Due to its extraordinary complexity, research on non-human animals will be necessary to efficiently explore the design of the human brain. A central problem in understanding the origin of the human brain concerns the role of social life and the demands it places on the brain to generate adaptive behavior. As humans evolved complex societies, it is thought that the brain increased in volume to enable advanced cognition. Social insects are outstanding models to examine brain evolution in light of social complexity. This research project employs ants as an ideal model system to analyze the relationship between sociality and brain evolution because different species form colonies that vary in size and the degree of complexity. This research will also help us understand how exceptionally small brains are able to process complex social information. The project will analyze differences in the size and organization of worker brains, and their metabolic costs to determine if complex social life has increased the efficiency of energy use in the brain. The project will train graduate and undergraduate who will become skilled in designing scientific studies and will acquire techniques that enable brains to be imaged. Students will also learn data analysis, and scientific writing and publication. The researchers will develop a curriculum to enrich the education of K-12 students by introducing them to the study of behavior and neuroscience. The researchers will recruit diverse participants from the Laboratory Schools of the University of Chicago to encourage minority students to become activity engaged in science. The project will broadly support science outreach in the Chicago STEM Pipeline, Arizona Assurance, Brain Awareness, and Boston Upward Bound programs to address the critical national need to improve science education and train the next generation of scientists.
To determine how social complexity has influenced brain evolution, the researchers will quantify neuronal metabolic requirements, neuropil investment and scaling, behavioral plasticity, and synaptic organization in brain regions considered key to cognitive function. Pairs of species representative of major ant subfamilies that accentuate variability in social complexity will form the sample groups. The researchers will: 1) quantify energetic requirements of functionally specialized neuropil using cytochrome oxidase staining to assess ATP use; 2) determine if brain development is experience-dependent; 3) quantify synaptic complexes associated with cognition; and 4) couple behavioral performance with neural and metabolic metrics. The researchers will determine neuron number and size and variation in peripheral sensory structures, and examine brain compartment scaling patterns. Controlling for phylogeny, analyses infer how independent evolutionary events associated with collective intelligence shaped brain evolution. All original images will be freely available upon publication, in the absence of copyright issues. Organismal data (specimen and colony collection data, phenotypic data, etc.) will be maintained in individual labs, and will be made freely available upon request. Voucher specimens will be deposited in the ant collection of the Field Museum.
