Abdominal Peripheral Nervous System of the Adult Female House Fly1 and Its Role in Mating Behavior and Insemination

Abstract

The abdominal peripheral nervous system of the adult female house fly, Musca domestica L. (Diptera: Muscidae) was studied by using leuco-methylene blue to stain the major abdominal nerves. Paired nerves to each of the 1st 5 abdominal segments were observed to arise from the ventral median abdominal nerve and innervate the spiracular muscles, the lateral and dorsal segmental muscles, and the longitudinal muscles on the surface of the heart. The median abdominal nerve bifurcates in the posterior part of the abdomen, and the 2 branches extend caudally throughout the length of the ovipositor. Branches arising from these 2 main nerves pass to the posterior part of the ovary and the lateral oviducts. Also, these 2 nerves give rise to smaller branches that innervate the common oviduct, vagina, and muscles of the spermathecal ducts. Two larger branches extend from the bifurcations anteriorly along the rectum and innervate the rectal papillae and muscles of the proctodaeum. Considerable variation was observed in the manner in which the segmental nerves arise from the median nerve and in the origin of the fork of the median nerve. Transection of the median abdominal nerve of virgin females caused about 73% of the females to have reduced amounts of spermatozoa in the spermathecae following mating. However, over 80% of the mated females treated in this way copulated a 2nd time.