1. Characteristics of eusocial societies
1. Group Living
2. Overlap of Two or More Generations
3. Cooperative Care of the Young
4. Reproductive Division of Labor - reproductive skew
Helping instead of reproducing is altruistic. This was a HUGE problem for Darwin - thought that it doomed natural selection. Darwin was a great thinker, though!

2. Where has eusociality evolved (sterility)?
Taxa number of times
Insects:
Hymenoptera Ants, bees, wasps 11
Isoptera Termites 1
Homoptera Gall-forming aphids 1
Coleoptera Bark-nesting weavils 1
Thysanoptera Gall-forming thrips 1
Non-insects
Snapping shrimps and naked mole rats 2
Total

3. Evolution of Social Behavior in Hymenoptera

5. Eciton burchelli, photo Alex Wild

7. number of new workers (log)
current number of workers (log)

8. Gall Aphids

9. Social Australian gall thrips

10. Synalpheus regalia

11. From Duffy 1996 Nature

12. Naked Mole Rats

13. Eusociality has Evolved Twice in Molerats

14. Live in:
Large under ground tunnel systems
Harsh environments
Dispersal is very costly
(there may even be a “dispersal caste”)

15. Something in common among these groups?
Live and feed in highly specialized habitat they created (or modified) that is defensible by specialized casts.

16. Something in common among these groups?
Can have large numbers of individuals (up to many million), facilitating the acquisition of resources and production of new individuals.

17. Something in common among these groups?
Next time… division of labor.