Search Results (73)

Under the background of global climate change, frequent drought events have significantly impacted plant–insect interaction. This study focuses on Ficus microcarpa, an important landscaping and urban greening tree species in tropical and subtropical regions, and its primary herbivorous pest, Perina nuda, by applying the age-stage, two-sex life table theory to systematically evaluate the effects on the life history traits and population dynamics of P. nuda reared on F. microcarpa subjected to different levels of drought stress. The results demonstrated that reared on drought-stressed F. microcarpa significantly altered multiple life history traits of P. nuda. All drought treatments significantly shortened the larval development period. Under both light and severe drought conditions, adult lifespan was prolonged, the total pre-oviposition period was reduced, fecundity per female increased, and generation time (T) was shortened. However, significant increases in pupal weight, intrinsic rate of increase (r), and finite rate of increase (λ) were observed only under light drought stress. The population prediction results indicate that both light and severe drought stress lead to obviously higher population growth rates and larger population sizes at 200 days compared to the control group. These findings suggest that the population fitness of P. nuda is enhanced under light and severe drought stress, potentially increasing the probability of pest outbreaks. This study provides an important theoretical basis and practical advice on forecasting population dynamics and implementing integrated management strategies for P. nuda in the context of climate change. Full article

The South American tomato leaf miner, Tuta absoluta (Meyrick, 1917) (Syn.: Phthorimaea absoluta), is a pest of great economic importance worldwide. Although T. absoluta shows a strong preference for tomato, it can also attack potato, eggplant, and various wild solanaceous plants, thereby posing new challenges for pest control. To assess the adaptability of this pest to different potato varieties, an age-stage, two-sex life table method was used to determine the development, survival, reproduction, and key population parameters of the pest on six common potato varieties (Hezuo No. 88, Lishu No. 6, Weiyu No. 3, Zhongshu No. 5, Qingshu No. 9, and Qingshu No. 10) in China. The results showed that T. absoluta could complete its entire life cycle on all cultivars. However, key life history parameters varied significantly. On cultivars Qingshu No. 9 and Qingshu No. 10, the pest exhibited significantly prolonged preadult duration and total pre-oviposition period (TPOP), as well as reduced adult fecundity. In contrast, Hezuo No. 88 supported the highest intrinsic rate of increase (r) and net reproductive rate (R₀). The 60-day population projections further highlighted this contrast, showing that the T. absoluta population on Hezuo No. 88 increased by a factor of 4.26 and 3.52 times compared to that on Qingshu No. 9 and Qingshu No. 10, respectively. We conclude that cultivars Qingshu No. 9 and Qingshu No. 10 exhibit antibiosis resistance against T. absoluta. This study not only provides a theoretical foundation and candidate materials for breeding pest-resistant potato varieties, but also establishes a basis for IPM strategies against T. absoluta that are founded on host resistance. Full article

The tomato leaf miner, Tuta absoluta, is a major pest affecting economically important crops like tomatoes, causing significant global economic losses and exhibiting increasing resistance to pesticides. The sterile insect technique (SIT) is an environmentally friendly control method that is sustainable for both ecosystems and human health. This study used age-stage, two-sex life tables, transcriptomics, and bioinformatics to analyze how irradiation affects the reproductive capacity of male T. absoluta. Compared to the control group, the irradiated offspring showed reduced total lifespan, pre-adult survival rate, net reproductive rate, and intrinsic growth rate. Transcriptomic analysis identified 232 differentially expressed genes (DEGs). GO and KEGG enrichment analyses revealed that irradiation impacted biological processes in male adults related to key biomolecules, hormone metabolism and synthesis, and immune responses. Of the 14 selected genes validated through RT-qPCR, 13 were identified as potential regulators of male reproductive capacity, offering possible targets for controlling T. absoluta using inherited sterility-based SIT strategies. Overall, this study provides a theoretical basis for applying SIT in field control and identifies potential genetic targets for managing T. absoluta populations through a genetic sterile insect technique. Full article

The cotton aphid, Aphis gossypii Glover, is among the most economically significant sap-sucking insect pests, inflicting substantial economic losses worldwide. Insecticides such as thiamethoxam, bifenthrin, and flonicamid are commonly used to manage this pest, despite the inherent risk of developing resistance. In this study, we investigated the evolution of insecticide resistance in A. gossypii after continuous selection with thiamethoxam, bifenthrin, and flonicamid over more than ten generations in a controlled laboratory environment. We assessed the fitness of resistant strains using an age-stage, two-sex life table approach, comparing them to a susceptible population. The results indicated that A. gossypii achieved resistance levels of 158.60-fold against thiamethoxam, 129.18-fold against bifenthrin, and 104.75-fold against flonicamid. Furthermore, life table analyses revealed that the developmental stages were significantly extended, while longevity decreased in all resistant strains compared to the susceptible population. Additionally, the net reproductive rate (R₀), fecundity, and reproductive days were notably reduced in the resistant cohorts when compared to the susceptible strain. Overall, these findings provide valuable insights into the laboratory-induced evolution of insecticide resistance and the associated fitness costs in A. gossypii when feeding on cotton plants. This information could be instrumental in formulating effective resistance management strategies to control this significant pest. Full article

The Tuta absoluta species represents a significant threat to solanaceous crops globally and has developed resistance to conventional synthetic insecticides. This study investigated the insecticidal properties of essential oils (EOs) from Melaleuca alternifolia and Eucalyptus staigeriana against T. absoluta using the age-stage, two-sex life table methodology. Initially, the EOs of M. alternifolia and E. staigeriana were chemically characterized by gas chromatography (GC) techniques. In this analysis, we identified 19 compounds in M. alternifolia essential oil, with terpinen-4-ol, γ-terpinene, and α-terpinene as the predominant constituents. Eucalyptus staigeriana essential oil contained 25 identified compounds, predominantly limonene, terpinolene, geranial, and neral. Essential oils were dissolved in acetone and applied topically to larval stages. Both treatments significantly reduced pest longevity and adversely affected key demographic parameters. Melaleuca alternifolia treatment resulted in a substantial decrease in the intrinsic rate of population increase, indicating potential for population suppression. These findings support the potential application of M. alternifolia and E. staigeriana EOs as biological control agents against T. absoluta in integrated pest management programs. Full article

Carbon nanotubes are promising in agriculture for improving crop resilience and delivering agrochemicals. However, their effects on insect pests, especially chewing pests such as the fall armyworm (Spodoptera frugiperda), remain underexplored. In this study, we investigated how two types of functionalized multi-walled carbon nanotubes—hydroxylated (MWCNTs-OH) and carboxylated (MWCNTs-COOH), both obtained from Jiangsu Xianfeng Nano (Nanjing, China)—affect the pest’s development and reproduction. Using an age-stage two-sex life table approach, we fed larvae diets containing 0.04, 0.4, or 4 mg/g of these nanomaterials. Both types of MWCNTs exhibited concentration-dependent inhibitory effects. At the highest dose (4 mg/g), larval development was significantly prolonged, adult pre-oviposition periods increased, and fecundity (egg production) sharply declined, especially with MWCNTs-OH. Population growth parameters were also suppressed: net reproductive rate (R₀), intrinsic rate of increase (r), and finite rate of increase (λ) were reduced at 4 mg/g, particularly with MWCNTs-OH, while mean generation time (T) was extended with MWCNTs-COOH. Overall, MWCNTs-OH demonstrated a greater inhibitory impact compared to MWCNTs-COOH. These findings suggest that functionalized MWCNTs could serve as potential novel pest control agents against S. frugiperda by impeding its development and reproduction. Full article

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

Phthorimaea absoluta, an important pest of tomato crops, has reportedly developed high levels of resistance to the insecticide chlorantraniliprole, which has a unique mode of action and high efficacy. This study evaluated the sustained multigenerational effects of chlorantraniliprole on P. absoluta, focusing on resistance development, growth, development, reproductive capacity, population parameters, and nutritional indicators. After continuous selection with sublethal chlorantraniliprole for eight generations (CX-Sub₈), bioassays showed that CX-Sub₈ had 225.37-fold higher resistance than the susceptible strain. The age-stage, two-sex life table analysis revealed that the preadult development time and mean generation time were significantly prolonged, while population reproduction and pupal weight were reduced. Moreover, the relative fitness of CX-Sub₈ was 0.62, and changes in the life table parameters correlated with an increase in the serial number of selection cycles. The second-instar larvae of CX-Sub₈ presented lower triglyceride, glycerol, trehalose, free fatty acid, and protein contents than the unselected strain (CX-S₈). Transcriptome analysis identified 2517 differentially expressed genes, with most being enriched in nutrient metabolism-related pathways, such as amino acid biosynthesis and fatty acid degradation metabolism. These results indicate that multigenerational sublethal chlorantraniliprole treatment disrupts the nutritional metabolism, and inhibits the growth, development, and reproduction of P. absoluta. Full article

Frankliniella intonsa (Thysanoptera: Thripidae) is a polyphagous pest that causes significant economic agricultural losses by damaging flowers, vegetables, and fruit trees. We performed an age-stage two-sex life table analysis to evaluate the performance and adaptability of F. intonsa against nine common vegetable crops cultivated in Guangxi: cowpea (Vigna unguiculata) (Fabales: Leguminosae), green beans (Phaseolus vulgaris) (Fabales: Leguminosae), soybean (Glycine max) (Fabales: Leguminosae), catjang cowpea (Vigna cylindrica) (Fabales: Leguminosae), courgette (Cucurbita pepo) (Cucurbitales: Cucurbitaceae), wax gourd (Benincasa hispida) (Cucurbitales: Cucurbitaceae), bitter gourd (Momordica charantia) (Cucurbitales: Cucurbitaceae), cucumber (Cucumis sativus) (Cucurbitales: Cucurbitaceae), and chieh-qua (Benincasa hispida) (Cucurbitales: Cucurbitaceae). Among the tested host crops, green beans, cowpea, and courgette significantly accelerated the growth rate and favored the reproductive success of F. intonsa. Green beans, cowpea, and courgette facilitated rapid growth and reproductive success. The mean generation times (T) and net reproductive rates (R₀) were as follows: 14.90 d, 17.09 d, 21.03 d, and 104.04, 45.51, 32.61. Bitter gourd and chieh-qua significantly suppressed population growth (T: 49.49 d, 0 d; R₀: 0.73, 0). Wax gourd, catjang cowpea, cucumber, and soybean exhibited moderate effects characterized by delayed development and lower reproductive output (T: 22.30 d, 20.30 d, 19.51 d, 32.73 d; R₀: 7.17, 25.22, 13.74, and 12.54). These findings highlight the critical role of crop type in F. intonsa population dynamics. Therefore, the agricultural production of green beans, cowpea, and courgette crops necessitates improved control measures and monitoring. Similar measures are needed for cucumber, catjang cowpea, soybeans, and wax gourds because they pose risks as potential hosts. Full article

This study aims to determine the local host plant range for Yuanjiang River Valley Danaus genutia (Cramer, 1779) and evaluate the effects of different host plants on its growth, development, and reproductive success. This research assesses adult oviposition preferences and larval feeding tendencies on various host plants. An age-stage, two-sex life table was constructed to analyze the butterfly’s growth, development, reproductive success, survival rates, and other physiological aspects on different host plants. Population dynamics over the next 60 days were simulated to offer a comprehensive evaluation of the host plant suitability for D. genutia. The results indicated that D. genutia adults preferred laying eggs on Cynanchum corymbosum, followed by C. annularium, C. rostellatum, and Asclepias curassavica, with very few eggs laid on Calotropis gigantea and Dregea volubilis. Larval feeding preferences were observed in the order of C. annularium > C. corymbosum > C. rostellatum, with A. curassavica consumed only by first-instar larvae, while C. gigantea and D. volubilis were avoided. Under identical room temperature conditions, larvae feeding on C. annularium and C. corymbosum completed a full generation. Larvae feeding on C. annularium exhibited shorter developmental periods and higher early survival rates compared to those feeding on C. corymbosum, with no significant differences in adult longevity, sex ratio, or number of eggs per female. Female adults did not die immediately after laying eggs. No significant differences in the intrinsic rate of increase (r), finite rate of increase (λ), net reproduction rate (R₀), or doubling time (T_d) were found between populations feeding on the two host plants. However, the gross reproductive rate (GRR) and mean generation time (T) were significantly lower in the population feeding on C. corymbosum. These results confirm C. annularium and C. corymbosum as host plants for D. genutia larvae and provide a theoretical and scientific basis for the conservation of the Yuanjiang River Valley D. genutia population. Full article

The tomato leafminer, Tuta absoluta, is a destructive invasive tomato pest worldwide. Bacillus amyloliquefaciens W10, a bacterium isolated from the rhizosphere of tomatoes, is classified as a plant growth-promoting rhizobacterium. However, whether B. amyloliquefaciens W10 can improve the resistance of tomato against T. absoluta remains unclear. In this study, we found that B. amyloliquefaciens W10 promoted the tomato growth and significantly reduced the fecundity of T. absoluta. To further evaluate the effects of B. amyloliquefaciens W10 on the tomato’s resistance to T. absoluta, the age-stage, two-sex life table, and oviposition preference test were carried out to investigate the individual fitness, population parameters, and preference behavior of T. absoluta. Compared to the control, the intrinsic rate of increase (r_m), net reproductive rate (R₀), and finite rate of increase (λ) of T. absoluta in the treatment group were significantly reduced, while the population doubling time (DT) was significantly increased. Meanwhile, the oviposition preferences of T. absoluta for the treated tomato plants were reduced. After T. absoluta infestation, electrical conductivity and hydrogen peroxide (H₂O₂) content in tomato leaves after B. amyloliquefaciens W10 treatment were significantly lower than those in the control, while peroxidase (POD), polyphenol oxidase (PPO), jasmonic acid (JA), and salicylic acid (SA) levels were significantly higher. In addition, the O₂⁻, superoxide dismutase (SOD), and catalase (CAT) levels were also affected. qRT-RCR analyses revealed that B. amyloliquefaciens W10 colonization induced the expressions of JA- and SA-related genes, including AOS1, AOC, PAL1, and SAMT, in tomato plants after T. absoluta infestation. These findings provide valuable insights and theoretical support for the application of beneficial endophytes to induce the resistance in tomatoes against T. absoluta. Full article

Life tables are indispensable in IPM, offering an analysis of insect population dynamics. These tables record survival rates, fecundity, and other parameters at various developmental stages, enabling the identification of key factors that affect population numbers and the prediction of growth trajectories. This review discusses the application of life tables in agricultural pest management, including the assessment of the pest control capacity of natural enemies, the evaluation of biological agents, and the screening of insect-resistant plant species. In vector insect control, life tables are used to evaluate the transmission risks, model the population dynamics, and interfere with the life cycles of vector insects. For invasive pests, life tables help us to monitor population dynamics and predict future population sizes. In chemical pest control, life tables assist in evaluating the fitness costs of pesticide resistance, guiding insecticide selection, and optimizing application timing. In the final section, we explore future research directions, emphasizing the potential of integrating new technologies such as genomics, ethology, and satellite remote sensing to enhance life table analysis and improve IPM strategies. Full article

Bactrocera latifrons (Hendel) is a serious pest requiring quarantine in many countries worldwide. It has caused huge economic losses to the cultivation of solanaceous plants, such as peppers and eggplants. In this study, we constructed an age-stage, two-sex life table using eggplant as the host to clarify the occurrence and damage patterns of B. latifrons on this crop for better field prevention and control in the laboratory. The results showed that the egg, larval, and pupal stages lasted 4.3, 11.3, and 9.3 days, respectively. The average lifespan of adult females and males was 101 and 102 days, respectively. The egg hatching rate, larval survival rate, and pupal emergence rate were 96%, 88%, and 84%, respectively. The average generation time was 43.96 days, with an intrinsic rate of increase of 0.097 d⁻¹ and a net reproductive rate of 73.4. We established the life table based on group rearing. The research findings provide essential data for rearing B. latifrons in the laboratory, offer a reference for the dynamic prediction of field population dynamics, and offer a theoretical foundation for developing pest control strategies for B. latifrons. Full article

Cadmium in agricultural soils has emerged as a substantial threat to crop health and yields through its bioaccumulation along the food chain, with further repercussions for the growth, development, and population dynamics of herbivorous insects. In this study, potted potato plants were treated with Cd²⁺ solutions at concentrations of 0 mg/kg, 30 mg/kg, 60 mg/kg, 90 mg/kg, and 120 mg/kg. Colorado potato beetles (Leptinotarsa decemlineata) were fed on potato leaves exposed to these varying concentrations of cadmium, and the effects on their growth and development were assessed. The results revealed that: 1. The developmental period, pupal stage, and pre-oviposition period of the first-instar larvae of L. decemlineata feeding on cadmium-contaminated leaves was significantly prolonged, while both the lifespan and fecundity were reduced. 2. Key population parameters, including the innate rate of increase (r), finite rate of increase (λ), net reproductive rate (R₀), and gross reproduction rate (GRR), were evidently lower in cadmium-exposed L. decemlineata, while the average generation time did not show a significant difference. 3. Cadmium exposure also resulted in a remarkable reduction in survival and reproductive rates at specific life stages, along with an increase in the incidence of deformations in newly emerged adults. These findings underscore the detrimental effects of cadmium on both crop health and pest populations. This study holds valuable implications for more effective implementation of pest control strategies in the future, offering robust scientific evidence to support the safeguarding of food security. Full article

Exogenous plant hormones regulate the agronomic and physiological performance of plants and thus can influence the abundance of insect groups. We surveyed the arthropods on flowering plants Cnidium monnieri and found that the abundance of natural enemies Propylaea japonica and Orius minutus in the plots treated with salicylic acid (SA) and indole acetic acid (IAA) was significantly increased compared with those in the clean water (control) plots. Then, we investigated the effects of spraying SA, IAA, and clean water on the population parameters of Semiaphis heraclei reared on C. monnieri. Our results from the age-stage, two-sex life table analysis revealed a significantly shorter pre-adult duration for aphids reared on SA-treated C. monnieri compared to those reared on the other two treatments. The intrinsic rate of increase, finite rate of increase, and net reproductive rate of aphids reared on SA- and IAA-treated C. monnieri were significantly higher than those of aphids reared on clean water-treated C. monnieri. The fecundity rate was higher under the SA and IAA treatments than in the control, but the difference was not significant. This improved the ability of flowering plants to attract natural enemies by providing a larger food source. Full article