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Bernard Dupont, Flickr // CC BY SA-2.0

Carnivorous Plant Uses Rain to Spring Its Trap

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Bernard Dupont, Flickr // CC BY SA-2.0

“Rain, rain, go away, come again another day” is not a sentiment that many would disagree with. But then there’s Nepenthes gracilis, a carnivorous plant found in Southeast Asia that relies on rain to help it eat. 

Carnivorous plants thrive in poor soils where most other plants would fail, because they get nutrients from consuming insects instead of taking them from the ground. They can’t stalk, chase, and attack their prey like animal predators, though, so they have to rely on lures and traps. Many of these traps, like the snapping “mouths” of Venus flytraps, take lots of time and energy to reset after use, while others, like the catapulting tentacles of sundews, can only be used once. In a new study, biologist Ulrike Bauer shows that N. gracilis works around these constraints by using rain drops to drive its traps and set them off with no energy costs. 

N. gracilis is a pitcher plant, and captures and digests insects in a modified leaf that looks like a champagne flute. Bugs are lured in by the plant’s smell and the nectar that coats the underside of the pitcher’s lid. While crawling around on the lid and collecting nectar, the bugs get knocked off and into the pitcher, where they’re devoured. 

Instead of flicking its prey into the trap by moving the lid itself, Bauer discovered, the plant lets the impact of rain drops do the work for it. Her study began when she noticed that N. gracilis’s lid is more rigid than those of its cousins. After taking high-speed video of the traps in action and looking at the mechanics of the lids in their lab, Bauer and her collaborators found that N. gracilis’s stiff lid doesn’t bend under the impact of rain drops like other pitcher plant lids do, but pivots on a flexible hinge at its base. That means there’s no safe spot for bugs to avoid getting shaken, like there would be if only part of the lid bent downward. Because the lid is small and light, it moves very quickly, and its rain-driven shaking is faster than both the Venus flytrap’s snapping trap and the sundew’s tentacles. 

All of this happens without any work from the plant. It doesn’t need to set the trap, activate it, and then wait to reset it, but can use it, Bauer writes, “instantly and indefinitely as long as the external driver, rain drop fall, persists.”

Useful as the effortless trap is, it does seem to have one big drawback in that it only works when it's raining. This isn’t too much of a problem for the plant, though, the researchers say. Water can keep dripping from other vegetation above the plants and keep the trap swinging long after a rain shower stops. When there’s no rain, social insects like ants that survive their encounter with the plant can recruit their nest mates to the food source, and they might not be so lucky to come check it out on a dry day. 

N. gracilis’s unique trap shakes up our picture of carnivorous plants, the researchers say. Traditionally, they’ve been divided into two groups: those with “active” moving traps like the Venus flytrap and those with “passive” motionless traps like pitcher plants. N. gracilis has a trap that the researchers call “passive-dynamic,” and uses movement but requires no activity from the plant. It suggests, they write, that the dividing line isn’t so clear and there’s a continuum between active and passive trapping mechanisms, with more traps like this potentially out there waiting to be discovered. 

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Animals
Why Do Female Spotted Hyenas Give Birth Through Their Pseudo-Penises?
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YouTube

At the zoo, you can sometimes tell the difference between male and female animals by noting their physical size, their behavior, and yes, their nether regions. Hyenas, however, flip the script: Not only are lady spotted hyenas bigger and meaner than their male counterparts, ruling the pack with an iron paw, they also sport what appear to be penises—shaft, scrotum, and all.

"Appear" is the key word here: These 7-inch-long phalluses don't produce sperm, so they're technically really long clitorises in disguise. But why do female hyenas have them? And do they actually have to (gulp) give birth through them? Wouldn't that hurt … a lot?

The short answers to these questions are, respectively, "We don't know," "Yes," and "OW." Longer answers can be found in this MinuteEarth video, which provides the full lowdown on hyena sex. Don't say we didn't warn you.

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science
Are Sex, Drugs, and Rock 'n' Roll Really Linked? Researchers Investigate
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Steve Wood/Express/Hulton Archive/Getty Images

Around the world, sex, drugs, and rock 'n' roll are said to go hand-in-hand. But do they? As PsyPost reports, a pair of Pennsylvania psychologists recently dove into the empirical evidence tying the three together, asking college students to talk about their drug use, sex lives, and music preferences and talents to suss out whether people who play and enjoy rock music really do have more active sex lives and drug use.

Published in the journal Human Ethnology Bulletin, the study [PDF] of 467 students relied on self-reporting, which isn't typically the most reliable evidence—people are wont to exaggerate how often they've had sex, for instance—but the survey also asked them about their desires, posing questions like "If you could, how frequently would you have sex?" It also asked about how often the students drank and what drugs they had tried in their lifetimes. They also described their musical experience and what kind of music they listened to.

The results were mixed, but the researchers identified a relationship between liking faster, "harder" music and having more sex and doing more drugs. Acoustic indie rock aficionados weren't getting quite as wild as heavy metal fans. High-tempo-music lovers were more likely to have taken hallucinogenic drugs like LSD, for example, and tended to have had more sexual partners in the previous year than people who favored slower types of music. According to the study, previous research has found that attention-seeking people are more likely to enjoy "hard" music.

The study didn't have a diverse enough group either in age or in ethnicity to really begin to make sweeping generalizations about humans, especially since college students (the participants were between 18 and 25) tend to engage in more risky behaviors in general. But this could lay the groundwork for future research into the topic. Until then, it might be more accurate to change the phrase to "sex, drugs, and heavy metal."

[h/t PsyPost]

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