Article
Biology
Shengqiang Zhang, Xichao Duan, Tonghua Zhang, Sanling Yuan
Summary: Biological invasions pose serious threats to ecosystem stability, biodiversity, and human health, but there are few effective measures for controlling them. By constructing a stochastic host-generalist parasitoid model, this study reveals that generalist parasitoids are more vulnerable to environmental noises compared to invasive hosts, and the prevention and control effects of biological control on invasive hosts are closely related to the initial population sizes.
BULLETIN OF MATHEMATICAL BIOLOGY
(2023)
Article
Mathematics, Interdisciplinary Applications
Zhan-Ping Ma, Zhi-Bo Cheng, Wei Liang
Summary: In this paper, a delayed host-generalist parasitoid diffusion model is studied, where generalist parasitoids are introduced to control the invasion of the hosts. The positive steady-state solution is explicitly expressed using the implicit function theorem and its linear stability is proved. Spatially inhomogeneous Hopf bifurcation near the positive steady-state solution is proved when the feedback time delay is varied through a sequence of critical values. Numerical simulations show that the period and amplitude of the inhomogeneous periodic solution increase with increasing feedback time delay.
INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS
(2023)
Article
Mathematics, Interdisciplinary Applications
Yong Ye, Yi Zhao, Jiaying Zhou
Summary: Hunting cooperation is widely observed in biological systems, but there is limited attention on generalist predator-prey models. This study examines the impact of cooperation mechanism on a delay-induced host-generalist parasitoid model. It is found that the cooperation mechanism does not cause instability in the system. Furthermore, the study investigates the dynamic changes induced by delay and discovers periodic oscillations, irregular oscillations, and chaotic attractors when double delays are introduced. Numerical experiments show that the cooperation levels have an impact on the dynamic properties, and it is concluded that the cooperation mechanism promotes the stability of the biological system. This study provides insights into predator cooperation in a more straightforward and practical manner.
CHAOS SOLITONS & FRACTALS
(2022)
Article
Microbiology
Matthew Schmitt, Aaron Telusma, Estelle Bigeard, Laure Guillou, Catharina Alves-de-Souza
Summary: By assessing the growth of two blooming dinoflagellates and their susceptibility to infection under different temperature conditions, the study found that temperature has significant impacts on the growth of dinoflagellates and parasitoid infections. Temperature shifts may not only affect bloom development in microalgal species, but also their control by parasitoids.
Article
Evolutionary Biology
Oscar Istas, Marianna Szucs
Summary: Laboratory-selected native parasitoids show improved control of invasive targets, but their performance in natural environments and comparison to co-evolved specialists is unclear. Rearing in artificial diet did not impair the ability of laboratory-selected native parasitoids to locate and attack hosts in natural conditions. Specialist and generalist parasitoids have different biocontrol potentials in nature.
EVOLUTIONARY APPLICATIONS
(2023)
Article
Multidisciplinary Sciences
Estelle Postic, Yannick Outreman, Stephane Derocles, Caroline Granado, Anne Le Ralec
Summary: Generalist parasitoids are widely used as biological control agents due to their ability to parasitize various insect species, but genetic differentiation among populations and alterations in genetic variation within mass-reared populations may lead to reduced efficiency in controlling targeted pest species. The genetic and ecological bases of inefficiency in controlling aphids with the generalist parasitoid Aphidius ervi in strawberry greenhouses were investigated, revealing a genetic differentiation between commercial and wild populations associated with a loss of genetic diversity within mass-reared populations.
Article
Biodiversity Conservation
Jinlin Chen, Owen T. Lewis
Summary: As average temperatures increase and heatwaves become more frequent, species are expanding their distributions and colonizing new habitats. This leads to novel species interactions that shape the reorganization of resident communities driven by temperature changes. Our study reveals the different and sometimes contrasting impacts of extreme temperatures and constant warming on community composition.
GLOBAL CHANGE BIOLOGY
(2023)
Article
Ecology
Ai-Ying Wang, Yan-Qiong Peng, James M. Cook, Da-Rong Yang, Da-Yong Zhang, Wan-Jin Liao
Summary: This study compares the codiversification patterns among fig plants, their herbivorous pollinating and galling wasps, and their parasitoids. The results show that the parasitoid phylogeny is more closely related to their host insects, and there is stronger interspecific competition among parasitoids associated with pollinators. Additionally, there is closer matching and fewer host shifts between parasitoids and galler hosts compared to parasitoids and pollinator hosts. Overall, this study highlights the important role of interspecific competition among high trophic level insects in plant-insect tri-trophic community assembling.
Article
Ecology
Abhyudai Singh, Brooks Emerick
Summary: Discrete-time models are commonly used in studying insect population dynamics in temperate regions. This study revisits classical discrete-time host-parasitoid models and provides novel insights on population dynamics stability. The results suggest that stability is more likely when the host escape response is a decreasing function of host density, and if the host escape response only depends on the parasitoid population density, the stability condition is further simplified.
ECOLOGICAL MODELLING
(2021)
Article
Biology
George E. Heimpel, Paul K. Abram, Jacques Brodeur
Summary: The interactions that shape parasitoid host ranges are influenced by the phylogenetic history of both hosts and parasitoids. Speciation of parasitoids associated with hosts can lead to increased host specificity or a broadening of the host range. Estimating host range has shifted from traditional lists to analyses detecting host phylogenetic signals and useful indices reflecting the breadth of host range in phylogenetic terms. These considerations have significant implications for biological control and risk assessment.
CURRENT OPINION IN INSECT SCIENCE
(2021)
Article
Biodiversity Conservation
Michele Ricupero, Francisca Zepeda-Paulo, Nuri Cabrera, Antonio Biondi, Chanchung Dai, Lucia Zappala, George E. Heimpel, Jacques Brodeur, Nicolas Desneux, Blas Lavandero
Summary: This study examined the variation in parasitism of D. coccinellae on H. axyridis populations in different regions and hosts, and inferred its putative origin. The results showed that parasitism rates of D. coccinellae on invasive H. axyridis and native hosts were remarkably similar, not supporting the enemy release hypothesis. However, parasitism rates of H. axyridis were much lower in its native range, indicating a potential contribution to the control of invasive populations. Genetic relationships analysis revealed widespread haplotypes of D. coccinellae with no host-associated genetic structure.
BIOLOGICAL INVASIONS
(2023)
Article
Multidisciplinary Sciences
Lucas D. Fernandes, Angelica S. Mata, Wesley A. C. Godoy, Carolina Reigada
Summary: Species distributions and dynamics are influenced by the interplay between dispersal at different spatial scales and landscape connectivity and composition. This study examines the effects of these factors on local species dynamics using a host-parasitoid model. The results demonstrate the importance of both local and regional scales, as well as the combined effects of species biological parameters and landscape structure, in shaping species density and occupancy. These findings have practical implications for the development of effective strategies for biological control.
Article
Agronomy
Antonino Cusumano, Ezio Peri, Tugcan Alinc, Stefano Colazza
Summary: This study examined the impact of extrinsic competition on host utilization and coexistence between two parasitoid species. The results showed that egg mass size was an important predictor of extrinsic competition, and reproductive traits of the parasitoid species contributed to their competitive advantage in different-sized egg masses. This study highlights the importance of considering extrinsic competitive interactions between parasitoid species in biological pest control.
PEST MANAGEMENT SCIENCE
(2022)
Article
Ecology
Benjamin J. M. Jarrett, Marianna Szucs
Summary: This study explored how life-history traits of parasitoid species and their herbivorous hosts interact to affect the establishment success of parasitoids. The results suggest that the host range of the parasitoid and the residence time of the herbivore host play important roles in determining the establishment success of parasitoids.
ECOLOGY AND EVOLUTION
(2022)
Article
Entomology
Kiran Mahat, Anthony R. Clarke
Summary: The study demonstrates that in co-parasitized B. tryoni, D. kraussii is suppressed by F. arisanus, and the competitive advantage of F. arisanus is not overcome by the close evolutionary relationship between D. kraussii and B. tryoni.
Article
Mathematics, Applied
Hao Kang, Shigui Ruan, Xiao Yu
Summary: This paper aims to develop basic theory for age-structured population dynamics with nonlocal diffusion. By studying the semigroup of linear operators associated to an age-structured model with nonlocal diffusion and using the spectral properties of its infinitesimal generator, the stability of the zero steady state is determined. Several results are obtained regarding the structure of the semigroup, the asymptotic behavior, the weak solution and comparison principle.
JOURNAL OF DYNAMICS AND DIFFERENTIAL EQUATIONS
(2022)
Article
Mathematics, Applied
Li Xie, Shigui Ruan
Summary: In this paper, a homogeneous Neumann initial-boundary value problem for a chemotaxis model with two species and two stimuli, including paracrine and autocrine loops, is considered. The existence of global bounded classical solutions is proved under certain conditions, and an inequality is derived that guarantees the existence of solutions.
COMMUNICATIONS ON PURE AND APPLIED ANALYSIS
(2022)
Article
Mathematics
Hao Kang, Shigui Ruan
Summary: This paper studies the principal spectral theory and asynchronous exponential growth for age-structured models with nonlocal diffusion of Neumann type. It provides two general sufficient conditions for the existence of the principal eigenvalue and proves that the semigroup generated by solutions of the model exhibits asynchronous exponential growth. It also overcomes the non-monotonicity issue of the principal eigenvalue of a nonlocal Neumann operator and establishes the strong maximum principle for the age-structured operator with nonlocal diffusion.
MATHEMATISCHE ANNALEN
(2022)
Article
Mathematics, Applied
Xinjian Wang, Guo Lin, Shigui Ruan
Summary: This paper investigates the propagation dynamics of vector-borne diseases in spatial expansion. The spreading speed and minimal wave speed are determined when the basic reproduction number is larger than one. The uniqueness and monotonicity of travelling wave solutions are proven. Numerical simulations are presented to illustrate the analytical results.
PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS
(2023)
Article
Mathematics, Applied
Xinjian Wang, Guo Lin, Shigui Ruan
Summary: This study investigates the spatial expansion speeds of viruses and infected cells within an infected host by establishing a within-host viral infection model. The findings provide important insights into the transmission mechanism of viral infections.
STUDIES IN APPLIED MATHEMATICS
(2022)
Article
Mathematics, Applied
Canrong Tian, Zuhan Liu, Shigui Ruan
Summary: This study investigates the impact of population mobility on the transmission dynamics of infectious diseases using an SEIR epidemic model and weighted networks. By constructing Liapunov functions, it is found that the basic reproduction number affects the global asymptotic stability of disease-free equilibrium and endemic equilibrium. Numerical simulations on Watts-Strogatz networks demonstrate that node degrees play a crucial role in determining peak numbers of infectious population and the time to reach these peaks.
EUROPEAN JOURNAL OF APPLIED MATHEMATICS
(2022)
Article
Mathematics, Applied
Liyan Pang, Shi-Liang Wu, Shigui Ruan
Summary: This paper investigates the long-time behavior of bounded solutions to a two-species time-periodic Lotka-Volterra reaction-diffusion system with strong competition. By transforming the system into a cooperative system on [0,1], it is shown that solutions converge to diverging periodic traveling fronts under certain conditions. Additionally, it is proved that solutions spread to 1 under certain conditions. Furthermore, it is demonstrated that if the two species are initially absent from the right half-line x > 0 and the slower one dominates the faster one on x < 0, solutions approach a propagating terrace with multiple invasion speeds.
CALCULUS OF VARIATIONS AND PARTIAL DIFFERENTIAL EQUATIONS
(2023)
Article
Parasitology
Jing Chen, Xi Huo, Andre B. B. Wilke, John C. Beier, Chalmers Vasquez, William Petrie, Robert Stephen Cantrell, Chris Cosner, Shigui Ruan
Summary: In this study, a deterministic mosquito population model was developed to assess the impact of rainfall on the abundance of Ae. aegypti in different urban built environments in Miami-Dade County. The results showed that rainfall affected breeding sites and mosquito abundance more significantly in tourist areas than in residential places. The model was also used to quantitatively evaluate the effectiveness of vector control strategies in the county.
Article
Mathematics, Applied
Shujing Shi, Jicai Huang, Yang Kuang, Shigui Ruan
Summary: This paper studies a three-dimensional tumor-immune system interaction model involving tumor cells, activated T cells, and an immune checkpoint inhibitor anti-PD-1. The growth of tumor cells is assumed to be exponential due to their uncontrollable nature without immune response or treatment. The distribution of equilibria is qualitatively discussed and the stability of equilibria with and without anti-PD-1 drug is studied. The model exhibits different outcomes based on the death rate of T cells and the presence of anti-PD-1 treatment, including tumor growth, eradication, bistable phenomena, and periodic orbits. The existence of local Hopf bifurcation and the stability of bifurcating periodic orbits are also established. The model demonstrates the long-term coexistence and balance of the tumor and immune system.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2023)
Article
Mathematics
Xiaomei Feng, Yunfeng Liu, Shigui Ruan, Jianshe Yu
Summary: In this paper, a seasonally interactive model between closed and open seasons is formulated based on management and capture methods of renewable resources using Michaelis-Menten type harvesting. The study finds that by setting an appropriate length threshold of the closed season, the population can achieve global asymptotic stability and the existence of a unique globally asymptotically stable T-periodic solution.
JOURNAL OF DIFFERENTIAL EQUATIONS
(2023)
Article
Mathematics, Applied
Yu Yang, Lan Zou, Jinling Zhou, Shigui Ruan
Summary: This paper focuses on a nonlocal within-host viral infection model with general incidence in a spatially heterogeneous environment. The well-posedness, boundedness, and asymptotic compactness of the model are established. The basic reproduction number R0 is defined using perturbation technique. The global stability of the infection-free steady state is studied, and it is shown that the system is uniformly persistent when R0 > 1. The existence, uniqueness, and global stability of the infection steady state for a special incidence function are also established. Finally, examples and numerical simulations are presented to illustrate the obtained results.
JOURNAL OF EVOLUTION EQUATIONS
(2023)
Article
Environmental Sciences
Zheng Chen, Jieyu Liu, Zhonghua Qian, Li Li, Zhiseng Zhang, Guolin Feng, Shigui Ruan, Guiquan Sun
Summary: This study analyzed the vegetation dynamics under the effects of climate change in arid ecosystems using a mathematical model. They found that the ecosystem might experience a catastrophic shift with the climatic deterioration and that recent climate changes were the main reason for land degradation. The results suggest that vegetation patterns can provide clues to whether the ecosystem is approaching desertification, which can help map vulnerable arid areas globally through model simulation and satellite images.
Article
Mathematics, Applied
Hao Kang, Shigui Ruan
Summary: This paper studies the principal spectral theory of age-structured models with nonlocal diffusion in a population of multigroups. A criterion for the existence of the principal eigenvalue is provided using the theory of positive resolvent operators with their perturbations. The generalized principal eigenvalue is defined and used to investigate the influence of diffusion rate on the principal eigenvalue. The strong maximum principle for age-structured nonlocal diffusion operators is established, and the established theory is applied to an age-structured cooperative system with nonlocal diffusion as an example.
CALCULUS OF VARIATIONS AND PARTIAL DIFFERENTIAL EQUATIONS
(2023)
Article
Biology
Shigui Ruan, Dongmei Xiao
Summary: A natural biological system under human interventions may exhibit complex dynamics that could lead to either the collapse or stabilization of the system. The bifurcation theory plays a significant role in understanding this evolution process by modeling and analyzing the biological system. This paper examines two types of biological models proposed by Fred Brauer: predator-prey models with stocking/harvesting and epidemic models with importation/isolation. The study shows that the system under human interventions undergoes imperfect bifurcation and Bogdanov-Takens bifurcation, resulting in richer dynamical behaviors such as the existence of limit cycles or homoclinic loops.
JOURNAL OF MATHEMATICAL BIOLOGY
(2023)
Article
Mathematics, Applied
Yancong Xu, Yue Yang, Fanwei Meng, Shigui Ruan
Summary: In this paper, the Holling-Tanner predator-prey model with constant-yield prey harvesting and anti-predator behavior is investigated. Various bifurcations and rich dynamical behaviors are observed, including saddle-node bifurcation, Hopf bifurcation, saddle-node bifurcation of limit cycles, and homoclinic bifurcation. The effects of harvesting and anti-predator behavior on population dynamics are discussed, and numerical simulations are provided to illustrate the theoretical findings.
NONLINEAR ANALYSIS-REAL WORLD APPLICATIONS
(2024)