CONFLICT AND COOPERATION

1. CONFLICT AND COOPERATION • Jacobus J. Boomsma • Institute of Biology • University of Copenhagen Sex Parasitism versus Mutualism Resource Allocation

2. Cooperation does not come easy • Who gives alarm calls? • Can policing and punishment evolve? • Are policing and punishment necessary for stable cooperation? • How important are kinship and reciprocity? • How special are human societies? • Reciprocal exploitation and conflicts in mutualisms

3. Evolution is essential for all biology “Nothing in biology makes sense, except in the light of evolution” (Dobzhansky, 1973)

4. A Portrait Gallery of Evolutionary Biologists 1800 1850 1900 1950 2000 Source of inspiration Darwin Malthus Wallace

5. A Portrait Gallery of Evolutionary Biologists 1800 1850 1900 1950 2000 Source of inspiration Darwin Malthus Mendel Wallace

6. A Portrait Gallery of Evolutionary Biologists 1800 1850 1900 1950 2000 Source of inspiration Fisher Darwin Malthus Haldane Mendel Wallace Wright

7. A Portrait Gallery of Evolutionary Biologists 1800 1850 1900 1950 2000 Source of inspiration Fisher Darwin Dobzhansky Malthus Haldane Mendel Mayr Wallace Wright

8. The roots of Behavioral Ecology: Tinbergen, Hamilton and Williams Tinbergen (1963) Survival value of behaviour Williams (1966) The first synthesis Hamilton (1964) Evolutionary roots of social behaviour

9. Ecology is essential for understanding evolution • “ Nothing in biology makes sense, except in the light of evolution ” (Dobzhansky, 1973) • “ Very little in evolution makes sense except in the light of ecology ”(Townsend, Harper & Begon, 2000) “Ecology provides the stage on which the “evolutionary play” is performed”

10. Darwinian Ecology Evolutionary Ecology proper (animals, plants, micro-organisms) Behavioural Ecology (animals) Sociobiology (social animals)

11. Darwinian Ecology Kin selection: The only real Innovation after Darwin e.g. Life Histories Natural selection and Sexual selection

12. Darwinian sexual selection Female choice Male-male competition

13. Darwin’s Problem with Insect Societies “ I……… will confine myself to one special difficulty, which at first appeared to me insuperable, and actually fatal to my whole theory. I allude to the neuters or sterile females in insect communities: for these neuters often differ widely in instinct and in structure from both the males and the fertile females, and yet, from being sterile, they cannot propagate their kind.”Darwin (1859) “The Origin of Species” queen workers

14. Hamilton’s Solution • Reproductive “altruism” evolves when:br > c • b = benefit (extra offspring of relatives raised because of helping) • r = relatedness of donor to recipient • c = cost (own offspring not raised due to helping)

15. Parent-offspring conflict (Trivers 1974) • Benefits gradually decrease per u.o.i. • Costs stay constant or increase • Parents weigh costs and benefits equally • Offspring discount parental costs by their average relatedness to future sibs

16. Parent-offspring conflict (Trivers 1974) • Young want more PI (y) than parents are selected to provide (p) • y-p is even larger when current of future sibs have a different father (maximize B – C/4) • Mother equally related to all offspring • Offspring related to itself by r=1

17. Parents Offspring Dad 1 Mom Dad 2 r = 0.5 r = 1.0 r = 0.5 r = 0.25 Genetic relatedness Parent-offspring conflict theory R.L. Trivers Parent-offspring conflict and sib-rivalry are relatedness-linked

18. 1 Swap? 1 Defect Cooperate Defect 1 2 2 2 2 2 2 1 1 1 Cooperate Reciprocal altruism -The “ prisoner’s dilemma ” “Defection” is favoured. Mutual cooperation only pays in repeated exchanges.

19. “Good for the species arguments” “ Nature, red in tooth and claw ”Tennyson (1850) • Merciless • Exploitative • Fundamentally selfish • Cooperation in nature needs to be explained by individual (gene) level selection and not by group selection

20. From centimeters…... Insect colonies as model systems 2 cm 2 cm Simple ant colony in an acorn Primitive wasp colony

21. …. to meters Large insect colonies 2 cm Previous slide 2 m Length: ~100 x Area: ~10 000 x Mass: ~1 000 000 x Advanced tropical antcolony

22. Long-lived Elaborate nests Large colonies are like societies Tropical honey bee Tropical termite Tropical wasp

23. x Parents complex half-sib family daughter queen mates and takes over x offspring x x simple full-sib family x Simple and complex family structures

24. Queens are specialized egg-laying females Single queen per colony Multiple queens per colony

25. Queen ovaries worker ovaries workers Mother queen Not mated No stored sperm no Fertiliz ation Fert ilization no Fertiliz ation father queen sons worker sons queen daughters Reproduction in haplodiploid social insects (ants, bees, wasps)

26. Relatedness consequences of haplodiploidy Reproductive Conflict over Sex ratio and Male production workers Mother queen 0.25 0.25 0.50 0.50 0.75 0.50 (own son) 0.375 (other worker’s son) father 0.25 0.50 0.00 queen son worker son queen daughter

27. The conflict over Male Production When there are more half sisters than full sisters workers are selected to remove each other’s eggs workers Mother queen 0.25 0.25 0.50 0.50 0.75 0.50 (own son) 0.375 (other worker’s son) father 0.25 0.50 0.00 queen son worker son queen daughter

28. Worker-Queen Conflict in Ants, Bees, Wasps • Worker control over sex allocation is common • Worker production of males is not

29. In species with small colonies many try to reproduce but queens manipulate reproduction to their own advantage Who wins reproductive conflicts ? Queens always win in Bumblebees

30. In species with large colonies queens monopolize reproduction but workers raise sisters or brothers depending on their own best interests Who wins reproductive conflicts ? Workers tend to win sex ratio conflicts in large ant societies

31. Nepotism is prevented by worker policing • Queen eggs are marked with a queen pheromone • Worker male eggslack this pheromone • Worker eggs arerecognised by other workers and removed • Worker policing is evolutionary stable in honey bees Photos and data: Francis Ratnieks

32. Cooperation does not come easy • Who gives alarm calls? • Can policing and punishment evolve? • Are policing and punishment necessary for stable cooperation? • How important are kinship and reciprocity? • How special are human societies? • Reciprocal exploitation and conflicts in mutualisms

33. How special are Human Societies? • We have culture !!! • But is culture really 100% independent of genes? • How relevant is fitness in human societies and can it be measured? • Do humans fit inclusive fitness theory? • If so, what does this imply? • Cooperation does not come easy

34. nitrogen binding bacteria mycorrhizae corals chloroplasts gut bacteria lichens mitochondria termites and fungi ants and fungi Mutualistic Symbiosis and Co-evolution Ectosymbionts of Insect Societies

35. The Conceptual Paradigm “Many of the benefits sought by living things are disproportionally available to co-operating groups...... The problem is that while an individual can benefit from mutual co-operation, each one can also do even better by exploiting the co-operative efforts of others”. R. Axelrod and W.D. Hamilton, The evolution of co-operation. Science 211: 1390-1396 (1981)

36. When and Why do Symbiotic Partners Cooperate? • Exploitation and monopolization of novel resources • Sufficient alignment of reproductive interests to stabilize interactions in spite of potential conflict • ....... i.e., to allow Stable Bilateral Exploitation

37. Attine Ants in Panama Macrotermitinae in West Africa Agricultural Insect Societies

38. Attine antsFungus growing termites

39. Fieldwork in Panama Smithsonian Tropical Research Institute Panama Canal

40. Mycocepurus nest Ant fungus-farming started simple Dead Substrate: Leaf debris Wood chips Insect body parts Insect frass

41. Ant Phylogeny: Schultz & Meier (1995) and Schultz et al.unpublished Mueller et al., 1998 Fungus rearing Special Clones Leafcutting Herbivory The evolutionary history of fungus-growing ants Lower Attines Higher Attines Large Colonies Leafcutters

42. Ant agriculture became “herbivorous”, ……

43. Split into two genera, …… One of which became really dominant, ……

44. Damaging, ……

45. Biggggg.. An underground metropolis which may live for decades A society with millions of workers, all daughters of the same long-lived queen After Jonkman

46. Acromyrmex Atta From Hölldobler and Wilson, 1990 castes gongylidia anal droplets The Leafcutter Ants And highly sophisticated

47. How an Atta colony starts fungus fragment Winged queen and male One year old nest

48. And What it Finally Becomes

49. Fungus rearing Assembly Lines • Evolution towards clonal fungi • More genetic diversity of ants per nest via multiple queen mating • Worker policing phenomena expected Ongoing work Mischa Dijkstra Photo: Mark W. Moffett

50. Microsatellite tandem repeat sequence # repeats variable among individuals Genetic Marker Studies