Acacia and Acacia ants

1. Defensive Mutualisms – Trade protection for food Acacia and Acacia ants

3. Induced and Constitutive Defenses in Acacia. The species in the right-hand column have mutualistic relationships with ant species - the ants nest in the thorns. Those on the left can attract ants with extra-floral nectary secretions, but the ants do not nest. The Acacia species on the left increase their nectar secretions after damage, inducing wandering ants to come visit and stay a while. The species on the right have to support the ant colonies all the time, and nectar production is uniformly high and unaffected by damage.

4. Induced and Constitutive Defenses in Acacia. The species in the right-hand column have mutualistic relationships with ant species - the ants nest in the thorns. Those on the left can attract ants with extra-floral nectary secretions, but the ants do not nest. The Acacia species on the left increase their nectar secretions after damage, inducing wandering ants to come visit and stay a while. The species on the right have to support the ant colonies all the time, and nectar production is uniformly high and unaffected by damage. WHICH CAME FIRST??

5. Induced and Constitutive Defenses in Acacia. Induced defenses first, then the obligate relationship evolved…

6. Todd M. Palmer,Maureen L. Stanton, Truman P. Young,Jacob R. Goheen,Robert M. Pringle,Richard Karban. 2008. Breakdown of an Ant-Plant Mutualism Follows the Loss of Large Herbivores from an African Savanna. Science 319:192-195. Fig. 1. Rewards produced in the presence (white bars) and absence (gray bars) of large herbivores by A. drepanolobium occupied by different species of Acacia ants. Ant species' abbreviations are indicated as: Cs, C. sjostedti; Cm, C. mimosae; Cn, C. nigriceps; Tp, T. penzigi. Plants produce fewer rewards and fewer thorns when large herbivores are absent and herbivory rates are LOWER. Bribing ants to stay and protect them is less important.

7. Todd M. Palmer,Maureen L. Stanton, Truman P. Young,Jacob R. Goheen,Robert M. Pringle,Richard Karban. 2008. Breakdown of an Ant-Plant Mutualism Follows the Loss of Large Herbivores from an African Savanna. Science 319:192-195. Fig. 2. The proportion of host trees occupied by the four Acacia-ant species in the presence of large herbivores (white bars) and in plots from which large herbivores had been excluded (gray bars) for 10 years. And if large herbivores are excluded and plants produce less nectar, then some ants abandon the trees (the mutualist).

8. “Our results indicate that the large herbivores typical of Africansavannas have driven the evolution and maintenance of a widespreadant-Acacia mutualism and that their experimentally simulatedextinction rapidly tips the scales away from mutualism and towarda suite of antagonistic behaviors by the interacting species.Browsing by large herbivores induces greater production of nectaryand domatia rewards by trees, and these rewards in turn influenceboth the behavior of a specialized, mutualistic ant symbiontand the outcome of competition between this mutualist and anon-obligate host-plant parasite. Where herbivores are present,the carbohydrate subsidy provided by host trees plays a keyrole in the dominance of the strongly mutualistic C. mimosae,which is consistent with the hypothesis that plant exudatesfuel dominance of canopy ant species that are specialized usersof these abundant resources (28). In the absence of large herbivores,reduction in host-tree rewards to ant associates results ina breakdown in this mutualism, which has strong negative consequencesfor Acacia growth and survival. Ongoing anthropogenic loss oflarge herbivores throughout Africa (29, 30) may therefore havestrong and unanticipated consequences for the broader communitiesin which these herbivores occur.” Todd M. Palmer,Maureen L. Stanton, Truman P. Young,Jacob R. Goheen,Robert M. Pringle,Richard Karban. 2008. Breakdown of an Ant-Plant Mutualism Follows the Loss of Large Herbivores from an African Savanna. Science 319:192-195.

9. Defensive Mutualisms – Trade protection for food Ants ‘farm’ aphids and drink their ‘honeydew’

10. Cleaning Mutualisms – Trade cleaning for food

11. Cleaning Mutualisms – Trade cleaning for food

12. Cleaning Mutualisms – Trade cleaning for food Fish visit non-cheating cleaners more And watched cleaners cheat less.

14. Dispersive Mutualisms – Trade dispersal for food

15. Dispersive Mutualisms – Trade dispersal for food

16. Dispersive Mutualisms – Trade dispersal for food Not mutualism (commensal or parasitic)

17. Mutualisms in Mimicry: “Mullerian” mimicry – toxic species resemble one another

19. Population Ecology I. Attributes II.Distribution III. Population Growth – changes in size through time IV. Species Interactions V. Dynamics of Consumer-Resource Interactions VI. Competition VII. Mutualisms VIII. Evolutionary Responses to Species Interactions Why won’t this population unit end?

21. Population Ecology I. Attributes II.Distribution III. Population Growth – changes in size through time IV. Species Interactions V. Dynamics of Consumer-Resource Interactions VI. Competition VII. Mutualisms VIII. Evolutionary Responses to Species Interactions The abiotic environment is often stable, or at least predictable. Other species in the environment are always changing, sometimes as a direct result of changes in other species.

22. “Now, here, you see, it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!”

23. A. Coevolution in Consumer-Resource Relationships: One species is evolving to ‘escape’ the relationship, the other to enhance it. “Arms Race” - crypsis and detection Predation

24. Coevolution in Consumer-Resource Relationships: One species is evolving to ‘escape’ the relationship, the other to enhance it. “Arms Race” - crypsis and detection

25. Coevolution in Consumer-Resource Relationships: One species is evolving to ‘escape’ the relationship, the other to enhance it. “Arms Race” - crypsis and detection

26. Coevolution in Consumer-Resource Relationships: One species is evolving to ‘escape’ the relationship, the other to enhance it. “Arms Race” - crypsis and detection

27. Coevolution in Consumer-Resource Relationships: One species is evolving to ‘escape’ the relationship, the other to enhance it. “Arms Race” - crypsis and detection

28. Coevolution in Consumer-Resource Relationships: One species is evolving to ‘escape’ the relationship, the other to enhance it. “Arms Race” - crypsis and detection

29. Coevolution in Consumer-Resource Relationships: One species is evolving to ‘escape’ the relationship, the other to enhance it. “Arms Race” - poisons and detoxification

30. Coevolution in Consumer-Resource Relationships: One species is evolving to ‘escape’ the relationship, the other to enhance it. “Arms Race” - poisons and detoxification

31. Coevolution in Consumer-Resource Relationships: One species is evolving to ‘escape’ the relationship, the other to enhance it. “Arms Race” - poisons and detoxification

32. Coevolution in Consumer-Resource Relationships: One species is evolving to ‘escape’ the relationship, the other to enhance it. “Arms Race” - poisons and detoxification

33. Coevolution in Consumer-Resource Relationships: One species is evolving to ‘escape’ the relationship, the other to enhance it. “Arms Race” - Mimicry “Batesian” mimicry – palatable mimic looks like a toxic/dangerous model

35. Plant “crypsis” and “mimicry” Heliconius and Passiflora

36. Plant “crypsis” and “mimicry” Heliconia and Passiflora

37. Host-pathogen “arms races”

38. B. Evolution of Competitors - competitive ability can evolve - can result in character displacement No positive feedback Competition

39. A. Coevolution in Consumer-Resource Relationships: B. Evolution of Competitors C. Coevolution of Mutualists Positive, coevolutionary feedback. Mutualism

40. A. Coevolution in Consumer-Resource Relationships: B. Evolution of Competitors C. Coevolution of Mutualists D. Relationships Change A. Competition Facilitation Initially facultative (commensal) relationships, like one plant shading another in the desert) can become competitive when they are large.

41. A. Competition Facilitation Trees may compete for light aboveground, but share nutrients via mycorrhizal fungi belowground – even between species

42. A. Competition Facilitation Old dieing trees shunt nutrients to younger trees – even between species- through mycorrhizal networks. May be change in relationships with the fungus, whereby ‘old tree’ is being parasitized while young tree is being facilitated. Net result is shunting of carbon.

43. Mutualism Parasitism Orchids, Euglossine Bees, and Wasps.

44. B. Mutualism Parasitism