Chap.10 Predation

1. Chap.10 Predation 鄭先祐 生態主張者 Ayo工作室

2. Fig. 10.1 Predation takes many forms (a) A double crested cormorant actively seeks and chases its fish prey. Ecology 2001 Chap.10 Predation

3. Fig. 10.1 Predation takes many forms (b) A little blue heron waits motionless to ambush its prey. (fish) Ecology 2001 Chap.10 Predation

4. Fig. 10.1 Predation takes many forms (c) A minke whale feeds on vast numbers of small crustaceans in the Antarctic ocean. Ecology 2001 Chap.10 Predation

5. Fig. 10.1 Predation takes many forms (d) A pitcher plant in a bog traps insects in its highly modified leaves. Ecology 2001 Chap.10 Predation

6. Fig. 10.1 Predation takes many forms (e) Insect larvae graze on the stems and leaves of fireweeds.. Ecology 2001 Chap.10 Predation

7. Fig. 10.1 Predation takes many forms (f) A moose feeds in the same patch of fireweed.. Ecology 2001 Chap.10 Predation

8. Predation • Carnivorous predation • Herbivorous predation • Optimal Foraging theory • Community-level effects of predation • Environmental application: Biological control of pests: Putting predators to work Ecology 2001 Chap.10 Predation

9. Carnivorous predation • Predator adaptations • Prey detection and recognition • Tactics for capturing prey • Prey adaptations • Avoiding detection • Avoiding capture • Disrupting predator handling Ecology 2001 Chap.10 Predation

10. Prey detection and Recognition • Resolving power of a bald eagle’s eye is approximately that of a pair of 7 x binoculars. • Smell (chemoreception) • Sound (Fig. 10.2 owls) • Electric fields to detect prey Ecology 2001 Chap.10 Predation

11. Fig. 10.2 The circles around the eyes of many species of owls are parabolic reflectors that help gather sound and channel it to the ears. Ecology 2001 Chap.10 Predation

12. Fig. 10.3 pulses(solid lines) emitted by a bat and echoes(dashed lines) received by the bat as it approaches and object. Ecology 2001 Chap.10 Predation

13. Tactics for capturing prey 分類： • Ambush its prey or actively seeks them • Hunts singly or in groups Ecology 2001 Chap.10 Predation

14. Fig. 10.4 Foraging success of captive black-headed gulls in flocks of different sizes. Ecology 2001 Chap.10 Predation

15. Prey adaptations • Avoiding detection Fig. 10.5 a white-tailed ptarmigan. Ecology 2001 Chap.10 Predation

16. Fig. 10.5b. The American bitten are examples of cryptic coloration. Ecology 2001 Chap.10 Predation

17. 隱藏的方法 • Its color matches the background. • Its shape is asymmetrical. • It is counter-shaded (the lower part of the body is light and upper part is dark) • Its outline blend into the background. • Its eyes are hidden. • It remains motionless. Ecology 2001 Chap.10 Predation

18. Avoiding capture • Antelope 快跑。 • 警告聲音。 • 停止不動。 • Provide False targets • Some marine invertebrates use flashes of bioluminescence to startle predators. • Safety in numbers strategy. Ecology 2001 Chap.10 Predation

19. Fig. 10.6 increase in musk ox group size as a function of wolf density in winter and summer. Ecology 2001 Chap.10 Predation

20. Fig. 10.7 Relative amount of the average total risk of predation incurred by Atlantic siversides in six positions within a school under attack by launchers and passers.F= front; B= back; O= outside; TM = true middle; CM= confused middle; AA = after attack. Ecology 2001 Chap.10 Predation

21. Fig. 10.7 Relative amount of the average total risk of predation incurred by Atlantic siversides in six positions within a school under attack by launchers and passers.F= front; B= back; O= outside; TM = true middle; CM= confused middle; AA = after attack. Ecology 2001 Chap.10 Predation

22. Predator swamping Fig. 10.8 The relationship between average effective brood size at fledging and hatch date in snow geese. Ecology 2001 Chap.10 Predation

23. Disrupting predator handling • The development of significant defensive weapons such as antlers, horns, shells, and chemical deterrents. • In the newt, Taricha torosa, a potent neurotoxin called tetrodotoxin acts as a chemical deterrent to predation. Ecology 2001 Chap.10 Predation

24. Herbivorous predation • 1. 植物的生產力和營養成分，隨著季節而有所不同。掠食者必要把握機會，配合green wave。 • 2. 植物有anti-grazing strategy。 • Koala 專食eucalyptus trees的樹葉。Eucalyptus樹葉，營養低，且含有lignin 和tannin，降低消化。Koala的代謝率低，直腸很長，食物留在腸子的時間很長(8天)。 • Monarch 蝴蝶的幼蟲，吃食含有毒素的葉子，這使Monarch蝴蝶的成蟲體內含有毒素。 • Squash 甲蟲使用行為的方法避開植物的化學防衛。先剪斷葉片的主要葉脈，是其無法傳導入化學物質，然後再吃葉片。 Ecology 2001 Chap.10 Predation

25. Two fundamental groups • Stealthy herbivores and Opportunistic herbivores • Stealthy herbivores：專精的覓食方式 • Opportunistic herbivores：大量多樣覓食的方式。 Ecology 2001 Chap.10 Predation

26. Ecology 2001 Chap.10 Predation

27. Plant adaptations to herbivores • Structural and chemical adaptations • Two hypotheses of the origin of Secondary compounds. • Secondary compounds, produced as by-products of plant metabolism and co-opted for defense because of their toxic nature. • These compounds are evolved de novo in response to grazing as a selection pressure. The energetic cost to the plant is high. Ecology 2001 Chap.10 Predation

28. 圖10.9 Lotus corniculatus可產生氰酸的植物體比率。比較溫暖的地區，比率較高。這與掠食壓力相關。 Ecology 2001 Chap.10 Predation

29. 範例： • 抗掠食的Secondary compounds 不僅發現在被子植物和裸子植物，而且也發生在低等植物。 • 譬如：cyano-bacteria (藍綠藻)，珊瑚礁的藻類，海草 (Fig. 10-10)。 • 當有掠食壓力時，Brown alga(Disyota manstrualis)會產生高濃度的diterpenoid dictyols。而其旁邊的同種個體，若沒有掠食壓力，則不會產生。 • 有蟲吃的Birch，隔年的樹葉，於其樹葉上吃食的蟲子營養都不良。原因是Birch 產生defense chemistry. Ecology 2001 Chap.10 Predation

30. 圖10.10 海草產生的六種代謝物質，對掠食者的影響力。 Ecology 2001 Chap.10 Predation

31. Allocation of resources to defense in Plants • Availability of plants to herbivores. • Plant architecture • Seasonal scarcity • Involvement of specialized herbivores Ecology 2001 Chap.10 Predation

32. The effects of herbivores • Consumption of plant parts is known to have negative effects. • However, some evidence suggests that the activity of herbivores has beneficial effects. • Grazing increases seed production, increases biomass production, increases nutrient content. Ecology 2001 Chap.10 Predation

33. 範例：Scarlet gilia • Grazing pressure by mule deer and elk was intense on their Arizona study sites. • The grazers fed on nearly 75% of all plants and removed as much as 95% of the above ground biomass. • When a single stalk was eaten, however, it was replaced with four new stalks. • 被掠食的植物體比沒有被掠食的植物體，可產生高達3.05倍的種仔。其fitness 比是2.4 : 1。 Ecology 2001 Chap.10 Predation

34. 圖10.12 Fruit production in matched pairs of plants of Scarlet gilia. Ecology 2001 Chap.10 Predation

35. Optimal foraging theory • Energy maximizers • Time maximizers Fundamental assumptions of the theory are: • Foraging behavior has a genetic basis • Fitness is related to the net energy intake. Ecology 2001 Chap.10 Predation

36. Optimal diet • E/h , where E is the energy in the diet and h is the handling time (or energy) required to capture, subdue, and consume the diet. • E / (s + h), where s is the search time. • Ei/hi >= E / (s + h) • i食物的能量價值必要高於目前的平均價值，掠食者才有可能轉而向i食物。 Ecology 2001 Chap.10 Predation

37. Optimal use of food patches • 掠食者停留於同一個覓食區的時間長短，這與移動到另一個覓食區所需要花的時間(travel time)長短有關。 • Fig. 10.13 Optimal patch theory. Ecology 2001 Chap.10 Predation

38. T1較小，離開的時間較快。 T2較長，離開的時間會較慢。 圖10.13 The curve depicts the cumulative amount of energy gained as a function of the amount of time a predator stays in a patch. Ecology 2001 Chap.10 Predation

39. Environmental application Biological control of pests: putting predators to work • Pests and weeds cause tremendous damage to both natural and agricultural habitats. • Some of these pests are exotic species, accidentally or intentionally introduced to regions beyond their natural range. • 若是使用殺蟲劑，至少有兩個問題： • 1. The targets of the chemicals develop resistance. (抗藥性) • 2. These toxins may themselves pose serious environmental problems. • 因此有所謂的 biological control Ecology 2001 Chap.10 Predation

40. Fig. 10B.1 A classic type of biological control in which the average abundance of an insect pest is reduced after the introduction of a predator. Ecology 2001 Chap.10 Predation

41. Integrated pest management • IPM, a program of carefully selected control techniques tailored to address each particular insect pest problem. • Insect numbers are monitored carefully and population models are used to predict irruptions of the pest. • Insecticides are used only sparingly and locally in response to this information. • Natural predators or parasites are released widely in areas of local infestation. • Sterilization procedures or sex pheromones may be used. Ecology 2001 Chap.10 Predation

42. 範例：運用IPM控制gypsy moth • 意外的被引進Massachusetts in 1869. • The population exploded across the northeastern US, defoliating many hectares of forest. • IPM 包含：pesticides, two species of parasitic flies and sex pheromones. Ecology 2001 Chap.10 Predation

43. Fig. 10B.2 The rapid increase in the distribution of the gypsy moth after its introduction to North America. Ecology 2001 Chap.10 Predation

44. 問題與討論！ ayo@faculty.pccu.edu.tw Ayo 文化站http://faculty.pccu.edu.tw/~ayo Ecology 2001 Chap.10 Predation