• Ants have been farming plants for millions of years, long before people

    From Garrison L. Hilliard@21:1/5 to All on Fri Nov 25 08:26:04 2016
    XPost: bit.listserv.skeptic

    By Deborah Netburn

    Los Angeles Times

    Could ants get any cooler?

    These amazing insects have been known to create rafts and bridges with
    their bodies and tend to vast fungus gardens. Now, a new study
    suggests they have also been farming plants for millions of years.

    High in the trees of the island nation of Fiji, evolutionary biologist Guillaume Chomicki, a post-doc at the University of Munich in Germany, discovered a specialized community of ants that actively cultivate six
    species of plants.

    DNA evidence suggests this farming behavior could go back as far as 3
    million years, he said.

    To put that in perspective, the earliest known evidence of human
    farming dates back to 23,000 years ago.

    The ant-farmed plants are all members of the Squamellaria family, also
    known as “ant-plants.” They are epiphytic, meaning they grow on other
    plants, usually trees.

    In a paper published Monday in Nature Plants, Chomicki describes how
    the industrious ants, a species called Philidris nagasau, are involved
    in nearly every aspect of the ant-plants’ life cycle.

    Even before the Squamellaria’s fruit is ripe, the ants begin gathering
    its seeds by cutting through the fruit’s wall. Next, the ants sow the
    seeds in holes in the tree bark and guard them until they begin to

    When the seedlings reach about } of an inch high, they begin to
    develop a soft, bulbous structure between the roots and the stem known
    as a domatium or “ant-house.” As soon as the domatium is big enough,
    the ants enter a cavity in it to defecate, providing the young plant
    with much-needed fertilizer.

    So, what do the ants get in return for all this attentiveness?

    First and foremost, a place to live.

    As the Squamellaria continues to grow, its domatium grows as well,
    eventually getting up to 8 to 16 inches across and sometimes even
    bigger. This structure is designed to be a perfect home to ants,
    Chomicki said.

    He described the inside as having “an incredibly complex system of interconnected galleries, which looks like a brain.”

    All those folds maximize the nesting surface available to the ants.
    That’s good for the ants and good for the long-term health of the
    plant, Chomicki said. The more ants that live in the domatium, the
    more ant-fertilizer the plant receives.

    Some species of Squamellaria sweeten the deal for the ants even more
    by providing sugar rewards that drip from their leaves.

    Over the course of his research Chomicki said he never encountered
    this species of ants not living in one of the six species of plants
    that they were observed to cultivate, nor did he see the plants living
    without the ants. That suggests the two organisms are now mutually
    dependent, he said.

    This is not the first time farming behaviors have been observed in the
    animal kingdom.

    The hairy chested-yeti crab that lives along hydrothermal vents deep
    in the ocean, farms sulfur-oxidizing bacteria on the hair of its chest
    and harvests it using a comb-like structure in its mouth.

    Three-toed sloths in Costa Rica have been shown to encourage green
    algae to grow on their fur to supplement their nutrient-poor leafy

    And leaf cutter ants are well known for keeping vast fungal farms that
    provide them with food.

    However, Chomicki said the ant farmers of Fiji are the first known
    ants to farm plants rather than fungus.

    He added that there is still more he would like to learn about the
    relationship between the ant farmers and their crops. For example, he
    noticed that the ants only defecate in particular cavities in the
    domatium. He suspects that the plant produces a chemical that tells
    the ant where to do their business.

    He’s also curious to learn more about the genes that allow the plants
    to use the nutrients in the ant poop.


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