Entomological Research最新文献

The relationship between the gut bacterial communities of carabid beetles and their habitats holds implications for understanding ecological dynamics. This study examined the gut bacterial communities of two carabid beetle species, Chlaenius pallipes and Pheropsophus jessoensis, in terraced and flat paddy fields. Differences in gut bacterial communities were evident at the species level and were based on habitat. Specifically, P. jessoensis had a greater presence of Firmicutes and Proteobacteria in terraced fields but more Actinobacteria in flatland fields. In comparison, C. pallipes consistently showed high levels of Firmicutes in both habitats. These differences were reflected at class and genus levels, emphasizing the role of host specificity in shaping gut microbiota. Alpha diversity metrics indicated that P. jessoensis hosted a more diverse bacterial community than C. pallipes. Terraced fields, however, showed slightly reduced diversity in P. jessoensis, suggesting environmental effects on microbial populations. Beta diversity analysis using Bray–Curtis distances differentiated the bacterial communities of the two beetles. Multivariate analysis of variance reinforced these findings. Insights from the Sloan neutral model indicate that environmental factors predominantly influence bacterial community assembly through stochastic processes. Functionally, metabolism was highlighted, indicating the role of gut bacteria in beetle metabolic processes. Notably, energy metabolism varied between field types, revealing environmental effects on gut bacterial functions. This study offers in-depth insights into interactions between host-specific and environmental factors influencing gut bacterial communities of carabid beetles, contributing to a broader understanding of microbial ecology and the roles of environment and host in microbiota dynamics.

Extracts of botanical origin naturally contain a complex mixture of chemicals considered effective in managing lepidopteran pests. Chemical screening of the ethanolic leaf extracts of two fig tree species, Ficus lyrata and Ficus auriculata, delivered 12 and 15 phyto-compounds with relatively high peak area percentages in phytol and flavone, respectively. Larvicidal activity against Spodoptera litura yielded higher mortality rates at maximum-concentration treatment (600 ppm) with Ficus lyrata (91.3%) and Ficus auriculata (98.5%) extracts during the second instar. Sub-lethal dosages (300 ppm) of both Ficus lyrata and Ficus auriculata extracts impeded the development and reproduction of lepidopteran pests. The enzyme-inhibition activity of both fig extracts elicited a significant reduction in the major digestive enzymes alkaline phosphatase, acid phosphatase, and lactate dehydrogenase dose-responsively. Mid-gut histological screening of Ficus lyrata and Ficus auriculata extracts displayed gut lumen disruptions, shape alterations of columnar cells, and brush-border membrane damage. Further, the non-target toxicity of fig extracts against the red worm Eisenia foetida was minimal compared with that of the chemical temephos. Overall, the Ficus extracts proved to be eco-friendly strategies for managing the polyphagous pest Spodoptera litura and are potentially more sustainable and less harmful to non-target earthworms. Nonetheless, in silico predictions suggest that the active compounds in fig extracts are predominantly toxic against honeybees (16 compounds) and violate TICE rules (10 compounds). Therefore, the biological actions of fig extracts' individual novel chemistries need to be examined on target and non-target species to develop better pest management strategies.

Decades of research have established that the Earth’s magnetic field (geomagnetic field, GMF) is broadly used as a sensory cue for magnetic orientation in various animal taxa, including insects. In contrast to the investigation of the total intensity or inclination of the GMF, the effect of declination on horizontal magnetic movement has been explored in a few species, including flies, cockroaches, and dogs. However, the potential role of declination in the vertical movement in magnetosensitive organisms is yet to be reported. In this study, we provide the first evidence that declination within a natural range of change can affect static geotaxis in fruit flies, as assessed using the tube-positioning assay. In open-field measurements conducted at 22 domestic and foreign locations, the variation in declination was notably dependent upon the specific location, regardless of altitude, with similar variation in total intensity. Flies subjected to a geographic range of declination under the same total intensity and inclination exhibited remarkably different geotactic positioning scores, irrespective of GMF polarity. Notably, we observed a significant negative correlation between the geotactic score and the absolute value of declination, indicating that declination can induce negative geotaxis effects in flies. These results reveal that flies have evolved to incorporate a declination compass into their multimodal sensorimotor system and suggest that declination may be complementary to gravity in terms of environmental factor-driven negative geotaxis in flies.

Grapholita molesta (Busck) is an important pest of pear trees. Numerous esters accumulate consistently in mature pear fruits. However, little is known about the effects of single esters from pear fruits at different concentrations on the responses of male and female G. molesta. In this study, the responses of virgin males, virgin females, and gravid females to five esters (3-methylbutyl acetate, ethyl hexanoate, ethyl butanoate, butyl acetate, and hexyl acetate) of pear fruits at three dosage levels (1, 5 and 10 μg/μL) were investigated using electroantennography (EAG), wind tunnel experiments, and field tests. Our results showed that ethyl butanoate (5 μg/μL) elicited higher EAG responses in virgin females and males than a mixture of all five volatiles, and elicited an equal EAG response to that for the mixture in gravid females, with all responses to ethyl butanoate and the mixture being higher than the response to hexane alone. For upwind flight, ethyl butanoate (5 μg/μL) excited equal moth flight–location behavior in virgin and gravid females to that for the mixture, which were both higher than the response to hexane. For close flight, ethyl hexanoate (5 μg/μL) and 3-methylbutyl acetate (10 μg/μL) appeared to be the activating compounds, eliciting equal responses from virgin females to that of the mixture, and higher responses of gravid females to that of the mixture, both of which were higher than the responses to hexane. Upwind and close flight responses of virgin males were lower than those of virgin and gravid females. In field trials, we verified that traps baited with ethyl butanoate (5 μg/μL) captured more moths than the other esters. Therefore, from the esters and concentrations tested, we recommend ethyl butanoate (5 μg/μL) for potential use as an attractant for G. molesta in orchards.

Oryctes rhinoceros nudivirus (OrNV) infects the larval stage of many coleopteran insects; however, the underlying mechanisms and biomarkers of infection are not fully characterised. In this study, an optimal culture condition was developed for OrNV replication and proteomic biomarkers were identified using comparative proteomic analysis. The highest level of viral copy number was observed in Sf9 cells treated with 450 μM of H₂O₂ and 2% foetal bovine serum (FBS). Among the 48 identified proteins, 14 proteins were significantly modulated in 2% FBS and H₂O₂- treated OrNV-infected cells (F2V) as compared with 10% FBS treated non-infected cells (F10M). Network analysis revealed that SLC25A5, VDAC3, PHB2, and ANXA1 act as signature proteins for OrNV replication. Moreover, viral envelope glycoproteins, GRBNV_gp28-like and GrBNV_gp62-like proteins could be used as sensitive diagnostic signatures for OrNV infection. Furthermore, to conveniently identify the OrNV-infection in Allomyrina dichotoma larvae, an image classification model was trained by Google Teachable Machine, which distinguished images with accuracy rates of 91% and 86% for infected and non-infected larvae, respectively, at a learning rate of 0.001. This study demonstrated that Sf9 cell medium treated with 2% FBS and 450 μM H₂O₂ is a permissible culture condition for OrNV replication. Proteomic signatures may be involved in the progression of viral infection. Additionally, a low-cost and non-invasive machine learning-derived digital imaging analysis may improve the prediction of OrNV infection in larvae.

Recent molecular approaches toward insect taxonomy are revealing cryptic diversity within biting midge genus Culicoides Latreille, 1809. A new biting midge species was collected from highly restricted area of Dokdo Island, East Sea of the Republic of Korea, and was identified as Culicoides dokdoensis, sp. nov., based on morphological characters and DNA barcoding. The specimens collected from the island were previously known as Culicoides circumscriptus Kieffer, 1918, a cosmopolitan blood-feeder, due to its morphological similarity. However, the specimens from Dokdo Island can be distinguished from other congeners by the following characters: more curved arms in male aedeagus, wing spot pattern, sensory pit depth, and absence of a spermatheca neck in female. In addition, mitochondrial cytochrome c oxidase I sequence exhibited substantial genetic difference compared to C. circumscriptus populations from the Korean Peninsula, sufficiently supporting the genetic differentiation between the two species. The discovery of this cryptic species highlights the necessity of integrated taxonomy for Culicoides.

In this study, we explore the interplay of seasonal insect assemblages and carcass weight change to refine the estimation of minimum post-mortem interval (PMI_min), a key variable in forensic investigations. By integrating these parameters, we shed light on their combined influence on decomposition stages, thus paving the way for a more robust method of PMI_min estimation. Our approach relies on rigorous field studies examining pig carcasses across spring, summer and autumn, with comprehensive measurements of carcass weight and detailed documentation of insect succession. We observed distinct insect assemblages and weight-change trends characteristic of each season, underlining the influence of seasonal variability on decomposition dynamics. To further enhance the reliability of our model, we combined the novel parameter of carcass weight change with the conventional total body score (TBS) method, ensuring a more objective assessment of decomposition stages. Although our study indicates promising advancements, it also acknowledges the limitations of using a single pig carcass per season, suggesting future research should incorporate larger sample sizes.

As the demand for sustainable construction practices increases, innovative ideas are being explored for the construction of insulated wall panels in contemporary buildings. The butterfly is a remarkable organism that uses a thermostatic mechanism to regulate its body temperature. The microstructure on the surface of its wing scales is responsible for reflecting incident light multiple times, extending the optical path, and increasing the light absorption, thus ensuring that its body temperature remains stable. This microstructure, also known as the light capture structure, has been simulated and analyzed using ANSYS software. The results indicate that this structure can improve the light-thermal conversion efficiency in the illuminated region, thus increasing the local heat using light radiation. Additionally, due to the unique arrangement of units in the light capture structure, the heat exchange rate with air is significantly reduced, resulting in a low heat flux. Therefore, if this butterfly-like trapped light structure is applied to the insulated wall panels, the requirements of modern architectural concepts can be realized.

The Argentine ant, Linepithema humile (Mayr, 1868), native to the Paraguay River in South America, was first discovered in Korea in 2019. With increasing reports of L. humile, its genetic variation according to domestic growth colonies and its effects on the domestic ecosystem should be studied. Here, the genomes of L. humile specimens found at three locations in Busan were analyzed for genetic changes. First, morphological observation of L. humile samples collected from the three sites showed no phenotypic differences among them. Next, single-nucleotide polymorphism (SNP)/insertion and deletion (INDEL) analyses on the genomic DNA from the three groups showed that in the 1-NIE sample, the most frequent mutations were G → A and C → T. The mutations A → C and T → G were confirmed in the 14-NIE and 19-NIE samples. Although the number of SNPs in the N section was small, sequences of 4681 bp (1-NIE), 4217 bp (14-NIE) and 4631 bp (19-NIE) in length were identified. From the INDEL length distribution of the three samples, most changes were associated with insertions and deletions of 1–2 bp. However, no heterogeneity was found in the population samples analyzed based on SNP data. Comparative analysis of the SNPs investigated revealed that 760 819 (11.72%) of the total 6 492 517 SNPs were found in common, demonstrating that the three groups analyzed had different genetic backgrounds. Overall, we have developed a method for analyzing the genetic diversity of L. humile invading the Republic of Korea, precisely classified its genetic characteristics and obtained genomic data on interspecies mutations, according to the local environment.

CD200 is a ligand that interacts with the CD200 receptor 1, with an anti-inflammatory effect. CD200 inhibits the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway, attenuating the inflammatory response and maintaining barrier function. In this study, human CD200 was fused with the fragment crystallizable (Fc) region of human immunoglobulin G (IgG) to generate the recombinant CD200-Fc protein, produced in insect cells using the baculovirus expression vector system. The CD200-Fc gene was cloned under the control of the polyhedrin promoter in the pFastBac-1 vector of the baculovirus expression vector system. Immunoblot analysis confirmed the expression of CD200-Fc in insect cells. The CD200-Fc protein was successfully purified using protein A affinity chromatography. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay revealed that purified CD200-Fc protein inhibited the proliferation of TCCSUP cells, a bladder epithelial cancer cell expressing CD200 receptor 1, at concentrations of 1, 10 and 100 ng/mL. Quantitative real-time reverse transcription PCR (qRT-PCR) and immunoblot analyses confirmed that the mRNA and protein levels of zonula occludens-1, a tight junction protein for barrier protection in epithelial tissues, were increased in TCCSUP cells treated with insect cell-derived CD200-Fc. These results suggest that insect cell-derived CD200-Fc could alter zonula occludens-1 expression in bladder epithelial cancer cells, enhancing the function of the cell barrier protein, which could inhibit cancer metastasis. Taken together, the baculovirus expression vector system can be applied to express antitumor therapeutic CD200-Fc protein for the inhibition of bladder cancer.