Archives of Insect Biochemistry and Physiology最新文献

Goji berry is an important economic crop, yet pest infestations pose a significant threat to its yield and quality. Traditional pest identification mainly relies on manual inspection by experts with specialized knowledge, which is subjective, time-consuming, and labor-intensive. To address these issues, this experiment proposes an improved convolutional neural network (CNN) for accurate identification of 17 types of goji berry pests. Firstly, the original data set is augmented using a multi-graph-occlusion data augmentation method. Subsequently, the augmented data set is imported into the improved CNN for training. Based on the original ResNet18 model, a new CNN, named GojiNet, is constructed by embedding multi-attention fusion modules at appropriate locations. Experimental results demonstrate that GojiNet achieves an average recognition accuracy of 95.35%, representing a 2.60% improvement over the ResNet18 network. Notably, compared to the original network, the training time of this model increases only slightly, while its size is reduced, and the recognition accuracy is enhanced. The experiment verifies the performance of the GojiNet model through a series of evaluation indicators. This study confirms the tremendous potential and application prospects of deep learning in pest identification, providing a referential solution for intelligent and precise pest identification.

The diversity of herbivorous insects is associated with host plant diversity. The determination of dietary profile is a central topic in insect ecology. DNA barcoding, that is, taxon identification using a standardized DNA region, have been important to the recent advances in food web understandings. In this study, three commonly plant barcoding loci (i.e., rbcL, matK, and trnH-psbA) were chosen for screening of ingested plant DNA in 207 specimens of 18 leaf-grazing katydid species representing 4 subfamilies in China. The obtained sequences were queried against the Barcode of Life Database (BOLD) and GenBank for taxa identification. The results of identification were as follow: 3 Conocephalinae species consumed 10 plant families, with preference for Poaceae; 1 Mecopodinae species consumed 18 plant families, with preference for Fabaceae and Vitaceae; 11 Phaneropterinae species consumed 43 plant families, with preference for Juglandaceae; 3 species Pseudophyllinae species consumed 9 plant families, with preference for Balsaminaceae. Among these, only 81 out of 207 samples were identified at the species level when compares with NCBI and BOLD database. Our study added a significant amount of dietary information for leaf-grazing katydids in China. It is crucial to fully understand coevolution of katydids and plant, katydids diet resource requirements, and best practices for habitat conservation.

Pardosa astrigera is a species of spider that plays an important role in controlling crops pests but is at risk due to human agricultural practices. To optimize laboratory rearing, we developed specialized diets and rearing containers for both mother spiders and spiderlings. The maximum survival to adulthood was achieved with a diet of Drosophila melanogaster, Acyrthosiphon pisum and Aphis gossypii. Spiderlings fed an artificial milk diet, consisting of milk, egg yolk, and honey, had a 33% survival rate until the 5th life stage. Increasing the rearing space using 250 mL plastic cups improved survival (66%) compared to 50 mL jars (38%). The findings of this study offer pivotal technical support for delving deeper into the biological traits, dietary necessities, and reproductive processes of spiders. Furthermore, these insights can serve as a valuable reference for the artificial cultivation of other beneficial insects, thereby facilitating the enhancement of biological control strategies.

Understanding gene expression in specific tissues and their modulation under environmental stimuli, such as nutritional deficiency, reveals the key physiological regulatory mechanisms of an organism. This study examined the tissue-specific expression of insulin-like peptide (ILP) genes (BmX and BmZ) in Bombyx mori larvae and their responses to hyperglycaemia, food deprivation and hormonal (20-hydroxyecdysone and bovine insulin) treatments. mRNA expression levels of BmX and BmZ were analyzed in the brain, fat body, midgut and ovary. The results revealed that BmX was highly expressed in the fat body, while both genes were abundant in the ovary. Hyperglycaemia increased BmX mRNA expression level in the midgut (3.07-fold) and brain (7.53-fold), while BmZ mRNA expression level was increased in all tissues except the midgut. Nutrient deficiency upregulated BmX mRNA expression level (1.36-fold) in the fat body while reducing it (−0.53-fold) in the midgut. Food deprivation progressively increased (0.77-fold at 24 h and 2.34-fold at 72 h) BmX mRNA expression level in the fat body, while both BmX and BmZ transcripts declined in the midgut. Insulin suppressed BmX (−0.25-fold) and BmZ (−0.91-fold) mRNA expression levels in food-deprived larvae in the fat body, whereas 20E consistently downregulated BmX, BmZ, and BmInR (insulin receptor) mRNA expression levels in all the conditions. These findings revealed the complex interaction of gene expression, tissue specificity, and environmental factors in B. mori larvae and provided insights into adaptive responses to nutritional stress and hormonal regulation in the insect with potential applications in sericulture and agricultural biotechnology.

Histone acetylation levels maintained by histone acetyltransferases (HATs) and histone deacetylases play important roles in maintaining local chromatin accessibility and expression of genes that regulate many biological processes, including development and reproduction. N-terminal acetylation of proteins catalyzed by N-terminal acetyltransferases (NATs) also regulates gene expression. We identified 25 HATs/NATs genes in the yellow fever mosquito, Aedes aegypti, and investigated their function in female reproduction using RNA interference (RNAi). Among the HATs/NATs studied, the knockdown of AANAT1 (Arylamine N-acetyltransferase), NAA40 (N-alpha-acetyltransferase 40), NAA80 (N-alpha-acetyltransferase 80), KAT7 (Histone lysine acetyltransferase 7), ACNAT (Acyl-CoA N-acyltransferase), and MCM3AP (Minichromosome maintenance complex component 3 associated protein) significantly reduced egg laying and caused severe problems in oocyte development compared to that in control insects injected with dsGFP. Gene expression analysis using RT-qPCR revealed that vitellogenin and its receptor genes are downregulated in mosquitoes injected with dsAANAT1, dsNAA40, dsNAA80, dsKAT7, dsACNAT, and dsMCM3AP compared to that in control animals. Also, the knockdown of HATs/NATs genes ATAT1 (Alpha-tubulin N-acetyltransferase 1), AANAT1, TAFIID (Transcription initiation factor TFIID subunit 1), HATB (Histone acetyltransferase type B) and NAT9 (N-acetyltransferase 9) decreased more than 50% egg hatch by blocking embryonic development. These results suggest that the acetylation of proteins, especially histones mediated by NATs and HATs, plays an important role in regulating female reproduction and embryonic development of Ae. aegypti.

The gut microbiota plays a vital role in nutrient and energy utilization, as well as in the host's ability to adapt its immune system to environmental changes. As a biological control agent for the invasive Parthenium weed, the Parthenium beetle Zygogramma bicolorata (Z. bicolorata) Pallister is often exposed to fluctuating temperatures, which may induce stress in its natural habitat. This study utilized 16S amplicon sequencing to explore the impact of temperature stress on the gut microbiome of Z. bicolorata under cold (15°C), control (27°C), and hot (35°C) conditions. A total of 11 bacterial phyla and 149 genera were identified, with Firmicutes, Proteobacteria, and Cyanobacteria being the most abundant. Temperature treatments significantly influenced the diversity of the gut microbiota, as evidenced by alpha diversity measures. Principal coordinate analysis further revealed substantial variations in microbiome composition across the different temperature conditions. Additionally, PICRUSt2 analysis suggested that the gut microbiota is linked to metagenomic functions related to amino acid and carbohydrate transport, inorganic ion metabolism, and cellular processes. Our findings suggest that thermal stress alters the gut microbiome of Parthenium beetles, offering new insights into how these beetles may have ecologically adapted to temperature fluctuations, while also highlighting the potential role of gut microbes in maintaining beetle health under environmental stress.

The low excretory rates of secreted digestive enzymes, such as trypsins, in insect species with peritrophic membranes led to the hypothesis of ectoperitrophic countercurrent water fluxes causing enzyme recycling. The midgut water flux model of Tenebrio molitor (T. molitor) is revisited and supported by in vivo experiments. Sequences from proteins putatively involved in water transport were retrieved from the T. molitor transcriptome by Blast and analyzed using bioinformatics tools. Gene expression of selected proteins was determined in three midgut sections (anterior, AM; middle, MM; posterior, PM) by RNA-seq, and transporter proteins were verified in microvillar-membrane-enriched midgut samples by proteomics. Genes encoding three cation chloride cotransporters (CCC) and four aquaporins were expressed in the midgut. TmNaCCC2, TmPrip, and TmEglp1 showed higher expression in the front half, while TmKCC, TmNKCC1, TmDrip, and TmEglp2 were more highly expressed in the back half. However, only TmNaCCC2 was found by proteomics. Midgut water fluxes were quantified by feeding T. molitor larvae with nonabsorbable dye and measuring its concentration along the midgut. The results suggest water absorption in AM and secretion in MM and PM, potentially caused by TmNaCCC2 and TmPrip in AM, and TmKCC and TmDrip in PM, whereas MM serves as a transition region. Larvae fed on furosemide, an NKCC and KCC inhibitor, showed altered midgut water fluxes, resulting in higher trypsin excretion into the hindgut, thus reinforcing the hypothesis of a countercurrent water flux generated by CCCs powering enzyme recycling in insect midguts.

Mirid plant bugs (Hemiptera: Miridae), including Lygus hesperus (western tarnished plant bug), are key pests of numerous agricultural crops. While management of this pest relies heavily on chemical insecticides, the evolution of resistance and environmental concerns underscore the need for new and more effective approaches. Genetic-based strategies that target male fertiliy are currently being evaluated for population suppression. However, a lack of candidate gene targets with appropriate function, specifically in non-model species like L. hesperus, has hindered progress in the development and application of such approaches. Given their conserved role in stabilization of the flagella axoneme and association with sperm motility in many organisms, members of the tektin gene family represent logical targets for genetic-based sterilization. Here, we identified four homologs of the non-vertebrate tektin family from L. hesperus and used RNA interference-mediated knockdown to assess their roles in male fertility. Although transcription of the four tektins was predominantly in the testis, knockdown had negligible effects on either sperm abundance or male fertility. Our results suggest that tektins do not play a critical role in sperm fertilization of eggs in L. hesperus and are thus likely poor targets for genetic-based sterilization approaches in this species.

Transgenerational immune priming (TGIP) is a phenomenon in which parental exposure to pathogen infection enhances resistance to pathogens in their offspring. TGIP has been reported in several insects, including Lepidoptera, but it has not yet been documented in silkworms. In this study, we demonstrated the existence of TGIP in silkworms by exposing the parental generation to a low dose of Bombyx mori nucleopolyhedrovirus (BmNPV). Notably, when maternal or paternal-primed moths were mated to produce the F1 generation, the F1 generation larvae from both primed groups were more resistant to the BmNPV challenge than silkworm larvae with only maternal or paternal priming. Importantly, both maternal and paternal contributions to offspring immunity were essential for TGIP. However, due to the characteristics of the BmNPV itself, no within-generation immune responses were detected following BmNPV priming. Further analysis revealed that immune-related genes might play a role in mediating specific TGIP in silkworms after BmNPV priming. These results broaden our understanding of TGIP and the antiviral memory of insects in their offspring.