Mushroom Body Calyx (Honey Bee)- 20x on LSM 710 by James Privitt

This week James Privitt defended his thesis and passed!  If you see him, please congratulate him.  James did his thesis work under Dr. Susan Fahrbach (lab page) and was an extensive user of the LSM 710 on the Reynolda campus.  In the fall he will be starting a PhD program at Cornell.

The following is an abstract of his work:

“IMPACT OF PESTICIDES ON THE NEURAL STRUCTURE OF THE HONEY BEE, APIS MELLIFERA

Thesis under the direction of Susan E. Fahrbach, Ph.D., Reynolds Professor of Developmental Neuroscience

Fipronil, a commonly used pesticide, is a GABA receptor antagonist that induces hyperexcitability in the central nervous system of insects. Its use is controversial because it is a suspected contributor to the global decline of non-target pollinator populations. Sublethal doses of fipronil reduce colony fitness and impair learning and memory in the honey bee, Apis mellifera. The mushroom bodies, insect brain regions required for learning and memory, receive GABAergic inputs that may be sensitive to fipronil. The synaptic organization of the mushroom bodies was investigated in adult worker honey bees exposed to fipronil using immunolabeling of the pre-synaptic marker anti-synapsin I and laser scanning confocal microscopy. This permits visualization of synaptic complexes called microglomeruli. Exposure of worker honey bees to fipronil at field-realistic (1 ppb), as well as lower (0.1 ppb) and higher (4 ppb) concentrations decreased the density of microglomeruli in the mushroom body lip (olfactory) and collar (visual) neuropil regions in adult-treated honey bees. These data indicate that sublethal doses of fipronil can alter the structure of the adult honey bee nervous system, possibly through induced synaptic pruning. These results potentially link impaired learning with abnormal synaptic organization, suggesting a mechanism by which fipronil reduces the fitness of honey bee foragers and, ultimately, colonies. These results will be compared with structural changes in the mushroom body neuropil observed after exposure of worker honey bees to two other commonly used pesticides, imidacloprid (a neonicotinoid) and coumaphos (an acetylcholinesterase inhibitor).”