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Reared alone: phase solitaria

Phase change: the defining feature of locust biology. Reared alone: phase solitaria. Reared crowded: phase gregaria. High resolution correlate for studying underlying mechanisms. Basis for exploring population dynamics: individual-based models. Environment.

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Reared alone: phase solitaria

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  1. Phase change: the defining feature of locust biology Reared alone: phase solitaria Reared crowded: phase gregaria

  2. High resolution correlate for studying underlying mechanisms Basis for exploring population dynamics: individual-based models Environment Behaviour: the engine of phase change Temporal dynamics of behavioural change

  3. Step 1: Rearing locusts

  4. Step 2: Measuring behavioural phase state

  5. Behaviour 1 Behaviour 2 Behaviour 3

  6. Multiple logistic regression model

  7. ? p (solitary) = 1.0 p(solitary) = 0.5 p(solitary) = 0 Behaviour 1 Behaviour 2 Behaviour 3

  8. Step 3: Quantifying the time-course of behavioural phase change A. Gregarisation of solitarious insects

  9. Median p (solitary) B. Re-isolation of gregarised solitarious insects

  10. Median p (solitary) C. Solitarisation of gregarious insects

  11. F (time previously crowded) crowded isolated Also accumulates across generations: epigenetic maternal effect 1.0 p (solitary) 0.0 moult moult moult moult Time

  12. What stimuli cause behavioural gregarisation? 1. Sight of other locusts? 2. Smell of other locusts? 3. Contact with other locusts? (4. Sound of other locusts)

  13. Millet seed Locust surface wax extract Contact with others: 1. Mechanosensory 2. Contact chemosensory

  14. % gregarious 0-25 26-50 51-75 76-100 Where on the body surface are the active sites?

  15. Neural pathways of gregarisation *

  16. Correlated changes in CNS neuromodulators

  17. Epigenetic transfer of phase-state

  18. Dissecting the basis of epigenetic transfer Stage 1: Treat parents 1. Mother’s phase state: solitary- or crowd-reared 2. Father’s phase state: solitary- or crowd-reared 3. Mother alone or crowded from mating until oviposition Stage 2: test behavioural phase-state of hatchlings

  19. % of hatchlings

  20. What is the mother’s memory of crowding?

  21. How does the mother influence hatchling phase-state? Egg laying locust

  22. What is the gregarising agent? – extensive HPLC, MS and NMR analysis nearing completion Where is it produced?

  23. Source of extracts for treatment of eggs Accessory gland extract Oviduct fluid

  24. Ligaturing the accessory glands of gregarious females

  25. Using behaviour as a means to explore population dynamics

  26. Individual-based modelling RESOURCES CONCENTRATED RESOURCES DISPERSED

  27. food dispersed food clumped

  28. Interaction between spatial distribution and nutritional quality of food resources

  29. Into the real world….

  30. Effect of spatial distribution of food plants in adult environment on hatchling phase-state

  31. Epigenetic transfer of phase-state to offspring Interaction with resource distribution at small spatial scales Identification of gregarising stimuli Nutritional ecology: geometric analysis of nutrient balancing Discovery of maternal gregarising agent Analysis of neural bases of behavioural phase change Individual-based models Identification of site of production Laboratory and field testing Evolution of colour forms: gut-mediated protection, aposematism Molecular analysis of modulator/peptide profiles and testing of behavioural effects Interaction between spatial distribution and resource quality Mode of action Speciation within the genus Schistocerca and the ecological correlates of phase change Chemical analysis Nutrients vs. allelochemicals Molecular developmental mechanisms Exploration of larger spatial scales (metapopulation responses, GIS) Population genetics Synthesis Applied aim: Swarm prediction Applied aim: Phase manipulation The Oxford Desert Locust Phase Project Development of behavioural assay and description of time course of behavioural phase change

  32. The Oxford Desert Locust Phase Project Oxford group Steve Simpson Peter Roessingh Saiful Islam Bouaichi Abdelghani Bernd Haegele Neil Oldham Emma Despland Matthew Collett (individual-based modelling) David Krakauer (individual-based modelling) Tim Dodgson Robin Aplin (foam chemistry MS; Dyson Perrins) Tim Claridge (NMR; Dyson Perrins) David Raubenheimer (geometry of nutrition) Spencer Behmer (geometry of nutrition) Steve Rogers (neurobiology, also Cambridge) Collaborators Alan McCaffery (maternal effect; Reading) Greg Sword (colour morphs, aposematism, speciation; Austin, Texas) Arnold De Loof (peptide profiles; Leuven, Belgium) Paul Pener (stimuli eliciting non-behavioural phase characters) Frantisek Sehnal (ecdysteroids; Czech Republic) Bouaichi Abdelghani (field work; Morocco) Hans Wilps (field work; Mauritania) Jane Rosenberg (GIS modelling; NRI, Greenwich) Malcolm Burrows (neurobiology; Cambridge) Tom Matheson (neurobiology; Cambridge) Kamal Ibrahim (population genetics; East Anglia) Ian Wilson (foam chemistry MS-NMR; AstraZeneca, Maccelsfield) Eva Lentz (foam chemistry MS-NMR; AstraZeneca, Maccelsfield) Iain Couzin David Sumpter Philip Maini

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