No. 0653 / 1 402

Brown recluse

Loxosceles reclusa

名前について： The scientific name reclusa means 'recluse', which refers to the spider's shy, hidden way of life.1

お医者さんが必要命にかかわることはまれだけど、かまれたらお医者さんへ。

クモ

かむ食べもの：肉

人への危険: 深刻かまれたらお医者さんへ。死ぬことはとてもまれだよ。

The brown recluse is a small spider with a violin-shaped mark on its back. It lives mainly in the central and southern United States, where it hides in dark, quiet places such as woodpiles and sheds. It is one of only two North American spiders with dangerous venom, the other being the black widow.1

すんでいる場所

Southern and central United States, from southeastern Nebraska south to central Texas and western Georgia1

北アメリカ

ホーム

Brown recluses build irregular webs in dry, undisturbed places such as woodpiles, sheds, closets, garages, plenum spaces and cellars. In homes they seem to favour cardboard. People are usually bitten when the spider is trapped against the skin, for example inside clothes, shoes, towels, bedding or work gloves.1

長さ

6 mmから2 cm (0.2 inから0.8 in)1

最高速度

時速約0.8 km（時速0.5マイル）

陸で, おおまかな予想

何を食べるの？

Brown recluses leave their lairs at night to hunt, unlike most web-weaving spiders. If food becomes scarce, they will occasionally, though not habitually, eat other brown recluses.1

Brown recluseの写真 — Brown recluse。写真：Rosa Pineda。 CC BY-SA 3.0, Wikimedia Commons.

見分け方

A dark violin-shaped marking on the top of the front body, with the neck of the violin pointing towards the rear of the spider1
Typically light to medium brown, though colours range from whitish to dark brown or blackish grey1
Six eyes arranged in three pairs, while most spiders have eight1
No obvious patterns on the abdomen or legs, and no spines on the legs1
Usually 6 to 20 millimetres in body length, but may grow larger1

よくまちがえられるのは： The violin marking is not a reliable identifier, because cellar spiders and pirate spiders can have similar markings. The Mediterranean recluse, an introduced species, is almost indistinguishable from the brown recluse, so many reports of recluses are misidentifications. A spider in the genus Titiotus is the most common spider mistaken for a brown recluse in California, and its bite is considered harmless.1

毒パワー

かむ

かむときに、毒が牙や歯から出るよ。

その毒（かむ・刺す毒）はどうなるの？

The venom is necrotic, meaning it destroys tissue. It contains a dermonecrotic agent called sphingomyelinase D, which kills the skin around the bite. In some cases the venom spreads through the body within minutes, causing nausea, vomiting, fever, rashes and muscle and joint pain. Rarely, it can burst red blood cells (hemolysis).1

人にとってどれくらい危険？

人への危険: 深刻かまれたらお医者さんへ。死ぬことはとてもまれだよ。

Most bites cause no skin damage, and the spider is rarely aggressive. In one clinical study, skin necrosis occurred in 37% of diagnosed bites and systemic illness in 14%. Rarely, bites can cause organ damage or death. Most fatalities have been in children under seven or in people with weak immune systems. Children, the elderly and seriously ill people may be more susceptible to systemic effects.1

こわいとき、どうするの？

When alarmed, it lowers its body, raises its pedipalps and stands still in a defensive pose. It usually flees, and if caught it may play dead.1

かまれたら

かまれたところを洗って、痛みには保冷剤をあてよう。痛みが強い、広がる、またはその人の具合が悪いときは、医療の助けを受けて。

まず必ず救急番号（112、000、911）に電話しよう。これは一般的な応急手当の案内で、医療のアドバイスではないよ。応急手当の基本

安全に過ごそう

野生の動物には、小さくても、ねているように見えても、死んでいるように見えても、ぜったいにさわったり、つかまえたり、からかったりしないこと。
近づかないで。出会ったら落ちついて、ゆっくりあとずさりして、そのまま行かせてあげよう。
かまれたら：落ちついて、じっとして、救急番号（112、000、911）に電話するか、急いで病院へ行こう。見た目をおぼえておいてね。写真があると役に立つよ。

きみをねらっているわけじゃないよ。毒はエサをとったり身を守ったりするために使うだけで、本当はかくれていたいんだ。安全に過ごすためにもっと知ろう

世界のどこ？

アフリカアジアヨーロッパ北アメリカ南アメリカオーストラリアとオセアニア

どれくらい大きい？

どれくらい長い？

だいたいゼムクリップくらいの長さ

Brown recluseは、きみとくらべてどれくらい大きい？

ブラウザで計算しているだけ。何も保存されないし、どこにも送られないよ。

どれくらい速い？

リクガメ 時速約0.3 km (0.19 mph)

Brown recluse 時速約0.8 km (0.5 mph)

歩いている人 時速約5 km (3.1 mph)

知っておく価値あり

データ

One brown recluse survived for over five seasons in captivity without any food at all.1

In 2001, more than 2,000 brown recluses were removed from a heavily infested home in Kansas, yet the four residents who had lived there for years were never harmed.1

When a leg is lost, the brown recluse does not grow a new one in later moults, unlike the huntsman spider.1

Brown recluses do not balloon, which limits how far they can spread across the landscape.1

Males move around more when hunting than females, which tend to stay near their webs.1

うそ・ほんとう

うそ： Brown recluses are common in California and the western United States, where they cause many bites.

ほんとう： The brown recluse has not established itself in California or anywhere outside its native range. Many reported bites there are misdiagnosed, and other spiders are often wrongly identified as brown recluses.1

毒のエキスパート向け

学名: Loxosceles reclusa
グループ: クモ
家族: Sicariidae2
ならびかえ: Araneae
大陸: 北アメリカ
赤ちゃん: Each female produces several egg sacs between May and July, with about 50 eggs in each sac. The eggs hatch in about one month, and the young take about a year to reach adulthood.1
人への危険: 3 / 5: 深刻3