Search Results (13)

Chlorantraniliprole, serving as a substitute for traditional insecticide, has been widely utilized in controlling lepidopteran pests. Loxostege sticticalis (Lepidoptera: Crambidae) is a polyphagous insect and poses a significant threat as a migratory insect. This study investigated the life history traits of a field-collected population in response to chlorantraniliprole exposure based on an age-stage, two-sex life table. After treating the third-instar larvae of L. sticticalis with three different doses of chlorantraniliprole, namely LC₁₀, LC₂₅, and LC₅₀, the survival, development, and fecundity of L. sticticalis were affected significantly in a dose-dependent manner. Chlorantraniliprole at doses of LC₁₀, LC₂₅, and LC₅₀ prolonged the average generation time (T) compared to the control group. The net reproductive rate (R₀) and intrinsic growth rate (r) were significantly higher in the LC₁₀ group but significantly lower in the LC₂₅ and LC₅₀ groups. Chlorantraniliprole used at a dose of LC₁₀ was shown to increase the finite growth rate (λ), while it decreased λ at doses of LC₂₅ and LC₅₀. These results suggested that chlorantraniliprole induces hormetic effects by enhancing fecundity and reproductive potential at lower sublethal concentration (LC₁₀), while reducing the reproductive output at higher doses (LC₂₅ and LC₅₀). Our results provide useful information for developing management strategies for L. sticticalis involving the use of chlorantraniliprole. Full article

Habrobracon hebetor is a globally acknowledged larval ectoparasitoid that is widely used to control lepidopteran pests. Wolbachia is a natural endosymbiont that regulates various aspects of the insect host biology. The ability of H. hebetor to paralyze and develop on lepidopteran larvae from five families was tested under laboratory conditions. Two lines of the wasp were used, “W+” containing a naturally occurring Wolbachia from the supergroup B, and “W−”, with the endosymbiont eradicated by antibiotic treatment, followed by propagation of 20 subsequent generations. The proportions of larvae in which host paralysis, as well as parasitoid oviposition, larval, pupal, and adult development were observed, were usually higher in W+ compared to W−. In Loxostege sticticalis, differences in these indices were not statistically significant. In Galleria mellonella, Mamestra brassicae, and Ostrinia nubilalis, some of the parasitism indices were significantly higher in W+ than in W−. In Bombyx mori and Plutella xylostella, H. hebetor could not complete its life cycle, but parasitism levels at the initial steps (from paralysis symptoms to the presence of larvae/pupae of the parasitoid) were 2–5 times lower in W− compared to W+ (p < 0.01). It can be suggested that the presence of Wolbachia is advantageous for H. hebetor, as it increases the success of parasitism in a broad range of lepidopteran hosts. Full article

Insects sense intraspecific or interspecific information about the chemical substances in the habitat through the sensitive olfactory system to carry out foraging, mating, oviposition, and other activities. The antennae serve as the primary olfactory organs in insects. The olfactory process involves the participation of many proteins, such as odorant-binding proteins (OBPs) and odorant receptors (ORs), but ORs play a central role in olfactory specificity and sensitivity. The beet webworm, Loxostege sticticalis, is an omnivorous agricultural pest that endangers crops and poses a significant risk to the agricultural and animal husbandry production in northern China. In this study, Illumina sequencing was conducted on the antennal transcriptome of male L. sticticalis trapped by three different sex pheromone blends. A total of 10,320 DEGs were identified, from which 46 candidate olfactory genes were selected for further analysis. These candidate olfactory genes comprise 13 odorant receptors, 6 ionotropic receptors (IRs), 3 gustatory receptors (GRs), 12 odorant-binding proteins, and 13 chemosensory proteins (CSPs). In summary, we analyzed the antennal transcriptome of male L. sticticalis trapped by three different sex pheromone blends and identified several candidate olfactory genes. This discovery offers a foundation for further molecular-level investigations into the olfactory system of L. sticticalis. Full article

To comprehensively investigate the impacts of increased atmospheric CO₂ concentrations on the growth, development and reproduction of the meadow moth Loxostege sticticalis when fed on pea plants (Pisum sativum), in this experiment, we simulated the two CO₂ conditions: ambient CO₂ (i.e., 400 μL/L designated as aCO₂) and elevated CO₂ (i.e., 800 μL/L designated as eCO₂) by using light-CO₂ climate chambers. Subsequently, the changes in several key nutrients and defensive compounds present in pea seedlings were assessed. Moreover, we assessed the growth, development, reproduction and changes in the nutritional components and enzyme activities of L. sticticalis as they fed on pea seedlings grown under aCO₂ and eCO₂. The results showed that the CO₂ level significantly affected the measured indexes of pea seedlings and L. sticticalis. Host pea seedlings grown under eCO₂ exhibited significant increases in soluble sugar (SS), soluble protein (SP) and total amino acid (TAA) contents by 42.52%, 77.06% and 62.50%, respectively, relative to those grown under aCO₂. In addition, total phenol (TP), ethylene (ET) and jasmonic acid (JA) contents grown under eCO₂ increased significantly by 20.60%, 71.72% and 36.22%, respectively, under eCO₂ compared to aCO₂. Furthermore, the duration of egg, larva and pupa of L. sticticalis was significantly shortened by 16.63%, 10.66% and 10.12%, respectively, while the adult longevity was significantly prolonged by 19.07% after feeding on pea seedlings grown under eCO₂ in contrast to aCO₂. Furthermore, for L. sticticalis, the content of SS, SP, TAA and free fatty acid was significantly increased, by 60.02%, 77.06%, 91.67% and 27.19%, respectively. Moreover, the enzyme activity of CAT, POD, CarE and GST was also enhanced by 56.70%, 63.89%, 128.08% and 93.45%, respectively, as they fed on pea seedlings grown under eCO₂ in contrast to aCO₂. The findings of our study revealed that eCO₂ not only improved the nutritional quality but also altered the defensive compounds in the seedlings, which in turn affected the growth, development, reproduction and changes in the physiology of L. sticticalis. Full article

The beet webworm, Loxostege sticticalis, is a typical migratory pest. Although miRNAs participate in many physiological functions, little is known about the functions of miRNAs in olfactory regulation. In this study, 1120 (869 known and 251 novel) miRNAs were identified in the antennae of L. sticticalis by using high-throughput sequencing technology. Among the known miRNAs, 189 from 49 families were insect-specific, indicating that these miRNAs might play unique roles in insects. Furthermore, based on the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, we found that 3647 and 1393 miRNAs were associated with localization and the regulation of localization, respectively, and 80 miRNAs were enriched in the neuroactive ligand–receptor interaction pathway. These miRNAs might be involved in the olfactory system of L. sticticalis. Notably, qRT-PCR showed that most of the tested miRNAs presented similar expression patterns compared with the RNA-seq data and that miR-87-3, novel-miR-78, and novel-miR-142 were significantly differentially expressed in the antennae of males and females. In addition, 21 miRNAs were predicted to target 23 olfactory genes, including 10 odorant-binding proteins (OBPs), 3 chemosensory proteins (CSPs), 4 odorant receptors (ORs), 1 ionotropic receptor (IR), and 5 gustatory receptors (GRs). The olfactory-related miRNAs exhibited low-abundance transcripts, except undef-miR-55 and undef-miR-523, and gender-biased expression was not observed for olfactory-related miRNAs. Our findings provide an overview of the potential miRNAs involved in olfactory regulation, which may provide important information on the function of miRNAs in the insect olfactory system. Full article

The beet webworm Loxostege sticticalis has caused significant economic losses to the production of agriculture and animal husbandry in China. Preference testing of larva feeding and adult oviposition and flight capability tests were carried out on five host plants: soybean, pigweed, pea, broad bean, and alfalfa. An experimental population life table and population growth trends over the subsequent 200 days were constructed. The test results show that the larvae showed no significant preference among different plants. However, adults lay more eggs on soybeans. The pests failed to complete a generation when fed on broad beans and alfalfas. When fed on pigweed, they showed the shortest larvae development period, the heaviest pupal weight, the longest adult longevity, and the largest egg-laying amount. The net reproductive rate (R₀), intrinsic rate of increase (r), finite rate of increase (λ), and simulated population growth trend of the pests fed on pigweed show the highest values, and those fed on peas showed the lowest values. The total flight distance and flight time of adults fed on pigweed and soybeans were significantly greater compared to those fed on peas. In summary, beet webworms fed on pigweed showed the fastest development and reproduction, the largest population, and the strongest flight capability. Full article

Histone acetylation is an important epigenetic mechanism that has been shown to play a role in diapause regulation. To explore the physiological and molecular mechanisms of histone deacetylase in the diapause process, LC-MS/MS analysis was used to perform TMT proteomic and metabolomic analysis on non-diapause (ND), pre-diapause (PreD), diapause (D), cold treatment (CT), and post-diapause (RD) stages of the meadow moth. A total of 5367 proteins were identified by proteomics, including 1179 differentially expressed proteins. We found 975 (602 up-regulated and 373 down-regulated), 997 (608 up-regulated and 389 down-regulated), 1119 (726 up-regulated and 393 down-regulated), 1179 (630 up-regulated and 549 down-regulated), 94 (51 up-regulated and 43 down-regulated), 111 (63 up-regulated and 48 down-regulated), 533 (243 up-regulated and 290 down-regulated), 58 (31 up-regulated and 27 down-regulated), and 516 (228 up-regulated and 288 down-regulated) proteins in ND and PreD, ND and D, ND and CT, ND and RD, PreD and D, PreD and CT, PreD and RD, D and CT, D and RD, and CT and RD stages, respectively. A total of 1255 differentially expressed metabolites were annotated by metabolomics. Through KEGG analysis and time series analysis of differentially expressed metabolites, we found that phospholipids were annotated in significantly different modules, demonstrating their important role in the diapause process of the meadow moth. Using phospholipids as an indicator for weighted gene co-expression network analysis, we analyzed the most relevant differentially expressed proteins in the module and found that ribosomal 40s and 60s subunits were the most relevant proteins for diapause. Because there have been studies that have shown that histone deacetylase is associated with the diapause of meadow moths, we believe that histone deacetylase regulates the 40s and 60s subunits of ribosomes, which in turn affects the diapause of meadow moths. This finding expands our understanding of the regulation of meadow moth diapause and provides new insights into its control mechanism. Full article

Beet webworms, Loxostege sticticalis L. (Lepidoptera: Pyralidae), are one of the most destructive pest insects in northern China, and their populations outbreak periodically. Developing an indicator that defines the ending and beginning of the occurrence period cycle is urgent for the population forecast and theoretical study. The sex ratio can be a primary pathway through which species regulate population size. We measured the maximum mating potential of both females and males and the population net reproductive rate under different sex ratios (e.g., 3:1, 2:1, 1:1, 1:2, 1:3). The maximum mating frequency of males was 2.91 times that of females. The progeny contribution per mating decreased with increased mating times in males. The variation in population net reproductive rate affected by the sex ratio fits the parabolic curve analysis and peaked at 1.82 for females vs. males. Our results illustrate the quantitative connection phenomenon shown by the historical data: population outbreaks occur at a sex ratio of two or more and collapse at a sex rate lower than one. Simultaneously, the sex ratio may be utilized as a definite indicator for the beginning and end of the future occurrence cycle in the beet webworm. Full article

The application of green manure is crucial for achieving sustainable agriculture and animal husbandry, but pest management is often overlooked. Conducting a risk assessment for insect pests in green manure is essential. The beet webworm, Loxostege sticticalis, a polyphagous insect, is currently experiencing an outbreak in northern China, and represents a significant migratory pest. A two-sex life table and flight mill test approach was used to comprehensively evaluate the effects of three major legume green manure crops (Pisum sativam, Vicia sativa, and Vicia villosa) on the growth, development, fecundity, and flight ability of L. sticticalis in China. Our findings indicate that L. sticticalis cannot utilize V. villosa for generational development. L. sticticalis shows reduced performance on P. sativam and V. sativa compared to its suitable host Chenopodium album. However, both the population parameters (R₀, r, λ, and T) and the population prediction results suggest that L. sticticalis can adapt to P. sativam and V. sativa. In the process of promoting green manure, careful consideration should be given to the selection of appropriate green manure varieties and the implementation of effective pest control measures during their planting. Our findings lay the groundwork for the promotion of green manure and implementation of an ecological management plan for L. sticticalis. Full article

Lepidopteran insects mainly rely on sex pheromones to complete sexual communications. Pheromone receptors (PRs) are expressed on the olfactory receptor neurons (ORNs) of the sensilla trichodea and play an essential role in sexual communication. Despite extensive investigations into the mechanisms of peripheral recognition of sex pheromones in Lepidoptera, knowledge about these mechanisms in L. sticticalis remains limited. In this study, five candidate LstiPRs were analyzed in a phylogenetic tree with those of other Lepidopteran insects. Electroantennography (EAG) assays showed that the major sex pheromone component E11-14:OAc elicited a stronger antennal response than other compounds in male moths. Moreover, two types of neurons in sensilla trichodea were classified by single sensillum recordings, of which the “a” neuron specifically responded to E11-14:OAc. Five candidate PRs were functionally assayed by the heterologous expression system of Xenopus oocytes, and LstiPR2 responded to the major sex pheromone E11-14:OAc. Our findings suggest that LstiPR2 is a PR sensitive to L. sticticalis’s major sex pheromone compound, E11-14:OAc. Furthermore, this study offers valuable insights into the sexual communication behavior of L. sticticalis, forming a foundation for further analysis of the species’ central nervous system. Full article

We aimed to monitor the species diversity and the dynamics of the number of soybean pests using light traps with an original design to develop protection systems against the main phytophages. Traps lured 44 species of insects from eight orders and 27 families. The capture of 15 species of economically important phytophages was recorded—representatives of various orders and families: order Lepidoptera—Noctuidae, Crambidae, Erebidae, and Geometridae; order Hemiptera—Flatidae; order Coleoptera—Elateridae, etc. Insect identification was carried out via morphological methods. Over the study period (93 days), 4955.41 insect specimens were caught on average per one trap. Most of the attracted insects belong to harmful entomofauna: namely the cotton bollworm (Helicoverpa armigera, Hübner)—58.9%, the beet webworm (Loxostege sticticalis, L.)—12.74%, the nutmeg moth (Anarta trifolii, Hufnagel)—6.5%, the European corn borer (Ostrinia nubilalis, Hübner)—2.68%, and some other species—19.2%. In addition to economically significant phytophages, we registered some indifferent and beneficial species. The summer dynamics of the cotton bollworm and the nutmeg moth were obtained for the entire research period. Then, we calculated the values of the indices of biodiversity and the dominance of insect species. An analysis of the index values allows us to conclude a balanced entomocomplex at the research site. Full article

The beet webworm (Loxostege sticticalis L.) is an important agricultural pest and can tolerate harsh environmental conditions by entering diapause. The diapause mechanism of beet webworm is unknown. Therefore, we conducted a transcriptomic study of the process from diapause induction to diapause release in beet webworms. The results revealed 393 gene modules closely related to the diapause of beet webworm. The hub gene of the red module was the HDACI gene, which acts through histone deacetylase (HDAC) enzymes. HDAC enzyme activity was regulated by the light duration and influenced the JH content under induced beet webworm diapause conditions (12 h light:12 h dark). In addition, transcriptomic data suggested that circadian genes may not be the key genes responsible for beet webworm diapause. However, we showed that the photoperiod affects HDAC enzyme activity, and HDAC can regulate the involvement of JH in beet webworm diapause. This study provided a new module for studying insect diapause and links histone acetylation and diapause at the transcriptome level. Full article

As the first crucial barrier in the midgut of insects, the peritrophic membrane (PM) plays an important role in preventing external invasion. PM proteins, as the major components of the PM, determine the structure and function of this membrane. A new PM protein, named LstiCBP, from the PM of Loxostege sticticalis larvae was identified using cDNA library screening. The full cDNA of LstiCBP is 2606 bp in length and contains a 2403 bp ORF that encodes an 808-amino acid preprotein with a 15-amino acid as signal peptide. The deduced protein sequence of the cDNA contains 8 cysteine-rich chitin-binding domains (CBDs). Recombinant LstiCBP was successfully expressed in BL21 cells using recombinant plasmid DNA and showed high chitin-binding activity. LstiCBP expression was detected in the midgut at both the transcriptional and translational levels; however, the biochemical and physiological functions of LstiCBP in L. sticticalis require further investigation. Full article