Caption: Black fly larva (Simulium hippovorum). Note the ribbon of silk coming from the mouth area. All known species of black flies produce silk for mooring lines for anchorage to substrates in flowing water. A pair of silk glands run the length of the body, The strands of silk emerge from a silk duct below the mouth and are cut and guided by a series of teeth on the mandible and hypostoma. Also shown is the prothoracic proleg is used to pull or hold threads of silk, as well as to grasp the silk pad it forms on a substrate in moving water. Black flies are considered a human pest in some areas of the US and Canada. Adult females of certain species are fierce biters, whereas others are strictly a nuisance by their presence around exposed skin areas. Female black flies require a blood meal; males feed mainly on nectar. Adult black fly females lay their eggs in slow moving waters. Larvae emerge from eggs and attach themselves to aquatic vegetation and rocks. Most black fly larvae are filter feeders. A head fan sweeps food material into the mouth. Larvae pass through six instar stages before reaching the pupal stage. Pupae are encased in a silken cocoon attached to vegetation or other objects in the water. Adults emerge from the pupal case through a slit in the pupal cuticle and float to the surface on a bubble of air. Black flies can transmit filarial worms to humans resulting in a disease called onchocerciasis, which cause blindness. They may also be potential transmitters of encephalitis.
Magnification*: x7
Type: SEM
Copyright 2006 Dennis Kunkel Microscopy, Inc.
Keywords: 07.01.06,black fly,black fly larva,black fly larvae,black fly nymph,blackfly,buffalo gnat,buffalo gnats,fly,human disease,human pest,insect,insect vector,insects,invertebrate,invertebrates,larva,larvae,onchocerciasis,prothoracic proleg,SEM,silk anchor,silk duct,silk gland,silk glands,Simulium ,Simulium hippovorum,turkey gnat,turkey gnats,26332C