Bees Across America Stopped Buzzing During Last Year's Total Solar Eclipse

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iStock.com/mafrmcfa

Most bees are diurnal creatures, meaning that they're active during daylight hours. After flying around all day, they start to slow down around dusk and return to their colonies at night to sleep.

Considering that daylight plays an important role in a bee's busy schedule, would a total solar eclipse thwart their plans? Would the bees think it's time to turn in for the night when the Moon passes in front of the Sun and blocks out its light? These are the questions researchers from the University of Missouri set out to answer when they tracked bee activity during the last total solar eclipse on August 21, 2017.

Their findings, published today in the Annals of the Entomological Society of America, yielded some surprises. Lead author Candace Galen said they expected to see bee activity gradually diminish as the sky darkened. "But we had not expected that the change would be so abrupt, that bees would continue flying up until totality [of the eclipse] and only then stop, completely," Galen said in a statement. "It was like 'lights out' at summer camp! That surprised us."

Of the 16 locations they tracked, only one bee was heard flying during the eclipse. This is one of the first studies to analyze how bees respond to a solar eclipse, and few studies like this have looked at similar behavior in other insects or animals. A 1991 study found that desert cicadas in Arizona stopped chirping for about 40 minutes during a partial solar eclipse. Another study from 1973 found that captive squirrels became restless and ran around far more during an eclipse, while other research showed that Blue bulls at a zoo in India altered their feeding and resting periods during a partial solar eclipse.

Before the latest bee study kicked off, researchers used tiny microphones and temperature sensors to track bee pollination by listening to them buzz about. That same method was applied to the solar eclipse experiment, and 16 monitoring stations were set up along the eclipse's path of totality in Oregon, Idaho, and Missouri. More than 400 scientists, citizens, and elementary school teachers and students assisted with the experiment.

The microphones were hung on flowers that bees had pollinated in semi-remote locations away from foot and vehicle traffic. After the eclipse, the recordings were sent off to Galen's lab, where researchers matched up flight activity with the different eclipse periods. In doing so, it was discovered that bees (mostly bumble and honey bees) kept flying during the partial-eclipse phases before and after the total eclipse. Practically no buzzing was recorded during the period of totality, save for one flight picked up by microphones.

Researchers also noticed that bees' flights were longer during those partial-eclipse phases, but they were likely slower flights as a result of the reduced light. They may have been returning to their hives, believing that it was time to rest, researchers suggested.

"The eclipse gave us an opportunity to ask whether the novel environmental context—mid-day, open skies—would alter the bees' behavioral response to dim light and darkness," Galen said. "As we found, complete darkness elicits the same behavior in bees, regardless of timing or context. And that's new information about bee cognition."

The next total solar eclipse in North America will take place on April 8, 2024, at which time Galen's team plans to do a second experiment. The researchers hope to improve their audio-analysis software to determine whether a bee is leaving or returning to its colony. That way, they'll be able to tell whether bees head home during a total eclipse.

What Caused Pangea to Break Apart?

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iStock.com/alfimimnill

Emily Devenport:

There's another way to look at this question. People tend to think in terms of supercontinents forming and then breaking up again due to convection currents in the mantle, hot material rising and causing rifts in weaker spots, possibly in old sutures where the continents were shoved together—but what is really happening is that ocean basins are opening and closing, and the ocean has an active role in subduction.

The opening and closing of an ocean basin is called a Wilson Cycle. It begins when hot material rising from the mantle stretches the overlying crust. As molten material rises, a rift is formed. The rift is widened as material continues to squeeze into it. If that rifting goes on long enough, through a broad enough swath of a continent, ocean water will eventually flow into it, and an ocean basin begins to form. The upwelling of hot material will continue to rise through that thinner area of crust, pushing the plates apart. The Atlantic Ocean is an example of a basin that is well along in the Wilson Cycle; eventually subduction is going to begin at its margins, and the whole shebang will pivot.

This will happen because at the edge of continents, sediments accumulate. The weight of those sediments, combined with the weight of the water, drives the heavier, denser edge of the oceanic plate under the continental crust, which is fatter and lighter. Eventually subduction begins, and the basin begins to close again. The Pacific Ocean is an example of a basin that's closing.

If you look at a map of the oceanic rift zones, you'll notice that the one in the Atlantic is pretty much in the middle of that ocean, but the Pacific rift zone has been pulled all the way over to North America above Central America. Subduction is actively occurring on all margins of that plate.

The simple picture is that the continents are moving toward each other across the Pacific Ocean while the Atlantic Basin continues to widen. The truth is more complicated. When plates subduct, the water in the crust lowers the melting point of those rocks, so partial melting occurs. The partially melted material begins to rise through the overlying rocks, because it's less dense, and decompression melting occurs. Eventually, the upwelling of hot material forms plutons and volcanoes above the subduction zones. Fore-arc and Back-arc [PDF] basins can form. As the oceanic crust is pulled under the continental plate, island chains and other chunky bits get sutured to the edge of the continent along with sediments, making it larger. Our world is ~4.6 billion years old, so our continents are really large, now. They're unlikely to rift through the ancient cratons that formed their hearts.

What will happen if subduction begins on the eastern side of North America before the Pacific Basin closes? The margin next to California is a transform fault; it's not subducting. Will it eventually push itself under that part of North America again, or will the transform zone get bigger? The hot spot that was driving the ancient Farallon Plate under North America was eventually overridden by the southwestern states (Arizona, New Mexico, etc.) forming a rift zone. Will it continue to rift or poop out?

There are computer models predicting what supercontinent may form next. They will continue to change as our understanding of tectonic processes gets more accurate.

This post originally appeared on Quora. Click here to view.

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