title: Volume and density of microglomeruli in the honey bee mushroom bodies do not predict performance on a foraging task.
abstract: The mushroom bodies (MBs) are insect brain regions important for sensory integration, learning, and memory. In adult worker honey bees (Apis mellifera), the volume of neuropil associated with the MBs is larger in experienced foragers compared with hive bees and less experienced foragers. In addition, the characteristic synaptic structures of the calycal neuropils, the microglomeruli, are larger but present at lower density in 35-day-old foragers relative to 1-day-old workers. Age- and experience-based changes in plasticity of the MBs are assumed to support performance of challenging tasks, but the behavioral consequences of brain plasticity in insects are rarely examined. In this study, foragers were recruited from a field hive to a patch comprising two colors of otherwise identical artificial flowers. Flowers of one color contained a sucrose reward mimicking nectar; flowers of the second were empty. Task difficulty was adjusted by changing flower colors according to the principle of honey bee color vision space. Microglomerular volume and density in the lip (olfactory inputs) and collar (visual inputs) compartments of the MB calyces were analyzed using anti-synapsin I immunolabeling and laser scanning confocal microscopy. Foragers displayed significant variation in microglomerular volume and density, but no correlation was found between these synaptic attributes and foraging performance. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1057-1071, 2017.
authors.affiliation: Department of Biology, Wake Forest University, Winston-Salem, North Carolina.|Wake Forest School of Medicine, Neuroscience Program, Winston-Salem, North Carolina.|Center for Molecular Communication and Signaling, Wake Forest University, Winston-Salem, North Carolina.
authors.forename: Byron N
authors.identifier: 0000-0002-4650-6264
authors.initials: BN
authors.lastname: Van Nest
authors.affiliation: Department of Biological Sciences, East Tennessee State University, Johnson City, Tennessee.
authors.forename: Ashley E
authors.identifier: 0000-0003-1374-6402
authors.initials: AE
authors.lastname: Wagner
authors.affiliation: Department of Biology, Wake Forest University, Winston-Salem, North Carolina.|Wake Forest School of Medicine, Neuroscience Program, Winston-Salem, North Carolina.|Center for Molecular Communication and Signaling, Wake Forest University, Winston-Salem, North Carolina.
authors.forename: Glen S
authors.identifier: 0000-0003-3006-3152
authors.initials: GS
authors.lastname: Marrs
authors.affiliation: Department of Biology, Wake Forest University, Winston-Salem, North Carolina.|Wake Forest School of Medicine, Neuroscience Program, Winston-Salem, North Carolina.|Center for Molecular Communication and Signaling, Wake Forest University, Winston-Salem, North Carolina.
authors.forename: Susan E
authors.identifier: 0000-0003-1037-8018
authors.initials: SE
authors.lastname: Fahrbach
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001516:Bees / Q000033:anatomy & histology; D003118:Color Perception / Q000502:physiology; D004215:Distance Perception / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology*; D007858:Learning / Q000502:physiology; D008297:Male; D018613:Microscopy, Confocal; D024521:Mushroom Bodies / Q000166:cytology*; D009473:Neuronal Plasticity / Q000502:physiology*; D019581:Neuropil / Q000378:metabolism / Q000502:physiology*; D012201:Reward; D018709:Statistics, Nonparametric; D016704:Synapsins / Q000378:metabolism
chemical_list: D016704:Synapsins
keywords: Apis mellifera; collar neuropil; color computation; lip neuropil; synapsin I