Entomological Research最新文献

Invasive alien species are an international problem because they can pose ecological and economic threats. Red swamp crayfish (Procambarus clarkii) is a representative invasive invertebrate species that has spread to Europe, North America, and Asia and causes ecosystem disturbances in freshwater and damages water management facilities. This study aimed to evaluate the species distribution and potential spread of P. clarkii, which was presumed to have been human-mediated introduced into South Korea. To achieve this purpose, this study predicted the global habitable areas of P. clarkii using a maximum entropy model based on global and South Korea-specific P. clarkii distribution data and five environmental variables. Shared socioeconomic pathway (SSP) scenarios were used to assess the effects of climate change on distribution. The model showed a good predictive performance for occurrence (AUC = 0.9707; TSS = 0.851; F1 score = 0.869). Temperature seasonality and mean temperature of the warmest quarter were the most influential factors for P. clarkii habitat. The model identified most regions with temperate climates and parts with continental and cold semiarid climates as high-risk areas. Under the SSP scenarios, the model predicted that the range might move into continental regions where habitat suitability is lower than that in temperate regions. In South Korea, habitat suitability was predicted to be high in the southern regions and eastern and western coasts. Also, suitability within the country is expected to increase. This study provides perspectives on P. clarkii invasion risk and highlights the need to prevent human-mediated introduction.

Niemann-Pick type C2 protein is a newly discovered odor molecule carrier protein in arthropods and has garnered widespread attention in recent studies. However, its functions in predatory mites remain largely unexplored. In this study, we cloned the coding sequences of nine NPC2 genes from the predatory mite Neoseiulus californicus and designated them as NcNPC2-1 to NcNPC2-9. These genes encode proteins ranging from 146 to 174 amino acids in length, with molecular weights between approximately 15.6 and 19.3 kDa. All proteins possess a conserved ML lipid recognition domain, and their tertiary structures are mainly composed of β-sheets, consistent with the characteristics of the NPC2 protein family. Phylogenetic analysis indicated that these genes are closely related to the NPC2 genes of other mites and spiders. All nine genes were expressed in the olfactory-functional leg I, with NcNPC2-5, NcNPC2-6, and NcNPC2-8 showing higher expression levels in leg I. After excision of leg I or both leg I and the gnathosoma, the expression level of NcNPC2-5, NcNPC2-6, NcNPC2-7, NcNPC2-8, and NcNPC2-9 significantly decreased compared with that in leg I. Next, RNA interference experiments were performed on NcNPC2‑5, NcNPC2‑6, and NcNPC2‑8. Knockdown of NcNPC2‑6 and NcNPC2‑8 did not significantly affect the attack latency of female N. californicus towards Tetranychus urticae eggs compared with the dsGFP control but did significantly reduce their daily predation rate. In contrast, knockdown of NcNPC2‑5 significantly increased attack latency and reduced daily predation rate. Our results support that NcNPC2-5 is involved in the prey recognition and localization process of N. californicus.

Understanding the molecular aspects of the susceptibility status of mosquitoes to insecticides could help tackle the problem of insecticide resistance. One of the most important molecular profiles is the amino acids involved in the synthesis of metabolic resistance proteins. In this study, the amino acid profile is compared for three different deltamethrin resistance statuses of Aedes albopictus (Skuse), namely, the VCRU strain (susceptible in the laboratory), the Balik Pulau strain (susceptible in the field), and the Glugor strain (resistant in the field). The resistance status to the insecticide was determined using the WHO adulticide tube test. The mosquito samples were later freeze-dried and derivatized by silylation and then analyzed by gas chromatography–mass spectrometry (GC–MS). Using standardized, known concentrations of amino acids, we quantified the amino acids in three different strains. A one-way ANOVA was performed to compare the concentrations of amino acids between the strains. Of the 12 amino acids obtained from the extraction, our results showed that the susceptible strains from the laboratory and the field were not significantly different, suggesting that the profile may represent the status of susceptibility. More importantly, the resistant strain in the field had a significantly higher concentration of alanine, valine, and glycine and a significantly lower concentration of the other eight amino acids. This suggests possible metabolic adaptations related to insecticide resistance, possibly involving detoxification processes or changes in protein synthesis.

The complete mitochondrial genome (mitogenome) of Tropilaelaps mercedesae (Acari: Laelapidae), which is a serious ectoparasite of several honeybee species, was sequenced and characterized for its genomic features. The results were then compared with those of other available Dermanyssoidea members and used to reconstruct phylogenetic relationships within Dermanyssoidea. Moreover, the current T. mercedesae mitogenome from South Korea was compared with publicly available data from China to determine suitable genes for a subsequent population-level study. Peculiarly, the 15,119-bp long T. mercedesae mitogenome has an 899-bp-long control region containing four copies of a repeat unit that are interrupted by non-repeat sequences. Additionally, T. mercedesae has a new gene arrangement among the Dermanyssoidea species, revealing eight translocated genes, one inverted tRNA block, and one inverted and translocated tRNA. Phylogenetic analyses, which included all available public data, clearly indicated non-monophyletic Laelapidae to which the current T. mercedesae is included. Comparison of two geographic samples of T. mercedesae evidenced several protein-coding genes, including nad5 and cytB (the two most variable), which had higher variability than that of cox1, thus suggesting the potential usefulness of these gene sequences for population genetic studies. Current T. mercedesae mitogenome sequences could provide baseline information for subsequent population-level studies and phylogenetic inferences at diverse taxonomic levels within Dermanyssoidea.

In this study, sequences of the mitochondrial NADH dehydrogenase 4 (ND4) gene for 137 native Apis mellifera jemenitica colonies from Saudi Arabia were analyzed. Results revealed eight new ND4 nucleotide haplotypes (1311 bp) and four amino acid haplotypes. Most mtND4 gene sequences (> 92%) of A. m. jemenitica were identical. However, four samples (3%) showed unusually highly polymorphic sequences. Within-population evolutionary diversity mean in ND4 nucleotide sequences was very low (0.0004). ND4 sequence variations among A. m. jemenitica and the most closely related subspecies A. m. syriaca and A. m. lamarckii were minimal by an average genetic distance of less than 0.005. The lowest evolutionary divergence mean was reported between A. m. jemenitica and A. m. syriaca. Results also showed that most A. mellifera subspecies included in this study could be separated from most A. m. jemenitica samples using one or more variations in amino acid sequences. Distinct amino acid sequence variations, particularly at codon 316, and differences in the restriction map of SspI can separate most A. m. jemenitica samples from the closely related subspecies, A. m. lamarckii and A. m. syriaca. Phylogenetic analyses showed that 19% of the DN4 nucleotide sequences of all samples and 100% of the amino acid sequences from Tabuk and Madinah clustered with the A. m. syriaca reference sequence, indicating a closer evolutionary relationship with the neighboring subspecies, A. m. syriaca. Results also demonstrated the likelihood of a small population with high genetic variability. This might indicate the presence of intensively hybridized colonies within the entire A. m. jemenitica population native to Saudi Arabia. Results also revealed that mtND4 sequence analyses could be used successfully to distinguish A. m. jemenitica of Saudi Arabia from other A. mellifera subspecies belonging to different evolutionary lineages such as A. m. mellifera, A. m. carnica, A. m. simensis, and A. m. intermissa. The close evolutionary relationship between A. m. jemenitica and A. m. syriaca or A. m. lamarckii and the approaches to separate them should be considered in any conservation efforts of A. m. jemenitica in Saudi Arabia.

This study investigates the effects of corn and an artificial diet on life history, and nutritional physiology of Conogethes punctiferalis larvae. Nutritional indices such as food consumption index (CI) and relative growth rate (RGR) were evaluated for the fourth and fifth instars on both diets. The results indicated no significant difference in CI between the diets. However, RGR was significantly higher for larvae reared on corn (p < 0.05). Fifth-instar larvae on corn exhibited the highest RGR (1.08 ± 0.01), while the lowest RGR was observed for 1-day-old fourth instars on artificial diet (0.02 ± 3.21). The efficiency of conversion of ingested food (ECI) and digested food (ECD) were also significantly higher for larvae on corn (p < 0.05), suggesting superior nutrient assimilation and conversion efficiency compared to artificial diet. Despite similar developmental durations, larvae on artificial diet had a higher survival rate (87.32%) than those on corn (75.01%). Pupal weight was slightly higher on artificial diet, but fecundity was greater on artificial diet (133.63 eggs with 90.76% fertility) compared to corn (129.67 eggs with 86.60% fertility). These findings indicate that corn while promoting higher growth rates and nutrient utilization efficiency, may include less digestible components, whereas artificial diet offers better overall survival and reproductive outcomes. This highlights the potential of optimizing artificial diets to enhance the laboratory rearing efficiency of C. punctiferalis for research and pest management applications.

C-type lectins (CTLs) are essential pattern-recognition receptors involved in insect innate immunity, mediating defense responses through carbohydrate binding. In this study, we aimed to clone and functionally characterize Bombyx mori CTL4 (BmCTL4), focusing on its immunity-related functions and binding specificity. To this end, the BmCTL4 cDNA was cloned and the recombinant BmCTL4 protein was expressed using a baculovirus expression system. The recombinant protein was then used to assess its binding specificity via carbohydrate-binding and microbial cell-binding assays. BmCTL4 contained a single carbohydrate recognition domain (CRD) with a QPD motif, suggesting specificity for galactose-type sugars. BmCTL4 was upregulated in the fat body following microbial inoculation. Recombinant BmCTL4 exhibited Ca²⁺-dependent binding to microbial cell wall constituents such as LPS, mannan, N-acetyl-D-glucosamine, and peptidoglycan, and directly bound to microbial cell surfaces as confirmed by confocal microscopy. Our findings demonstrate that BmCTL4 acts as a pattern-recognition receptor with broad carbohydrate-binding activity, contributing to the immune defense mechanisms of B. mori.

Pest development of resistance to Bacillus thuringiensis (Bt) insecticidal proteins threatens the sustainability of Bt crops, and it is therefore necessary to explore ecofriendly alternative insecticides for controlling Bt-resistant populations. Isothiocyanates are plant secondary metabolites that exhibit a diverse array of types and resistance against a broad spectrum of insect pests, but their effects on pink bollworms remain unexplored. Here, we evaluated the effects of phenyl isothiocyanate on Bt-susceptible and Bt-resistant pink bollworms (Pectinophora gossypiella). The LC₅₀ values of phenyl isothiocyanate for Bt-susceptible and Bt-resistant larvae were 26.4 and 28.6 μg/mL, respectively. The LC₃₀ sublethal dose of phenyl isothiocyanate significantly impaired the 7-day larval survival, the pupation rate, neonate-to-adult survival, the pupal weight, eggs per female and the egg hatching rate and prolonged the larval developmental period but not pupal duration for both strains. The response to phenyl isothiocyanate ingestion did not differ significantly between the two strains, implying that the Bt-resistant strain did not possess cross-resistance to phenyl isothiocyanate. These results provide scientific evidence for enriching green control technologies, resistance management tactics and comprehensive management measures for pink bollworm.