Sean O'Donnell

sodonnel@u.washington.edu
Associate Professor, Department of Psychology

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My research focuses on the behavior and ecology of eusocial insects, including wasps (Vespidae) and other Hymenoptera (ants, Formicidae; bumblebees and stingless bees, Apidae). I am especially interested in how behavioral differences among individuals within colonies are determined by social, neuro-physiological, and genetic factors. In swarm-founding paper wasps (genus Polybia) my lab is assessing whether neural plasticity in the brain, particularly in the mushroom bodies, may play a functional role by influencing workersU task performance. One goal is to assess whether individual differences in rates of behavioral development are associated with brain anatomy variation. This study will take advantage of Polybia workers' naturally occurring developmental plasticity, which results in a partial decoupling of task performance and age. Another study will assess the temporal relationship of task performance changes and brain structure following experimental manipulations (forager removals). For both studies I am collaborating with Dr. Theresa Jones, a neuroanatomist at the University of Texas-Austin. In addition to measuring brain region volumes, we are using stereological microscopy techniques to estimate mushroom body intrinsic neuron (Kenyon cell) numbers and cell packing densities. We will also examine the development of workers' neuronal processes using Golgi staining methods. Golgi staining will allow us to quantify changes in axons and dendrites that may underlie changes in neuropil volume. These data will complement measurements of brain region volume, and will indicate how changes in brain region volume are achieved at the neuronal level.