens, BPH) is a serious insect pest responsible for causing immense economic losses to rice growers around the globe. The development of high-throughput sequencing technologies has significantly improved the research on this pest, and its genome structure, gene expression profiles, and host–plant interactions are being unveiled. The integration of genomic sequencing, transcriptomics, proteomics, and metabolomics has greatly increased our understanding of the biological characteristics of planthoppers, which will benefit the identification of resistant rice varieties and strategies for their control. Strategies like more optimal genome assembly and single-cell RNA-seq help to update our knowledge of gene control structure and cell type-specific usage, shedding light on how planthoppers adjust as well. However, to date, a comprehensive genome-wide investigation of the genetic interactions and population dynamics of BPHs has yet to be exhaustively performed using these next-generation omics technologies. This review summarizes the recent advances and new perspectives regarding the use of omics data for the BPH, with specific emphasis on the integration of both fields to help develop more sustainable pest management strategies. These findings, in combination with those of post-transcriptional and translational modifications involving non-coding RNAs as well as epigenetic variations, further detail intricate host–brown planthopper interaction dynamics, especially regarding resistant rice varieties. Finally, the symbiogenesis of the symbiotic microbial community in a planthopper can be characterized through metagenomic approaches, and its importance in enhancing virulence traits would offer novel opportunities for plant protection by manipulating host–microbe interactions. The concerted diverse omics approaches collectively identified the holistic and complex mechanisms of virulence variation in BPHs, which enables efficient deployment into rice resistance breeding as well as sustainable pest management. Full article

The mass rearing of animals in close quarters can be highly conducive to microbe transmission, including pathogens. This has been shown multiple times in the case of important industrial insects such as crickets, silkworms, and honeybees. One industrial insect of increasing importance is the black soldier fly (Diptera: Hermetia illucens), as it can convert organic waste into high-quality protein and fatty acids. Along with this, they take up far less space than traditional protein sources, as millions of black soldier flies can be reared in a relatively small facility. Because of this, there is a growing interest in the pathogens that could impact black soldier fly-rearing efforts. So far, only three black soldier fly-associated viruses have been identified. We used metatranscriptomic sequencing to survey black soldier fly guts, frass, and diet for viruses. We detected sequences from two novel viruses. One, which we name Hermetia illucens sigma-like virus 1, is phylogenetically related to viruses of the genus Sigmavirus, which have been highly studied in Drosophila. The other novel virus, which we name Hermetia illucens inse-like virus 1, is the second double-stranded RNA virus of the order Ghabrivirales described in the black soldier fly, and groups within a new family of insect viruses called the Inseviridae. We also detected two black soldier fly-associated viruses previously identified by our group: BSF nairo-like virus 1 and BSF uncharacterized bunyavirus-like 1. Consistent with our previous study, these two viruses are found primarily in frass samples and occur together more often than expected at random. When analyzing host transcription, we found significant differences in gene expression for eight candidate antiviral genes in the black soldier fly when comparing samples with and without viral sequences. Our results suggest that black soldier fly–virus interactions are ongoing, and they could be of interest to black soldier fly producers. Full article

The use of endophytic microbes is increasing in commercial agriculture. This review will begin with a strain selection. Most strains will not function well, so only a few provide adequate performance. It will also describe the endophyte–plant relationship and the fungi and bacteria involved. Their abilities to alleviate biotic (diseases and pests) and abiotic stresses (drought, salt, and flooding) to remediate pollution and increase photosynthetic capabilities will be described. Their mechanisms of action will be elucidated. These frequently result in increased plant yields. Finally, methods and practices for formulation and commercial use will be described. Full article

Insects are the most diverse form of life, and as such, they interact closely with humans, impacting our health, economy, and agriculture. Beneficial insect species contribute to pollination, biological control of pests, decomposition, and nutrient cycling. Pest species can cause damage to agricultural crops and vector diseases to humans and livestock. Insects are often exposed to toxic xenobiotics in the environment, both naturally occurring toxins like plant secondary metabolites and synthetic chemicals like herbicides, fungicides, and insecticides. Because of this, insects have evolved several mechanisms of resistance to toxic xenobiotics, including sequestration, behavioral avoidance, and enzymatic degradation, and in many cases had developed symbiotic relationships with microbes that can aid in this detoxification. As research progresses, the important roles of these microbes in insect health and function have become more apparent. Bacterial symbionts that degrade plant phytotoxins allow host insects to feed on otherwise chemically defended plants. They can also confer pesticide resistance to their hosts, especially in frequently treated agricultural fields. It is important to study these interactions between insects and the toxic chemicals they are exposed to in order to further the understanding of pest insect resistance and to mitigate the negative effect of pesticides on nontarget insect species like Hymenopteran pollinators. Full article

(1) Background. At subzero temperatures, water crystallizes on ice nucleation agents. Researchers have identified ice-nucleating microbes (INMs) in insect digestive tracts that can raise the insect’s supercooling point, causing freezing at higher temperatures but slower rates. For freeze-tolerant insects, such gut microbes should allow for slower freezing away from tissues and higher survival rates. For freeze-susceptible insects, however, such microbes could cause a fatal freeze at higher temperatures, and could possibly be used as biocontrol. (2) Methods. A first-ever scoping review was carried out of research on insect-associated INMs, from observational studies attempting to isolate these microbes, to experimental studies applying them and checking for increased mortality. (3) Results. Relatively few research groups have studied insect-associated INMs in any capacity. (4) Conclusions. Several authors hypothesized that such microbes are probably abundant, and their contribution to ice nucleation activity in insects is under-reported. Biocontrol assays using ice-nucleating microbes showed promise, but a risk to non-target organisms has been experimentally confirmed. Future surveys of insect–microbe interactions using molecular tools are likely to reveal new examples, if not new microbe species capable of ice nucleation. Full article

The composition of microbiota in the digestive tract gut is essential for insect physiology, homeostasis, and pathogen infection. Little is known about the interactions between microbiota load and oral infection with baculoviruses. CnmeGV is an obligative baculovirus to Cnaphalocrocis medinalis. We investigated the impact of CnmeGV infection on the structure of intestinal microbes of C. medinalis during the initial infection stage. The results revealed that the gut microbiota profiles were dynamically driven by pathogen infection of CnmeGV. The numbers of all the OTU counts were relatively higher at the early and later stages, while the microbial diversity significantly increased early but dropped sharply following the infection. The compositional abundance of domain bacteria Firmicutes developed substantially higher. The significantly enriched and depleted species can be divided into four groups at the species level. Fifteen of these species were ultimately predicted as the biomarkers of CnmeGV infection. CnmeGV infection induces significant enrichment of alterations in functional genes related to metabolism and the immune system, encompassing processes such as carbohydrate, amino acid, cofactor, and vitamin metabolism. Finally, the study may provide an in-depth analysis of the relationship between host microbiota, baculovirus infection, and pest control of C. medinalis. Full article

The biological impacts of the nuclear accidents in Chernobyl (1986) and Fukushima (2011) on wildlife have been studied in many organisms over decades, mainly from dosimetric perspectives based on laboratory experiments using indicator species. However, ecological perspectives are required to understand indirect field-specific effects among species, which are difficult to evaluate under dosimetric laboratory conditions. From the viewpoint that microbes play a fundamental role in ecosystem function as decomposers and symbionts for plants, we reviewed studies on microbes inhabiting soil and plants in Chernobyl and Fukushima in an attempt to find supporting evidence for indirect field-specific effects on plants and insect herbivores. Compositional changes in soil microbes associated with decreases in abundance and species diversity were reported, especially in heavily contaminated areas of both Chernobyl and Fukushima, which may accompany explosions of radioresistant species. In Chernobyl, the population size of soil microbes remained low for at least 20 years after the accident, and the abundance of plant-associated microbes, which are related to the growth and defense systems of plants, possibly decreased. These reported changes in microbes likely affect soil conditions and alter plant physiology. These microbe-mediated effects may then indirectly affect insect herbivores through food-mass-mediated, pollen-mediated, and metabolite-mediated interactions. Metabolite-mediated interactions may be a major pathway for ecological impacts at low pollution levels and could explain the decreases in insect herbivores in Fukushima. The present review highlights the importance of the indirect field effects of long-term low-dose radiation exposure under complex field circumstances. Full article