CLOSE
Original image
Youtube

This Wasp Turns Spiders Into Zombie Construction Workers

Original image
Youtube

In another post, we were talking about what happens to spiders and their webs when scientists give them a little bit of marijuana and other drugs. While researching that post, I learned that it's not just humans that alter spiders’ behavior with chemicals. There’s a wasp in Costa Rica that does the same thing, in a more gruesome and sinister way, as part of its journey to adulthood. 

The tropical wasp species Hymenoepimecis argyraphaga is a parasite, and it takes advantage of an unlikely host. The web of the orb weaver spider Plesiometa argyra is normally a place where bugs meet their untimely death and become spider snacks. Using an arsenal of toxins and mind-altering chemicals, though, H. argyraphaga is able to turn the spider into a slave and a meal, and its web into a safe haven.  

When the female wasp is ready to lay her egg, she seeks out a spider to help raise her child. She stings the spider to paralyze it and then lays an egg on its abdomen. Soon, the egg hatches and the larva that emerges remains attached to the spider, living on its abdomen and sucking hemolymph (kind of the arthropod version of blood) from its body for nourishment. After a few weeks like this, during which the spider goes about its life as normal, the wasp larva is ready to move on to the next stage of its life cycle. To do this, it needs to make a cocoon. A spider’s web is a decent place to build one, but not perfect. It’s suspended above the ground and the sticky threads provide defense from predators that might eat the wasp, but it’s far too flimsy to support the heavy cocoon and the adult wasp that will come out of it. 

The wasp gets around this problem by forcing the spider to build a web that suits its needs. It injects a chemical (which hasn’t been identified yet) into the spider that alters the host’s behavior. The spider begins building its web as normal, but instead of completing all the steps and getting a carefully-patterned web, the zombified spider simply repeats the first few steps over and over again, resulting in a web that’s just a few heavily-reinforced anchor threads and a small center section. 

Once the web is done, the spider crawls to the center of the web and sits there complacently. The larva molts, kills the only companion it has ever known, sucks any remaining useful bits out from its corpse, and discards it. Then, it builds its cocoon on a web custom-built for the job. A few weeks later, the adult wasp emerges and flies away, and the cycle starts over. 

For more on parasitic wasps, see any of Carl Zimmer’s paeans to the Emerald Cockroach Wasp. 

Original image
iStock
arrow
Big Questions
Why Do Cats Love Scratching Furniture?
Original image
iStock

Allergy suffering aside, cat ownership has proven health benefits. A feline friend can aid in the grieving process, reduce anxiety, and offer companionship.

The con in the cat column? They have no reservations about turning your furniture into shredded pleather. No matter how expensive your living room set, these furry troublemakers will treat it with the respect accorded to a college futon. Do cats do this out of some kind of spite? Are they conspiring with Raymour & Flanigan to get you to keep updating home decor?

Neither. According to cat behaviorists, cats gravitate toward scratching furniture mostly because that love seat is in a really conspicuous area [PDF]. As a result, cats want to send a message to any other animal that may happen by: namely, that this plush seating belongs to the cat who marked it. Scratching provides both visual evidence (claw marks) as well as a scent marker. Cat paws have scent glands that can leave smells that are detectable to other cats and animals.

But it’s not just territorial: Cats also scratch to remove sloughed-off nail tips, allowing fresh nail growth to occur. And they can work out their knotted back muscles—cramped from sleeping 16 hours a day, no doubt—by kneading the soft foam of a sectional.

If you want to dissuade your cat from such behavior, purchasing a scratching post is a good start. Make sure it’s non-carpeted—their nails can get caught on the fibers—and tall enough to allow for a good stretch. Most importantly, put it near furniture so cats can mark their hangout in high-traffic areas. A good post might be a little more expensive, but will likely result in fewer trips to Ethan Allen.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

Original image
iStock
arrow
Animals
7 Fun Facts for Elephant Appreciation Day
Original image
iStock

Happy Elephant Appreciation Day! Celebrate the occasion with some facts about everyone's favorite gentle giant. 

1. ELEPHANTS CAN RECOGNIZE OTHER ELEPHANT CARCASSES.

iStock

The University of Sussex's Karen McComb told National Geographic that elephants "become excited and agitated if they come across a dead elephant," and, in particular, will investigate skulls and tusks. McComb teamed up with researchers at the Amboseli Elephant Research Project in Kenya to study the behavior, showing wild elephants a range of objects that included skulls. They found that the elephants examined skulls—and tusks in particular—of their own kind twice as long as other skulls, and examined tusks six times as long as they did pieces of wood. They were even able to recognize elephant skulls with the tusks removed, but didn't show preference for certain elephant skulls over others, which suggests they didn't know which skulls belonged to their own relatives. "Animals that are intensely social in life may be most likely to display an interest in their dead," McComb told National Geographic. "But what goes on in their minds while they are doing this is a total mystery."

2. THEY'RE SCARED OF BEES.

iStock

Forget about mice scaring off elephants: When farmers need to keep elephants away from their crops, they should use bees. Researchers in Kenya discovered that even the recorded sound of buzzing bees was enough to make elephants retreat—and cause them to emit a low-frequency sound, inaudible to humans, that warns other elephants of the bees' presence.

"It's impossible to cover Africa in electric fences," Lucy King, author of the paper, told The Huffington Post. "The infrastructure doesn't exist in many places and it would restrict animals' movement." But something like a bee fence—hives strung on strong wires a certain distance apart that would move when elephants walked into them, disturbing the hives—"could be a better way to direct elephants away from farmers' crops," she said.

3. THEY MIGHT UNDERSTAND POINTING.

iStock

Humans often use pointing as a way to nonverbally get a message across, though not many other animals grasp the concept. But according to a two-month study of 11 tame African elephants, these pachyderms might be able to: When presented with two identical buckets and pointed in the direction of the one containing food, elephants picked up on the cue fairly consistently: Elephants had a success rate of 67.5 percent (1-year-old humans have a success rate of 72.7 percent). But an earlier study of Asian elephants indicated that they don’t notice pointing gestures, which is a bit of a mystery.

4. ONE ELEPHANT CAN "TALK." 

iStock

Koshik, an elephant in a South Korean zoo, developed the ability to imitate the sounds of five words he's heard from his trainer—annyeong (hello), anja (sit down), aniya (no), nuwo (lie down), and joa (good)—by sticking his trunk in his mouth. The scientists who first noticed Koshik’s ability speculate that he learned to “talk” because he was lonely.

5. THEY'RE DIGITIGRADES.

iStock

It's Latin for "finger walking," and what it means is that elephants walk on their toes (there are five of them, as well a sixth false toe). According to the book Mammal Anatomy: An Illustrated Guidemost of the animals' weight "rests on a broad pad of elastic tissue behind the toes" which "acts as a shock absorber and prevents the skeleton from jolting too much when the animals walk. It also allows elephants to move surprisingly quietly despite their size."

6. AN ELEPHANT PREGNANCY LASTS ABOUT TWO YEARS.

iStock

If you thought being pregnant for nine months was a long time, be glad you're not an elephant, which can be pregnant for up to 680 days, according to the BBC. All that time in the oven has a benefit, though: Elephant calves are born with highly-developed brains, capable of learning their herd's complex social structures and ready to put their trunks to use.

7. NINETY-SIX ELEPHANTS ARE KILLED IN AFRICA EVERY DAY.

iStock

Unfortunately, elephant poaching remains a very big problem: An estimated 35,000 elephants are killed annually, their tusks sold illegally in the ivory market. Do the math, and that comes out to nearly 96 elephants every day. Find out what you can do to help elephants and stop poaching at 96Elephants.org.

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios