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5 Ways Plants Communicate

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You may not think of plants as particularly chatty or active organisms, but they’re not as passive as they might seem. Plants can’t run away, so they have to develop other strategies to stay alive, as James Cahill, an environmental plant ecologist at the University of Alberta, explains in “What Plants Talk About,” a documentary from the PBS show NATURE. They’ve evolved the use of chemicals to communicate with insects and each other in order to thrive. Here are five behaviors that show how active plants can be. 

1. Plants can call for help

When you inhale the sweet smell of freshly mown grass or cut flowers, what you’re actually smelling is the plant’s distress call. “It’s the plant's way of crying out for help,” Cahill says. The scent attracts insects that will eat the pests currently munching on their plant-bodies. For instance, the wild tobacco plant can identify a hornworm caterpillar by its saliva. When attacked by this caterpillar, the tobacco plant emits a chemical signal that appeals to the insect’s enemies. Within hours, caterpillar predators like the big-eyed bug show up, ideally driving the pest away. 

2. Plants can eavesdrop

Plants can eavesdrop on the chemical signals of their brethren, and sometimes respond to another plant’s SOS cry by ramping up their own defenses proactively, knowing that a hungry insect is nearby. 2013 review found 48 studies support the idea that plants increase their defenses after their neighbors are damaged. For instance, when wounded by a hornworm, sagebrush releases defensive proteins called trypsin proteinase inhibitors (TPIs), which prevent the insect from digesting protein and stunt its growth. When neighboring plants—even other species—are exposed to the chemical signals of damaged sagebrush, they begin readying their defenses. Wild tobacco, scientists found, begins prepping to make these TPIs when it senses a distress call from sagebrush, giving it a head start on defending itself if the caterpillar comes calling. 

3. Plants can defend their territory 

Plants compete with each other for sunlight, jostling for position among their neighbors. They also can push out competition in other ways. The invasive knapweed plant—native to Eastern Europe but wrecking havoc on U.S. grasslands—has roots that release certain chemicals to help the plant take in nutrients from the soil. Those same chemicals also kill off native grasses. Thus, the knapweed ends up taking over large territories and killing off its competitors, much like some animals do. Some plants, however, have formed a defense. Lupin roots secrete oxalic acid, which forms a protective barrier against the toxic chemicals given off by knapweed. Lupin can even protect other plants in its vicinity from falling prey to the invasive species. 

4. Plants can recognize their siblings 

Plants can sense when other plants are growing around them. This helps them compete for resources like sunlight, growing more if another plant is shading them, for instance. But like animals, they tend to recognize and support their kin. In an experiment with sea rocket, a plant that often grows close together with its siblings, plants that were grown in pots with relatives had more restrained root growth than plants grown with random strangers. The plants in the stranger condition grew more roots in order to better compete for food, whereas the sibling plants were more considerate of each other’s needs. Further experiments showed that sibling plants recognize each other via chemical signals.  

5. Plants can communicate with mammals

Plants go out of their way to attract more than just insects. A carnivorous pitcher plant native to Borneo has evolved to hijack bat communication systems, turning the bats’ echolocation to its advantage. According to a new study in Current Biology, Nepenthes hemsleyan has a concave structure that is specially suited to reflect bat echolocation, helping the bats find the plant. The bats roost in the pitcher plant, and provide important nutrients by way of the bat guano that gets distributed in the soil nearby.   

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Which Rooms In Your Home Have the Most Types of Bugs, According to Entomologists 
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Insects can make any home their own, so long as it contains cracks, doors, and windows for them to fly, wriggle, or hitchhike their way in. And it turns out that the creepy crawlers prefer your living room over your kitchen, according to a new study that was recently highlighted by The Verge.

Published in the journal Scientific Reports, the study looked at 50 homes in Raleigh, North Carolina, to measure their insect populations. Entomologists from both North Carolina State University and the California Academy of Sciences ultimately discovered more than 10,000 bugs, both alive and dead, and a diverse array of species to boot.

The most commonly observed bugs were harmless, and included ladybugs, silverfish, fruit flies, and book lice. (Luckily for homeowners, pests like bedbugs, termites, and fleas were scarcer.) Not all rooms, though, contained the same distribution of many-legged residents.

Ground-floor living rooms with carpets and windows tended to have the most diverse bug populations, as the critters had easy access inside, lots of space to live in, and a fibrous floor habitat that could be either a cozy homestead or a death trap for bugs, depending on whether they got stuck in it. The higher the floor level, the less diverse the bug population was, a fact that could be attributed to the lack of doors and outside openings.

Types of bugs that were thought to be specific to some types of rooms were actually common across the board. Ants and cockroaches didn’t limit themselves to the kitchen, while cellar spiders were present in all types of rooms. As for moths and drain flies, they were found in both common rooms and bathrooms.

Researchers also found that “resident behavior such as house tidiness, pesticide usage, and pet ownership showed no significant influence on arthropod community composition.”

The study isn’t representative of all households, since entomologists studied only 50 homes within the same geographical area. But one main takeaway could be that cohabiting bugs “are an inevitable part of life on Earth and more reflective of the conditions outside homes than the decisions made inside,” the researchers concluded. In short, it might finally be time to make peace with your itty-bitty housemates.

[h/t The Verge]

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Special Viewfinders Allow Colorblind People to Experience Fall Foliage in All Its Glory
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Each autumn, the foliage of the Great Smoky Mountains erupts into a kaleidoscope of golds, reds, and yellows. Visitors from around the world flock to the area to check out the seasonal show, and this year some guests will have the chance to see the display like they’ve never seen it before. As the Associated Press reports, Tennessee is now home to three special viewfinders at scenic overlooks that allow colorblind users to see the leaves of the forests in all their glory.

The new amenities cost $2000 apiece and have been installed by the Tennessee Department of Tourist Development at the Ober Gatlinburg resort, at Big South Fork National River and Recreation Area near Oneida, and at the westbound Interstate 26 overlook near Erwin in Unicoi County. The lenses are similar to glasses that allow people with red-green vision disorders to see in full color, but according to state officials this is likely the first time the technology has been implemented in scenic tower viewers.

Color blindness varies from person to person, but those who have it may tend to see mostly green or dull brown when looking at a brilliant autumnal landscape. Before the new features debuted at the beginning of November, tourism officials allowed a group of colorblind individuals to test them out. You can watch their reactions to seeing the true spectrum of fall colors for the first time in the video below.

[h/t AP]

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