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  • It's June, just after a heavy rainfall,

  • and the sky is filling with creatures we wouldn't normally expect to find there.

  • At first glance, this might be a disturbing sight.

  • But for the lucky males and females of Solenopsis invicta,

  • otherwise known as fire ants, it's a day of romance.

  • This is the nuptial flight,

  • when thousands of reproduction-capable male and female ants,

  • called alates, take wing for the first and last time.

  • But even for successful males who manage to avoid winged predators,

  • this mating frenzy will prove lethal.

  • And for a successfully mated female, her work is only beginning.

  • Having secured a lifetime supply of sperm from her departed mate,

  • our new queen must now single-handedly start an entire colony.

  • Descending to the ground,

  • she searches for a suitable spot to build her nest.

  • Ideally, she can find somewhere with loose, easy-to-dig soil

  • like farmland already disturbed by human activity.

  • Once she finds the perfect spot, she breaks off her wings

  • creating the stubs that establish her royal status.

  • Then, she starts digging a descending tunnel ending in a chamber.

  • Here the queen begins laying her eggs, about ten per day,

  • and the first larvae hatch within a week.

  • Over the next three weeks,

  • the new queen relies on a separate batch of unfertilized eggs

  • to nourish both herself and her brood,

  • losing half her body weight in the process.

  • Thankfully, after about 20 days,

  • these larvae grow into the first generation of workers,

  • ready to forage for food and sustain their shrunken queen.

  • Her daughters will have to work quickly though

  • returning their mother to good health is urgent.

  • In the surrounding area,

  • dozens of neighboring queens are building their own ant armies.

  • These colonies have peacefully coexisted so far,

  • but once workers appear,

  • a phenomenon known as brood-raiding begins.

  • Workers from nests up to several meters away

  • begin to steal offspring from our queen.

  • Our colony retaliates,

  • but new waves of raiders from even further away

  • overwhelm the workers.

  • Within hours, the raiders have taken our queen's entire brood supply

  • to the largest nearby nest

  • and the queen's surviving daughters abandon her.

  • Chasing her last chance of survival,

  • the queen follows the raiding trail to the winning nest.

  • She fends off other losing queens and the defending nest's workers,

  • fighting her way to the top of the brood pile.

  • Her daughters help their mother succeed where other queens fail

  • defeating the reigning monarch, and usurping the brood pile.

  • Eventually, all the remaining challengers fail,

  • until only one queenand one brood pileremains.

  • Now presiding over several hundred workers in the neighborhood's largest nest,

  • our victorious queen begins aiding her colony in its primary goal:

  • reproduction.

  • For the next several years, the colony only produces sterile workers.

  • But once their population exceeds about 23,000,

  • it changes course.

  • From now on, every spring,

  • the colony will produce fertile alate males and females.

  • The colony spawns these larger ants throughout the early summer,

  • and returns to worker production in the fall.

  • After heavy rainfalls, these alates take to the skies,

  • and spread their queen's genes up to a couple hundred meters downwind.

  • But to contribute to this annual mating frenzy,

  • the colony must continue to thrive as one massive super-organism.

  • Every day, younger ants feed the queen and tend to the brood,

  • while older workers forage for food and defend the nest.

  • When intruders strike,

  • these older warriors fend them off using poisonous venom.

  • After rainfalls, the colony comes together,

  • using the wet dirt to expand their nest.

  • And when a disastrous flood drowns their home,

  • the sisters band together into a massive living raft

  • carrying their queen to safety.

  • But no matter how resilient,

  • the life of a colony must come to an end.

  • After about 8 years, our queen runs out of sperm

  • and can no longer replace dying workers.

  • The nest's population dwindles, and eventually,

  • they're taken over by a neighboring colony.

  • Our queen's reign is over, but her genetic legacy lives on.

It's June, just after a heavy rainfall,

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交尾の狂乱、精子の大群、雛の襲撃:ヒアリの女王の生活 - Walter R. Tschinkel (Mating frenzies, sperm hoards, and brood raids: the life of a fire ant queen - Walter R. Tschinkel)

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    Taka に公開 2021 年 01 月 14 日
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