Natures wonders: insects using electrostatic forces (Introduction)

by David Turell , Monday, September 30, 2024, 20:12 (22 days ago) @ David Turell

A new field of study :

file:///C:/Users/pacemaker/Downloads/The%20Hidden%20World%20of%20Electrostatic%20Ecolog...

"In 2013, Daniel Robert(opens a new tab), a sensory ecologist at the University of Bristol in England, broke ground in this discipline when his lab discovered that bees can detect and discriminate(opens a new tab) among electric fields radiating from flowers. Since then, more experiments have documented that spiders, ticks and other bugs can perform a similar trick.

"This animal static impacts ecosystems. Parasites, such as ticks(opens a new tab) and roundworms(opens a new tab), hitch rides on electric fields generated by larger animal hosts. In a behavior known as ballooning, spiders take flight(opens a new tab) by extending a silk thread to catch charges in the sky, sometimes traveling hundreds of kilometers with the wind. And this year, studies from Robert’s lab revealed how static attracts pollento butterflies and moths, and may help caterpillars to evade predators.

"This new research goes beyond documenting the ecological effects of static: It also aims to uncover whether and how evolution has fine-tuned this electric sense. Electrostatics may turn out to be an evolutionary force in small creatures’ survival that helps them find food, migrate and infest other living things.

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"In a similar way, Ortega-Jiménez considered, friction from beating insect wings could shed negative charges from body to air, leaving the insects with a positive charge while creating regions of negative static. He realized that if a web carries negative charge and insects a positive one, then a spiderweb might not just be a passive trap — it could move toward and attract its quarry electrostatically. His lab experiments revealed precisely that. Webs deformed instantly(opens a new tab) when jolted with static from flies, aphids, honeybees and even water droplets. Spiders caught charged insects more easily. He saw how static electricity altered the physics of animal interactions.

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“'As humans, we are living mostly in a gravitational or fluid-dynamics world,” Ortega-Jiménez said. But for tiny beings, gravity is an afterthought. Insects can feel air’s viscosity. While the same laws of physics reign over Earth’s smallest and largest species, the balance of forces shifts with size. Intermolecular forces flex beneath the feet of water striders on a pond, capillary forces shoot water impossibly upward through a plant’s thin roots, and electrostatic forces can ensnare any oppositely charged flecks that lie in their path.

“'Charged fleck” is an apt physical description of a pollen grain. A few years after Ortega-Jiménez noticed spiderwebs nabbing bugs, Robert’s team found that bees can gather negatively charged pollen(opens a new tab) without brushing up against it. When a bee drank nectar from a flower, the pollen shot right onto its body. “There was no contact required between the bee and the flower for that pollen to jump,” Robert said. “This is a trajectory that responds to electrostatic forces.”

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"Over the past decade, Robert has built a body of work that reveals the many ways insects and arachnids use and experience static. Ticks jump, spiders balloon, bees sense the negative charge of a flower recently visited by another positively charged bee. He even found that the charged relationship between air and insects goes both ways: Honeybee swarms shed so many negative charges that they alter the electrical gradient(opens a new tab) around them. Based on Robert’s estimates, the atmospheric charge resulting from a swarm of desert locusts rivals that of clouds and electrical storms.

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"For insects to act on static information, they must be able to detect electrical fields. Microscopic hairs on bees and spiders seem to aid in sensing, according to work from Robert’s lab. England recently expanded this unresolved science by studying how the minuscule hairs of caterpillars deflect under static, to glean how electric information may help a caterpillar survive.

"When England’s team exposed caterpillars to electric fields similar to those generated by a flying wasp, caterpillars displayed defensive behaviors(opens a new tab) such as coiling, flailing or biting. “This basically insinuates,” England said, that “prey and predator can detect each other just using static electricity.”

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"It’s starting to become impossible to ignore the idea that electrostatics may be more influential in the animal kingdom than we know today. Whole ecosystems may depend on hidden electric fields. “If you suddenly took away electrostatics, I don’t think you’d get a mass extinction,” England said. “But I think we’d be surprised by how many animals would have to adapt to not using it.”

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"If static charges aid pollination, they could shift plant evolution, too. “Maybe some fundamental features of flowers are actually just in service of generating the correct electrostatic field,” Dornhaus said, “and because we can’t see them, we’ve ignored that whole dimension of a flower’s life.” The idea isn’t so far-fetched: In 2021, Robert’s team observed petunias releasing more compounds that attract bugs(opens a new tab) around beelike electric fields. This suggests that flowers wait until a pollinator is nearby to actively lure them closer, Robert said."

Comment: an entirely new field of study of which this is a little glimpse.