2005flies_myiasis - THE FLIES (THE DIPTERA) INTRODUCTIONTO...

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THE FLIES (THE DIPTERA) INTRODUCTIONTO THE FLIES AND THE NEMATOCERA. Two wings (one on each side) are present on the first thoracic segment. Behind the wings have another set of highly modified wings (halteres) that look like lollipops; these are wings that have been highly modified for balance. All diptera undergo complete (or complex metamorphosis, i.e., wormlike larva changes into a fly – like caterpillar into a butterfly) Many adult forms feed on blood. This allows them to transmit (vector) various agents found in the blood. Larvae of some invade living tissues produce a pathological condition called myiasis OVERALL CLASSIFICATION Three major groups 1. Nematocera includes the Culicidae (mosquitos), Simuliidae (black flies), ceratopogonidae (biting midges), and psychodidae (sand flies) 2. Brachycera – includes the horseflies and the deerflies (the Tabanidae) 3. Cyclorrhapha includes Muscidae (house and stable flies), Hippoboscidae (keds), Sarcophagidae (flesh flies), Calliphoridae (bottle flies), and the BOT Flies (Oestridae, Gasterophilidae, Hypodermidae, Cuterebridae) Only adult females of the Nematocera and the Brachycera take blood meals, in the Cyclorrhapha both the males and the females take blood when adults feed. THE MOSQUITOS – CULICIDAE Mosquitoes come in two major types, have those with short palps (The Culicine mosqutoes – including the important genera Culex and Aedes – the pricipal vector of Yellow Fever Virus) and those with long palps (the Anopheline mosquitoes – including the important genus Anopheles (the principal vector of malaria). Mosquitoes feed by inserting the sytlet portion of the mouthparts and directly sucking blood out of a small vessel – similar to sucking juice up through a straw. However, to keep the blood from clotting, mosquitoes also inject saliva that contains clotting inhibitors. It is an immune reaction to the saliva that causes the urticaria at individual mosquito bite sites.
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Mosquito mouthparts folded apart to show the numerous different bits that go together to make the working proboscis that is inserted into the host. Lateral view of the head of Aedes aegypti showing the short palps and the long antennae (the proboscis comes out at the base of the shorter palps). Scanning electron micrographs showing the various cutting blades in at the tip of the proboscis. Image of a feeding mosquito showing how part of the proboscis bens away frokm the inserted stylets and siphon and serves as a supporting structure.
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This mosquito is on the surface of its host probing and moving about looking for a place on which to take a blood meal. Notice that this poor mosquito has lost one leg. A feeding Aedes aegypti with a majority of its proboscis embedded in the skin of its host.
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2005flies_myiasis - THE FLIES (THE DIPTERA) INTRODUCTIONTO...

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