Purpose The purpose of this study is to investigate the competitive dynamics between cattle and invertebrates for grass biomass in a grassland ecosystem using a fractional-order nonlinear mathematical model. Design/methodology/approach A fractional-order grassland competition model is formulated using the Caputo fractional derivative of order ρ ∈ (0, 1]. The qualitative behavior of the system is analyzed by establishing the non-negativity and boundedness of solutions, followed by a stability analysis of the equilibrium points. Numerical simulations are performed using a generalized fractional Runge–Kutta second-order (RK2) scheme to examine the influence of fractional orders and interspecific competition parameters on system dynamics. Findings The results demonstrate that the proposed model admits biologically feasible solutions that remain non-negative and bounded. Stability analysis reveals that fractional-order dynamics significantly affect the equilibrium behavior of the system. Numerical simulations show that varying the fractional order and competition coefficients leads to substantial changes in grass biomass and population dynamics. In particular, fractional-order models exhibit enhanced stability and reduced oscillatory behavior compared to classical integer-order models. Originality/value This study provides a novel fractional-order framework for modeling grassland competition involving cattle and invertebrates. The findings highlight the advantages of fractional-order models in capturing memory effects and improving stability characteristics, offering valuable insights for ecological modeling and sustainable grassland management.

Pulses of plant resources can influence the spatial aggregation and population dynamics of primary consumers, but the extent to which these effects cascade up the food chain to affect secondary consumers remains poorly understood. Mast fruiting events in Southeast Asian dipterocarp forests, for example, are known to impact a wide range of bird and mammal granivores, but it remains unclear whether the predators of these vertebrates are indirectly affected by seed production. Here, we assess bottom-up effects of masting on a suite of primary and secondary consumers in a tropical rainforest in Borneo, using structural equation models to characterize a network of frugivore/granivores and carnivores. The models were parameterized using 10years of camera trap and seed availability data collected between 2013 and 2024, spanning two major masting events. These models also account for an outbreak of introduced disease (African swine fever) and the reduced abundance of human visitors in the forest during the COVID-19 pandemic. Dipterocarp seed availability was correlated with the intensity of local site use by omnivorous Malay civets (Viverra tangalunga) and bearded pigs (Sus barbatus), but not granivorous murid rodents or pheasants. Leopard cat site use was correlated with murid rodents, but not pheasants. These findings suggest that masting in this ecosystem is associated with site use intensity of some large-bodied primary consumers but not smaller granivores, and therefore did not percolate up the food web to influence the predators of these taxa, in contrast to research from temperate masting systems.

Since 1990, Mediterranean striped dolphins, Stenella coeruleoalba, have suffered two mass mortality events caused by the dolphin morbillivirus (DMV), but the population-level impact is unknown because abundance estimates are spatio-temporally sparse. This study investigates whether data from epibionts of striped dolphins-the barnacle Xenobalanus globicipitis, the cyamid Syncyamus aequus, and the copepod Pennella balaenoptera, with different life cycles and degrees of specificity-could provide indirect evidence on host population dynamics. To address this question, we combined empirical and theoretical approaches. First, we used Generalized Additive Models (GAMs) to examine occurrence trends of the three epibiotic species over the period 1980-2023 for both striped dolphins and other sympatric cetacean species that did not suffer DMV outbreaks. Second, we developed a two-step theoretical modeling approach to investigate the epidemiology of these DMV outbreaks (SIR model) and to link dolphin population abundance shifts with the epibiont trends observed empirically (mechanistic model). The SIR model provided coarse estimates of the impact of DMV on the striped dolphin population under two scenarios with varying virus-induced mortality and duration of the infectious period. These estimates were then used to simulate the effect of dolphin population shifts on its epibionts through mechanistic models. Models indicated that DMV-induced shifts in striped dolphin population dynamics have cascading effects on the population abundance of X. globicipitis and S. aequus, whereas the population of the less host-specific P. balaenoptera was unaffected. Together, long-term trends in the occurrence of host-specific epibionts can serve as an indicator of host abundance shifts.

Given its ecological and socioeconomic importance, the Atlantic tomcod (Microgadus tomcod (Walbaum, 1792)) population of the St. Lawrence estuarine transition zone is the focus of conservation efforts and requires a better understanding of its population dynamics. Here, we use otolith microchemistry to define the structure of the St. Lawrence tomcod estuarine population and identify the key contributing spawning grounds. We rely on two sampling surveys, otolith microchemistry data, and machine-learning approaches to identify two main sources contributing to the tomcod stock recruitment. The main source contributed approximately two-thirds of the recruitment, whereas the second source accounted for the residual third. Both sources exhibited distinct temporal and spatial habitat use in the St. Lawrence estuarine transition zone, highlighting questions regarding the presence of multiple stocks within the population. Our findings emphasize the importance of identifying the main contributing natal sites to fish stock recruitment when implementing effective management plans in the context of increased environmental change and human activities affecting aquatic ecosystems.

Abstract Crown-of-thorns starfish (COTS) are a leading cause of coral decline on the Great Barrier Reef (GBR), with the majority of their impact occurring during outbreaks. These outbreaks involve rapid increases in populations followed by abrupt declines, and spread between reefs via larval dispersal—a key process in COTS reproduction. Given the difficulty in quantifying dispersal empirically, predictions are instead formed using coupled models of ocean currents and larval biology. Previous efforts have linked dispersal models to COTS population dynamics, however do so indirectly, or at spatiotemporally limited scales. Using an improved set of dispersal estimates and expanded COTS monitoring data, we assess the role of dispersal in determining a reef’s susceptibility to outbreaks. Our results indicate that while there is minimal evidence that dispersal patterns alone drive outbreaks, once combined with COTS population data it becomes clear that dispersal still plays a major role. By predicting COTS populations on undersampled reefs, we estimate that, on average, reefs that have experienced an outbreak receive 50–100% more larvae than those that have not. This is irrespective of whether we assume reefs hold their long-term predicted average COTS abundance, or their predicted maximum abundance. Given the difficulty in directly validating dispersal models, these results provide evidence that highlights their utility in understanding marine population dynamics. Furthermore, our results emphasise the critical role of resolving dispersal networks in guiding COTS control efforts. Specifically, they indicate that suppressing larval production through culling may reduce the risk of outbreaks on downstream reefs connected via larval dispersal.

Human papillomavirus remains a leading cause of cervical cancer globally, particularly affecting women in low- and middle-income countries. A gender-stratified deterministic compartmental model is formulated to assess the impact of HPV vaccination on cervical cancer dynamics in a heterosexual population. The model stratifies individuals into vaccinated, exposed, infectious, cancer, treated, and recovered compartments, and simulations are conducted using epidemiological data from Poland. Results show that the basic reproduction number is greater than one under current epidemiological HPV vaccination policy, resulting in persistent transmission, but reduces below unity when male vaccination coverage is included and expanded. The disease-free equilibrium becomes stable under these enhanced coverage levels, and a forward bifurcation is observed, confirming that elimination can be achieved without complex threshold behavior. Sensitivity analysis identifies transmission rates, vaccine efficacy, and male vaccination rates as the parameters most strongly influencing HPV spread. The findings demonstrate that including males in national HPV immunization programs substantially enhances the reduction of secondary infections and accelerates progress toward disease elimination.

Abstract The population of vibrational levels of the N2 gas molecules in the conditions of low-pressure and low-temperature plasma induced by an external microwave electric field was investigated. The calculations were performed by using an extended Monte-Carlo simulation of electron transport through the N2 molecule gas. The simulation included processes of electron-molecule elastic scattering, electron impact vibrational excitation, electronic excitation, dissociation and ionization of the N2 molecules. The electron-molecule super elastic scattering and de-excitations of excited molecular vibrational levels were also included. The algorithm tracks the dynamic balance between electron impact vibrational excitation and de-excitation processes on the N2 gas ensemble. The processes of vibrational population redistribution and relaxation, induced by the gas molecule-molecule collisions, are also included in the simulation. This is achieved through the Kinetic Module of algorithm by solving master balance equations at every simulation step. All these simulated processes jointly change the states both the molecular and the electronic ensembles, and self-consistently evolve to a dynamic equilibrium state. In this way, a new self-consistent method of simulation is developed. The investigation was conducted in the conditions of the low-pressure and low-temperature plasma at the N2 gas temperature of 300 K, when the gas collision vibrational population redistribution is a concurrent process to the electron impact vibrational population. The calculations for temporal development and the dynamic equilibrium vibrational level populations were performed for the standard microwave frequency value of 2.45 GHz, at effective reduced electric field (E/N) values from 40 Td to 70 Td. The study also includes vibrational level populations in the conditions of various ratios of electron concentration to gas density. In addition, an orthogonal magnetic field to microwave electric field was included in the simulation in order to investigate the vibrational level population at the region of electron cyclotron resonance.

Bemisia tabaci is a cosmopolitan pest affecting a wide range of crops including but not limited to horticultural and ornamental crops. Damage is caused through direct feeding on the phloem sap of host crops thereby inducing physiological disorders and serving as vector causing viral diseases in insect population. Both forms of damage have direct consequences on crop production, productivity leading to drastic reduction of economic values of the crops . Management of B. tabaci in Sierra Leone has been dominated by the use of broad-spectrum chemical pesticides, though having the intrinsic feature of reducing the pest population below the economic injury level, yet their usages are associated with adverse effects on the environment, non-targets organisms and development of resistant genes in insects . Equally important, cost and affordability of pesticides for large scale applications are being considered constant economic burden to smallholder farmers. These challenges have prompted to seek alternative substitutes to broad-spectrum chemical pesticides, with a paradigm shift of the use of plant derived bio-active ingredients significant from plants and fungi serving as bio-pesticides. These bio-pesticides have proven to be quite useful in managing sap sucking insects like B. tabaci though their abilities have not been fully exploited in under Sierra Leonean circumstance . This investigation aimed at determining the impact of bio-active ingredients of Neem and Papaya on the reproduction and development of B. tabaci under controlled laboratory conditions. Concentrations of the active ingredients of A. papaya and A.indica were prepared and serially diluted at different concentrations and assayed against eggs and developmental stages of B. tabaci in bioassay cages and maintained under controlled laboratory conditions of 25±2OC and photoperiodism of 12:12 (L:D). No significant impact % hatchability (p=0.0001) as > 60% of eggs hatched into crawlers, however larval mortality was dose-dependent, larval mortality was significantly impacted and varied with age of immature in the order 2nd instars >3rd instars > pupa at (P<0.0.001). LT50 values varied across developmental stage, 2nd instars required 2.54 and 4.3 days to inflict 50% mortality in population treated with Neem and Papaya respectively. Larval mortality was dose-dependent with mortality proportionally increasing with increased in concentration of the active ingredients. The LC50 values strongly correlated with developmental stage and concentration in the order 2nd instars <3rd instars < pupa for neem and papaya extracts respectively. Moreover, the extracts impacted the population dynamics of B. tabaci as the population parameters were significantly influenced by the toxicity of the extracts suppressing the growth and population parameters as compared to the control. Comparatively, the neem extracts significantly impacted the demographic parameters Ro, ƛ, rm 13.66, 1.103, 0.018 as compared to A. papaya extract 18.97, 1.106 0.101 and control 23.56 1.130 , 0.123 respectively . The importance and potentials of A. indica and A. papaya as effective bio-pesticides for sustainable management B. tabaci were well highlighted and discussed.

Abstract Hierarchical occupancy and abundance models (HOAMs) have become a leading approach for inferring wildlife population dynamics because they explicitly account for imperfect detection. HOAMs are suitable for sampling approaches that produce detection histories from repeated visits to the same sites, including direct observations (e.g. bird point counts), indirect observations (e.g. tracks, dung) and remote and passive sensors (e.g. camera traps, acoustic recorders). Wildlife often exhibits non‐linear temporal trends or threshold‐like responses to environmental conditions. However, traditional HOAMs address non‐linearity crudely using global polynomial functions, despite well‐documented limitations. Generalised additive models (GAMs) provide a more flexible approach to non‐linearity, allowing smooth data‐driven estimation through basis functions and penalised splines. Yet, GAMs have remained sparsely adopted in hierarchical occupancy modelling, in part due to the need for custom code in Bayesian modelling languages. We demonstrate the applicability of GAMs within the occupancy and abundance modelling framework (hereafter ‘OccuGAMs’) by comparing traditional HOAMs with polynomials to OccuGAMs. In simulations, OccuGAMs recovered non‐linear relationships more accurately and more often, scoring better on energy and variogram metrics and produced more stable responses at smaller sample sizes. Polynomials performed well in some scenarios but were less generalisable, making OccuGAMs the more robust overall choice, especially when there is no a priori guidance about the functional form. Limitations of OccuGAMs include interpretability of model parameters and sensitivity to the choice and number of basis functions, which can be assessed with diagnostic tools. To promote wider accessibility, we provide code for OccuGAM implementation in JAGS and Stan as well as in the R packages flocker and mvgam .

Studying multiple generations provides a more accurate and realistic understanding of how pollen affects phytoseiid mites over time. It is useful to assess potential negative effects on population dynamics, fitness, predatory behavior, and adaptation, which may not be apparent in a single-generation study. In this study, we investigated the effects of cattail pollen on the development, survival, and population growth of Euseius scutalis (Athias-Henriot) from the 1st to the 50th generations (G1–G50) to provide a comprehensive assessment of whether this pollen is a long-term viable diet for E. scutalis. Although the duration of immature development and adult longevity varied among generations, these fluctuations did not follow a clear pattern, indicating overall stability in developmental performance. Several reproductive traits, including APOP, TPOP, oviposition period, fecundity, and sex ratio, also differed among generations but without showing a consistent directional trend. Among life table parameters, including intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R₀), and gross reproductive rate (GRR) were slightly higher in early generations, decreased in G10, remained relatively stable up to G40, and then declined in G50. Offspring sex ratio was generally female-biased, with temporary male bias at the beginning or end of the oviposition period in some generations. Overall, cattail pollen can enhance growth and reproduction in E. scutalis during intermediate generations; however, lower fecundity and reduced population growth in later generations indicate that this diet is not sustainable over the long term (up to 50 generations).

Leucoptera malifoliella has become a severe leaf-mining pest in Chinese apple orchards, especially under expanding organic and green cultivation practices, with effective management hindered by insufficient contemporary ecological data. To fill this gap, this 2023–2025 study conducted in Shijiazhuang, Hebei, combined field monitoring, morphological analysis, flight mill assays, and parasitoid release trials to clarify the moth’s phenology, develop rapid pupal sexing methods, quantify adult flight capacity, and assess Trichogramma dendrolimi biocontrol potential. The results showed five annual generations (overwintering as pupae), peak damage in July–August, and marked generational overlap. A reliable pupal sexing method was established via genital opening morphology. Adult flight peaked at 3 days post-emergence (max distance: 1.223 km), with no sexual dimorphism. Timely T. dendrolimi releases boosted parasitism rates, achieving 23.4–49.6% control efficacy during peak damage, with the parasitism rate positively correlated with efficacy. This study confirms the moth’s potential for generational increase under climate warming and medium-distance dispersal capacity, validating Trichogramma’s utility and laying a scientific foundation for precise, regionally coordinated ecological management.

Fire is a major ecological force that shapes population dynamics and community structure in terrestrial ecosystems. Understanding seed germination responses to fire cues is crucial for predicting post-fire vegetation recovery. However, under the changing global fire regime, such responses in non-fire-prone ecosystems remain largely unknown. Here, we aimed to understand how fire influences population recruitment in non-fire-prone temperate grasslands and whether this influence is associated with key regenerative traits. We conducted a seed germination experiment with 80 species originating from a non-fire-prone temperate grassland ecosystem, using Bayesian phylogenetic mixed-effects models to examine the effects of fire cues on seed germination. We found that smoke and heat resulted in modest yet statistically significant increases in germination percentage. Germination of 24 species was significantly promoted by fire cues, among which 11 species responded significantly to heat shock and 13 species to smoke. However, these responses showed no significant phylogenetic signal. Furthermore, dormancy types were closely associated with the specific fire cues required to release dormancy, and annual and perennial species displayed markedly different germination responses to fire cues. This study investigates the critical role of fire cues in breaking seed dormancy in a non-fire-prone temperate grassland ecosystem. The differential germination responses among species are driven by dormancy type and lifespan. Although the overall increase in germination percentage was modest, the differential responses of seed germination to fire cues among species and functional groups reveal the potential importance of wildfires in reshaping community structure and composition. Our findings provide new insights into post-fire vegetation dynamics in the temperate grasslands.

Studies on population dynamics and bio-intensive management of the mango hopper, Idioscopus nagpurensis (Pruthi) (Cicadellidae: Hemiptera) under high-density planting system conditions of the Eastern hill and plateau region of India

The current guidelines for stopping treatment and verifying elimination of onchocerciasis recommend entomological and epidemiological surveys to be performed during the peak transmission season, which is generally assumed to occur during the rainy season-although this may not necessarily hold true in all transmission zones (TZ). This review has synthesized data, from literature search, on the effects of seasonality on transmission in West and Central Africa. Seasonality affects vector population dynamics by altering terrestrial and aquatic ecology. In TZs with perennial rivers, peak transmission and peak vector density may either coincide or occur at different periods. These peaks could occur in either the rainy or the dry season in both forest and savanna zones, and the periods may change between years. Therefore, countries should establish updated local biting patterns at a TZ prior to vector collection. Also, while using peak biting density as a convenient indicator for when to commence vector collection (because of the need for sufficient sample size), the survey period should include months in both seasons to increase chances of collecting during peak transmission. Seasonality significantly impacts onchocerciasis transmission elimination; and it also offers critical avenues for effective intervention and transmission evaluation.

Abstract Purpose Rare diseases (RD) produce an important public health impact, but their specific morbimortality burden remains unknown. Based on Death Certificates (1997–2017), the secular trend (ST) and spatial distribution of deaths due to RD are analyzed. Methods The ICD-10 classified Death Certificates were obtained from the Ministry of Health. A Python web scraper was developed to query the orpha.net web catalogue to establish a correspondence between Orpha and ICD-10 codes. The RDs mortality rate per 1,000 deaths (RD*1000) was calculated by sex, age groups, and by ICD-10 chapters for the five regions of Argentina (Northwest, Northeast, Centro, Cuyo, and Patagonia), as well as for its 24 provinces and 513 departments. Secular trend (ST) was analyzed using Joinpoint software, while spatiality was assessed through Moran’s and LISA indices. Results The RD*1000 death rate at country level was 189.4. Patagonia exhibited the highest rate, followed by Cuyo, Centro, Northeast and Northwest, being these conditions higher in women. The ST was negative between 1997 and 2009 and positive between 2009 and 2017. The geographical distribution of the clusters exhibiting high and low rates was mainly observed in the central and northern regions of the country, respectively. According to ICD-10, the prevalent categories were neoplasms, followed by eye diseases, congenital malformations, diseases of the nervous and digestive systems and diseases of the blood. Conclusion The geographical distribution of RD deaths in Argentina exhibits significant heterogeneity, characterized by a latitudinal arrangement. This phenomenon can be attributed to socioeconomic inequalities, intricately linked to population dynamics and migratory patterns. Clinical trial registration Not applicable. This study involved the analysis of secondary data and did not require clinical trial registration.

The present study investigates the length–weight relationship (LWR) of Sillago sihama, commonly known as silver whiting, collected from the Mangaluru coast between December 2024 and July 2025. The study involved 295 Sillago sihama specimens measuring from 13.4 to 27 cm total length (TL), with 215 males and 80 females included. For males, the length-weight equation was W=0.0298L2.5177, while for females, it was W=0.0118L2.8549. The relative condition factor (Kn) ranged from 0.996–1.004 in males and 0.985–1.063 in females. Analysis of 295 specimens (73% males, 27% females) revealed negative allometric growth for both sexes. Length–weight relationships are critical for estimating stock biomass, understanding population dynamics, and managing fisheries resources sustainably. The results confirm the progressive slenderization of the species with growth and provide a robust reference for future ecological and management assessments.

Approaches to Studying Virus Pangenome Variation Graphs.

ABSTRACTThe Eurasian crane (Grus grus), a symbol of conservation success in Europe, has made an impressive recovery since the 1979 Birds Directive, with current estimates reaching around 590,000 individuals. However, this transition from vulnerability to abundance brings new challenges, particularly arising from interactions with human activities (e.g., conflicts with agriculture). Understanding the future dynamics of crane populations requires knowledge of demographic parameters that are crucial for predicting population trends and informing management and conservation measures. We analysed 37 years of data (1985–2021) from 5049 juvenile‐banded cranes and 172,725 resightings, providing estimates of survival rates across age classes and over time. Our findings indicate that juveniles exhibit the lowest survival rates, while sub‐adults have higher survival, and adults show a decrease in their survival probability with age, as expected with the senescence process. Over the study period, juvenile survival declined by almost 30% overall, while sub‐adults experienced a smaller decrease, and adults showed no change. Life expectancy at birth was 10 years, and maximum lifespan reached 25 years. We found no difference in the survival estimates of males and females. The decline in juvenile survival over the years highlights the growing challenges likely driven by habitat degradation, climate change, agricultural practices, and increasing population densities. These findings align with previous research on crane survival and underscore the importance of understanding age‐specific survival dynamics in response to environmental changes. This study highlights the challenges facing Eurasian crane populations, where further declines in juvenile and immature survival rates could lead to population declines unless compensated by a stable or higher adult survival. Effective conservation strategies will require further research into reproductive success and details on age‐specific mortality causes and environmental pressures, although targeted interventions can already be implemented to mitigate current impacts of habitat degradation and climate change.

Weeds, especially purple nutsedge, are not just alternative hosts but highly susceptible host that drive the persistence and spread of rice root-knot nematodes. This study provides a comprehensive assessment of the host status of eight plant species, including rice and common rice-associated weeds, to the root-knot nematode Meloidogyne graminicola. By integrating quantitative infection assays with confocal laser scanning microscopy, we combined whole-plant measurements of nematode development with cellular-level visualization of feeding-site structures to characterize host suitability more precisely. The results revealed a continuum of responses ranging from weakly supportive to highly susceptible hosts. Purple nutsedge (Cyperus rotundus) showed the highest susceptibility under controlled conditions, with a reproduction factor (Rf = 77.25) exceeding that of rice (Oryza sativa, Rf = 15.45) and jungle rice (Echinochloa colona, Rf = 19.81). Digitaria sanguinalis also supported considerable nematode multiplication (Rf = 10.92). Confocal imaging provided temporal snapshots of feeding-site formation, giant cell development and gall progression in C. rotundus, complementing the quantitative findings. Several species, including Glinus oppositifolius and Stellaria media, supported minimal development, indicating limited suitability as hosts. Overall, the study demonstrates that multiple weeds commonly present in rice ecosystems can sustain M. graminicola development to varying degrees under experimental conditions. These results highlight the importance of considering weed species when evaluating nematode population dynamics and designing integrated management strategies for rice-based agroecosystems.

ABSTRACTThe Qinghai‐Tibet Plateau (QTP) is a global biodiversity hotspot where Quaternary climatic oscillations profoundly shaped the evolution of endemic alpine flora. Understanding how genetic diversity and structure in these species responded to past climate change is crucial for deciphering regional evolutionary mechanisms. Using chloroplast and nuclear genome data of 958 samples from 48 populations, we evaluated the genetic diversity and population structure of Primula sikkimensis. We then investigated the lineage differentiation and dynamics of species by combining an Approximate Bayesian Computation procedure and species distribution modeling. Our study indicates that P. sikkimensis maintained separate glacial refugia in the Hengduan Mountains and eastern Himalayas during the Last Glacial Maximum (LGM). Our results suggest that postglacial range expansions onto the inner QTP plateau were accompanied by gene flow arising from both intraspecific secondary contact between previously isolated populations and interspecific hybridization events, which collectively enhanced genetic diversity and adaptive capacity in plateau populations. Our findings underscore the critical role of postglacial population dynamics and gene flow in shaping genetic diversity and adaptive potential of alpine endemics like P. sikkimensis, highlighting evolutionary responses to Quaternary climate change on the QTP.