結婚飛行

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結婚飛行(けっこんひこう)とは、おおくのアリ類、シロアリ類、ハチ類の種において、重要な再生産の段階である。飛行中、未交尾の女王はオスと交尾し、着陸後に新たなコロニーを作ったり、ミツバチの場合にはすでにあるコロニーの継承をおこなったりする。

飛行前[編集]

結婚飛行にむけて準備をおこなうツムギアリの仲間のオス

成熟したアリのコロニーでは、羽の生えた未交尾の女王とオスが季節的に生産される。無精卵はオスになる。有精卵は通常、羽をもたない不妊の働きアリになるが、幼虫の時期に特別な餌を与えられたものは女王となる。

若い女王とオスは、結婚飛行に適したコンディションになるまでは彼らの親コロニーに滞在する。雨は飛翔性昆虫に破滅的な影響を及ぼすため、結婚飛行は天候の良い日に行われる。

多くの場合、同種間の異なるコロニーにおいては、環境要因により結婚飛行の時期を同期し、異なる巣のオスと女王とが交尾できるようにすることによって、近親交配を避けている。この飛行時期の同期は、多数のコロニーの個体が同時に結婚飛行を行なうことで、捕食者回避にも役立っている。

飛行中[編集]

一般的に、まず未交尾の女王とオスは異系交配を確保するために分散する。つぎに女王はフェロモンを発してオスを誘引する。しかしながら、女王はしばしばオスから逃れるようにし、最も速く最も適したオスのみと交尾を行なう。交尾は飛翔中に行なわれる。

One queen usually mates with several males. The sperm is stored in a special organ, known as a spermatheca, in the queen's abdomen, and lasts throughout her lifetime. This can be as long as 20 years, during which time the sperm can be used to fertilize tens of millions of eggs.

飛行後[編集]

新たなコロニーを掘りはじめる若い女王

The males have evolved for the single purpose of inseminating the queen. Male honey bees can't even feed themselves for the first few days of their lives.[1] During "the quick and violent mating," the male literally explodes his internal genitalia into the genital chamber of the queen and quickly dies.[1][2]

The young mated queens land and, in the case of ants, remove their wings. They then attempt to found a new colony. The details of this vary from species to species, but typically involve the excavation of the colony's first chamber and the subsequent laying of eggs. From this point the queen continuously lays eggs which hatch into larvae, exclusively destined to develop into worker ants.[3] The queen usually nurses the first brood alone. After the first workers appear, the queen's role in the colony typically becomes one of exclusive (and generally continuous) egg-laying. For an example of a colony founding process, see Atta sexdens.

The young queens have an extremely high failure rate. During its lifetime a very large ant colony can send out millions of virgin queens. Assuming that the total number of ant colonies in the area remains constant, on average only one of these queens succeeds. The rest are destroyed by predators (most notably other ants), environmental hazards or failures in raising the first brood at various stages of the process. This strict selection ensures that the queen has to be both extremely fit and extremely lucky to pass on her genes to the next generation.

Variations[編集]

Not all ants follow the basic pattern described above. グンタイアリの場合オスのみが羽を持つ。 They fly out from their parent colony in search of other colonies where virgin queens wait for them. A colony with an old queen and one or more mated young queens then divides, each successful queen taking a share of the workers. The reason for this behavior is the fact that army ants do not have a physical nest. The queens are thus absolutely dependent on workers to protect them.

Another variation is found in species with multi-queen colonies, such as Solenopsis invicta. The males and virgin queens mate and the queens then often return to the parent colony, where they then remain. This process greatly increases the success rate of virgin queens and allows the creation of extremely large colonies or networks of cooperating colonies. The colony also becomes essentially immortal as it is no longer dependent on the continued health of a single queen. This allows Solenopsis invicta colonies to become entrenched in their surroundings, achieving a dominant position in the ecosystem. However, the price for this is inbreeding and the resulting loss of adaptability. This may result in sudden collapses in population when the environment changes or a new predator or parasite is introduced.

Flying ant day[編集]

"Flying ant day" is an informal term for the day on which queen ants emerge from the nest to begin their nuptial flight.[4] In most species, the male ants also fly alongside them, although they are smaller and less noticeable. The queens fly around—some very long distances, and others going only a few meters—then mate, and drop to the ground where they lose their wings, and attempt to start a new ant colony [5] The mass of flying insects often attracts the attention of predators such as birds, and it is common to see flocks of feeding birds gorging on the readily available food.

This phenomenon occurs in many colonies simultaneously when the local weather conditions are appropriate, to reduce the effectiveness of predation and to ensure that the queens and males from different colonies stand a chance of meeting and interbreeding. It therefore has the appearance of being a 'timed' event or that the ants somehow communicate. However neither of these is likely to be the case - it is simply a common response to temperature, humidity and windspeed and time of year.[citation needed]

In October 2009, a swarm of flying ants briefly disrupted play between innings at cricket matches during the ICC Champions trophy, in South Africa.[6] The matches were the semi-final between Australia and England, and the ensuing final between Australia and New Zealand, both day-night 50 over games.[7]

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