Post on 04-Jul-2015
Competing for resource
Ch
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Evolutionaryily Stable Strategy(ESS) 演化穩定策略
A strategy that was adopted by all members of a population,
cannot be bettered by alternative strategy.
(Smith & Price, 1973)
ESS
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The Hawk-Dove game
Each strategy does best when it is relatively rare.
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The stable mixture
h = the proportion of Hawks in population
H average= -25h + 50 (1-h)
D average= 0 h + 25 (1-h)
h = 1/2
V<C
In V<C V/C (the stable proportion of Hawks)
If V>C, then Hawk is an ESS!
Competition by exploitation : the ideal free distribution
The ideal free model 理想自由模型 (Fretwell, 1972)
當資源豐富的棲地在有a個競
爭者的情況下,個體報酬會趨
近於競爭者較少的低資源棲地。
Fig. 5.1 The ideal free distribution. 5
Which line will you choose?
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Competing for food: sticklebacks and ducks
Competition by exploitation : the ideal free distribution
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Competing for food: sticklebacks (Milinski, 1979)
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(Milinski, 1979)
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B=2A A=2B
理想值
實驗平均值
Competing for food: Ducks (Harper, 1982)
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N=33
Numerical prediction 數值預測
Equal intake prediction 等量攝取預測
Prey risk prediction 獵物風險預測
Fish and Ducks settle in a stable distribution between feeding patches.
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Competing for mates: dung flies
What is the optimum time to spend waiting for females at each cowpat?
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(Parker, 1970)Males adopt evolutionarily stable waiting times.13
Fig. 5.3
牛糞上的雄糞蠅數量會
隨著時間的增加而減少
在不同的等待時間,
雄糞蠅的交配成功率皆一致
Competition by resource defence : the despotic distribution 專橫的分佈
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Fig. 5.4
(Brown, 1969)
The ideal free distribution with unequal competitors
The Competitive unit model
Hypothesis:
the number of competitive units ,
rather than the number of
individual, is equalized across
patches.
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(Parker & Sutherland, 1986)
2:1
8:4
8:4
Fig. 5.5
Habitat Selection
in Gill aphid (Whitham, 1978)
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窄葉楊
每片葉子上的雌蚜蟲數
每隻
雌蚜
蟲的
子代
數
葉片面積
繁殖成功率在不同數量
的競爭者皆無顯著差異
Fig. 5.6
Average success is equal on leaves of different quality,
but individuals near the leaf base do better.
Leaf is not a
homogeneous habitat.
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The economics of resource defence
Economic defendability 經濟的可防禦性 (Brown, 1964)
18Fig. 5.7
The Economics of territory defence in the
Golden-Winged sunbird
Box 5.1
(Gill & Wolf, 1975)
Forage time
Net energy saving
of defending
Extra cost of defence
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Metabolic costs
The economics of resource defence
Shared resource defence 資源的共同防禦
With satellite20
With satellite
NO satellite
Fig. 5.8
Producers and scroungers 生產者與投機者
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Fig. 5.9
Make the best of a bad job.
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The variable foraging techniques
of ruddy turnstone
Routingexpose prey
Stone
turning
Digging
Probing
Surface
pecking
Hammering
barnacles
(Whitfield, 1990)
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Dominant Subordinate
Routingexpose prey
Steal
Routing
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Variation could also be maintained in a
population even if there was no difference in
competitive ability between individuals.
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(Mottley & Giraldeau, 2000)The stable equilibrium frequency
of producers and scroungers
Covered Uncovered
pridected
stable
equilibrium
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Alternative mating strategies and tactics 替代的交配策略與戰術
Strategy
Tactic
A genetically based decision rule, so differences between
strategies are due to differences in gene.
A behaviour pattern played as part of a strategy.
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Natterjack toads:
callers & satellites
Conditional strategies with alternative tactics
(Arak, 1983)
兩倍
callers
satellites
Fig. 5.11
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Satellite males make adaptive choice concerning
which callers to parasitize.
Fig. 5.12
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Morphological switches with body size:
dung beetles and earwigs
Fig. 13
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Fig. 5.14
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The threshold morphological switch between alternative within a
conditional strategy. (Gross, 1996)
(Hunt & Smon, 2001)
閾值
Fig. 5.15
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(Emlen, 1996)
Use selection experiment shows : Threshold has a genetic basis
Fig. 5.16
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(Tomkins & Brown, 2004)
How selection has shifted a threshold switch in morphology
forceps
Knoxes Reef
Bass Rock
K
B
B
K
(北海上22個島上的結果)
Forcept變長能保護越多雌性
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Alternative strategies: equilibria and cycles 平衡與循環
參考fig.5.9 (b)
Proportion of scroungers
Fitn
ess
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Ruffs:
fighters, satellites and female mimics
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A marine isopod with three male morphs
alpha beta gamma
Each male morph gains equal success.
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Side-blotched lizards:
cycles of orange, blue and yellow
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