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Ch05 competing for resource

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  • 1. Ch Competing for resource 1

2. Evolutionaryily Stable Strategy(ESS) (Smith & Price, 1973)A strategy that was adopted by all members of a population, cannot be bettered by alternative strategy.ESS2 3. The Hawk-Dove gameEach strategy does best when it is relatively rare. 3 4. The stable mixture VC, then Hawk is an ESS! 4 5. Competition by exploitation : the ideal free distributionThe ideal free model (Fretwell, 1972)a Fig. 5.1 The ideal free distribution.5 6. Which line will you choose? 6 7. Competition by exploitation : the ideal free distributionCompeting for food: sticklebacks and ducks7 8. Competing for food: sticklebacks (Milinski, 1979)8 9. B=2AA=2B(Milinski, 1979) 9 10. Competing for food: Ducks (Harper, 1982) N=3310 11. Fish and Ducks settle in a stable distribution between feeding patches. Numerical prediction Equal intake prediction Prey risk prediction11 12. Competing for mates: dung fliesWhat is the optimum time to spend waiting for females at each cowpat?12 13. Fig. 5.3 Males adopt evolutionarily stable waiting times.(Parker, 1970) 13 14. Competition by resource defence : the despotic distribution Fig. 5.4(Brown, 1969)14 15. The ideal free distribution with unequal competitors2:1 The Competitive unit model (Parker & Sutherland, 1986)Hypothesis: the number of competitive units , rather than the number of individual, is equalized across patches.8:48:4 Fig. 5.515 16. Habitat Selection in Gill aphid(Whitham, 1978) Fig. 5.616 17. Leaf is not a homogeneous habitat.Average success is equal on leaves of different quality, but individuals near the leaf base do better. 17 18. The economics of resource defenceEconomic defendability (Brown, 1964)Fig. 5.718 19. Box 5.1The Economics of territory defence in theGolden-Winged sunbird(Gill & Wolf, 1975)Metabolic costs Forage time Net energy saving of defending Extra cost of defence 19 20. The economics of resource defenceShared resource defence With satellite NO satelliteWith satellite Fig. 5.820 21. Producers and scroungers Fig. 5.9Make the best of a bad job.21 22. The variable foraging techniques of ruddy turnstone(Whitfield, 1990)Routing expose preyHammering barnaclesStone turningSurface peckingDigging Probing 22 23. DominantSubordinate RoutingRoutingStealexpose prey23 24. Variation could also be maintained in a population even if there was no difference in competitive ability between individuals.24 25. The stable equilibrium frequency of producers and scroungersCovered(Mottley & Giraldeau, 2000)Uncoveredpridected stable equilibrium25 26. Alternative mating strategies and tactics StrategyA genetically based decision rule, so differences between strategies are due to differences in gene. TacticA behaviour pattern played as part of a strategy.26 27. Conditional strategies with alternative tactics Natterjack toads: callers & satellites(Arak, 1983) callers satellitesFig. 5.11 27 28. Satellite males make adaptive choice concerning which callers to parasitize.Fig. 5.12 28 29. Morphological switches with body size: dung beetles and earwigsFig. 13 29 30. Fig. 5.14 30 31. The threshold morphological switch between alternative within a conditional strategy. (Gross, 1996) (Hunt & Smon, 2001) Fig. 5.1531 32. Use selection experiment shows : Threshold has a genetic basis (Emlen, 1996)Fig. 5.1632 33. forcepsHow selection has shifted a threshold switch in morphology(Tomkins & Brown, 2004) Knoxes Reef Bass RockBKK B (22) Forcept33 34. Alternative strategies: equilibria and cycles Fitnessfig.5.9 (b)Proportion of scroungers 34 35. Ruffs: fighters, satellites and female mimics35 36. A marine isopod with three male morphs alphabetagammaEach male morph gains equal success. 36 37. Side-blotched lizards: cycles of orange, blue and yellow37 38. Thanks for your Listening38