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Title: ABDOMINAL PERICARDIAL SINUS: A NEUROHEMAL SITE IN THE TSETSE AND OTHER CYCLORRAPHAN FLIES

Author
item Meola, Shirlee
item SITTERTZ-BHATKAR, H - TEXAS A&M UNIV
item LANGLEY, P - UNIV OF WALES, UK
item KASUMBA, I - YALE UNIVERSITY
item AKSOY, S - YALE UNIVERSITY

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/14/2003
Publication Date: 11/1/2003
Citation: Meola, S.M., Sittertz-Bhatkar, H., Langley, P., Kasumba, I., Aksoy, S. 2003. Abdominal pericardial sinus: A neurohemal site in the tsetse and other cyclorraphan flies. Journal of Medical Entomology. 40(6):755-765.

Interpretive Summary: New methods are needed to control agricultural insect pests in a manner that targets selected species of insects and has low potential of target insects acquiring resistance to the insecticide. One means of doing this is to utilize compounds called neuropeptides that are required for all phases of an insect's activity including metamorphosis, finding hosts, digesting food and producing eggs. In this study we found a neuropeptide storage organ adjacent to the heart of a group of flies (including houseflies, fruit flies, stable flies, horn flies, tsetse flies, and screwworm flies) that vector some of the most well known diseases of economic importance. The discovery of this organ in these flies is important because it is the largest such organ that has been found in this group of flies; is found only in the adults of these flies; and regulates functions of the adult flies such as mating, egg development, and egg laying. It may be possible to develop mimics of the neuropeptides stored in this organ that would be effective against this specific group of agricultural pests but have limited effect on beneficial insects.

Technical Abstract: An ultrastructural study of the heart of the tsetse fly, Glossina morsitans, and of several other species of cyclorraphan flies revealed that the ventral region of the heart of adult flies is encircled by a muscular septum not present in the larval stage. The pericardial septum of the adult heart is composed laterally of alary muscles and a central longitudinal muscle that extends the length of the abdominal aorta, whereas the larval heart is supported ventrally only by alary muscles and strands of connective tissue. Thus, unlike the larval stage, and the heart of other insects, the pericardial septum of adult cyclorraphan flies contains a central band of longitudinal muscle that along with the alary muscle forms a large pericardial sinus lying between the septum and the heart. Neurosecretory nerves arising from the lateral nerves of the thoracicoabdominal ganglion extend dorsal to the pericardial septum where they form neuromuscular junctions on the pericardial muscle fibers of the septum and terminate as neurohemal fibers in the pericardial sinus, thereby creating the largest neurohemal region in these flies. In the tsetse fly, some of these fibers also extend between the muscle fibers of the myocardium and terminate in the lumen of the heart, into which they release their secretory products.