Fly (hae) - fly (English spelling)

Japanese: ハエ（蠅） - はえ（英語表記）fly

A general term for insects belonging to the suborder Cyclorrhapha of the order Diptera. In taxonomic terms, flies are defined in the narrow sense as those belonging to the group of antlers, while in the broad sense, they refer to all insects belonging to the order Diptera, including the suborder Brachyceratopsids, such as mosquitoes and black flies, and the suborder Brachyceratopsids, such as horseflies. In general, valvate flies, which include large, easily visible flies such as house flies, blowflies, black flies, and flesh flies, are called "flies," while small valvate flies, such as fruit flies, are commonly called "small flies." In all insects of the suborder Cyclorrhapha, the skin of the third instar larva (mature) does not molt but becomes keratinized to form a bale-shaped puparium, within which the true pupa develops. When the adult emerges, the puparium splits in a ring shape along the third segment, and the adult emerges by molting its thin pupal skin.

[Hiroshi Kurahashi]

form

The scientific name for Diptera, Diptera, is a Greek word given by Aristotle and means two-winged. Flies are thought to be a group that evolved from an ancestral form with two pairs of wings, the basic body shape of winged insects, into a haltere when the hind wings degenerated. Some flies that live in special groups (such as spider flies) or in special environments (windy islands, caves) have also degenerated their forewings. The head is mostly taken up by large compound eyes, which are connected to the thorax by a thin neck and can rotate freely. Some compound eyes show secondary sexual characteristics, with the size differing between males and females.

Mouthparts are broadly divided into licking types with well-developed lip palps and biting types that sting like mosquitoes. Rare species have degenerated mouthparts like the sheep fly. Legs range from long and slender to sturdy, thick and short, and are well developed. The body is usually covered with many setae and hairs. Antennae consist of three segments, the third being the largest, with terminal spines extending from the dorsal surface of their base. The terminal spines are sometimes feather-like, comb-like, whip-like, or thread-like. The forehead pouch group, which is a fly in the strict sense, further develops a forehead pouch line on both sides from the base of the antennae toward the anterior mouth edge, clearly joining the face and sides of the face, giving it the typical head characteristics of a fly. This reflects the habits of the forehead pouch group, which usually undergoes pupation underground, and when the adult emerges, it inflates and contracts the forehead pouch on the front of its head like a balloon, pushing aside the soil to reach the ground's surface, where its wings extend and its body hardens, and the forehead pouch is absorbed into the head, and later the face takes on a closed appearance, with this boundary remaining as the forehead pouch line. This does not exist in the non-forehead pouch group, which includes the Phoridae, Doryidae, and Melastomatidae families. In the Melastomatidae family, this line disappears midway through, showing an underdeveloped state, so they are sometimes treated as the proto-forehead pouch group, distinguished from the forehead pouch group.

The cephalic sac group is a large group that includes many species, and is broadly divided into lobe-pterygite flies, which have developed thoracic scales that cover the haltere, such as the Muscidae, Calliphoridae, and Flesh Flies, and underdeveloped lobe-pterygite flies, such as the Drosophilidae and Tephritidae. The tail tip of the male is the hypopygium, which grasps the female during mating, and the female is the ovipositor. The arrangement of the wing veins varies depending on the group, which is a classification characteristic, but the number is generally smaller than that of insects in the suborders of the Deutocerata and Brachycerata. There are usually three ocelli, but they are missing in nocturnal flies such as the Deutocerata.

[Hiroshi Kurahashi]

Ecology

Flies are holometabolous insects that develop from egg to larva to pupa to adult, molting twice during the larval stage and living through three instars. The larvae are headless, with an undeveloped head that is retracted into the prothorax, and the mouthparts have degenerated to only a pair of oral hooks. They are generally bamboo-shoot-like maggots, but some, such as the larvae of flea flies and little house flies, develop fleshy protrusions and spines on the surface of their bodies. Their life cycles are extremely diverse, and while many species, such as house flies, are oviparous as adults, flesh flies and other insects are larviparous, in which fertilized eggs hatch in the uterus and give birth to first-instar larvae, and pedigreed flies and spider flies are pupiparous, giving birth to pre-pupae that have matured to the point of pupation. There are various types of larvae, including those that parasitize animals and plants, those that prey on small animals and insects, those that suck blood, and those that develop in humus, carrion, algae, fungi, feces, food, etc. Most flies pupate in the soil.

[Hiroshi Kurahashi]

Relationship with human life

Many flies have a close relationship with humans. Drosophila umbellata, bot fly, horse fly, cow fly, sheep fly, human house fly, flesh fly, etc., which parasitize the subcutaneous tissue of the human body and cause myiasis (also called fly larvae or fly maggots), and stable flies and tsetse flies, which come to suck blood, are important sanitary pests. Many types of flies, such as house flies, blow flies, and flesh flies, invade homes from unclean places and mechanically transport infectious gastrointestinal disease pathogens such as dysentery, typhoid, cholera, and amoebic dysentery, as well as parasitic eggs and viruses, making them important environmental sanitary pests. Tsetse flies in Africa biologically transmit the sleeping sickness pathogen Trypanosoma when sucking blood from humans and livestock. House flies that infest livestock, such as the black house fly, are problematic in veterinary medicine as they are intermediate hosts for the horse stomach worm Habronema and the cattle eye worm Thelazia , and the domestic fly is an intermediate host for the dog eye worm. Fruit flies, leaf miners, radish flies, seed flies, and beet flies are well-known as pests of agricultural crops.

Moreover, to modern people, all flies are unpleasant pests in the sense that they cause discomfort. Parasitic flies such as head flies, tree flies, burrowing flies, and tachinid flies, as well as predatory flies such as food flies, are considered beneficial insects as they are natural enemies of pests such as aphids (aphids), planthoppers, leafhoppers, and tussock moths. To eradicate flies, it is effective to clearly identify the species and locate the source of their infestation, reduce the source of infestation by improving livestock sheds, compost areas, toilets, garbage dumps, etc., and use various insecticides, fly ribbons, fly traps, etc. as supplementary measures to comprehensively control them.

[Hiroshi Kurahashi]

Schematic diagram of the fly's body structure
©Tatsuo Ikeda ">

Schematic diagram of the fly's body structure

Major types of flies (1) The omental group - valvate flies [specimen drawing]
©Tatsuo Ikeda ©Kenzo Otawa ©Kei Daishoji ">

Major types of flies (1) Buccal group - petals-winged…

Major types of flies (2) The omental group - Apetoptera [specimen drawing]
©Tatsuo Ikeda ©Kenzo Otawa ©Kei Daishoji ">

Major types of flies (2) Buccal group - wingless…

Major types of flies (3) The omental group - Apetoptera [specimen drawing]
©Tatsuo Ikeda ©Kenzo Otawa ©Kei Daishoji ">

Major types of flies (3) Buccal group - wingless…

Major types of flies (4) Anophthalmos group [specimen drawing]
©Tatsuo Ikeda ©Kenzo Otawa ©Kei Daishoji ">

Major types of flies (4) Anophthalmos group [specimen painting...

Flesh fly
They usually have three thick black vertical stripes on their backs and a checkered pattern on the back of their abdomens. They are a sanitary pest that occurs in pit toilets. Body length is 8-14mm. Flesh fly ©Shogakukan Photo by Hideyuki Asakura ">

Flesh fly

Broad-headed fly
The back of the thorax is greenish, and the male's head forehead is quite wide. This genus of flies is also called "Milky Way" in some regions. Body length 8-9 mm. Calliphoridae ©Shogakukan Photo by Hideyuki Asakura ">

Broad-headed fly

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

昆虫綱双翅(そうし)目環縫(かんほう)亜目Cyclorrhaphaに属する昆虫の総称。分類学的にはこのうちの有額嚢(ゆうがくのう)群に所属するものを狭義のハエと定義したり、広義にはカやブユなどの糸角亜目やアブ類の短角亜目を含めた双翅目に属する昆虫全体をさしたりする。一般には、イエバエ、キンバエ、クロバエ、ニクバエなど目につきやすい大形のハエが所属する有弁翅蠅(ゆうべんしばえ)類を「ハエ」とよび、ショウジョウバエなど小形のものが所属する無弁翅蠅類を「コバエ」などと俗称する。環縫亜目の昆虫はいずれも3齢幼虫（成熟）の皮膚が脱皮されずに角質化して俵状の囲蛹(いよう)pupariumを形成し、その中に真性の蛹(さなぎ)pupaができる。成虫の羽化時に囲蛹殻が第3環節に沿って環状に割れ、中から成虫が薄い蛹の皮膚を脱皮して脱出してくるのが特徴である。

［倉橋　弘］

形態

双翅目の学名Dipteraは、古くアリストテレスによる命名のギリシア語で、2枚のはねをもつものを意味している。ハエはもともと有翅昆虫の基本体形である2対のはねをもった祖先型から後翅が退化して平均棍(こん)に変形したグループと考えられている。特殊なグループ（クモバエなど）や特殊な環境（風の強い島、洞穴中）に生活するハエのなかには前翅も退化してしまったものもある。頭部は大きな複眼で大部分占められ、細い頸(くび)で胸部につながっており、回転は自由である。複眼は雌雄によって大きさが異なる二次性徴を示すものがある。

　口器はよく発達した唇弁をもつ舐食(としょく)型と、カのように刺す刺咬(しこう)型に大別される。まれにヒツジバエのように口器の退化した種類もある。脚(あし)は細長いものから頑丈で太く短いものまであり、よく発達している。体には普通、剛毛や毛を多く装う。触角は3節よりなり第3節が最大で、その基部背面より端刺が伸びている。端刺はときに羽毛状、櫛(くし)状、鞭(べん)状、糸状を呈す。狭義のハエである有額嚢群はさらに触角基部から前口縁に向かって左右に額嚢線の発達がみられ、これによって顔面と顔側面とが明瞭(めいりょう)にくぎられ、ハエらしい頭部の特徴を示す。これは有額嚢群の習性を反映したもので、普通、蛹化が土中で行われるため、成虫が羽化する際に、前頭部にある額嚢を風船のように膨らませたり収縮させたりして土をかき分けて地表に達し、はねが伸び、体が硬化して、額嚢も頭の中に吸収され、のちに顔面が蓋(ふた)をするかっこうになり、この境界が額嚢線として残るからである。ノミバエ科、ヤリバエ科、ショクガバエ科などの無額嚢群にはこれがない。メバエ科ではこの線が途中で消える未発達の状態を示すため、額嚢群と区別して原額嚢群として取り扱われることもある。

　有額嚢群は多くの種類を含む大きな群であり、イエバエ科、クロバエ科、ニクバエ科など平均棍を覆い隠すように発達した胸部鱗弁(りんべん)のある有弁翅蠅類と、ショウジョウバエ科、ミバエ科など未発達の無弁翅蠅類に大別される。雄の尾端は交尾の際に雌を把握する尾器hypopygiumとなっており、雌は産卵管ovipositorとなっている。翅脈の配列はグループによって異なり、それが分類上の特徴となるが、一般に糸角亜目や短角亜目の昆虫に比べて数が少ない。単眼は普通3個あるが、デガシラバエ科など夜行性のハエでは欠失している。

［倉橋　弘］

生態

ハエは完全変態昆虫で、卵→幼虫→蛹→成虫と発育し、幼虫期に2回脱皮して3齢期を過ごす。幼虫は無頭形で、頭部は発達せず前胸内に引き込まれていて、口器は1対の口鉤(こうこう)だけに退化している。一般にタケノコ状のウジであるが、ノミバエやヒメイエバエの幼虫のように体表に肉質突起や棘(きょく)状突起を発達させるものがある。生活史は実に多様であり、イエバエなど多くのものは成虫が産卵性oviparousであるが、ニクバエなどでは受精卵が子宮内で孵化(ふか)し、1齢幼虫を産む産仔(さんし)性larviparousであり、さらに、シラミバエ、クモバエなどでは蛹化寸前まで成熟した前蛹を産む蛹生性pupiparousである。幼虫は動物や植物体に寄生するもの、小動物や昆虫を捕食するもの、吸血するもの、腐植物や腐肉、藻類、菌類、糞(ふん)、食品等に発生するものなどいろいろである。ハエ類の多くは土中で蛹化する。

［倉橋　弘］

人間生活との関係

ハエには人類と密接な利害関係をもつものが多い。人体の皮下などに寄生してハエ症myiasis（ハエ幼虫症、ハエうじ症ともいう）を引き起こすヒトヒフバエ、ヒトクイバエ、ウマバエ、ウシバエ、ヒツジバエ、ヒトチスイバエ、ニクバエなどや、吸血にくるサシバエ、ツェツェバエなどは重要な衛生害虫である。イエバエ、キンバエ、クロバエ、ニクバエなど多くの種類が不潔な場所から住家に侵入し、赤痢、チフス、コレラ、アメーバ赤痢など消化器伝染病病原体や寄生虫卵、ウイルスなどを機械的に運搬するので環境衛生害虫として重要である。アフリカのツェツェバエは人畜から吸血する際に睡眠病病原体であるトリパノソーマを生物学的に伝播(でんぱ)する。クロイエバエなど家畜にたかるイエバエはウマの胃虫Habronemaやウシの眼虫(がんちゅう)Thelaziaの、メマトイはイヌ眼虫の中間宿主として獣医学上問題になる。キモグリバエ、ハモグリバエ、ダイコンバエ、タネバエ、ビートバエなどは農作物の害虫として著名である。

　また、現代人にとってどのハエも不快感を与えるという点で不快害虫ということになる。アタマアブ、ツリアブ、デガシラバエ、ヤチバエ、ヤドリバエなど寄生性のハエやショクガバエなど捕食性のものは、アブラムシ（アリマキ）やウンカ、ヨコバイ、ドクガなどの害虫の天敵として有益虫とみなされる。ハエの駆除のためには、明確な種を同定し、発生源をつきとめて、畜舎、堆肥(たいひ)場、便所、ごみためなどを改善して発生源を縮小し、補助的に各種殺虫剤やハエ取りリボン、ハエ取り籠(かご)などを利用して総合的に防除すると効果があがる。

［倉橋　弘］

ハエの体制模式図

ハエのおもな種類(1)有額嚢群―有弁翅…

ハエのおもな種類(2)有額嚢群―無弁翅…

ハエのおもな種類(3)有額嚢群―無弁翅…

ハエのおもな種類(4)無額嚢群〔標本画…

センチニクバエ

ヒロズキンバエ

出典　小学館　日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について　情報 | 凡例

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