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Professor W301 Seeley G. Mudd Hall |
My scientific work focuses on understanding one of the five major transitions in evolution, namely the transition from organism to group as the highest level of functionally organized entity. Relative to the four other major transitions-from replicator to prokaryotic cell, from prokaryotic to eukaryotic cell, and from eukaryotic cell to multicellular organism, the organism-to-group transition is by far the most easily studied. To understand this transition, we must solve two puzzles: Why is there strong cooperation among the members of a highly integrated group? and How do the members of such a group work together as an adaptive unit? My students and I address both of these questions by investigating colonies of honey bees. A honey bee colony is a model system for studying functional organization at the group level because it interacts with the environment as a coherent whole and possesses numerous adaptations for group functioning, yet is unusually amenable to experimental analysis. To date, we have directed most of our efforts at understanding why there is so little reproductive conflict in a honey bee colony, and how a colony is internally organized to effectively gather its food and water, choose a nest site and build its nest, and protect itself from predators and parasites.
Some of the principal findings that I and my students have made in studying the functional unity of honey bee colonies are described briefly below (click on a topic for a more detailed description). Much of this work is reviewed in detail in my book, The Wisdom of the Hive (Harvard University Press, 1995).
1. Worker reproduction is blocked by worker-worker policing.
2. Queen-worker signalling is mutualistic, not manipulative.
3. A colony effectively monitors its environment for rich food sources.
4. A colony's foragers distribute themselves among nectar sources in a way that optimizes the colony's energy collection.
5. A colony adjusts its selectivity among nectar sources in relation to forage abundance.
6. A colony adjusts the percentage of its workers engaged in nectar collection in relation to forage abundance.
7. A colony adjusts the percentage of its workers engaged in nectar reception in relation to forage abundance.
8. A colony controls tightly its investment in comb construction.
9. The control of the type of comb constructed-worker comb or drone comb- is decentralized.
10. The collection of pollen is controlled by negative feedback from the nurse bees to the foragers.
11. The collection of water is controlled by negative feedback from the receiver bees to the foragers.
12. A colony chooses its future home site carefully and well.
13. The decision-making process during nest-site selection utilizes a curious means of consensus building.
14. Queen honey bees may mate multiply as a means of coping with parasites.
15. Predation has had a pervasive influence on the functional organization of honey bee colonies.
Courses Taught
Introduction to Behavior; Animal Communication; Mechanisms of Insect Behavior; Biology of Social Insects; Major Transitions in Evolution