The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae), is a major global pest whose management increasingly relies on insect growth regulators (IGRs) to mitigate resistance to conventional insecticides. This study evaluated the sublethal and transgenerational effects of hexaflumuron-a benzoylurea IGR-on FAW through a 2-generation laboratory bioassay. Newly molted third instars were exposed to diet-incorporated hexaflumuron, yielding LC10 and LC25 values of 0.485 and 0.898 mg L-1, respectively. Sublethal exposure reduced F0 pupal mass and decreased adult longevity and fecundity. Age-stage, two-sex life-table analysis was conducted for the untreated F1 offspring only and showed dose-dependent demographic costs. Offspring of exposed parents exhibited prolonged development (egg-to-adult period: 30.64 to 40.26 d at LC25), shorter adult lifespans (females: 10.33 to 8.00 d; males: 8.22 to 6.72 d), and reduced lifetime fecundity (1058.6 to 829.3 eggs female-1). Key population parameters declined, including net reproductive rate (R0: 508.1 to 273.7 offspring), intrinsic rate of increase (r: 0.176 to 0.123 d-1), and finite rate of increase (λ: 1.193 to 1.131 d-1), while mean generation time increased (T: 35.4 to 45.5 d). These results show that low-lethal hexaflumuron exposure imposes lasting demographic costs on FAW populations and highlight the importance of incorporating sublethal and transgenerational endpoints when integrating benzoylurea IGRs into FAW integrated pest management and resistance management programs.

Binodoxys communis (Gahan) (Hymenoptera: Braconidae) is an aphid parasitoid capable of developing in a wide range of pest aphids. Currently, laboratory rearing of B. communis in China mainly depends on the cotton aphid Aphis gossypii Glover (Hemiptera: Aphididae)-cotton system. Although technically reliable, this method entails high labor demands, extensive space requirements, and overall elevated costs. To identify a more efficient aphid-plant combination for mass rearing of B. communis, we evaluated this parasitoid's developmental performance, population growth, and rearing cost-effectiveness on four aphid-plant combinations: A. gossypii-cotton (Ago-Cot), A. gossypii-zucchini (Ago-Zuc), bean aphid Aphis fabae Scopoli (Hemiptera: Aphididae)-faba bean (Afa-FB), and greenbug Schizaphis graminum (Rondani) (Hemiptera: Aphididae)-wheat (Sgr-W). The Afa-FB and Sgr-W combinations shortened the developmental time of B. communis from larva to adult. Analysis of age-stage, two-sex life table showed that female parasitoids reared on Afa-FB reached their peak reproductive value earlier and reproduced at a higher level than those reared on the other three combinations, indicating enhanced reproductive potential. Comparative evaluation of rearing cycles further revealed that parasitizing A. fabae reared on faba bean supported rapid and consistently high rates of mummy formation, along with the highest rate of parasitism (38.68 ± 0.69%), highlighting the strong parasitic potential of the Afa-FB combination. Moreover, cost analysis indicated that, compared with the other three combinations, Afa-FB produced the highest number of mummies and had the lowest total material and labor costs (9.18 USD per 10,000 mummies), offering economic advantages. In conclusion, the Afa-FB combination represents a promising approach for more efficient mass rearing of B. communis.

Modeling vaccine failures and behavioral change: Effects on disease transmission dynamics and thresholds.

Basic reproduction number of a deterministic and stochastic predator–prey model with novel fear functions

Dynamics of a tick-borne disease transmission model with acquired tick resistance.

The epidemiology of pathogens with pandemic potential: A review of key parameters and clustering analysis.

From wastewater to infection estimates: Incident COVID-19 infections during Omicron in the U.S.

Spatiotemporal dynamics of chikungunya transmission in Foshan City, China: a modelling analysis.

Evaluating mobility restrictions through spatiotemporal effective reproduction number analysis in a multi-patch model with complex mobility data.

Multigenerational exposure to the fungicide tebuconazole reveals hormetic effects on the demography and biology of a non-target vector mosquito Aedes albopictus.

Poor democratic governance continues to constrain sustainable national development in Nigeria; however, most existing studies rely on qualitative or econometric approaches that do not adequately capture the dynamic evolution of governance practices. This study develops a nonlinear compartmental dynamical model to examine the persistence of poor democratic governance and its implications for national development. The population is divided into politically apathetic citizens, participants in poor democratic practices, and advocates of good governance, while a national development index is introduced to explicitly link governance dynamics with development outcomes. Fundamental qualitative properties of the model, including positivity and boundedness of solutions, are established. A threshold parameter, the basic reproduction number R0, is derived and shown to determine whether poor governance dies out or persists. Stability analysis reveals that the poor governance-free equilibrium is globally asymptotically stable when R0< 1, whereas an endemic equilibrium exists and is globally stable when R0> 1. Numerical simulations based on Nigeria-informed baseline parameters drawn from published sources support the analytical results. Normalized sensitivity analysis identifies the transmission of poor governance behaviours and political recruitment as the strongest drivers of persistence, while reform, sanctions, and turnover exert stabilizing effects. The findings highlight the importance of preventive institutional reforms and sustained civic engagement for long-term national development.

Abstract Recent global epidemics have triggered widespread negative emotions such as anxiety, fear, and anger. Understanding the dynamics of epidemic-related fear has therefore become a crucial aspect of public health research. This study proposes a new social mathematical model to investigate the epidemic-related fear propagation dynamics within a population. In the model, people are divided into five psychological states based on their fear status and awareness level: susceptible, aware, exposed, fearful, and recovered. Additionally, fear propagates among exposed and fearful people through terrible news in the media. The basic reproduction number is calculated in association with exposed and fearful people and terrible news. The sensitivity of this threshold parameter is analyzed with respect to the model parameters. The local and global stability of the proposed fear propagation model is discussed at the fear-free and endemic equilibrium points. The model parameters are hypothesized based on existing studies on COVID-19 fear in Turkey, and numerical simulations are presented accordingly. The results show that fear propagation behavior is exacerbated by loss of awareness and direct interpersonal interaction with exposed and fearful people, as well as indirect contact with terrible news in media. Under the influence of fear, people are concentrated in the fearful compartment and interact with susceptible and aware compartments, affecting the overall behavior of fear propagation dynamics. These findings highlight the critical role of psychological factors, particularly fear, in shaping behavioral responses during epidemics and underscore the need for targeted public health interventions that address both direct interpersonal interaction and indirect media-influenced fear propagation.

This study established an optimized artificial diet rearing system for the fruit-boring pest Carposina sasakii Matsumura (Lepidoptera: Carposinidae), evaluating both rearing performance and economic feasibility. Three methodological refinements were implemented: (ⅰ) by transferring newly hatched larvae directly onto a fresh artificial diet rather than egg-bearing filter paper, (ⅱ) with individual rearing in separate tubes, and (ⅲ) by using standardized diet replacement protocol (initial change at day 7, followed by 5-d intervals). Three novel experimental diet formulations were developed: CP (a chemical preservative 2,4-Hexadienoic acid supplemented diet), FS (a feeding stimulant 3-Methylbutyl 3-methylbutanoate supplemented diet), and CPFS (a combined chemical preservative 2,4-Hexadienoic acid and feeding stimulant 3-Methylbutyl 3-methylbutanoate supplemented diet). The improved system's efficacy was evaluated through age-stage, two-sex life table analysis of reproductive, developmental, and population parameters. Cost-effectiveness was also assessed. Results demonstrated that populations reared using the refined process and CPFS diet achieved a significantly higher intrinsic rate of increase (r = 0.0854 ± 0.0039 d-1), finite rate of increase (λ = 1.0891 ± 0.0042 d-1), and net reproductive rate (R0 = 38.95 ± 6.10 eggs) compared to apple-reared cohorts (P < 0.05). Based on a daily 1,000 pupae harvest, the artificial rearing system reduced costs by 90.00%, achieving a daily cost of only 58.00 CNY compared to 564.52 CNY for the apple-based system. These advancements establish a robust platform for mass-rearing and facilitate diverse experimental applications for the economically significant pest species, C. sasakii.

Intraguild predation (IGP) regulates predator populations through direct predation and risk effects, shaping the life-history traits of intraguild prey. This study examines the impacts of IGP on life-history traits of two biocontrol agents, Neoseiulus barkeri and Scolothrips takahashii, reared on their shared prey Tetranychus urticae, using age-stage, two-sex life-table analysis and computer simulations. Life-table analysis revealed that IGP significantly reduced pre-adult survival of both predators. Neoseiulus barkeri developed faster, but exhibited reduced fecundity under IGP, which resulted in declines in its net reproductive rate (R0, from 30.76 to 10.51 offspring per individual), intrinsic rate of increase (r, from 0.2555 to 0.1872 day-1), and finite rate of increase (λ, from 1.2911 to 1.2059 day-1). Conversely, S. takahashii maintained stable development and fecundity, showing no significant differences in R0, r, λ and mean generation time (T) between IGP and control groups. The net predation rate (C0) of N. barkeri decreased from 381.00 to 172.97 prey per individual, and that of S. takahashii from 416.58 to 25.31, under IGP. Computer simulations indicated that IGP led to smaller populations and reduced predation potential for N. barkeri, whereas S. takahashii showed an increase in both. IGP differentially alters the population parameters and predation capacity of these two species. Neoseiulus barkeri experiences a decline in population growth, whereas S. takahashii benefits from IGP. These findings highlight species-specific adaptive strategies in response to IGP, providing insights for designing compatible multipredator application programs in biological control. © 2026 Society of Chemical Industry.

This study explores the role of mass testing in controlling the COVID-19 pandemic using an age-stratified compartmental model. The model evaluates the impact of different testing strategies on the pandemic's reproduction number, , while also considering social distancing measures and demographic characteristics. The analysis highlights the importance of combining mass testing with isolation strategies to reduce the spread of the virus. The simulations demonstrate that in countries characterized by high levels of elderly cohabitation with younger individuals, vertical isolation is insufficient; horizontal isolation with work restrictions, alongside testing and susceptibility reduction measures, is crucial. For aged developed countries, where cohabitation of the elderly with younger individuals is less prevalent, and for least developed countries, where the population has a predominantly youthful age structure, pandemic control is more feasible with fewer tests. The study also emphasizes the critical role of identifying asymptomatic cases to achieve optimal epidemic control. Lastly, the cost-effectiveness of various testing strategies is examined, providing insights for public health policy decision-making.

Abstract In many countries, the roll-out of the Covid-19 vaccines was accompanied by vaccine passports. In Sweden, anyone aged 18 or above was required to have taken two doses of an approved vaccine to visit any venues with a capacity of a hundred guests or more. This article compares Swedish 17- and 18-year-olds in difference-in-difference and event-study analyses. These indicate that the vaccine passports produced an effect that lasted around four or five weeks and led to at most approximately one per cent of unvaccinated 18-year-olds getting vaccinated. The vaccines were not sterilizing but plausibly lowered the reproductive value and thereby slowed the spread of the virus. However, with at most a negligible effect on take-up, there is little to recommend the vaccine passports.

In this work, we provide a spatiotemporally heterogeneous diffusive SIS epidemic model. A generalized nonlinear incidence function of the type f ( t , x , S , I ) is under consideration. Our analysis is split into two different cases, (i) the disease-induced death is positive, (ii) there is no illness-induced death. For the first case, we obtain that the total size of the population is nonconstant, the susceptible population will eventually tend to either a zero or a positive constant, and the disease will always be extinct. For the second case, we obtain that the total size of the population is constant. Assuming that the model's coefficients functionals are time-periodic and spatially heterogeneous, we show that this model has threshold dynamics with the well-known threshold parameter R 0 , the basic reproduction number. For some natural assumptions on the nonlinear incidence, and the model's coefficients, we demonstrate the global attractivity of the infection-free steady state by building suitable Lyapunov functions or by comparison principle when R 0 < 1 . Furthermore, when 1 $ ]]> R 0 > 1 , we prove that the associated semiflow to the model is strongly uniformly persistent.

Respiratory syncytial virus (RSV) is a single-stranded RNA virus responsible for a wide range of respiratory tract infections, including those affecting the lungs, airways, and middle ear. Understanding its transmission dynamics remains essential for effective disease control. A bio-inspired stochastic delay model for RSV transmission is proposed and analyzed. The model's qualitative properties including positivity, boundedness, equilibrium states, and the basic reproduction number are rigorously established through well-posedness theorems. Parameter sensitivity is also examined. To investigate the system's stochastic behavior, numerical schemes such as Stochastic Euler, Runge-Kutta, and Euler-Maruyama methods are applied. However, these traditional approaches fail to fully preserve the dynamic characteristics of the model. To address these limitations, a stochastic nonstandard finite difference (NSFD) scheme with delay is developed. This approach ensures non-negativity, boundedness, consistency, and unconditional convergence, overcoming issues of instability and divergence often observed in standard stochastic numerical methods. Comparative simulations demonstrate that the NSFD method reliably reproduces the true dynamic states of the model. The proposed stochastic delayed modeling framework enhances our understanding of RSV dynamics and provides a stable computational tool for analyzing complex biological systems. The findings open new avenues for exploring nonlinear stochastic processes in epidemiological and neurobiological modeling.

ABSTRACT This study investigates male pedipalp chela dimorphism and its association with reproductive behaviour in the litter-dwelling scorpion, Tityus pusillus. Using geometric morphometrics, two distinct male morphotypes were identified based on pedipalp chela shape: robust and gracile. These morphotypes were associated with measurable variation in courtship behaviour aspects. Males with robust chelae performed a higher number of reproductive attempts and female manipulations than gracile-chela males, although these differences were not statistically significant. Notably, robust-chela males completed courtship significantly faster than gracile-chelae males (8.03 ± 5.14 minutes vs. 18.40 ± 13.84 minutes), measured as the time until mating successful conclusion. Both morphotypes exhibited similar reproductive success rates (37% and 31%, respectively). These results indicate that robust and gracile differ in courtship dynamics, particularly in courtship duration and patterns of female handling. Variation in female resistance during courtship may help explain why male reproductive behaviours vary. This study documents male chela dimorphism in T. pusillus and reports its correlation with variation in courtship behaviour.

Brucellosis presents a severe challenge to public health due to its complex transmission mechanism. In China, regions are categorized into three types based on the number of new human brucellosis cases or provinces affected by animal outbreaks, with tailored control strategies adopted accordingly. Currently, most research on brucellosis transmission modeling focuses on Type I regions. However, due to regional variations in farming practices, influencing factors, and control measures, existing studies are highly region-specific, restricting their direct application to Type II regions such as Zhejiang Province. Notably, annual brucellosis outbreaks in Zhejiang Province are worsening, highlighting the need for targeted research. In this study, a non-autonomous patch dynamical model was developed for Zhejiang Province, incorporating the "live sheep - mutton - human" transmission chain. The effective reproduction number was defined to calculate infection metrics for pathogen transmission in three pathways: sheep-to-sheep, sheep-to-human, and mutton-to-human. Multi-source data, including demographics, livestock farming, and meat transportation data from 2018 to 2024, were integrated. Key drivers of brucellosis transmission were explored through parameter estimation, sensitivity analysis, and multi-scenario numerical simulations. The findings indicated a significant positive correlation between the number of live sheep imported from Region I and human brucellosis incidence rates, suggesting that imported infections have become the primary challenge for brucellosis control in Zhejiang Province. The baseline projected incidence in Zhejiang Province is expected to remain 0.3 per 100,000 by 2026 under current interventions. A 71.4% increase in human incidence (peaking at 0.6 per 100,000) in 2025 would occur if live sheep imports from other provinces were doubled, underscoring the risk of external introduction. Conversely, enhancing transport detection by 15% could reduce incidence below 0.2 per 100,000, while an integrated strategy combining improved culling, transport detection, and consumption monitoring could lower incidence to 0.1 per 100,000, representing a 66.7% reduction. Similarly, reducing both live sheep and mutton imports by 50% would decrease incidence by 40%, preventing an estimated 91 infections. Furthermore, improving comprehensive protection awareness by 50% is projected to reduce incidence to below 0.15 per 100,000, corresponding to a 53.3% decrease by 2026. Under non-immunization intervention scenarios, surveillance gaps in the farming-transportation-consumption chains could lead to a significant expansion of the epidemic. Implementing an integrated strategy combining source quarantine (testing imported live sheep), process control (regular monitoring of farming environments), and end-point protection (personal protective measures) was found to substantially reduce incidence rates within two years. The results of this study suggest that strengthening the monitoring of the inter-provincial live animal transportation surveillance network is crucial, as it can facilitate early warning of brucellosis transmission risks. This highlights the importance of targeted measures to address imported infections and enhance surveillance across the entire transmission chain for effective brucellosis control in Type II regions like Zhejiang Province.