Natures wonders: ant geopolitics (Introduction)

by David Turell , Friday, February 16, 2024, 16:14 (71 days ago) @ David Turell

Ants have invaded the whole Earth:

https://aeon.co/essays/the-strange-and-turbulent-global-world-of-ant-geopolitics?utm_so...

"...it is the story of a group of ant species, living in Central and South America a few hundred years ago, who spread across the planet by weaving themselves into European networks of exploration, trade, colonisation and war – some even stowed away on the 16th-century Spanish galleons. During the past four centuries, these animals have globalised their societies alongside our own.

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"Global ant societies... are something new in the world, existing at a scale we can measure but struggle to grasp: there are roughly 200,000 times more ants on our planet than the 100 billion stars in the Milky Way.

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"Ants, however, operate differently by forming ...‘anonymous societies’ in which individuals from the same species or group can be expected to accept and cooperate with each other even when they have never met before. What these societies depend on, Moffett writes, are ‘shared cues recognised by all its members’.

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"Social insects – ants, wasps, bees and termites – rely on chemical badges of identity. In ants, this badge is a blend of waxy compounds that coat the body, keeping the exoskeleton watertight and clean. The chemicals in this waxy blend, and their relative strengths, are genetically determined and variable. This means that a newborn ant can quickly learn to distinguish between nest mates and outsiders as it becomes sensitive to its colony’s unique scent. Insects carrying the right scent are fed, groomed and defended; those with the wrong one are rejected or fought.

"The most successful invasive ants, including the tropical fire ant (Solenopsis geminata) and red fire ant (S invicta), share this quality. They also share social and reproductive traits. Individual nests can contain many queens (in contrast to species with one queen per nest) who mate inside their home burrows. In single-queen species, newborn queens leave the nest before mating, but in unicolonial species, mated queens will sometimes leave their nest on foot with a group of workers to set up a new nest nearby. Through this budding, a network of allied and interconnected colonies begins to grow.

"In their native ranges, these multi-nest colonies can grow to a few hundred metres across, limited by physical barriers or other ant colonies. This turns the landscape to a patchwork of separate groups, with each chemically distinct society fighting or avoiding others at their borders. Species and colonies coexist, without any prevailing over the others... As new nests are created, colonies bud and spread without ever drawing boundaries because workers treat all others of their own kind as allies. What was once a patchwork of complex relationships becomes a simplified, and unified, social system.

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"All five of the ants included in the International Union for the Conservation of Nature’s (IUCN) list of 100 of the world’s worst invasive alien species are unicolonial. Three of these species – are originally from Central and/or South America...
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"Unicolonial ants are superb and unfussy scavengers that can hunt animal prey, eat fruit or nectar, and tend insects such as aphids for the sugary honeydew they excrete.

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"Nowadays, targeted insecticides can be effective for clearing relatively small areas. This has proved useful in orchards and vineyards (where the ants’ protection of sap-sucking insects makes them a hazard to crops). Large-scale eradications are a different matter, and few places have tried. New Zealand, the world leader in controlling invasive species, is the only country to have prevented the spread of the red fire ant, mostly by eradicating nests on goods arriving at airports and ports.

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"Unlike many ant species, in which a worker who finds a new food source returns to the nest to recruit other foragers, the Argentine ant enlists other workers already outside the nest, thus recruiting foragers more quickly. However, the decisive advantage of unicolonial ant species lies in their sheer force of numbers, which is usually what decides ant conflicts. They often become the only ant species in invaded areas.

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"Expanding in parallel with the world-spanning supercolony are separate groups of the Argentine ant that bear different chemical badges – the legacy of other journeys from the homeland. Same species, different ‘smells’. In places where these distinct colonies come into contact, hostilities resume.

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"Unicolonial ants can turn a patchwork of colonies created by different ant species into a landscape dominated by a single group. As a result, textured and complex ecological communities become simpler, less diverse and, crucially, less different to each other. This is not just a process; it is an era.

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"...a colony’s ability to take bits of information from thousands of tiny brains and turn it into a distributed, constantly updated picture of their world. Even ‘smell’ seems a feeble word to describe the ability of ants’ antennae to read chemicals on the air and on each other."

Comment: An enormous essay I trimmed down by skipping the examples of invasion. I need not comment on the last paragraph which is my thought.