【正文】 population. Densitydependent factor 密度制約因子 : 1. 種間因素 .食物、空間資源 ? 種內(nèi)、種間競爭 .病蟲害傳播速度 .個體成熟速度 .體質(zhì)和繁殖力、生長發(fā)育、自相殘殺、外遷 .植物結(jié)實(shí)數(shù)量 .抗逆性 在橡樹蛾的生活史裡，有不同的生活環(huán)境，不同的掠食者 ,寄生、競爭、環(huán)境壓力，在不同時期裡會有不同的死亡率。Chapter 10 Predation 169。 2020 by Prentice Hall, Inc. Upper Saddle River, NJ 07458 Outline ? There are a variety of antipredator adaptations, which suggests that predation is important in nature ? Predatorprey models can explain many outes ? Field data suggests that predators have a large impact on prey populations Outline ? Experiments involving the removal or introduction of exotic predators provide good data on the effects of predators on their prey ? Field experiments involving the manipulations of native populations show predation to be a strong force Equilibrium theories of population regulation ? A. Extrinsic biotic school – 1. Food supply and population regulation – 2. Predation and population regulation – 3. Disease and population ? B. Intrinsic school – 1. Stress and territoriality – 2. Geic polymorphism hypothesis – 3. Dispersal The causes of population change key factor analysis 主導(dǎo)因子分析 (一 ) Densitydependent factor 密度制約因子 : (種內(nèi)、種間因素 )作用強(qiáng)度隨種群密度而變。 .競爭 .掠食、寄生 .遺傳反饋機(jī)制 (抗病種的培育 ) 澳洲野兔 ? 粘液病毒 ? 抗病種 Density independent factor .氣候因素 .土壤因素 .營養(yǎng) .理化 .空間 .汙染 Extrinsic factors: External factors acting on populations . Predation, parasitism . Competition for food ? density depended . Competition for space ? density depended . Random stochastic change ? density independent . Weather 種群是一個具有自我調(diào)節(jié) (self regulation)機(jī)制的生活系統(tǒng)，可以按照自身的性質(zhì)及環(huán)境狀況調(diào)節(jié)它們的數(shù)量。llerian mimicry – Fritz M252。Reinforce basic distasteful design 187。Mimicry ring: a group of sympatric species, often different taxa, share a mon warning pattern ? Batesian mimicry – Henry Bates, 1862 – Mimicry of unpalatable species by palatable species Antipredator Adaptations ? Batesian mimicry (cont.) – Ex. hoverflies resemble stinging bees and wasps (Figure ) Antipredator Adaptations ? Difficulty distinguishing type of mimicry – Monarch butterflies and viceroy butterflies (Figures ,e) Antipredator Adaptations ? Displays of intimidation – Ex. Toads swallow air to make themselves appear larger – Ex. Frilled lizards extend their collars to produce the same effect (Figure ) Antipredator Adaptations ? Polymorphism – Two or more discrete forms in the same population – Color polymorphism ? Predator has a preference (usually the more abundant form) ? Prey can proliferate in the rarer form Antipredator Adaptations – Color polymorphism (cont.) ? Ex. leafhopper nymphs (orange and black) ? Ex. Pea aphids (red and green) – Reflexive selection ? Every individual is slightly different ? Examples: brittle stars, butterflies, moths, echinoderms, and gastropods Antipredator Adaptations – Reflexive selection (cont.) ? Thwart predators’ learning processes ? Prey phenologically separated from predator – Ex. Fruit bats ? Either diurnal or nocturnal ? Only nocturnal in the presence of predatory diurnal eagles Antipredator Adaptations ? Chemical defense – Used to ward off predators – Ex. bombardier beetles ? Possess a reservoir of hydroquinone and hydrogen perioxide ? When threatened, eject chemicals into “explosion chamber” Antipredator Adaptations – Ex. bombardier beetles (cont.) ? Mix with peroxidase enzyme ? Mixture is violently sprayed at attacker ? Masting – Synchronous production of many progeny by all individuals in population Antipredator Adaptations ? Masting (cont.) – Satiate predators – Allows for some progeny to survive – Common to seed herbivory – Ex. 17year and 13year periodical cicadas Antipredator Adaptations ? Comparison of defense mechanisms – Table , chemical defense is most mon PredatorPrey Models ? Effects of predators on prey ? Depend on such things as prey and predator densities, and predator efficiency ? Graphical method to monitor relationship PredatorPrey Models ? Graphical method to monitor relationship (cont.) – Prey isoclines have characteristic hump shape ? Figure Prey increase i) Prey iscoline K N N N N K 1 1 1 2 2 2 ii) Predator iscoline Prey density Predator increases Predator decreases Predator density Predator density PredatorPrey Models – Prey isoclines have characteristic hump shape (cont.) ? In the absence of predators, prey density would be equal to the carrying capacity, K1 ? Lower limit, individuals bee too rare to meet for reproduction PredatorPrey Models – Prey isoclines have characteristic hump shape (cont.) ? Between these two values, prey population can either increase or decrease depending on predator density ? Above the isocline, prey populations decline PredatorPrey Models – Prey isoclines have characteristic hump shape (cont.) ? Below the isocline, prey populations increase – Predator isoclines ? Threshold density, where predator population will increase ? Predator population can increase to carrying capacity PredatorPrey Models – Predator isoclines (cont.) ? Mutual interference or petition between predators – More prey required for a given density predator – Predator isoclines slopes toward the right – Superimpose prey and predator isoclines ? Figure PredatorPrey Models – Superimpose prey and predator isoclines (cont.) ? One stable point emerges: the intersection of the lines ? Three general cases – Inefficient predators require high densities of prey (Figure ) Damped oscillations Prey isocline Predator isocline a) PredatorPrey Models ? Three general cases (cont.) – A moderately efficient predator leads t