Pheromone - pheromone (English spelling)

Japanese: フェロモン - ふぇろもん（英語表記）pheromone

A general term for substances released by an individual animal that have the effect of causing changes in the behavior, growth, differentiation, and other physiological conditions of other individuals of the same species, and is one of the typical attractants. Unlike hormones that are secreted internally and act within the same body, pheromones are characterized by their ability to transmit information between individuals. The phenomenon of male moths being attracted to females from afar was already described in Fabre's Book of Insects, written in the 19th century, but it was in 1959 that Butenandt demonstrated in silkworm moths that this was due to a signal substance secreted by the female. In the same year, P. Karlson and M. Lüscher proposed to give the general name pheromone (a coined word meaning something that carries a stimulus) to such inter-individual signal substances. Pheromones usually have a moderate degree of volatility, diffuse into the air, and are received by the olfactory organs of other individuals, and are effective in extremely small amounts. For example, it has been shown that the pheromone bombykol, which is secreted from the abdominal glands of female silkmoths and attracts males, elicits significant approach behavior from males at a concentration of just 200 molecules per milliliter of air.

There are exceptions, however, where pheromones act through contact chemical senses (such as taste). Many examples are known from insects, but they are widely present in other animals, and the chemical structures and actions of the substances are diverse. They can be divided into releaser effects, which affect behavior immediately upon acceptance by the other animal, and primer effects, which cause physiological changes, but the same pheromone can also have both effects. Here, we will mainly discuss attractive pheromones.

Pheromones that have a releaser effect include sex pheromones (in insects, mammals, etc.) that control the recognition and sexual behavior of the opposite sex, alarm pheromones (in ants, bees, etc.) that warn of danger to companions, and trail pheromones (in ants, bees) that indicate the location of food or nests.

[Takeji Kimura]

Sex pheromones

Also called sex attractants, substances released by individuals attract the opposite sex of the same species. There are substances released by males that attract females (as has been studied in the Satyrti butterfly), but more often females release sex pheromones to attract males. Active substances have been isolated and identified in many insects, and the presence of sex pheromones has been proven in various species of fish, amphibians, reptiles, and mammals. The chemical structure of the substance varies depending on the species, and usually acts as a signal only between individuals of the same species. This fact has been applied to the use of pheromone substances of certain insects (agricultural and forest pests) as attractants to attract and capture insects of the opposite sex, and to test the status of their occurrence. In addition to natural sex pheromones, related compounds and plant components are also known to have sex-attracting effects, and these are also called sex attractants.

[Takeji Kimura]

Aggregation pheromone

This refers to a substance that attracts individuals of the same species regardless of sex and acts to form colonies. It has been studied in wood beetles, mites, cockroaches, etc.

[Takeji Kimura]

Alarm pheromone

In ants and bees, when an individual senses danger, it releases it to summon its companions. This can be considered a kind of attractant. On the other hand, when an individual senses danger and its companions flee, as in the case of alarm pheromones in fish, this has the opposite effect of attracting.

[Takeji Kimura]

Guidepost pheromone

Pheromones, which bees use to tell their fellow bees where their nest is and ants use to show the way to food sources, are also a type of attractant.

[Takeji Kimura]

Other pheromones

Pheromones with a primer effect include caste differentiation pheromones, such as the queen substance of honeybees, which suppress the reproductive ability of other individuals, and substances secreted by male house mice to promote sexual maturity and estrus in females. The primer effect also affects behavior through these physiological changes.

[Takeji Kimura]

[Reference] | Attractant

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

動物の個体が体外に放出し、同種の他個体の行動や発育、分化そのほかの生理的状態に変化をおこす効果をもつ物質の総称で、典型的な誘引物質の一つ。体内で分泌され同じ体内で作用するホルモンと異なり、個体間での情報伝達に働く点にフェロモンの特徴がある。ガの雄が遠くから雌にひかれて集まる現象は19世紀に書かれたファーブルの『昆虫記』にもすでに記載されているが、それが雌の分泌する信号物質によるということが、ブーテナントによってカイコガで実証されたのは1959年である。同年、カールソンP. KarlsonとリューシャーM. Lüscherによって、このような個体間信号物質にフェロモン（刺激を運ぶものという意味の造語）という一般名を与えることが提唱された。フェロモンは通常、適度の揮発性をもち、空気中に拡散して他個体の嗅覚(きゅうかく)器に受容され、きわめて微量で効果を及ぼす。たとえば、カイコガの雌の腹部分泌腺(せん)から分泌されて雄を誘引するフェロモン（ボンビコール）は、空気1ミリリットル当りわずか200分子の濃度で雄の顕著な接近行動を引き起こすことが確かめられている。

　例外的には接触化学感覚（味覚など）を介して働くものもある。昆虫で多くの例が知られているが、ほかの動物にも広く存在し、物質の化学構造や作用も多岐にわたっている。相手に受容されるとただちに行動に影響をもたらすリリーサー効果と、生理的変化をおこすプライマー効果とに分けることができるが、同じフェロモンが両方の効果を示す場合もある。ここではおもに誘引性のフェロモンについて述べる。

　リリーサー効果をもつフェロモンとしては、異性の認知および性行動を支配する性フェロモン（昆虫、哺乳(ほにゅう)類など）、仲間に危険を知らせる警報フェロモン（アリ、ハチなど）、食物や巣の場所を知らせる道しるべフェロモン（アリ、ハチ）などがある。

［木村武二］

性フェロモン

性誘引物質ともいい、個体から放出された物質が同種の異性個体を誘引する。雄が放出して雌を誘引する物質（ジャノメチョウなどで研究されている）もあるが、雌が放出して雄を誘引する例のほうが多い。多くの昆虫で有効物質の単離・同定がなされているほか、魚類、両生類、爬虫(はちゅう)類、哺乳類でも性フェロモンの存在がさまざまな種で証明されている。物質の化学構造は種によって異なっていて、通常は同種の個体間でのみ信号として働く。このことを応用して、特定の昆虫（農業害虫や森林害虫）のフェロモン物質を用いて誘引・捕殺する誘引剤として利用したり、発生状況の検査に役だてている例もある。天然の性フェロモンのほかに、類縁化合物や植物成分のなかにも性誘引効果をもつ物質が知られていて、これらも性誘引物質とよばれている。

［木村武二］