scholarly journals Predicting the Spatial Dynamics ofWolbachiaInfections inAedes AegyptiArbovirus Vector Populations in Heterogeneous Landscapes

2018 ◽  
Author(s):  
Penelope A. Hancock ◽  
Scott A. Ritchie ◽  
Constantianus J. M. Koenraadt ◽  
Thomas W. Scott ◽  
Ary A. Hoffmann ◽  
...  
Keyword(s):  
Spatial Dynamics ◽  
Field Trials ◽  
Mosquito Vector ◽  
List Type ◽  
Fitness Costs ◽  
Fitness Components ◽  
Spatial Spread ◽  
Mosquito Abundance ◽  
Heterogeneous Landscapes ◽  
Spatio Temporal

ABSTRACTA promising strategy for reducing the transmission of dengue and other arboviral human diseases byAedes aegyptimosquito vector populations involves field introductions of the endosymbiotic bacteriaWolbachia.Wolbachiainfections inhibit viral transmission by the mosquito, and can spread between mosquito hosts to reach high frequencies in the vector population.Wolbachiaspreads by maternal transmission, and spread dynamics can be variable and highly dependent on natural mosquito population dynamics, population structure and fitness components.We develop a mathematical model of anAe. aegyptimetapopulation that incorporates empirically validated relationships describing density-dependent mosquito fitness components. We assume that density dependence relationships differ across subpopulations, and construct heterogeneous landscapes for which model-predicted patterns of variation in mosquito abundance and demography approximate those observed in field populations. We then simulateWolbachiarelease strategies similar to that used in field trials.We show that our model can produce rates of spatial spread ofWolbachiasimilar to those observed following field releases.We then investigate how different types of spatio-temporal variation in mosquito habitat, as well as different fitness costs incurred byWolbachiaon the mosquito host, influence predicted spread rates. We find that fitness costs reduce spread rates more strongly when the habitat landscape varies temporally due to stochastic and seasonal processes.Our empirically based modelling approach represents effects of environmental heterogeneity on the spatial spread ofWolbachia.The models can assist in interpreting observed spread patterns following field releases and in designing suitable release strategies for targeting spatially heterogeneous vector populations.

scholarly journals Does agricultural intensification cause tipping points in ecosystem services?

2021 ◽  
Author(s):  
Stephen C. L. Watson ◽  
Adrian C. Newton ◽  
Lucy E. Ridding ◽  
Paul M. Evans ◽  
Steven Brand ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Agricultural Intensification ◽  
Spatial Dynamics ◽  
Policy Option ◽  
List Type ◽  
Tipping Points ◽  
Software Models ◽  
Non Linear ◽  
Study Interval ◽  
The Impact

Abstract Context Agricultural intensification is being widely pursued as a policy option to improve food security and human development. Yet, there is a need to understand the impact of agricultural intensification on the provision of multiple ecosystem services, and to evaluate the possible occurrence of tipping points. Objectives To quantify and assess the long-term spatial dynamics of ecosystem service (ES) provision in a landscape undergoing agricultural intensification at four time points 1930, 1950, 1980 and 2015. Determine if thresholds or tipping points in ES provision may have occurred and if there are any detectable impacts on economic development and employment. Methods We used the InVEST suite of software models together with a time series of historical land cover maps and an Input–Output model to evaluate these dynamics over an 85-year period in the county of Dorset, southern England. Results Results indicated that trends in ES were often non-linear, highlighting the potential for abrupt changes in ES provision to occur in response to slight changes in underlying drivers. Despite the fluctuations in provision of different ES, overall economic activity increased almost linearly during the study interval, in line with the increase in agricultural productivity. Conclusions Such non-linear thresholds in ES will need to be avoided in the future by approaches aiming to deliver sustainable agricultural intensification. A number of positive feedback mechanisms are identified that suggest these thresholds could be considered as tipping points. However, further research into these feedbacks is required to fully determine the occurrence of tipping points in agricultural systems.

scholarly journals Variation in host home range decreases rabies vaccination effectiveness by increasing the spatial spread of rabies

2019 ◽  
Author(s):  
Katherine M. McClure ◽  
Amy T. Gilbert ◽  
Richard B. Chipman ◽  
Erin Rees ◽  
Kim M. Pepin
Keyword(s):  
Home Range ◽  
Home Range Size ◽  
Wildlife Disease ◽  
Pathogen Transmission ◽  
Range Size ◽  
Effective Control ◽  
List Type ◽  
Wildlife Diseases ◽  
Spatial Spread ◽  
Pathogen Invasion

ABSTRACTAnimal movement influences the spatial spread of wildlife infectious diseases through host-host contact structure and hence pathogen transmission. Wildlife disease hosts vary in characteristics related to pathogen transmission, which can increase the spread and intensity of disease outbreaks. The consequences of home range size variation on wildlife disease dynamics are poorly understood, but could help to predict disease spread and determine more effective disease management strategies.We developed a spatially-explicit individual-based model to examine the effect of variation in host home range size on the spatial spread rate, persistence, and incidence of rabies virus (RABV) in raccoons (Procyon lotor). We tested the hypothesis that host home range area variation decreases vaccination effectiveness in wildlife host populations following pathogen invasion into a vaccination zone.We simulated raccoon demography and RABV dynamics across a range of magnitudes and variances in weekly home range radius distributions for raccoons, and compared results to conditions that assumed a fixed host home range area. We examined how variable host home range radius distributions influenced the relative effectiveness of three components of orally-baited raccoon RABV vaccination (ORV) programs—timing and frequency of bait delivery, width of the zone where ORV baits were delivered, and proportion of hosts immunized.Variability in home range radius distributions increased RABV spread rates by 1.2 - 5.2-fold compared to simulations with fixed radii. More variable host home range radius distributions decreased relative vaccination effectiveness by 71% compared to less variable host home range radius distributions under conventional vaccination conditions. We found that vaccination timing was more influential for vaccination effectiveness than vaccination frequency or vaccination zone width.Our results suggest that variation in wildlife home range exploration increases the spatial spread and incidence of wildlife disease. Our vaccination results underscore the importance of prioritizing individual-level space use data collection to understand the dynamics of wildlife diseases and plan their effective control and elimination.

scholarly journals THE DUAL-TASK COST IS DUE TO NEURAL INTERFERENCES DISRUPTING THE OPTIMAL SPATIO-TEMPORAL DYNAMICS OF THE COMPETING TASKS

2020 ◽  
Author(s):  
Diego Mac-Auliffe ◽  
Benoit Chatard ◽  
Mathilde Petton ◽  
Anne-Claire Croizé ◽  
Florian Sipp ◽  
...  
Keyword(s):  
Dual Task ◽  
Temporal Dynamics ◽  
Anterior Cingulate ◽  
List Type ◽  
Intracranial Eeg ◽  
Ample Evidence ◽  
Dual Tasking ◽  
Dual Task Cost ◽  
Neural Origin ◽  
Spatio Temporal

ABSTRACTDual-tasking is extremely prominent nowadays, despite ample evidence that it comes with a performance cost: the Dual-Task (DT) cost. Neuroimaging studies have established that tasks are more likely to interfere if they rely on common brain regions, but the precise neural origin of the DT cost has proven elusive so far, mostly because fMRI does not record neural activity directly and cannot reveal the key effect of timing, and how the spatio-temporal neural dynamics of the tasks coincide.Recently, DT electrophysiological studies in monkeys have recorded neural populations shared by the two tasks with millisecond precision to provide a much finer understanding of the origin of the DT cost. We used a similar approach in humans, with intracranial EEG, to assess the neural origin of the DT cost in a particularly challenging naturalistic paradigm which required accurate motor responses to frequent visual stimuli (task T1) and the retrieval of information from long-term memory (task T2), as when answering passengers’ questions while driving.We found that T2 elicited neuroelectric interferences in the gamma-band (>40 Hz), in key regions of the T1 network including the Multiple Demand Network. They reproduced the effect of disruptive electrocortical stimulations to create a situation of dynamical incompatibility, which might explain the DT cost. Yet, participants were able to flexibly adapt their strategy to minimize interference, and most surprisingly, reduce the reliance of T1 on key regions of the executive control network – the anterior insula and the dorsal anterior cingulate cortex – with no performance decrement.HIGHLIGHTS- First direct evidence in humans of neural interferences between two tasks.- First explanation of the Dual-Task cost at the neural level in humans.- First Dual-Tasking study with intracranial EEG in naturalistic conditions.

scholarly journals Screening and potent applicability analysis of commonly used pesticides against desert locust: an integrative entomo-informatics approach

2020 ◽  
Author(s):  
Anik Banik ◽  
Md. Fuad Mondal ◽  
Md. Mostafigur Rahman Khan ◽  
Sheikh Rashel Ahmed ◽  
Md. Mehedi Hasan
Keyword(s):  
Binding Affinity ◽  
Large Scale ◽  
Schistocerca Gregaria ◽  
Indian Subcontinent ◽  
Locusta Migratoria ◽  
Field Trials ◽  
The Other ◽  
List Type ◽  
Agricultural Pesticides ◽  
Global Threat

AbstractThe locust problem is a global threat for food security. Locusts can fly and migrate overseas within a zip and creating a large-scale devastation to the diversified agro-ecosystem. GIS based analysis showed the recent movement of locusts, among them Schistocerca gregaria and Locusta migratoria are predominant in Indian subcontinent and are found more notorious and devastating one. This devastation needs to be stopped to save human race from food deprivation. In our study, we screened some commonly used agricultural pesticides and strongly recommended three of them viz. biphenthrin, diafenthiuron and silafluofen which might be potential to control the desert locusts based on their binding affinity towards the locust’s survival proteins. Our phylogenetic analysis reveals that these three recommended pesticides might also show potency to the other locust species as well as they are also way safer than the other commercially available pesticides. These proposed pesticide’s bioactive analogs from fungus and bacteria may also show efficacy as next generation controlling measures of locust as well as different kind of pests. These recommended pesticides are expected to be highly effective against locusts and needs to bring forward by the entomologists’ by performing experimental field trials.HighlightsGIS map unmasked the 2020 migratory pattern of locusts which now predominant towards Indian subcontinent.Biphenthrin, diafenthiuron and silafluofen showed maximum binding affinity.Biphenthrin and diafenthiuron were relatively safer than silafluofen.Bioactive analogs from fungus and bacteria could be an alternative to control locusts.Pesticides inhibition hotspots for desert locusts were unrevealed.

scholarly journals Spatially mismatched trophic dynamics: cyclically outbreaking geometrids and their larval parasitoids

2010 ◽  
Vol 6 (4) ◽  
pp. 566-569 ◽  
Author(s):  
Snorre B. Hagen ◽  
Jane U. Jepsen ◽  
Tino Schott ◽  
Rolf A. Ims
Keyword(s):  
Trophic Interactions ◽  
Travelling Waves ◽  
Methodological Approach ◽  
Spatial Dynamics ◽  
Population Cycles ◽  
Trophic Levels ◽  
Trophic Dynamics ◽  
Spatial Mismatch ◽  
Larval Parasitoids ◽  
Spatio Temporal

For trophic interactions to generate population cycles and complex spatio-temporal patterns, like travelling waves, the spatial dynamics must be matched across trophic levels. Here, we propose a spatial methodological approach for detecting such spatial match–mismatch and apply it to geometrid moths and their larval parasitoids in northern Norway, where outbreak cycles and travelling waves occur. We found clear evidence of spatial mismatch, suggesting that the spatially patterned moth cycles in this system are probably ruled by trophic interactions involving other agents than larval parasitoids.

Effects of spatio-temporal variation in food supply on red squirrelSciurus vulgarisbody size and body mass and its consequences for some fitness components

Ecography ◽  
2007 ◽  
Vol 30 (1) ◽  
pp. 51-65 ◽  
Author(s):  
Lucas A. Wauters ◽  
Marleen Vermeulen ◽  
Stefan Van Dongen ◽  
Sandro Bertolino ◽  
Ambrogio Molinari ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Body Mass ◽  
Food Supply ◽  
Fitness Components ◽  
Spatio Temporal

scholarly journals Modelling the mobility of living organisms in heterogeneous landscapes: does memory improve foraging success?

2010 ◽  
Vol 368 (1933) ◽  
pp. 5645-5659 ◽  
Author(s):  
Denis Boyer ◽  
Peter D. Walsh
Keyword(s):  
Foraging Efficiency ◽  
Mobility Patterns ◽  
Heterogeneous Landscapes ◽  
Technological Advances ◽  
Spatio Temporal ◽  
Living Organisms ◽  
Large Animals ◽  
Micro Organisms ◽  
Random Nature ◽  
Basic Movement

Thanks to recent technological advances, it is now possible to track with an unprecedented precision and for long periods of time the movement patterns of many living organisms in their habitat. The increasing amount of data available on single trajectories offers the possibility of understanding how animals move and of testing basic movement models. Random walks have long represented the main description for micro-organisms and have also been useful to understand the foraging behaviour of large animals. Nevertheless, most vertebrates, in particular humans and other primates, rely on sophisticated cognitive tools such as spatial maps, episodic memory and travel cost discounting. These properties call for other modelling approaches of mobility patterns. We propose a foraging framework where a learning mobile agent uses a combination of memory-based and random steps. We investigate how advantageous it is to use memory for exploiting resources in heterogeneous and changing environments. An adequate balance of determinism and random exploration is found to maximize the foraging efficiency and to generate trajectories with an intricate spatio-temporal order, where travel routes emerge without multi-step planning. Based on this approach, we propose some tools for analysing the non-random nature of mobility patterns in general.

SPATIO-TEMPORAL PATTERNS IN A CHOLERA TRANSMISSION MODEL

2015 ◽  
Vol 23 (03) ◽  
pp. 471-484 ◽  
Author(s):  
A. K. MISRA ◽  
MILAN TIWARI ◽  
ANUPAMA SHARMA
Keyword(s):  
Spatial Patterns ◽  
Dimensional Space ◽  
Spatial Dynamics ◽  
Transmission Model ◽  
Cholera Epidemic ◽  
Temporal System ◽  
Spatially Extended ◽  
Variable Population ◽  
Spatio Temporal ◽  
Variable Population Size

Cholera has been a public health threat for centuries. Unlike the biological characteristics, relatively less effort has been paid to comprehend the spatial dynamics of this disease. Therefore, in this paper, we have proposed a cholera epidemic model for variable population size and studied the spatial patterns in two-dimensional space. First, we have performed the equilibrium and local stability analysis of steady states obtained for temporal system. Afterwards, the local and global stability behavior of the endemic steady state in a spatially extended setting has been investigated. The numerical simulations have been done to investigate the spatial patterns. They show that dynamics of the cholera epidemic varies with time and space.

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