It's Friday. Yes, I know I missed it last week. But it's time for a new Science Friday video.
"The latest on the bug beat: To survive floods, fire ants band together to form a raft. They can sail for weeks. But how does the raft stay afloat? Researchers report the answer in PNAS this week. Plus, engineers at Tufts are looking to the caterpillar for inspiration for soft-bodied robots. The problem is that squishy bodies make it difficult to move quickly--but some caterpillars have developed a workaround."
I've been fascinated by ants since childhood. Back then, I loved to watch them working, or use their large anthills for my imaginary and devastating bombing runs, or incinerate them with a focused sunbeam from a magnifying glass (for scientific purposes, mind you). So here's a cool video from the Science Channel about the amazing complexities of an ant colony (or two). The little buggers are still fascinating.
Courtesy Scott CamazineWell, I understand that Science Buzz generally focuses on science in the news, as well as seasonal phenomena, and, frankly, this post doesn’t fall into either of those categories.
But yesterday I was starting to work on the next Object of the Month (I don’t want to spoil anything… but it’s “wasps’), and I came across an article on the tarantula hawk. The tarantula hawk is neither a hawk nor a tarantula—it’s a giant freakin’ wasp.
Growing up to 2 inches long, the tarantula hawk is one of the largest wasps in the world. It gets its name from its habit of paralyzing tarantulas, dragging the spiders back to their burrows (the wasps are that big), and then laying an egg on the tarantula’s living body. When the egg hatches, the wasp larva sucks the tarantula’s juices until it grows large enough to burrow into the hosts body. There it will eat the still-living spider’s organs, saving the vitals for last. When the wasp matures into an adult, it gives up its tarantula devouring ways, and lives off of fruit and nectar. How nice.
Anyway, the article also mentions that the tarantula hawk can have a stinger as long as 1/3rd of an inch, and that its sting is reported to be the second most painful sting in the world, according to the Schmidt sting pain index. (The Schmidt index was developed to the effects of insect venoms only, so I’m assuming that potentially fatal spider bites don’t count.) Naturally, the tarantula hawk’s position on the index begs the question, “What is the most painful sting?”
Answer: The bullet ant, so called because, supposedly, a sting from the bullet ant is like getting shot by a crossbow. I mean a gun. With bullets.
Native to central and South America, worker class bullet ants grow to about an inch, and are called “hormigas veinticuatro” by locals, or the “twenty-four [hour] ant” because the pain from a sting is supposed to remain unabated for a full day.
While the bullet ant will also bite, it delivers its sting the same way wasps and bees do, through a modified ovipositor on its abdomen (that’s all stingers are—egg-laying tubes evolved to inject venom).
The injected venom is a neurotoxin unique to the bullet ant: poneratoxin. A neurotoxin is a poison that affects the nervous system; poneratoxin interferes with the chemicals that allow nerve cells to send electrical signals to each other. So, when other insects and arthropods are stung with poneratoxin, they can be paralyzed (because, remember, you need nerves to control your muscles). When humans are stung with poneratoxin, they just experience extreme pain. Repeated stinging can lead to uncontrollable shaking, and temporary paralysis of the limbs.
But bullet ants aren’t generally aggressive, so how do we know about the affects of repeated stinging? Because some folks get themselves stung a lot. On purpose!
The Satere-Mawe people in Brazil use bullet ants as part of an adult-initiation tradition. (Or an initiation into adulthood. Whatever’s better.) Here:
Now, keep in mind, the tone of that video is pretty ridiculous. (That is, the “look at the weird stuff these weird people do” thing. We all do weird stuff, but other people’s weird stuff is just less familiar.) Also, if you go to the youtube page that video is hosted by, the description says that their hands “turn completely BLACK with poison.” That actually doesn’t make any sense, and it’s not true—the color is from charcoal.
Still, though… wild!
Oh, also, folks who have lived around the ants for a long time have used their stings to treat rheumatism (painful joints, etc), and have found that their bites are so strong that the ants’ mandibles can be used to pull the edges of a cut together, like stitches. The ant’s body is then twisted off, and the head (still biting) is left on the wound as a suture.
But we like the sting gloves. It’s news to me, right?
Courtesy Fir0002How do you secure your home at night? With a deadbolt lock? Switching on some high-tech electronic security system? A pit bulls (without lipstick)?
Whatever you do, it's probably not as problematic as what a few ants do each night in Brazil. Researchers have observed that one to eight ants from a colony each night sacrifice themselves for the well being of the colony. They stay above ground pushing sand over the entrance to the colony to protect their peers from predators during the night. Because they're left outside, they most often die in the night, either from freezing in chilly temperatures, getting blown away in high winds or being a midnight snack for a predator.
A typical ant colony in Brazil can number over 100,000, so the few ants lost each night for security is not a huge mathematical loss. How exactly the night workers are selected isn't known for sure, but researchers think they're probably older ants who are approaching the end of their natural life span.
Courtesy WikipediaMighty acacia trees tower and spread across the African skies. Little ants scramble about as a protective army. Without each other, they’re nothing.
That’s what ten years of research is confirming. Scientists have known for a long time about the symbiotic relationship between the big trees and the little bugs. The trees give the ants a place to live. The ants bite and pester large animals that try to eat the tree’s leaves and limbs.
But what happens when the conditions get reversed?
After ten years of study, we’re starting to get some answers.
With the numbers of large animals in Africa in decline, researchers thought they’d try to find out, on a limited scale, what the impact would be of fewer creatures bothering the acacia tree.
Fences were set up around some trees that prevented large animals from feasting on the trees.
Even after just a few years, the trees were looking rather ragged and their growth rates slowed down. What was going on?
The trees no longer had need to take care of the ants. They didn’t produce as much nectar that the ants feed on and they had fewer, smaller thorns for the ants to live in. Consequently, the ants started to abandon the trees for other locations, giving way to other insects that were damaging the trees.
While the original “mutualism” relationship developed over a long period of time, researchers point out that it can break down in a quick amount of time.
Researchers are going to take this experiment to one more level. They’re going to “reverse” the reverse process on some of the fenced trees, taking the fences down and seeing how quickly, if at all, the ants come back to the trees if the large animals start eating the trees’ greens.
What do you think of all of this? Share your thoughts here with other Science Buzz readers.
Once termites are finished solving our fuel problems, ants can help us with traffic. Iain Couzin, a mathematical biologist at Princeton and Oxford, studies army ants in Panama, trying to deduce the simple rules that allow millions of individuals to move smoothly and efficiently. He hopes these rules may someday be used to alleviate traffic congestion for humans.