In this book, the biologist Raghavendra Gadagkar focuses on the single species he has worked on throughout his career. Found throughout southern India, Ropalidia marginata is a primitively eusocial wasp--a species in which queens and workers do not differ morphologically and even the latter retain the ability to reproduce. New colonies may be founded by a single fertile female or by several, which then share reproductive and worker duties.
R. marginata has provided Gadagkar with a unique opportunity to study the evolution of eusociality; its long-lived dynasties can continue almost indefinitely, as old or weakened queens are replaced by young and healthy ones and new colonies are founded throughout the year. Understanding such primitively eusocial species is crucial, Gadagkar argues, if we are to understand the evolution of the greater degrees of sociality found in other wasp species and in ants, termites, and bees. His years of study have led him to believe that ecological, physiological, and demographic factors can be more important than genetic relatedness in the selection for or against social traits.
Raghavendra Gadagkar is Professor and Chairman of the Centre for Ecological Sciences, Indian Institute of Science, and Honorary Professor at the Jawaharlal Nehru Centre for Advanced Scientific Research in Bangalore, India.
Preface Part I: Introduction 1. A Primer of Eusociality 2. In Praise of Ropalidia Part II: Social Biology 3. Some Methodological Necessities 4. Natural History 5. Behavioral Caste Differentiation 6. Dominance Behavior and Regulation of Worker Activity 7. Age and Division of Labor Part III: The Evolution of Eusociality 8. The Theoretical Framework 9. Genetic Predisposition I: Intracolony Genetic Relatedness 10. Genetic Predisposition II: Kin and Nestmate Recognition 11. Ecological Predisposition 12. Physiological Predisposition 13. Demographic Predisposition 14. Synthesis 15. Factors That Remain to Be Explored Part IV: Beyond Ropalidia marginata: Social Evolution, Forward and Reverse 16. A Route to Sociality 17. The Evolution of Caste Polymorphism 18. Reverse Social Evolution Summary References Index