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© Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington MSc Student Supervisors : Dr Stephen Hartley, Dr Marcus Frean Victoria.

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Presentation on theme: "© Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington MSc Student Supervisors : Dr Stephen Hartley, Dr Marcus Frean Victoria."— Presentation transcript:

1 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington MSc Student Supervisors : Dr Stephen Hartley, Dr Marcus Frean Victoria University, Wellington Jim Barritt Spatially explicit simulation of individual foraging behaviour across patchy resources http://www.oulu.fi/

2 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Introduction Spatial ecology - Animal Movement - Resource distribution (patches) Study species - Cabbage white butterfly (Pieris rapae) - Diamondback moth (Plutella xylostella) - Parasitoid wasps (Cotesia glomerata)

3 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Study species Herbivorous caterpillars Host plants are cabbages (Brassicaceae family) http://www.oulu.fi/ © Smithsonian Institute Cabbage White (Pieris rapae)Diamondback (Plutella xylostella)

4 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Parasitoids Cotesia glomerata Parasatised (brown) Pieris rapae pupa Cotesia glomerata emerge from Pieris larvae. © www.aries.ento.vt.edu/ento © Marc Hasenbank Parasitoid eggs.

5 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Foraging for an oviposition site

6 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Foraging for an oviposition site Which cabbage ?

7 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Hypotheses Define a relationship between - Number of eggs per plant - Density of plants in a patch Three alternatives….

8 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington 1 Ideal Free Distribution

9 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington 2 Resource concentration DRAW A PICTURE HERE Resource concentration hypothesis - Root (1973) Resource dilution hypothesis - Grez & Gonzalez (1995) Ideal free distribution - Fretwell & Lucas (1970)

10 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington 3 Resource Dilution Insert a picture here!!!

11 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Hypotheses Correlation between plant density and eggs per plant BUT … Density and Isolation depend on scale … Resource concentration Resource dilutionIdeal free distribution

12 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Density and Isolation are scale dependant 10 m 1 plant 20 plants, density = 0.2 plants / m 2

13 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Density and Isolation are scale dependant 30 m 1 plant 54 plants, density = 0.06 plants / m 2

14 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Density and Isolation are scale dependant 432 plants, density = 18.75 plants / m 2 90 m 1 plant Figures incorporating concept from S.Hartley

15 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Project Aims Create a simulation environment - Baseline from published simulation methods - Introduce biologically realistic mechanisms - Integrated statistical analysis, e.g. R ( http://www.r-project.org/ ) Investigate resource distribution hypotheses at different scales - How does the scale and pattern of movement relate to egg distributions at different scales ? - Move length, directionality, dispersal ability - Can we observe different effects at different scales ? Explore multi-species dynamics (Parasitoids)

16 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Existing Simulations Observational (Jones 1977) - Based on field observations - Maximum likelihood estimation for parameters Correlated Random walk (Cain 1985) - Importance of mortality Perceptual (Olden et al 2004) - E.g. Visual or Olfactory - Perceptual range

17 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Observational MOVE (directionality) LAY (plant species, plant age) STOP (plant species, plant age, fecundity of butterfly) CONT

18 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Correlated Random Walk Start Plant Radius of detection Figure from Cain (1985)

19 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Perceptual Olfactory / visual stimuli Direction influenced by stimuli Stimulus strength - Caterpillars munching Wind Start

20 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Methods Simulation framework (Java) - Provide a spatially and temporally explicit landscape - Continuous space - Grid-based view - Agents interact with landscape Common output allows different simulation methods to be compared

21 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington First Steps Random walk into a pit - Based on experiments using pitfall traps

22 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Summary Spatially explicit simulation Individual foraging behavior - Biological realism (olfactory and visual) - Effects of scale Resource concentration / dilution hypotheses Predator (Parasitoid) / Prey interactions http://www.oulu.fi/ Jim Barritt (jim@planet-ix.com)

23 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Acknowledgements Thanks to - Dr Stephen Hartley - Dr Marcus Frean - Marc Hasenbank - Victoria University Bug Group http://www.oulu.fi/ © Smithsonian Institute © www.aries.ento.vt.edu/ento

24 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington References Aldrich, J. (1997). R.A. Fisher and the making of maximum likelihood 1912-1922. Statistical Science 12, pp.162-176. Bukovinszky, T., R. P. J. Potting, Y. Clough, J. C. van Lenteren, and L. E. M. Vet. (2005). The role of pre- and post-alighting detection mechanisms in the responses to patch size by specialist herbivores. Oikos 109, pp. 435-446. Byers, J. A. (2001). Correlated random walk equations of animal dispersal resolved by simulation. Ecology 82, pp.1680-1690. Cain, M. L. (1985). Random Search by Herbivorous Insects: A Simulation Model. Ecology 66, pp. 876-888. Finch, S., and R. H. Collier. (2000). Host-plant selection by insects - a theory based on 'appropriate/inappropriate landings' by pest insects of cruciferous plants. Entomologia Experimentalis Et Applicata 96, pp. 91-102. Fretwell, S. D., and H. L. Lucas. (1970). On territorial behaviour and other factors influencing habitat distribution in birds. Acta Biotheoretica 19, pp. 16-36. Grez, A. A., and R. H. Gonzalez. (1995). Resource Concentration Hypothesis - Effect of Host-Plant Patch Size on Density of Herbivorous Insects. Oecologia 103, pp. 471-474. Holmgren, N. M. A., and W. M. WGetz. (2000). Evolution of host plant selection in insect under perceptual constraints: A simulation study. Evolutionary Ecology Research 2, pp. 81-106. Jones, R. E. (1977). Movement Patterns and Egg Distribution in Cabbage Butterflies. The Journal of Animal Ecology 46, pp. 195-212. Olden, J. D., R. L. Schooley, J. B. Monroe, and N. L. Poff. ( 2004). Context-dependent perceptual ranges and their relevance to animal movements in landscapes. Journal of Animal Ecology 73, pp. 1190-1194. Otway, S. J., A. Hector, and J. H. Lawton. (2005). Resource dilution effects on specialist insect herbivores in a grassland biodiversity experiment. Journal of Animal Ecology 74, pp. 234-240. Root, R. B. (1973). Organization of a Plant-Arthropod Association in Simple and Diverse Habitats: The Fauna of Collards (Brassica Oleracea). Ecological Monographs 43, pp. 95-124. Tilman, D., and P. M. Kareiva. (1997). Spatial Ecology: The Role of Space in Population Dynamics and Interspecific Interactions. Monographs In Population Biology 30

25 © Jim Barritt 2005School of Biological Sciences, Victoria University, Wellington Questions ? Spatially explicit simulation Individual foraging behavior - Biological realism (olfactory and visual) - Effects of scale Resource concentration / dilution hypotheses Predator (Parasitoid) / Prey interactions http://www.oulu.fi/ Jim Barritt (jim@planet-ix.com)


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