Author
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Cook, Benjamin |
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Pryor, Nan |
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Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/12/1996 Publication Date: N/A Citation: N/A Interpretive Summary: The stable fly is a major pest of livestock and other animals, especially cattle that are held in confinement. Because the stable fly is a worldwide pest that causes heavy economic losses each year, it is essential to search continuously for new or improved methods for its control. An effective systematic approach to the development of novel chemical control agents depends upon a thorough understanding of physiological systems in the pest that will be targeted by new management technology. Current research is focusing on the development of ways to disrupt the functions of neuropeptides--natural hormonal agents which serve as indispensable chemical intermediates in the regulation of a variety of essential physiological functions by the central nervous system of the stable fly. This report presents detailed information on the structure and properties of the peripheral nervous system that moves eggs through the stable fly's oviduct. The research provides important new information on certain characteristics of the pest's reproductive system, a potentially vulnerable target for new chemical agents aimed at disrupting that critical life process. It is anticipated that novel chemicals which mimic the actions of the neuropeptides will be active at very low concentrations and highly selective for a specific pest, thus providing a new control technology that will be less harmful to the environment and non target organisms than conventional insecticides. Technical Abstract: Fine structure of both peripheral nerve cells and neuromuscular junctions associated with the oviduct of Stomoxys calcitrans (L.) was described. Twelve or more multipolar peripheral neurons were found along major branch nerves that enter the ovipositor. Several were suspended in the haemacoel while others were in close proximity to the surface of the oviduct. Some peripheral neurons contained an abundance of neurosecretory granules that ranged in size from 32 nm to 180 nm in diameter. No glial elements enveloped the perikarya of such cells. Neurosecretory axons were usually found in the boundary region of large nerves just beneath the stroma. Peripheral nerve cells in close apposition to oviduct muscles were generally non-neurosecretory and were ensheathed in a glial perineurium. Peripheral neurons were occasionally surrounded by an extensive network of extracellular spaces in the glial perineurium. Other smaller neurons were found within large nerve trunks. Nerve-muscle junctions contained large clusters of synaptic vesicles and occasionally included small groups of neurosecretory granules. Many nerve terminals on the surface of the oviduct contained a complex postsynaptic folding of sarcolemma. Active transmission sites were indicated by increased densities along the neurolemma. Some neurohemal release sites were also evident. |
