The International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.
This award will support a twenty-two-month research fellowship by Dr. Jamie C. Theobald to work with Dr. Eric J. Warrant at Lund University in Sweden and at the Smithsonian Tropical Research Institute on Barro Colorado Island in Panama.
This project examines the neural mechanisms through which animals maintain reliable vision in darkness. Megalopta genalis are fully nocturnal neotropical bees which visually navigate through forests 20 times dimmer than starlight. Night activity is rare among bees because they possess apposition compound eyes, a design unsuited to low light, and leaving little room to improve vision optically. Their retinas absorb signals compromised by the quantum phenomenon of photon noise. This research tests the hypothesis that Megalopta rely on neural summation to see well in the dark. Behavioral and neurobiological experiments reveal the signal processing between sensory input and muscular output, and produce mathematical models to describe it analytically. Behavior is characterized by filming bee flight around a nest to correlate light level with flight agility. Neural processing is examined by displaying visual scenes while electrically recording from retinal cells, and brain cells that detect self-motion during flight. The expectation is that Megalopta uses neural summation to fly and navigate in darkness which manifests in low optimum spatial and temporal frequencies in motion-detecting neurons, and flight that sacrifices sharp maneuvers in the dark.
