© jim barritt 2005school of biological sciences, victoria university, wellington msc student...

© 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/


Introduction

• Spatial ecology- Animal Movement

- Resource distribution (patches)

• Study species- Cabbage white butterfly (Pieris rapae)

- Diamondback moth (Plutella xylostella)

- Parasitoid wasps (Cotesia glomerata)


Study species

• Herbivorous caterpillars• Host plants are cabbages (Brassicaceae family)

http://www.oulu.fi/ © Smithsonian Institute

Cabbage White (Pieris rapae) Diamondback (Plutella xylostella)


Parasitoids

Cotesia glomerata Parasatised (brown) Pieris rapae pupa

Cotesia glomerata emerge from Pieris larvae.

© www.aries.ento.vt.edu/ento © www.aries.ento.vt.edu/ento

© www.aries.ento.vt.edu/ento

© Marc Hasenbank

Parasitoid eggs.


Foraging for an oviposition site


Foraging for an oviposition site

Which cabbage ?


Hypotheses

• Define a relationship between- Number of eggs per plant

- Density of plants in a patch

• Three alternatives….


1 Ideal Free Distribution


2 Resource concentration

• DRAW A PICTURE HERE

• Resource concentration hypothesis - Root (1973)

• Resource dilution hypothesis - Grez & Gonzalez (1995)

• Ideal free distribution- Fretwell & Lucas (1970)


3 Resource Dilution

• Insert a picture here!!!


Hypotheses

• Correlation between plant density and eggs per plant

• BUT …

• Density and Isolation depend on scale …

Resource concentration Resource dilution Ideal free distribution


“Density” and “Isolation” are scale dependant

10 m

10 m

1 plant

20 plants, density = 0.2 plants / m2



30 m

30 m

1 plant





90 m

90 m

1 plant

Figures incorporating concept from S.Hartley


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)


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


Observational

MOVE (directionality)

LAY (plant species, plant age)

STOP (plant species, plant age, fecundity of butterfly)

CONT


Correlated Random Walk

Start

Plant

Radius of detection

Figure from Cain (1985)


Perceptual

• Olfactory / visual stimuli

• Direction influenced by stimuli

• Stimulus strength- Caterpillars munching

• Wind

Start


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


First Steps

• “Random walk into a pit”- Based on experiments using pitfall traps


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 ([email protected])


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


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


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 ([email protected])

© jim barritt 2005school of biological sciences, victoria university, wellington msc student...

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