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Title: SCANNING ELECTRON MICROSCOPY OF THE OVIPOSITOR OF THE HORN FLY

Author
item BAY, D - TEXAS A&M UNIVERSITY
item Meola, Shirlee
item WHITE, S - LILLY RESEARCH LABORATORY

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/29/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: The egg laying organ of flies (called the ovipositor) is very important in the reproductive process because certain regions of the ovipositor (known as sensory organs) sense the presence of specific odors, providing the female with information including where to lay the eggs and even stimulating the female to release the eggs into the growth media. Sensory organs on the tip of the ovipositor can determine whether the eggs are being laid in a nutritious manure patty, or in wet mud where the larvae would soon starve. We studied by scanning electron microscopy the ovipositor of the horn fly (a serious blood sucking pest of livestock), and gained much knowledge of the location, types, and functions of such sensory organs. This knowledge could result in better methods to control the horn fly; for example, odors similar to those sought out by horn flies to lay their eggs could be used to attract horn flies to specific areas such as pesticide stations. This would result in much less pesticide use, less environmental contamination, and no effects on organisms other than the horn fly. 

Technical Abstract: Scanning electron microscopy of the ovipositor of the horn fly, Haematobia irritans, revealed that tactile hairs are present on all the plates comprising this organ, but are especially numerous on the median plates and paired anal leaflets. Since the median plate is situated at the posterior edge of the oviduct, deflection of the tactile hairs provides feedback to the female, monitoring passage of the egg. Multiparous cone-shaped sensory pegs on the tip of the anal leaflets are chemoreceptors determining placement of the egg in the proper substrate. A new group of conical sensory pegs was found on the ventral plates of the ovipositor. The function of these sensory pegs is not known, but sensory organs of this type have been found to detect temperature and moisture content.