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Addictive Drugs That Are Actually Pesticides

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From coca leaves to coffee beans, people use plants to produce many of the most popular drugs in the world. But whether it’s your $5 morning latté or a line of coke, you might be surprised to learn why plants bother to build the molecules behind that buzz in the first place. Strangely enough, many plant-based drugs—such as caffeine, cocaine, nicotine and morphine—are all made for the exact same reason: to fight off insects. Why exactly do humans love ingesting insect repellent so much?

Caffeine, Cocaine, Nicotine and Morphine: Pleasurable Pesticides

According to Dr. David Kennedy, who studies plants and the human brain at Northumbria University, to understand what it is about nature’s pesticides that gets us so enjoyably high, it first helps to look at the world from a plant’s perspective. “Unlike animals, plants are rooted in where they live, and can’t really get away from any threats they might need to avoid,” Kennedy says. So to keep hungry herbivores at bay, he explains, many plants can manufacture a slew of defensive chemicals.

Now some plants, like the itchy poison ivy or poison oak, use brute force chemical weapons. But others—such as opium poppies and tobacco plants—take a more delicate approach. These plants still require some animals to get close enough to help them pollinate and breed, so rather than launching a full-scale toxic offensive, they’ll merely mess with a munching bug’s mind.

To do so, these plants produce neurotoxic drugs called alkaloids, which change the balance of chemicals in a bug’s brain. At high enough levels, these drugs can kill insects (and overdose humans) but small amounts will only send them on a bad trip.

Human and Insect Brains

Oddly enough, although these alkaloids evolved to interact with insect brains, “their effects on humans are often strangely similar,” says Kennedy. “For instance, if you give cocaine to bees, it will make them dance more. If you give caffeine or other amphetamines to flies, it will wake them up and make them more aroused. And if you give morphine to insects, it’ll have the same analgesic sort of effect.”

But Kennedy explains this isn’t all that surprising. “Humans have essentially the same brain as an insect. Ours are a little more complicated, but functionally they’re both very similar,” he says. For example, in both brains many of the chemicals that the neurons use to communicate—called neurotransmitters—have the same jobs.

But the mental effect of these drugs does differ in one huge way. “Insects don’t find these drugs addictive or pleasurable, they just find them repulsive,” says Kennedy. This is because human brains have a pleasure-causing reward system which is unlike anything found in the head of a bug—and is based around a neurotransmitter called dopamine. “In humans, by total chance, these drugs just hijack that reward system,” and can flood our brains with dopamine, says Kennedy.

This dopamine rush is what causes the pleasurable effect of these drugs—which can range from a perky disposition (caffeine) to gripping euphoria (cocaine)—and is also what makes these drugs so addictive. But bugs just feel crazed or twitchy, without the pleasure.

Marijuana and Psychedelics

Not all alkaloids or insect repellents in the plant world elicit such a big wave of pleasure in humans. In fact, drugs like cocaine and caffeine are only a tiny subset, and there are plenty of similar drugs out there that will make you little more than sick.

And Kennedy says that when speaking about these addictive drugs, it’s also worth mentioning a few other chemicals that plants produce to interact with the wildlife around them: psychedelic drugs like psilocin (the active ingredient in magic mushrooms) and tetrahydrocannabinol (the active ingredient in marijuana).

Kennedy explains that these psychedelics are distinct from the addictive alkaloids—and this is because of both their chemical structure and the fact that they’re not used solely by plants as pesticides. Rather, these psychedelic drugs can have a large mix of jobs inside the plant, from fighting fungus and microbes to luring in pollinating insects. But just like the alkaloids, their insane effect on the human mind is entirely coincidental, says Kennedy.

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Massive Tumbleweeds Invaded a California Town, Trapping Residents in Their Homes
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For Americans who don’t live out west, any mention of tumbleweeds tends to conjure up images of a lone bush blowing lazily across the desert. The reality is not so romantic, as Californians would tell you.

The town of Victorville, California—an 85-mile drive from Los Angeles—was overtaken by massive tumbleweeds earlier this week when wind speeds reached nearly 50 mph. The tumbleweeds blew across the Mojave Desert and into town, where they piled up on residents’ doorsteps. Some stacks towered as high as the second story, trapping residents in their homes, according to the Los Angeles Times.

City employees and firefighters were dispatched to tackle the thorny problem, which reportedly affected about 150 households. Pitchforks were used to remove the tumbleweeds, some of which were as large as 4 feet tall by 4 feet wide.

"The crazy thing about tumbleweeds is that they are extremely thorny, they connect together like LEGOs," Victorville spokeswoman Sue Jones told the Los Angeles Times. "You can't reach out and grab them and move them. You need special tools. They really hurt."

Due to the town’s proximity to the open desert, residents are used to dealing with the occasional tumbleweed invasion. Similar cases have been reported in Texas, New Mexico, and other states in the West and Southwest. In 1989, the South Dakota town of Mobridge had to use machinery to remove 30 tons of tumbleweeds, which had buried homes, according to Metro UK.

Several plant species are considered a tumbleweed. The plant only becomes a nuisance when it reaches maturity, at which time it dries out, breaks from its root, and gets carried off into the wind, spreading seeds as it goes. They’re not just unsightly, either. They can cause soil dryness, leading to erosion and sometimes even killing crops.

[h/t Los Angeles Times]

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Afternoon Map
A New NASA Map Shows Spring Is Coming Earlier Each Year
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Climate change is shifting Earth’s seasons. Winters are getting shorter, and the warmth of spring has started to arrive earlier and earlier, messing with the timing of processes like animal migrations and the budding of new plant growth. In a series of graphics spotted by Flowing Data, the NASA Earth Observatory shows how much earlier new leaves are arriving in some parts of the U.S., and how much earlier they reach full bloom.

The data comes from a 2016 study of U.S. national parks, so the maps only cover seasonal changes within the park system. But since there are so many parks spread across the U.S., it’s a pretty good snapshot of how climate change is affecting the timing of spring across the country. The map in green shows the difference in “first leaf” arrival, or when the first leaves emerge from tree buds, and the map in purple shows the arrival of the first blooms.

A map of the U.S. with a colored grid showing where leaves are coming earlier
Joshua Stevens, NASA Earth Observatory

Around 75 percent of the 276 parks analyzed in the study have been experiencing earlier springs, and half had recently seen the earliest springs recorded in 112 years. In Olympic National Park in Washington, the first leaves are now appearing 23 days earlier than they did a century ago, while the Grand Canyon is seeing leaves appear about 11 days earlier. National parks in the Sierras and in Utah are seeing leaves appear five to 10 days earlier, as are areas along the Appalachian Trail. Some parks, however, particularly in the South, are actually seeing a later arrival of spring leaves, shown in dark gray in the graphic.

A map of the U.S. with a colored grid showing where blooms are coming earlier
Joshua Stevens, NASA Earth Observatory

The places that are witnessing earlier first blooms aren't always the ones with extra-early first leaves. The Appalachian Trail is blooming earlier, even though the first leaves aren't arriving any earlier. But in other places, like Olympic National Park, both the first leaves and the first blooms are arriving far earlier than they used to.

“Changes in leaf and flowering dates have broad ramifications for nature,” National Park Service ecologist John Gross explained in the Earth Observatory’s blog. “Pollinators, migratory birds, hibernating species, elk, and caribou all rely on food sources that need to be available at the right time.” When temperatures get out of sync with usual seasonal changes, those species suffer.

[h/t Flowing Data]

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