Fenvalerate treatment affects development of olfactory glomeruli in Manduca sexta

Low doses of fenvalerate, a widely used type-II pyrethroid insecticide, hav e been shown previously to produce abnormal olfactory centers in the brain and abnormal olfactory-mediated behavior in beetles (Wegerhoff et al. [1998 ] Neuroreport 9:3241-3245). Here, we use the experimental advantages of the moth Manduca sexta to explore the cellular changes that lead to these abno rmalities. Our results indicate that treatment with fenvalerate may affect multiple aspects of the development of the primary olfactory centers, the a ntennal lobes, in Manduca, including ingowth of olfactory receptor axons, a xon fasciculation, and targeting within the antennal lobe, and intercellula r signaling between the receptor axons and the glial cells that ordinarily surround and stabilize the developing olfactory glomeruli. (C) 2001 Wiley-L iss, Inc.