The venom of Habrobracon hebetor induces alterations in host metabolism.

The ability of parasitic wasps to manipulate a host's metabolism is under active investigation. Components of venom play a major role in this process. In the present work, we studied the effect of the venom of the ectoparasitic wasp Habrobracon hebetor on the metabolism of the greater wax moth host (Galleria mellonella). We identified and quantified 45 metabolites in the lymph (cell-free hemolymph) of wax moth larvae on the second day after H. hebetor venom injection, using NMR spectroscopy and liquid chromatography coupled with mass spectrometry. These metabolites included 22 amino acids, nine products of lipid metabolism (sugars, amines and alcohols) and four metabolic intermediates related to nitrogenous bases, nucleotides and nucleosides. An analysis of the larvae metabolome suggested that the venom causes suppression of the tricarboxylic acid cycle, an increase in the number of free amino acids in the lymph, an increase in the concentration of trehalose in the lymph simultaneously with a decrease in the amount of glucose, and destructive processes in the fat body tissue. Thus, this parasitoid venom not only immobilizes the prey but also modulates its metabolism, thereby providing optimal conditions for the development of larvae.

Impact of diet and bacterial supplementation regimes on Orius strigicollis microbiota and life history performance.

Given the growing interest in manipulating microbiota to enhance the fitness of mass-reared insects for biological control, this study investigated the impact of an artificial diet on the microbiota composition and performance of Orius strigicollis. We compared the microbiota of O. strigicollis fed on an artificial diet and moth eggs via culturing and 16S rRNA gene amplicon sequencing. Subsequently, we assessed life history traits and immune gene expression of O. strigicollis fed on the artificial diet supplemented with Pantoea dispersa OS1. Results showed that microbial diversity remained largely unaffected by the artificial diet, with similar microbiota compositions in both diet groups. OS1, a minor member of the microbiota but significantly enriched in bugs fed on the artificial diet, improved nymphal survival rates and shifted adult longevity-reproduction life history in females. Additionally, OS1 supplementation elevated the transcription of antimicrobial peptide diptericin. According to population parameters, the group receiving OS1 only during the nymphal stage showed higher population growth potential compared to the group supplemented across all life stages. These findings reveal the resilience of O. strigicollis microbiota under distinct dietary conditions and highlight the potential of using natural symbionts and specific supplementation regimes to improve Orius rearing for future biocontrol programs.

The effect of developmental temperature on olfaction in a moth revealed by its interaction with body mass.

There is a growing interest in the effects of climate warming on olfaction, as temperature may affect this essential sense. In insects, the response of the olfactory system to developmental temperature might be mediated by body size or mass because body size and mass are negatively affected by developmental temperature in most ectotherms. We tested this hypothesis of a mass-mediated effect of developmental temperature on olfaction in the moth Spodoptera littoralis. We measured the olfactory sensitivity of male to female sex pheromone and five plant odors using electroantennography. We compared males reared at an optimal temperature (25 °C with a daily fluctuation of ±5 °C) and at a high temperature (33 ± 5 °C) close to the upper limit of S. littoralis. On average, the olfactory sensitivity of males did not differ between the two developmental temperatures. However, our analyses revealed an interaction between the effects of developmental temperature and body mass on the detection of the six chemicals tested. This interaction is explained by a positive relationship between antennal sensitivity and body mass observed only with the high developmental temperature. Our results show that the effect of developmental temperature may not be detected when organism size is ignored.

The irregular developmental duration mainly caused by the broad-complex in Chilo suppressalis.

Chilo suppressalis, a critical rice stem borer pest, poses significant challenges to rice production due to its overlapping generations and irregular developmental duration. These characteristics complicate pest management strategies. According to the dynamic analysis of the overwintering adults of C. suppressalis in fields, it indicates that the phenomenon of irregular development of C. suppressalis exists widely and continuously. This study delves into the potential role of the Broad-Complex (Br-C) gene in the developmental duration of C. suppressalis. Four isoforms of Br-C, named CsBr-C Z1, CsBr-C Z2, CsBr-C Z4, and CsBr-C Z7, were identified. After CsBr-Cs RNAi, the duration of larva development spans extended obviously. And, the average developmental duration of dsCsBr-Cs feeding individuals increased obviously. Meanwhile, the average developmental duration of the dsCsBr-C Z2 feeding group was the longest among all the RNAi groups. After dsCsBr-Cs feeding continuously, individuals pupated at different instars changed obviously: the proportion of individuals pupated at the 5th instar decreased and pupated at the 7th instar or higher increased significantly. Moreover, the pupation rate of dsCsBr-Cs (except dsCsBr-C Z7) were significantly lower than that of dsGFP. The same results were obtained from the mutagenesis in CsBr-C genes mediated by CRISPR/Cas9. The average developmental duration of CsBr-Cs knockout individuals was significantly prolonged. And, the instar of pupation in knockout individuals was also delayed significantly. In conclusion, this work showed that CsBr-Cs played a crucial role in pupal commitment and affected the developmental duration of C. suppressalis significantly.

RNAi targeting Nav and CPR via leaf delivery reduces adult emergence and increases the susceptibility to λ-cyholthin in Tuta absoluta (Meyrick).

The tomato leafminer, Tuta absoluta (Meyrick), one of the most economically destructive pests of tomato, causes severe yields losses of tomato production globally. Rapid evolution of insecticide resistance requires the development of alternative control strategy for this pest. RNA interference (RNAi) represents a promising, innovative control strategy against key agricultural insect pests, which has recently been licensed for Colorado Potato Beetle control. Here two essential genes, voltage-gated sodium channel (Nav) and NADPH-cytochrome P450 reductase (CPR) were evaluated as targets for RNAi using an ex vivo tomato leaf delivery system. Developmental stage-dependent expression profiles showed TaNav was most abundant in adult stages, whereas TaCPR was highly expressed in larval and adult stages. T. absoluta larvae feeding on tomato leaflets treated with dsRNA targeting TaNav and TaCPR showed significant knockdown of gene expression, leading to reduction in adult emergence. Additionally, tomato leaves treated with dsRNA targeting these two genes were significantly less damaged by larval feeding and mining. Furthermore, bioassay with LC30 doses of λ-cyholthin showed that silencing TaNav and TaCPR increased T. absoluta mortality about 32.2 and 17.4%, respectively, thus indicating that RNAi targeting TaNav and TaCPR could increase the susceptibility to λ-cyholthin in T. absoluta. This study demonstrates the potential of using RNAi targeting key genes, like TaNav and TaCPR, as an alternative technology for the control of this most destructive tomato pests in the future.

Juvenile responses to immune challenges are not carried through to subsequent life stages in an insect.

Environmental variability can significantly impact individual survival and reproduction. Meanwhile, high population densities can lead to resource scarcity and increased exposure to parasites and pathogens. Studies with insects can offer valuable insights into eco-immunology, allowing us to explore the connections between these variables. Here we use the moth Anticarsia gemmatalis to examine how increases in population density and immunological challenge during the larval stage shape its investment in immune defence and reproduction. Larvae reared at a high population density exhibited greater lytic activity against bacteria compared to those reared at low density, whilst bacterial challenge (i.e. bacteria-immersed needles) also increased lytic activity. There was no interaction between the variables population density and bacterial challenge, indicating that these are independent. Surprisingly, neither increase in lytic activity carried through to activity in prepupal haemolymph. Rearing of larvae at a high density delayed pupation and decreased pupal weight. The immunological stimulus did not significantly influence pupal development. Lower population density as a larva resulted in greater adult weight, but did not significantly influence lytic activity in the eggs or the number of eggs laid. Negative correlations were found between lytic activity in the eggs and the number of eggs, as well as between adult weight and the number of eggs. Overall, this study demonstrates that high population density and immune challenge trigger increased lytic activity in caterpillars, but this effect is transient, not persisting into later stages. The trade-offs observed, such as delayed pupation and reduced prepupal weights under high density, suggest a balancing act between immune investment and developmental aspects. The findings hint at a short-term adaptive response rather than a sustained strategy. The implications of delayed pupation and smaller adult moths could influence the moth's life history strategy, impacting its role in the ecosystem. Further research tracking larval immune investment and subsequent reproductive success will unveil the evolutionary dynamics of this relationship in changing environments.

The transcription factor RUNT-like regulates pupal cuticle development via promoting a pupal cuticle protein transcription.

Holometabolous insects undergo morphological remodeling from larvae to pupae and to adults with typical changes in the cuticle; however, the mechanism is unclear. Using the lepidopteran agricultural insect Helicoverpa armigera, cotton bollworm, as a model, we revealed that the transcription factor RUNT-like (encoded by Runt-like) regulates the development of the pupal cuticle via promoting a pupal cuticle protein gene (HaPcp) expression. The HaPcp was highly expressed in the epidermis and wing during metamorphosis and was found being involved in pupal cuticle development by RNA interference (RNAi) analysis in larvae. Runt-like was also strongly upregulated in the epidermis and wing during metamorphosis. Knockdown of Runt-like produced similar phenomena, a failure of abdomen yellow envelope and wing formation, to those following HaPcp knockdown. The insect molting hormone 20-hydroxyecdysonen (20E) upregulated HaPcp transcription via RUNT-like. 20E upregulated Runt-like transcription via nuclear receptor EcR and the transcription factor FOXO. Together, RUNT-like and HaPCP are involved in pupal cuticle development during metamorphosis under 20E regulation.

Transgenic poplar (Populus davidiana×P. bolleana Loucne) expressing dsRNA of insect chitinase gene: lines identification and resistance assay.

Poplar is a valuable tree species that is distributed all over the world. However, many insect pests infest poplar trees and have caused significant damage. To control poplar pests, we transformed a poplar species, Populus davidiana × P. bolleana Loucne, with the dsRNA of the chitinase gene of a poplar defoliator, Clostera anastomosis (Linnaeus) (Lepidoptera: Notodontidae), employing an Agrobaterium-mediated approach. The transgenic plant has been identified by cloning the T-DNA flanking sequences using TAIL-PCR and quantifying the expression of the dsRNA using qPCR. The toxicity assay of the transgenic poplar lines was carried out by feeding the target insect species (C. anastomosis). The results showed that, in C. anastomosis, the activity of chitinase was significantly decreased, consistent with the expression on mRNA levels, and the larval mortality was significantly increased. These results suggested that the transgenic poplar of dsRNA could be used for pest control.

Fitness costs, realized heritability, and mechanism of resistance to tenvermectin B in Plutella xylostella.

Tenvermectin B (TVM-B) and five TVM-B analogs were produced by fermentation of a genetically engineered strain Streptomyces avermitilis HU02, and TVM-B is being developed as a new insecticide. Through 11 generations of resistance selection against TVM-B in the diamondback moth, Plutella xylostella, the median lethal concentration (LC50) was increased from 14.84 to 1213.73 mg L-1. The resistance to TVM-B in P. xylostella developed fast and its realized heritability was high (h2 = 0.2901 (F7), h2 = 0.4070 (F11)). However, the relative fitness was 0.6916 suggesting a fitness cost in the resistant strains. The fitness cost was partially explained by the upregulation of the detoxification enzyme activity by 2.15 folds in carboxylate esterase (CarE) and the gene expressions of ATP-binding cassette transporter gene (ABCC2) and the alpha subunit of the glutamate-gated chloride channel (GluCl) by 1.70- and 2.32 folds, respectively. The resistance was also explained by two points of mutations at the alpha subunit of the glutamate-gated chloride channel in the P. xylostella (PxGluClα) subunit in F11. However, there was little change in the binding affinity. These results provided helpful information for the mechanism study of TVM-B resistance and will be conducive to designing rational resistance management strategies in P. xylostella.

Lipases are differentially regulated by hormones to maintain free fatty acid homeostasis for insect brain development.

BACKGROUND: Free fatty acids (FFAs) play vital roles as energy sources and substrates in organisms; however, the molecular mechanism regulating the homeostasis of FFA levels in various circumstances, such as feeding and nonfeeding stages, is not fully clarified. Holometabolous insects digest dietary triglycerides (TAGs) during larval feeding stages and degrade stored TAGs in the fat body during metamorphosis after feeding cessation, which presents a suitable model for this study. RESULTS: This study reported that two lipases are differentially regulated by hormones to maintain the homeostasis of FFA levels during the feeding and nonfeeding stages using the lepidopteran insect cotton bollworm Helicoverpa armigera as a model. Lipase member H-A-like (Lha-like), related to human pancreatic lipase (PTL), was abundantly expressed in the midgut during the feeding stage, while the monoacylglycerol lipase ABHD12-like (Abhd12-like), related to human monoacylglycerol lipase (MGL), was abundantly expressed in the fat body during the nonfeeding stage. Lha-like was upregulated by juvenile hormone (JH) via the JH intracellular receptor methoprene-tolerant 1 (MET1), and Abhd12-like was upregulated by 20-hydroxyecdysone (20E) via forkhead box O (FOXO) transcription factor. Knockdown of Lha-like decreased FFA levels in the hemolymph and reduced TAG levels in the fat body. Moreover, lipid droplets (LDs) were small, the brain morphology was abnormal, the size of the brain was small, and the larvae showed the phenotype of delayed pupation, small pupae, and delayed tissue remodeling. Knockdown of Abhd12-like decreased FFA levels in the hemolymph; however, TAG levels increased in the fat body, and LDs remained large. The development of the brain was arrested at the larval stage, and the larvae showed a delayed pupation phenotype and delayed tissue remodeling. CONCLUSIONS: The differential regulation of lipases expression by different hormones determines FFAs homeostasis and different TAG levels in the fat body during the feeding larval growth and nonfeeding stages of metamorphosis in the insect. The homeostasis of FFAs supports insect growth, brain development, and metamorphosis.

Day-night gene expression reveals circadian gene disco as a candidate for diel-niche evolution in moths.

Temporal ecological niche partitioning is an underappreciated driver of speciation. While insects have long been models for circadian biology, the genes and circuits that allow adaptive changes in diel-niches remain poorly understood. We compared gene expression in closely related day- and night-active non-model wild silk moths, with otherwise similar ecologies. Using an ortholog-based pipeline to compare RNA-Seq patterns across two moth species, we find over 25 pairs of gene orthologs showing differential expression. Notably, the gene disco, involved in circadian control, optic lobe and clock neuron development in Drosophila, shows robust adult circadian mRNA cycling in moth heads. Disco is highly conserved in moths and has additional zinc-finger domains with specific nocturnal and diurnal mutations. We propose disco as a candidate gene for the diversification of temporal diel-niche in moths.

Gut Microbiota Mediate Plutella xylostella Susceptibility to Bt Cry1Ac Protoxin and Exopolysaccharides.

Exopolysaccharides (EPSs) are carbohydrate polymers that are synthesized and secreted into the extracellular during the growth of microorganisms. Bacillus thuringiensis (Bt) is a type of entomopathogenic bacterium, that produces various insecticidal proteins and EPSs. In our previous study, the EPSs produced by Bt strains were first found to enhance the toxicity of insecticidal crystal proteins against Plutella xylostella. However, the response of the intestinal bacterial communities of P. xylostella under the action of EPSs is still unelucidated. In this study, 16S rRNA amplicon sequencing was used to characterize the intestinal bacterial communities in P. xylostella treated with EPSs alone, Cry1Ac protoxin alone, and both the Cry1Ac protoxin and EPSs. Compared with the control group, alpha diversity indices, the Chao1 and ACE indices were significantly altered after treatment with EPSs alone, and no significant difference was observed between the groups treated with Cry1Ac protoxin alone and Cry1Ac protoxin + EPSs. However, compared with the gut bacterial community feeding on Cry1Ac protoxin alone, the relative abundance of 31 genera was significantly changed in the group treated with Cry1Ac protoxin and EPSs. The intestinal bacteria, through the oral of Cry1Ac protoxin and EPSs, significantly enhanced the toxicity of the Cry1Ac protoxin towards the axenic P. xylostella. In addition, the relative abundance of the 16S rRNA gene in the chloroplasts of Brassica campestris decreased after adding EPSs. Taken together, these results show the vital contribution of the gut microbiota to the Bt strain-killing activity, providing new insights into the mechanism of the synergistic insecticidal activity of Bt proteins and EPSs.

Genome-wide investigation of the OR gene family in Helicoverpa armigera and functional analysis of OR48 and OR75 in metamorphosis development.

The cotton bollworm, Helicoverpa armigera, is a significant global agricultural pest, particularly detrimental during its larval feeding period. Insects' odorant receptors (ORs) are crucial for their crop-feeding activities, yet a comprehensive analysis of H. armigera ORs has been lacking, and the influence of hormones on ORs remain understudied. Herein, we conducted a genome-wide study and identified 81 ORs, categorized into 15 distinct groups. Analyses of protein motifs and gene structures revealed both conservation within groups and divergence among them. Comparative gene duplication analysis between H. armigera and Bombyx mori highlighted different duplication patterns. We further investigated subcellular localization and protein interactions within the odorant receptor family, providing valuable insights for future functional and interaction studies of ORs. Specifically, we identified that OR48 and OR75 were abundantly expressed during molting/metamorphosis and feeding stages, respectively. We demonstrated that 20E induced the upregulation of OR48 via EcR, while insulin upregulated OR75 expression through InR. Moreover, 20E induced the translocation of OR48 to the cell membrane, mediating its effects. Functional studies involving the knockdown of OR48 and OR75 revealed their roles in metamorphosis development, with OR48 knockdown resulting in delayed pupation and OR75 knockdown leading to premature pupation. OR48 can promote autophagy and apoptosis in fat body, while OR75 can significantly inhibit apoptosis and autophagy. These findings significantly contribute to our understanding of OR function in H. armigera and shed light on potential avenues for pest control strategies.

Differences in adult nutritional requirements impact the population growth and survival of two related species of rice leaffolders to produce interspecific differentiation.

Nutrition is a limiting feature of species evolution. The differences in nutritional requirements are the evolutionary result of differential adaptations to environmental changes, explaining differences in their ecological traits. Cnaphalocrocis medinalis and Cnaphalocrocis exigua, two related species of rice leaffolders, have similar morphology and feeding properties but different migration and overwintering behaviors. However, it is unclear whether they have evolved adult nutritional differentiation traits to coexist. To explore this issue, this study examined the effects of carbohydrates and amino acids on their reproductive and demographic parameters. The findings indicate that carbohydrate intake prolonged the longevity and population growth of two rice leaffolders, but amino acid intake promoted egg hatching only. However, nutrient deficiency made it impossible for C. medinalis to reproduce successfully and survive, but it did not affect C. exigua. The population expansion and survival of migratory C. medinalis relied on adult nutritional intake. Conversely, the nutrients necessary for C. exigua overwintering activity mostly came from the storage of larvae. The difference in nutritional requirements for population growth and survival between the two rice leaffolders partially explained their differences in migration and overwintering.

Silence of Aminopeptidase N 2 gene reveals the trade-offs for acquiring Cry1Ac resistance in Plutella xylostella.

Bacillus thuringiensis (Bt) is widely used as a biopesticide worldwide. To date, at least eight pest species have been found to be resistant to Bt in the field. As the first pest that was reported having resistance to Bt in the field, considerable research has been done on the mechanisms of Bt resistance in Plutella xylostella. However, whether the acquisition of Bt resistance by P. xylostella comes at a fitness cost is also a valuable question. In this study, Aminopeptidase-N 2 (APN2), a Cry toxin receptor gene of P. xylostella, was knocked down by RNA interference, resulting in improved resistance to Cry1Ac. It was also found that larval mortality of APN2 knockdown P. xylostella was significantly higher than that of the control, while the pupation rate, pupal weight, eclosion rate, fecundity (egg/female), hatchability, and female adult longevity were significantly lower in APN2 knockdown P. xylostella than in the control. These results illustrate that if Cry1Ac resistance was obtained only through the reduction of APN2 expression, P. xylostella would need to incur some fitness costs for it.

Effect of temperature on the biological parameters of pink bollworm, Pectinophora gossypiella Saunders (Lepidoptera: Gelechiidae).

Pink bollworm (PBW) Pectinophora gossypiella is an important pest cotton worldwide. There are multiple factors which determines the occurrence and distribution of P. gossypiella across different cotton growing regions of the world, and one such key factor is 'temperature'. The aim was to analyze the life history traits of PBW across varying temperature conditions. We systematically explored the biological and demographic parameters of P. gossypiella at five distinct temperatures; 20, 25, 30, 35 and 40 ± 1 °C maintaining a photoperiod of LD 16:8 h. The results revealed that the total developmental period of PBW shortens with rising temperatures, and the highest larval survival rates were observed between 30 °C and 35 °C, reaching 86.66% and 80.67%, respectively. Moreover, significant impacts were observed as the pupal weight, percent mating success, and fecundity exhibited higher values at 30 °C and 35 °C. Conversely, percent egg hatching, larval survival, and adult emergence were notably lower at 20 °C and 40 °C, respectively. Adult longevity decreased with rising temperatures, with females outliving males across all treatments. Notably, thermal stress had a persistent effect on the F1 generation, significantly affecting immature stages (egg and larvae), while its impact on reproductive potential was minimal. These findings offer valuable insights for predicting the population dynamics of P. gossypiella at the field level and developing climate-resilient management strategies in cotton.

Impact of Exposure to Leaves From Metal-Polluted Sites on the Developmental Parameters of Larvae of the Dark Sword-Grass, Agrotis ipsilon (Lepidoptera: Noctuidae).

Insects are impacted by pollutants in their environments and food sources. Herein, we set out a semi-field study to assess the impact of environmental heavy metal contamination on developmental parameters, energy reserves, and acidic and alkaline phosphatases in the larval Agrotis ipsilon (Lepidoptera: Noctuidae). Castor leaves from contaminated and uncontaminated (reference site) areas were fed to A. ipsilon larvae in all treatments. The heavy metal concentrations in the plant from different areas (contaminated and reference sites) and in the larvae were analyzed. Toxic effects were observed in the larvae feeding on the leaves from the metal contaminated areas. Larval and pupal weights, growth indices, and larval fitness were all significantly lower than in the reference group. Likewise, in the third and fourth instars, there was a significant decrease in both the survival and moth emergence rates. In contrast, the pupation duration was significantly longer. Total protein, lipid, and glycogen content showed significant reductions in treated larvae. Larval homogenate samples contaminated with heavy metals showed a significant increase in acid- and alkaline- phosphatase levels. The results obtained could provide a basis for a long-term evaluation of the risk associated with heavy metals and their impact on plant populations and important agricultural pests.

Timing-dependent effects of elevated temperature on reproductive traits in the European corn borer moth.

Elevated temperature often has life stage-specific effects on ectotherms because thermal tolerance varies throughout ontogeny. Impacts of elevated temperature may extend beyond the exposed life stage if developmental plasticity causes early exposure to carry-over or if exposure at multiple life stages cumulatively produces effects. Reproductive traits may be sensitive to different thermal environments experienced during development, but such effects have not been comprehensively measured in Lepidoptera. In this study, we investigate how elevated temperature at different life stages alters reproduction in the European corn borer moth, Ostrinia nubilalis. We tested effects of exposure to elevated temperature (28 °C) separately or additively during larval, pupal, and adult life stages compared to control temperatures (23 °C). We found that exposure to elevated pupal and adult temperature decreased the number of egg clusters produced, but exposure limited to a single stage did not significantly impact reproductive output. Furthermore, elevated temperature during the pupal stage led to a faster transition to the adult stage and elevated larval temperature altered synchrony of adult eclosion, either by itself or combined with pupal temperature exposure. These results suggest that exposure to elevated temperature during development alters reproduction in corn borers in multiple ways, including through carry-over and additive effects. Additive effects of temperature across life stages are thought to be less common than stage-specific or carry-over effects, but our results suggest thermal environments experienced at all life stages need to be considered when predicting reproductive responses of insects to heatwaves.

Effects of industrial pollution and ambient air temperature on larval performance and population dynamics of Eriocrania leafminers (Lepidoptera).

Pollution is an integral part of global environmental change, yet the combined and interactive effects of pollution and climate on terrestrial ecosystems remain inadequately understood. This study aims to explore whether pollution alters the impacts of ambient air temperature on the population dynamics of herbivorous insects. Between 1995 and 2005, we studied populations of two closely related moths, Eriocrania semipurpurella and E. sangii, at eight sites located 1 to 64 km from a large copper­nickel smelter in Monchegorsk, Russia. We found that pollution and temperature influence the performance of Eriocrania larvae mining in the leaves of mountain birch, Betula pubescens var. pumila, through multiple pathways. This is evident from the unconsistent changes observed in larval and frass weight, mine area, and leaf size. We found increases in both leaf quality and larval weight with decreasing pollution levels at both spatial and temporal scales and attributed these to the impact of sulphur dioxide, rather than trace elements (nickel and copper). The quality of birch leaves increased with spring (May) temperatures, enabling Eriocrania larvae to achieve greater weight while consuming less biomass. During the larval growth period (early June to early July), Eriocrania larvae increased their consumption with rising temperatures, presumably to compensate for increased metabolic expenses. Contrary to our expectations, the per capita rate of population change did not correlate with larval weight and did not vary along the pollution gradient. Nevertheless, we detected interactive effects of pollution and climate on the rate of population change. This rate decreased with rising winter temperatures in slightly polluted and unpolluted sites but remained unchanged in heavily polluted sites. We conclude that pollution disrupts mechanisms regulating the natural population dynamics of Eriocrania moths.

Response of growth and physiological enzyme activities in Eriogyna pyretorum to various host plants.

Morphological attributes and chemical composition of host plants shape growth and development of phytophagous insects via influences on their behavior and physiological processes. This research delves into the relationship between Eriogyna pyretorum and various host plants through studuying how feeding on different host tree species affect growth, development, and physiological enzyme activities. We examined E. pyretorum response to three distinct host plants: Camphora officinarum, Liquidambar formosana and Pterocarya stenoptera. Notably, larvae feeding on C. officinarum and L. formosana displayed accelerated development, increased pupal length, and higher survival rates compared to those on P. stenoptera. This underlines the pivotal role of host plant selection in shaping the E. pyretorum's life cycle. The activities of a-amylase, lipase and protective enzymes were the highest in larvae fed on the most suitable host L. formosana which indicated that the increase of these enzyme activities was closely related to growth and development. Furthermore, our investigation revealed a relationship between enzymatic activities and host plants. Digestive enzymes, protective enzymes, and detoxifying enzymes exhibited substantial variations contingent upon the ingested host plant. Moreover, the total phenolics content in the host plant leaves manifested a noteworthy positive correlation with catalase and lipase activities. In contrast, a marked negative correlation emerged with glutathione S-transferase and α-amylase activities. The total developmental duration of larvae exhibited a significant positive correlation with the activities of GST and CarE. The survival rate of larvae showed a significant positive correlation with CYP450. These observations underscore the insect's remarkable adaptability in orchestrating metabolic processes in accordance with available nutritional resources. This study highlights the interplay between E. pyretorum and its host plants, offering novel insights into how different vegetation types influence growth, development, and physiological responses. These findings contribute to a deeper comprehension of insect-plant interactions, with potential applications in pest management and ecological conservation.