1. Cooperative Breeding Diversity and consequences Why not disperse? Why provide help? Conflict over reproduction (reproductive skew theory)

2. Diversity 220 species of birds have helpers at the nest 120 species of mammals have some form of alloparental care, e.g. communal nursing

3. Consequences Conclude: Helpers invariably increase offspring production

4. Why not disperse? Group living advantage Ecological constraints: habitat or mate saturation –Dispersal is difficult or risky –Species defend year-round all purpose territories –Residency improves competition for territories

5. Habitat saturation Seychelles warblers Acorn woodpeckers

6. Mate or nest limitation Superb blue fairy wren 1.8 breeding males/female; 1.5 helpers/nest Male dispersal Yes No Male removed and transplanted 31 1 Male and female removed 0 7 Red-cockaded woodpeckers Occupied next year Yes No New nest boxes in old territories 18 2 New nest boxes in similar habitat 0 20

7. Why provide help? Nonadaptive result of parental care Increase own survival –Improving survival of offspring increases group size Increase fecundity –Through practice - no evidence Enhance breeding opportunities Increase inclusive fitness

8. Why provide help? Enhance breeding opportunities –Helpers recruit offspring to join coalitions - green woodhoopoes –Gain access to mates - stripe-backed wrens Open = intact families Filled = families with female replacements

9. Why provide help? Increase inclusive fitness by decreasing parental feeding rate –W IF = W H + r BH W B –Increased breeding Grey-crowned babblers –Enhanced survival Florida scrub jays

10. Why provide help? Increase inclusive fitness by improving offspring survival –Reproductive success must correlate with helper number (independent of territory quality) –Must preferentially help close relatives

11. Is the benefit of helping independent of territory quality? Test by removing helpers then compare RS before vs after removal Conclude that helpers make a difference in babblers and scrub jays but not moorhens

12. Helpers are usually related Florida scrub jay Seychelles warbler White-fronted bee-eater

13. Bee-eaters help closest relatives When male breeding attempts fail

14. Helping increases inclusive fitness in pied kingfishers Males either help at home (primary helper), help elsewhere (secondary helper) or delay breeding for a year Total 0.99 0.84 0.29

15. Conflicts over reproduction Requirements –Ecological constraints limits dispersal –Group breeding enhances individual RS –Individuals in group vary in social dominance –Individuals in group are related

16. Reproductive skew theory W  = fitness of dominant W  = fitness of subordinate

17. Reproductive skew predictions If group is unrelated, subordinates should do no worse than if they left the group If group members are related, then subordinates should permit more skew and allow the dominant to reproduce for them

18. Reproductive skew evidence: paper wasps