Wildfeuer via Wikimedia Commons // CC BY 2.5
Wildfeuer via Wikimedia Commons // CC BY 2.5

Study Finds That Plant Emits the Scent of an Injured Honeybee to Lure Flies

Wildfeuer via Wikimedia Commons // CC BY 2.5
Wildfeuer via Wikimedia Commons // CC BY 2.5

Plants are liars. There, we said it. All right, fine, not all plants. But a lot of them. Meet the newest member of the botanical pants-on-fire club: a little flower that stinks like an injured bee in order to attract bee-eating flies. Researchers published a report today on the plant’s trickery in the journal Current Biology

Most plant deception is pretty crude. Consider the reeking corpse flower, or the bee orchid, whose lady bee-shaped flowers are irresistible to passing bee dudes. The male bees zoom in and get busy. Before too long they realize they’ve been had—but not before they’ve pollinated the devious, devious orchid.

Other plants employ slightly subtler devices. Plants in the Ceropegia family depend on flies for pollination. Their flowers are trap-shaped, so once a fly gets in, it will pretty much have to rub itself all up on the plant’s sexual parts in order to escape. But for that to happen, the fly first has to show up.

To catch a fly, you need to think like a fly. Fortunately, many of the flies that pollinate Ceropegia are fairly easy to predict. They like flying, buzzing, mating, and, most importantly, they like stealing other bugs’ food. Rather than hunting for its own honeybee, a kleptoparasitic fly waits until a predator like a spider has caught one, then buzzes down and digs in.

Flies could presumably follow spiders around until they made a kill. But it’s much more efficient to just sniff the air for the scent of a bee in trouble. It’s kind of the arthropod form of ambulance-chasing lawyers.

A team of European scientists suspected that the little South African flower Ceropegia sandersonii was using flies’ own trickery against them.

To find out, the researchers studied both the flowers and the bees. The first thing they noticed was that a spider-caught bee would eject its stinger, which released a droplet of venom. The team tested the venom and found it riddled with alarm pheromones, which, when released, would warn nearby bees to beat it.

A bee covered in kleptoparasitic flies. Check out the drop of venom at the tip of its stinger! Image Credit: Gernot Kunz

Next they captured and tested C. sandersonii’s oh-so-innocent floral fragrance, looking for chemical similarities with the bee venom. They found them. In an act of chemical mimicry, flowering C. sandersonii plants were in fact emitting what seemed to be appealing olfactory distress calls.

Biologist Daniel Janzen studies plant-animal relationships at the University of Pennsylvania. (He was unaffiliated with this study.) “Tropical nature is packed with these kinds of detailed eco-behavioral interactions,” he told mental_floss in an email. “It’s nice to have another one worked out.”

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Watch a Tree Release a Massive "Pollen Bomb" Into the Air

In case your itchy, watery eyes hadn't already tipped you off, spring is in the air. Some trees release up to a billion pollen grains apiece each year, and instead of turning into baby trees, many of those spores end up in the noses of allergy sufferers. For a visual of just how much pollen is being released into our backyards, check out the video below spotted by Gothamist.

This footage was captured by Millville, New Jersey resident Jennifer Henderson while her husband was clearing away brush with a backhoe. He noticed one tree was blanketed in pollen, and decided to bump into it to see what would happen. The result was an explosion of plant matter dramatic enough to make you sniffle just by looking at it.

"Pollen bombs" occur when the weather starts to warm up after a prolonged winter, prompting trees and grasses to suddenly release a high concentration of pollen in a short time span. Wind, temperature, and humidity levels all determine the air's pollen count for any given day, but allergy season settles down around May.

After determining that your congestion is the result of allergies and not a head cold, there are a few steps you can take to stave off symptoms before they appear. Keep track of your area's pollen report throughout the week, and treat yourself with antihistamines or nasal spray on days when you know it will be particularly bad outside. You can also keep your home a pollen-free zone by closing all the windows and investing in an air purifier. Check out our full list of seasonal allergy-fighting tips here.

[h/t Gothamist]

Why Some Trees in Norway Are Missing Their Rings

Dendrochronologists are experts at reading tree rings. They can learn a great deal of information—including past climate in an area and the age of the tree—by taking a tree core sample and reading between the lines (literally).

But as the BBC reports, one climate researcher was stumped when she discovered that many trees in the Norwegian village of Kåfjord were missing their rings. Extreme weather and invasive insects can cause some degree of damage to trees, but not enough to render them ringless.

Claudia Hartl, from Johannes Gutenberg University in Germany, knew that these trees dated back to 1945, but that alone wasn't enough information. Two other clues that helped Hartl and her colleagues solve the mystery were location and history. During World War II, Nazi soldiers moored the Tirpitz—the largest battleship of Hitler's navy—off the waters of Kåfjord to intercept vessels carrying Allied supplies to the Soviet Union. The Germans released an artificial smoke containing chlorosulphuric acid to conceal the ship's location, and this is believed to be the root of the trees' problem.

Artificial smoke could have damaged the needles of the trees, halting the photosynthesis process and stunting the trees' growth, researchers found. It takes time for the trees to recover, but it is possible. One tree saw no growth at all from 1945 to 1954, but after 30 years its growth had returned to normal. Hartl presented the findings at the European Geosciences Union General Assembly in Vienna this week [PDF].

"I think it's really interesting that the effects of one engagement are still evident in the forests of northern Norway more than 70 years later,” Hartl told BBC News. She believes her "warfare dendrochronology" will unearth similar findings elsewhere in the world.

[h/t BBC News]


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