Frontiers in insect science最新文献

The tobacco cutworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), is a major defoliating pest in East and South Asia and serves as an alternative host for the mass propagation of the parasitoid Telenomus remus. Therefore, optimizing the rearing cost of S. litura is critical for large-scale production to enhance efficiency and reduce costs. We evaluated 18 artificial diet formulations derived from a standard diet by incorporating corn flour and adjusting the ingredient ratios. The diets were grouped into high-, medium-, and low-cost categories, and their biological performance was assessed under controlled laboratory conditions (26 ± 1 °C, 70 ± 5% RH, and a16:8 h L:D photoperiod). Among the tested diets, formulation 15 produced the best results, yielding shorter larval (19.52 d) and pupal durations (10.46 d), higher pupal mass (500 mg), greater fecundity (2,658 eggs/female), and improved egg hatch (73.77%) compared with the control. Population parameters, including the intrinsic (r) and finite (λ) rates of increase, were significantly improved, whereas the mean generation time (T) and net reproductive rate (R₀ ) decreased. Importantly, formulation 15 lowered rearing costs by 5.9% relative to the original diet. These findings demonstrate that replacing soybean flour with corn flour as the primary protein source provides a cost-effective and biologically robust diet for S. litura. This optimized diet will facilitate large-scale rearing of S. litura and mechanized production of T. remus, providing a model for reducing artificial diet costs in other insect systems.

Ambrosia beetles rely on mutualistic fungi as a food source for themselves and especially for their offspring, yet the influence of host tree species on fungal growth and specialization remains poorly understood. In this study, we investigated the growth performance of the ambrosia fungus Dryadomyces montetyi, an important nutritional symbiont of the oak pinhole borer Platypus cylindrus, on semi-artificial media infused with extracts of four tree species: Quercus robur, Fagus sylvatica, Abies alba, and Pseudotsuga menziesii. Fungal growth was quantified over time using logistic models of the growth area and final dry weight measurements. The growth of D. montetyi differed significantly among the different host tree substrates. Growth on F. sylvatica was comparable to that on Q. robur; however, both conifer-derived media (A. alba and P. menziesii) exhibited significantly reduced surface expansion speed. Interestingly, growth speed on the European native A. alba was measurably higher than on the non-native P. menziesii. Q. robur medium had the highest fungal density of all tree hosts. However, density estimates were close and only nutrient-rich laboratory growth medium without tree extract differed significantly, as it had by far the highest density as well as growth speed of all measured media. Our findings show that fungal performance reflects the known preference of P. cylindrus for deciduous host trees. Host-related specialization of the fungal symbiont certainly determines host tree selection by P. cylindrus, which affects the evolution of the tripartite interactions between beetle, fungus and host trees.

Introduction: Wolbachia-based vector control strategies have been successfully implemented as a sustainable long-term solution and a promising tool for controlling Aedes mosquitoes, primarily Ae. aegypti, the main vector of major arboviral diseases. Since it is essential to rear healthy and competent adult mosquitoes for mass release under Wolbachia-based vector control strategies, optimising larval diet is essential. Therefore, the current study tested and compared four different larval diets to examine their statistical significance on the Wolbachia transinfected and uninfected Ae. aegypti life table traits.

Methods: We tested and compared the effects of four larval diets: LD1 (fish feed), LD2 (laboratory rodent diet), LD3 (mushroom powder), and LD4 (dog biscuit plus brewer's yeast) on hatchability, pupation, adult emergence, fecundity, and adult survival of Wolbachia-transinfected (wMel and wAlbB) Puducherry strains, as Among the tested diets, fish feed (LD1) and the combination of dog biscuit with brewer's yeast (LD4) have significant effects in both Wolbachia-transinfected and uninfected Ae. aegypti strains regarding egg hatchability, pupation, adult emergence, fecundity, and adult survival.

Results: The highest fecundity was observed under LD1 for uninfected Ae. aegypti, with approximately 84 eggs/female (84.0 ± 6.0), followed by wMel (Pud) mosquitoes (~78 eggs/female, 78.0 ± 5.2) and uninfected mosquitoes (~75 eggs/female,74.6 ± 23.3) under LD4 diet in the F0 generation. The uninfected Ae. aegypti females exhibited significantly lower mortality risk under LD2 (Hazard Ratio (HR)=0.56<1, P<0.001), with a high median survival of 57 days compared to all other diets.

Discussion: The results of this study suggest that LD1 (fish feed) can be recommended as the superior larval diet for the mass rearing of Wolbachia-transinfected strains, although both LD1 and LD4 diets demonstrated positive effects on all the Ae. aegypti strains. Meanwhile, LD4 (dog biscuit + brewer's yeast) can be recommended for the routine rearing of uninfected Ae. aegypti colonies, as it is comparatively cost-effective and readily available in India. These findings could contribute to the large-scale mosquito rearing programs under the Wolbachia strategy, ultimately supporting the implementation of sustainable vector control approaches for arboviral disease management.

The brown planthopper, Nilaparvata lugens is a major rice pest in Asia, with its high fecundity contributing to recurrent outbreaks. G protein-coupled receptors (GPCRs) are a critical class of transmembrane proteins in insects that sense diverse extracellular and intracellular signals and regulate a wide range of physiological processes. In this study, we characterized GPCR A35 and its function in N. lugens fecundity. Expression profiling revealed that GPCR A35 was highly enriched in female heads and fat bodies, with peak levels in females at 4 days post-eclosion. RNAi-mediated the silencing of GPCR A35 in fifth-instar nymphs by 57-60%, and was effectively delivered to female adults, resulting in a 14.8% reduction in juvenile hormone (JH) titer and marked downregulation of JH biosynthetic and signaling genes, including HMGCR (-60.1%), FPPS (-57.0%), JHAMT (-52.7%), Met (-24.2%), and Kr-h1 (-78.3%). Silencing of GPCR A35 further decreased Vg and VgR expression by 82.1% and 72.9% in females at 4 days post-eclosion, reduced protein contents in fat body and ovaries, and impaired ovarian development with fewer mature oocytes. Consequently, female fecundity declined by 51.3%, oviposition duration shortened by 18.5%, and the F1 population growth index decreased by 46.8%. These results demonstrate that GPCR A35 regulates fecundity in N. lugens by modulating JH-mediated vitellogenesis and oogenesis, providing a novel molecular target for RNAi-based green pest control.

Many insect species that could benefit humanity cannot be reared or domesticated because of the lack of adequate artificial diets. In the case of insect pests which are controlled via the Sterile Insect Technique, the prospects of improving biological traits of mass-reared individuals hinge on the development of new diet formulations. 3D food printing technology holds unique potential to create customized artificial diets simulating the shape, texture, and distribution of nutrient and non-nutrient components (e.g., dietary fiber and secondary metabolites) of natural insect foods. We present an overview on the use of state-of-the-art 3D printing technology to develop artificial diets that mimic the dynamic nature of natural insect diets, characterized by compartmentalized food components. The challenges and limitations of 3D food printing technology for its application in the field of diet development and artificial insect rearing are discussed, and future research priorities are highlighted. Examples are provided of beneficial and pestiferous insect species that could be reared on 3D-printed diets such as the cocoa pod borer and tephritid flies.

Faba bean (Vicia faba L.) is one of the most important cool-season legume crops worldwide, particularly in the Mediterranean regions. It plays a crucial role in cereal-based crop rotations and serves as an accessible and cost-effective protein source for both human diets and livestock feed. Despite its significance, faba bean production is heavily impacted by the stem borer Lixus algirus L. (Coleoptera: Curculionoidea), a prominent insect pest in the Mediterranean region. This research aimed to assess the impact of L. algirus on grain yield and seed nutritional profile of a local variety 'Defes'. The experiment was conducted using insect-proof cages at ICARDA - Marchouch research station during the 2018-2019 and 2019-2020 seasons. The findings revealed that L. algirus infestation caused grain yield losses ranging from 14% to 20%. Larval feeding within plant stems significantly altered seed nutritional composition compared to seeds from non-infested plant, ICP-OES analysis revealed significant declines were observed in magnesium (44%), manganese (38%), calcium (37%), zinc (30%), and iron (27%) concentrations in seeds collected from infested plants. In contrast, an increase in seed protein content and total sugar levels was recorded in infested plant seeds compared to non-infested plants. Similar results were observed for both essential amino acids (such as threonine, isoleucine, leucine, phenylalanine, histidine, lysine, and arginine) and non-essential amino acids (including glutamic acid, tyrosine, and alanine). Multivariate analyses, including PCA and correlation, revealed distinct nutrient and morphological trait patterns between infested and non-infested faba bean samples across both seasons. Collectively, these results show that L. algirus not only reduces grain yield but also reconfigures seed nutritional quality, lowering mineral density despite higher protein and sugars, highlighting the need for integrating host plant resistance for stem borer management and timely IPM to preserve both productivity and food/feed quality.

Diaprepes abbreviatus is an agricultural pest known to affect around 270 plant species across the Caribbean and the United States, posing significant challenges to pest management. Chemical control dominates management, but environmental and health concerns motivate microbiome-informed alternatives. However, limited information exists on the gut anatomy, physicochemical environment, and microbial composition of D. abbreviatus. In this study, we provide the first comprehensive characterization of the gut morphology, pH, and microbiota of adult D. abbreviatus in both females and males collected in Puerto Rico. Using dye-based gut tracing, we identified foregut, midgut, and hindgut or posterior gut compartments, and confirmed the presence of a muscular, sclerotized gizzard. Colorimetric analysis revealed a mildly acidic gut environment (approximately pH 4-5, based on qualitative ranges), consistent across sexes and regions. Shotgun metagenomic sequencing of dissected guts from males and females revealed microbial communities distinct from the leaf samples microbiota. While alpha and beta diversity did not differ significantly between sexes, co-occurrence analyses identified sex-specific correlation patterns among bacterial taxa. Notably, Enterobacter cloacae, Pantoea vagans, Lactococcus lactis, and Pseudomonas monteilii were repeatedly detected across individuals and generated metagenomic datasets, and some were localized to the hindgut, suggesting possible niche specialization. The presence of taxa, such as Enterobacter cloacae, previously reported as symbionts in other phytophagous insects further supports the hypothesis that certain bacteria may contribute to host digestion or adaptation. These findings establish a framework for understanding the gut environment and microbial community of D. abbreviatus, and highlight candidate taxa for future functional studies. More broadly, this work supports further research into the potential roles of gut microbiota in the ecology and management of this pest.

Termites are eusocial and economically important insects which are found in the world's tropical regions as a harmful or beneficial organism. They play a dual role, both as pests damaging crops and urban structure and as an ecological engineer sustaining the ecosystem. Pakistan is part of the Indomalayan realm hosting diverse flora and fauna including termites; however, the status (diversity, distribution, feeding hosts, pest and non-pest) of the genus Angulitermes in the northwestern region (Khyber Pakhtunkhwa, Pakistan) has been largely neglected. Termite cultures were collected from diverse ecosystems, cleaned, and preserved in alcohol-filled vials for subsequent morphometric identification and DNA barcoding. Coordinates with relevant ecological data were also recorded. Soldiers were used for capturing refined images and morphometric identification through available literature, which resulted as an Angulitermes dehraensis and a new locality record. A revised and updated world's species list for the genus was made along with the distribution map of this study via ArcGIS. The identified representative soldier's leg was processed for mtDNA extraction followed by amplification and sequencing. The received sequence was subjected to BLASTn search, and only top 15 sequences via BLASTn search and then via manual search for taxon Angulitermes were retrieved from GenBank. Aligned and trimmed sequences were processed for phylogenetic tree (neighbor-joining and maximum-likelihood) construction and validation of understudy species sequence analogy. A novel sequence was submitted to GenBank for accession number (PX423737). Based on the available and recorded feeding host substrate data, it is a pest species which needs management.

While biopesticides have been around for 70 years, starting with Bacillus thuringiensis bioinsecticides, they are experiencing rapid growth as the products have gotten better and more science-based and there are more restrictions on synthetic chemical pesticides. The growth of biopesticides is projected to continue to outpace that of chemical pesticides, with compounded annual growth rates of 10%-20% versus single digits for chemicals. When integrated into pest management programs, biopesticides offer the potential for higher crop yields and quality than chemical-only programs. Added benefits include the reduction or elimination of chemical residues, therefore easing export, delay in the development of resistance by pests and pathogens to chemicals, shorter field re-entry, biodegradability and lower carbon footprint and greenhouse gas emissions, and low risk to non-target organisms, including pollinators. However, many challenges still exist to drive further the adoption of biopesticides. These include lack of awareness and education in how to test and deploy their unique modes of action in integrated programs, resulting in lingering perceptions about performance and cost-effectiveness. This article addresses these issues with suggestions on how to increase farmer and key influencer confidence in the deployment of biologicals in integrated pest management (IPM) programs, including adjusting IPM thresholds and practice based on the modes of action of biopesticides compared to synthetic chemicals.