Because of its long association with humans, the honeybee's rich behavioral repertoire is well-characterized, both in the field and in the laboratory. The proposed cell and molecular level studies will use naturally occurring changes in bee behavior and brain structure to address a key question in neuroscience: How do our experiences alter our brains? When honeybees forage at flowers for pollen and nectar, the region of their brains involved in learning and memory becomes larger. The honey bee forms of a family of nuclear hormone receptors that have structures similar to the steroid hormone receptors of vertebrates were identified by searching a database of genes known to be expressed in the bee brain. Several of these receptors were found to be expressed in the nerve cells that regulate bee learning and memory and that grow as a result of foraging experience. Because steroid hormones such as estrogens are important regulators of brain structure in vertebrates, it is hypothesized that the bee nuclear hormone receptors have a similar function in the bee brain. To investigate the role of nuclear hormone receptors in experience-induced brain growth, nerve cells from bees with different amounts of foraging experience will be placed in culture. The growth of neuronal processes called dendrites in these cultured cells will be studied under different combinations of hormones and nuclear receptor expression. The graduate students participating in this research project will also develop a computer-based workshop for undergraduates that will use the honeybee genome as a teaching tool for methods of DNA sequence analysis.
