Introduction; 1. Are behavioural classifications blinders to natural variation?; 2. Life beneath silk walls: a review of the primitively social Embiidina; 3. Post-ovulation parental investment and parental care in cockroaches; 4. The spectrum of eusociality in termites; 5. Maternal care in the Hemiptera: ancestry, alternatives and current adaptive value; 6. Evolution of parental care in the giant water bugs (Heteroptera: Bolostomatidae); 7. The evolution of sociality in aphids: a clone's eye view; 8. Ecology and evolution of social behaviour among Australian gall thrips; 9. Interactions among males, females and offspring in bark and ambrosia beetles: the significance of living in holes for the evolution of social behaviour; 10. Biparental care and social evolution in burying beetles: lessons from the larder; 11. Subsocial behaviour in Scarabaeiinae; 12. Evolution of social behaviour in Passalidae (Coleoptera); 13. The evolution of social behaviour in the Augochlorine bees (Hymenoptera: Halicitidae) based on a phylogenetic analysis of the data; 14. Demography and sociality in halictine bees (Hymenoptera: Halictidae); 15. Behavioural environments of sweat bees (Halictinae) and variability in social organization; 16. Intrinsic and extrinsic factors associated with social evolution in allodapine bees; 17. Cooperative breeding in wasps and vertebrates: the role of ecological constraints; 18. Morphologically 'primitive' ants: comparative review of social characters, and the importance of queen-worker dimorphism; 19. Social conflict and cooperation among founding queens in ants (Hymenoptera: Formicidae); 20. Social evolution in the lepidoptera: ecological context and communication in larval societies; 21. Sociality and kin selection in Acari; 22. Colonial web-building spiders: balancing the costs and benefits of group living; 23. Causes and consequences of cooperation and permanent-sociality in spiders; 24. Evolution and explanation of social systems; Index.