1
|
When host populations move north, but disease moves south: Counter-intuitive impacts of climate change on disease spread. THEOR ECOL-NETH 2023. [DOI: 10.1007/s12080-022-00551-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|
2
|
Ahmed DA, Benhamou S, Bonsall MB, Petrovskii SV. Three-dimensional random walk models of individual animal movement and their application to trap counts modelling. J Theor Biol 2021; 524:110728. [PMID: 33895179 DOI: 10.1016/j.jtbi.2021.110728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 04/11/2021] [Accepted: 04/15/2021] [Indexed: 11/15/2022]
Abstract
BACKGROUND Random walks (RWs) have proved to be a powerful modelling tool in ecology, particularly in the study of animal movement. An application of RW concerns trapping which is the predominant sampling method to date in insect ecology and agricultural pest management. A lot of research effort has been directed towards modelling ground-dwelling insects by simulating their movement in 2D, and computing pitfall trap counts, but comparatively very little for flying insects with 3D elevated traps. METHODS We introduce the mathematics behind 3D RWs and present key metrics such as the mean squared displacement (MSD) and path sinuosity, which are already well known in 2D. We develop the mathematical theory behind the 3D correlated random walk (CRW) which involves short-term directional persistence and the 3D Biased random walk (BRW) which introduces a long-term directional bias in the movement so that there is an overall preferred movement direction. In this study, we focus on the geometrical aspects of the 3D trap and thus consider three types of shape; a spheroidal trap, a cylindrical trap and a rectangular cuboidal trap. By simulating movement in 3D space, we investigated the effect of 3D trap shapes and sizes and of movement diffusion on trapping efficiency. RESULTS We found that there is a non-linear dependence of trap counts on the trap surface area or volume, but the effect of volume appeared to be a simple consequence of changes in area. Nevertheless, there is a slight but clear hierarchy of trap shapes in terms of capture efficiency, with the spheroidal trap retaining more counts than a cylinder, followed by the cuboidal type for a given area. We also showed that there is no effect of short-term persistence when diffusion is kept constant, but trap counts significantly decrease with increasing diffusion. CONCLUSION Our results provide a better understanding of the interplay between the movement pattern, trap geometry and impacts on trapping efficiency, which leads to improved trap count interpretations, and more broadly, has implications for spatial ecology and population dynamics.
Collapse
Affiliation(s)
- D A Ahmed
- Center for Applied Mathematics and Bioinformatics (CAMB), Department of Mathematics and Natural Sciences, Gulf University for Science and Technology, P.O. Box 7207, Hawally 32093, Kuwait
| | - S Benhamou
- Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, Cogitamus Lab, Montpellier, France
| | - M B Bonsall
- Mathematical Ecology Research Group, Department of Zoology, University of Oxford, Mansfield Road, OX1 3SZ Oxford, UK
| | - S V Petrovskii
- School of Mathematics and Actuarial Science, University of Leicester, University Road, Leicester LE1 7RH, UK; Peoples Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya St, Moscow 117198, Russian Federation
| |
Collapse
|
3
|
Filipović I, Hapuarachchi HC, Tien WP, Razak MABA, Lee C, Tan CH, Devine GJ, Rašić G. Using spatial genetics to quantify mosquito dispersal for control programs. BMC Biol 2020; 18:104. [PMID: 32819378 PMCID: PMC7439557 DOI: 10.1186/s12915-020-00841-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 08/05/2020] [Indexed: 11/10/2022] Open
Abstract
Background Hundreds of millions of people get a mosquito-borne disease every year and nearly one million die. Transmission of these infections is primarily tackled through the control of mosquito vectors. The accurate quantification of mosquito dispersal is critical for the design and optimization of vector control programs, yet the measurement of dispersal using traditional mark-release-recapture (MRR) methods is logistically challenging and often unrepresentative of an insect’s true behavior. Using Aedes aegypti (a major arboviral vector) as a model and two study sites in Singapore, we show how mosquito dispersal can be characterized by the spatial analyses of genetic relatedness among individuals sampled over a short time span without interruption of their natural behaviors. Results Using simple oviposition traps, we captured adult female Ae. aegypti across high-rise apartment blocks and genotyped them using genome-wide SNP markers. We developed a methodology that produces a dispersal kernel for distance which results from one generation of successful breeding (effective dispersal), using the distance separating full siblings and 2nd- and 3rd-degree relatives (close kin). The estimated dispersal distance kernel was exponential (Laplacian), with a mean dispersal distance (and dispersal kernel spread σ) of 45.2 m (95% CI 39.7–51.3 m), and 10% probability of a dispersal > 100 m (95% CI 92–117 m). Our genetically derived estimates matched the parametrized dispersal kernels from previous MRR experiments. If few close kin are captured, a conventional genetic isolation-by-distance analysis can be used, as it can produce σ estimates congruent with the close-kin method if effective population density is accurately estimated. Genetic patch size, estimated by spatial autocorrelation analysis, reflects the spatial extent of the dispersal kernel “tail” that influences, for example, the critical radii of release zones and the speed of Wolbachia spread in mosquito replacement programs. Conclusions We demonstrate that spatial genetics can provide a robust characterization of mosquito dispersal. With the decreasing cost of next-generation sequencing, the production of spatial genetic data is increasingly accessible. Given the challenges of conventional MRR methods, and the importance of quantified dispersal in operational vector control decisions, we recommend genetic-based dispersal characterization as the more desirable means of parameterization.
Collapse
Affiliation(s)
- Igor Filipović
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD, 4006, Australia.
| | | | - Wei-Ping Tien
- Environmental Health Institute, National Environment Agency, 11, Biopolis Way, #06-05-08, Singapore, 138667, Singapore
| | | | - Caleb Lee
- Environmental Health Institute, National Environment Agency, 11, Biopolis Way, #06-05-08, Singapore, 138667, Singapore
| | - Cheong Huat Tan
- Environmental Health Institute, National Environment Agency, 11, Biopolis Way, #06-05-08, Singapore, 138667, Singapore
| | - Gregor J Devine
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD, 4006, Australia
| | - Gordana Rašić
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD, 4006, Australia.
| |
Collapse
|