Entomological Research最新文献

To determine the control mechanism of garlic on Myzus persicae, volatiles from garlic plants were collected, and the components were determined by GC–MS. Then, the volatile extracts and standard components were screened by electroantennogram (EAG) apparatus and Y-tube olfactometer, and the toxic effects were determined by the immersion method. The results showed the main components from garlic plant volatile were 2-methoxyphenol, 2,4-di-tert-butylphenol, diallyl disulfide, butyl phthalate esters, (1-hydroxycyclohexyl) phenyl ketone, and 2,6-di-tert-butylp-cresol. The volatile extracts and the standard components had significant repellent effects (P ≤ 0.05) on M. persicae when the volume ratio was 1:100. The relative values of EAG from volatile extracts and diallyl disulfide were significantly higher than those of the other substances (P ≤ 0.05) when the volume ratio was 1:100. The toxicity of garlic volatile extracts to M. persicae significantly (P ≤ 0.05) increased with increasing concentration. After 72 h (treated), the adjusted mortality of the extract to M. persicae was 36.99% at 90 ml/L. The standard components had the significant toxic effect on M. persicae at 30 mg/mL, and the rates of mortality were over 78.95%. Thus, the results suggested that the volatile extracts and the four standard components from garlic plants had significant repellent effects and electroantennogram responses for M. persicae, and the toxic effects were stronger than the repellent effects for M. persicae.

Bacteria-originated volatile molecules play a crucial role in chemical communications between insects, representing their promising application as odor bait traps in pest control. In this study, we investigated the behavioral preferences of the fruit fly Drosophila melanogaster (Diptera: Drosophilidae) towards the fermentation broth of seven gut-associated bacteria using trap choice assays. All seven bacterial fermentations significantly attracted adults and larvae compared to the medium control. We assessed the effects of bacterial fermentations on bayberry attractiveness to fly adults, and found that the bayberries sprayed with fermentation broth of seven bacteria were all significantly more attractive to adults than the non-sprayed, following in increased total egg numbers. We also compared the attractive effect of bacterial fermentations with a sugar-vinegar mixture and a commercial odor-bait. The commercial odor bait proved more enticing than the unconcentrated 5-day fermentation broths. However, out of the seven bacteria, 64-fold concentrated bacterial fermentation of Corynebacterium (Actinomycetota phylum) was significantly more attractive than commercial bait. Finally, we chemically identified the predominant compounds 2-methylpropanal and acetaldehyde, which are likely responsible for the behavioral preference of fruit flies. Our findings provide a deeper understanding of how gut microbes affect insect behavior and offer a potential bacteria-originated odor bait for fly control in the orchard.

This study investigates the mosquitocidal potential of crude petroleum ether extract fractions derived from Gloriosa superba against the dengue mosquito vector Aedes aegypti. Chemical profiling through gas chromatography identified four major metabolites, with nonadecane showing the highest peak area percentage (70.34%). A lethal dosage of fraction IV of G. superba (Gs-F4), at a maximum concentration of 5.0 ppm, exhibited high mortality rates in second (78%), third (71%) and fourth (51%) instars of Ae. aegypti. A sublethal dosage of Gs-F4 (3.0 ppm) significantly altered the larval midgut enzymes of cytochrome P450, esterases and glutathione S-transferases. The repellent activity of Gs-F4 was dosage dependent, with repellency percentages decreasing from 96% to 50% as the exposure time increased from 15 to 210 mins. The impact of Gs-F4 on aquatic mosquito predators was marginally toxic (<50%) compared with the commercial compound temephos (1.0 ppm), which exhibited a higher toxicity (>50%). In silico toxicity screening using the BeeToxAI server indicated that three of the four compounds in Gs-F4 were safe or non-toxic to honeybees, except for α-gurjunene (6.29 μg/bee). Although G. superba demonstrates effective larvicidal and repellent activity against Ae. aegypti, the non-target toxicity against mosquito predators necessitates further toxicological screening on beneficial species under field conditions.

Fas-associated death domain protein (FADD) is an apoptotic adapter molecule that recruits caspases and facilitates the formation of death-inducing signaling complexes in mammals. In lower animals, FADD forms a complex with immune deficiency and death-related ced-3/Nedd2-like caspase to elicit antimicrobial responses. In this study, we characterized the FADD sequence of Tenebrio molitor (TmFADD) using molecular informatics to understand its role in immune surveillance of the host against microorganisms. The 618 bp open reading frame of TmFADD encodes a polypeptide of 204 amino acids. The protein includes two promiscuous domains, the death-effector domain and the death domain, found at the N- and C-termini, respectively. TmFADD is clustered with the coleopteran FADD sequences in the phylogenetic tree. Homology-based structural analysis showed an α-helical model with a QMEAN score of 0.58. The expression of TmFADD mRNA was conspicuous in the larval and early pupal stages. TmFADD mRNA was distributed in the immune tissues of the larva and was found predominately in the gut of the adult. Infection of the host with Candida albicans, Escherichia coli or Staphylococcus aureus increased the expression of TmFADD mRNA, suggesting that these microorganisms trigger the innate immunity of the host. The silencing of TmFADD transcripts resulted in an increased susceptibility of T. molitor larvae to infection with E. coli, but not to infection with C. albicans or S. aureus. Hence, these results indicate that FADD plays a role in the defense of T. molitor and could open avenues for understanding insect immunity.

This research delves into the effects of weir-induced habitat fragmentation on the diversity and structure of benthic macroinvertebrate communities in Topyeong Stream in the Republic of Korea. Through comprehensive zonation, environmental assessments and analyses of macroinvertebrate populations, the study brings to light the significant impact of physical barriers within aquatic ecosystems. Findings reveal notable differences in macroinvertebrate diversity among various stream zones, with alpha diversity measurements demonstrating the significant influence of habitat conditions on biodiversity. Beta diversity analyses uncovered considerable species turnover, pointing to distinct ecological features within fragmented habitats. Mantel tests solidified a significant link between geographical separation and species composition, highlighting the critical impact of spatial isolation arising from habitat fragmentation. The research also pinpointed environmental factors, including habitat size and depth variation, as critical influences on macroinvertebrate community dynamics. Discussions on conservation tactics centered on habitat restoration and forward-thinking water management strategies aim to counteract the negative consequences of fragmentation and drought. This study emphasizes the essential need for cohesive conservation initiatives to preserve aquatic biodiversity and the functionality of ecosystems amidst human-induced challenges.

Tick-borne pathogens (TBPs) are an emerging concern to humans and animals in the Republic of Korea, especially within the military zones of Gangwon Province, a mountainous region abundant with wild fauna and ticks. This study aimed to detect six TBPs in military working dogs (MWDs) and ticks in this region using Nested polymerase chain reaction (nested PCR) and sequencing. The targeted pathogens included Anaplasma phagocytophilum, Bartonella henselae, Borrelia spp., Orientia tsutsugamushi, Severe fever with thrombocytopenia syndrome virus (SFTSV) and tick-borne encephalitis virus (TBEV). A total of 164 serum samples from MWDs were collected at the Korean Army Military working dog training center and 1418 ticks were collected at various training sites between June 2021 and August 2022. Haemaphysalis longicornis was identified as the predominant species (98.3%, n = 1394), followed by Haemaphysalis flava (1.6%, n = 22) and Ixodes nipponensis (0.1%, n = 2). This study detected A. phagocytophilum and Borrelia theileri in 1.4% (1/72) of the tick pools and detected SFTSV in 0.6% (1/164) of MWD serum samples. The MWD found to be infected with SFTS was a German Shepherd, but showed no significant clinical signs, with a normal complete blood count (CBC). In the phylogenetic analysis, three sequences were acquired. One sequence (OR865211) exhibited 100% homology with 16S rRNA of A. phagocytophilum identified from animals and human patients in the Republic of Korea. Another sequence (OR865152) displayed 99.34%–100% sequence similarity with 16S rRNA of B. theileri fragments. The third sequence (OR865115), which belongs to the SFTS B-1 genotype, showed 94.7% sequence similarity to a strain identified in the Republic of Korea (KY789441).

Dung beetles are considered a key element in ecosystems as they are involved in many ecological processes, being one of the main decomposers of organic matter in the landscape. They can be classified into 3 subfamilies: Aphodiinae, Geotrupinae and Scarabaeinae, with each subfamily exhibiting specific adaptations and evolutionary strategies that have developed over time. The global patterns of dung beetle diversity are influenced by ecological factors, such as climatic (temperature, humidity, atmospheric pressure) and time-related variables. Thus, the aim of the study is to see how these variables affect a dung beetle community and whether there are different responses among the subfamilies. The study was carried out in Mataelpino, a town located in Central Spain (Madrid, Spain). Monthly sampling was conducted from May 2018 to February 2020. According to the results the variables considered exert an effect on dung beetles, with differences observed among the subfamilies. To our knowledge, atmospheric pressure has been considered for the first time in a study of this type, with a greater effect being observed in the Aphodiinae subfamily than in the rest of the dung beetle groups. Regarding the other subfamilies, it has been observed that temperature is a determining factor for Scarabaeinae species, whereas humidity seems to have a greater effect on Geotrupinae species.

Anti-inflammatory protein (AIP)-1 and AIP-2, identified as parasite excretory/secretory (ES) proteins, play a crucial role in promoting the survival of the parasite and evading the host immunological response. Both proteins inhibit inflammatory reactions, induce apoptosis in effector cells, and influence the phenotype of the immune response. Numerous parasite-derived proteins have shown promise as therapeutic targets for inflammatory and allergic diseases. Despite this, the precise biological roles, and molecular characteristics of many such proteins remain unclear.

In this study, AIP-1 and AIP-2 were produced in the baculovirus-insect cell expression system (BEVS). The multiplicity of infection (MOI) and the duration of infection conditions for AIP-1 and AIP-2 protein expression were successfully optimized to induce the highest expression levels of AIP-1 and AIP-2 proteins in insect cells. The insect cell-derived AIP-1 and AIP-2 exhibited inhibitory functions against human matrix metalloproteinases (MMPs). This study demonstrates that insect cell-derived AIP-1 and AIP-2 have the potential as therapeutic proteins for MMP-TIMP (Metalloprotease-Tissue inhibitor of metalloprotease) axis related disease.

Dengue fever disease is an important health issue in the city of Jeddah, Saudi Arabia. Chemical pesticides play a vital role in dengue control, through combating the mosquito vector Aedes aegypti L. Standard methods recommended by the World Health Organization were applied in the current work to conduct resistance experiments in both adult and larval stages of Ae. aegypti mosquitoes against eight types of pyrethroid and organophosphorus pesticides used in control programs in Jeddah. The results prove that Ae. aegypti is resistant against the pesticides deltamethrin 0.05%, α-cypermethrin 0.05%, fenitrothion 1% and temephos, is tolerant with some degree of resistance against cyfluthrin 0.15% and λ-cyhalothrin 0.5%, as well as tolerant against malathion 5% and pirimiphos-methyl 0.25%. On the other hand, the bacterial insecticide Bacillus thuringiensis ssp. israelensis (Bti) demonstrated high activity against the field strain of Aedes aegypti larvae, with a resistance ratio (RR) of 1.25. In general, we conclude from these findings that the continuous and frequent application of synthetic pesticides induces resistance in mosquitoes against pesticides. This, of course, forces us to reconsider the pesticides currently used in control programs and do our best towards finding alternative means to combat mosquitoes and the diseases that they can transmit.

This study investigated the in vivo efficacy of a chromium derivative extracted from date palms pit against Aedes aegypti the third instar larvae, the known vector of dengue fever in Saudi Arabia. Chromone 1, a flavonoid chromone component, was isolated from the alcoholic extract of date palm pits (DPP) using High-performance liquid chromatography (HPLC). The results showed that exposure of A. aegypti larvae to whole DPP extract and chromone 1 for 24 h resulted in significant insecticidal efficacy with LC₅₀ values of 132.82 and 54.64 ppm, respectively. The same concentrations also effectively inhibited AChE (acetylcholinesterase) activity up to −56.83 and −58.58%, respectively, compared to controls. The acetylcholine bromide test further confirmed the interaction between chromone 1 and AChE. The results also revealed that the chromone 1 treatment altered Deoxyribonucleic Acid (DNA) and protein content. It also exhibited that the extract of date palm pits DPP can effectively serve as sustainable ingredients for the control management of A. aegypti.