Males Can Sniff Out A Well Fed Female July 8, 2011Posted by Mrs Weird Scientist in Animals, Brain Power, Insects, Think About It.
Tags: black widow spider, cannibal, female, male
If they’re a male black widow spider, that is. Simply by taking a little saunter across the female’s web, a male black widow can sense if a female is hungry or not. Why does it matter? Because female black widow spiders have a rather freaky habit of eating the male after mating. It’s how they earned their dangerous name.
The Smell Of Safety
Males have developed this very useful technique, which tells them whether or not a female has recently eaten. But if a female is hungry, she would be more likely to cannibalize the male spider. They take a sniff of those silk strands and then decide if they want to proceed or scurry away. A new study discovered this interesting skill and published the findings in the journal Animal Behaviour. So, how do researchers actually go about testing something like this?
Feeding Time For The Ladies
First things first. The researchers fed a bunch of hungry female back widow spiders. Using a cricket neatly held between forceps, they rested it on the web and waited for the female to come over, wrap the cricket in silk and chow down. The females got one cricket each week. Yet, by the time the fourth week came around, they weren’t so hungry anymore and didn’t really want to eat the crickets.
Another bunch of female black widow spiders were starved for a few weeks. It apparently didn’t put their lives at risk, but they did get a bit smaller. Now, let’s find out what happened when a male was placed on the web of a well fed or a starved spider.
One Step, Two Step, Three Step…Four
Since the male spiders can pick up scents with their feet, they were able to figure out the difference from one female to another just by walking on the web. Normally, a male black widow spider has a special dance he does to court the female.
In this experiment, the males danced far more actively on the webs of well fed females. Smart dudes! If anything, dancing and mating would leave them ready to eat – not be eaten! Typically, they dance around for an hour or two, which sure shows their dedication to the purpose. They wave their legs and pluck and tap at the web in a unique way, so that unlike prey they show the female they are interested to mate rather than become dinner.
If Only I Had Such Powers
Now I have a strong sense of smell but definitely nothing like these male black widow spiders. It’s too bad because I’m really scared of spiders even though I know most are harmless. If I had my way, I’d be able to simply smell any spider from several meters away. That would give my timid self enough time to run!
Too Young And Too Much June 19, 2010Posted by Mrs Weird Scientist in Alcohol and Illegal Drugs, Brain Power, Human Body, Nutrition and Health, Think About It.
Tags: alcohol, binge drinking, brain, teens
One drink. Two drinks. Three drinks….seven drinks. Does this sound like you each weekend? It isn’t news that teens can be binge drinkers. Even the wicked hangover the next day isn’t necessarily enough to stop teens – or adults – from going wild on booze. But a new study suggests that binge drinking has some effects on teens that we won’t necessarily see in adults. To understand what researchers discovered, we have to delve into the brain. The monkey brain, that is.
Lasting Brain Damage
To find out what binge drinking does to the brain, a group of researchers led by Chitra Mandyam of the Scripps Research Institute in California looked at how the drinking affected normal nerve cell development in the hippocampus, a part of the brain responsible for long-term memory. They used monkeys, an animal with brain development that is very similar to humans. Their work was published in the Proceedings of the National Academy of Sciences.
Researchers gave four adolescent monkeys alcoholic drinks for an hour each day over nearly a year. A couple of months later, the animals were put down so that researchers could compare their brains to monkeys that had not been given alcohol. So, what did they learn?
The binge drinking monkeys had 50 to 90 percent fewer stem cells in their hippocampus compared to the other monkeys. This could leave monkeys struggling with memory and spatial skills, plus loads of other important functions in the brain.
You’re Not Alone
Just how common is binge drinking? In a European study last year, Britain came in as one of the worst offenders. More than half of teens had been binge drinking in the last month. For the United States, around 11 million teens drink and approximately 7 million are binge drinkers. According to MADD, Canadian statistics are very similar.
Binge drinking is harmful at any age and can hurt adults too. But this study suggests that its effects in teens can be especially dangerous because of teens’ brains being quite vulnerable during these years. Fortunately, there are ways to get confidential help, whether it’s through a doctor, substance abuse centre or even a counsellor at school. If you feel like your drinking is a problem or you’re worried about someone you know, talk to a trusted adult.
Humans Bite Harder Than Vampires April 21, 2010Posted by Mrs Weird Scientist in Book Reviews, Brain Power, Forensic Science, Human Body, Think About It.
Tags: forensics, history, vampires
When National Geographic asked me to review their new book called Vampire Forensics, I had to ask myself if I had the guts to do it! As a self-proclaimed scaredy-cat, I wasn’t sure if learning about the origins of vampires would be something my timid self could take. Worse still was what happened when I attempted to grab Tiko for comfort. Once he heard me say “vampire,” he raced into the wardrobe and refused to emerge.
Like many people, I’m fascinated by popular vampire culture, from entertaining television shows to famous books such as Bram Stoker’s Dracula. The question that remains is – where did it all start and how did it become what it is today? And maybe the second question I had when I started reading Vampire Forensics was whether this book was a bite I could handle. Let’s find out!
Disease, Death And Burial
Researched and edited by Mark Jenkins, Vampire Forensics traces the history of vampire culture. Early on in the book, Jenkins writes about a mysterious, 16th century skull discovered in Venice that was thought to be the remains of a female vampire. The skull was buried with a brick jammed in its mouth, which people thought would stop the vampire from rising up to feed on others. In other areas of the book, diseases such as the plague or tuberculosis are linked to vampire myths, mostly due to signs of the disease such as paleness and the fact victims would waste away. Jenkins also goes on to merge ideas about burial and death with vampire culture.
While I expected a lot on forensics, this part of the book fell short. Instead, I read about all kinds of folklore that were scattered together without the structure a reader needs to make sense of it all. Where historical facts were relayed, these suggested a possible link to vampires, without the real forensic guts to strengthen the connection. It felt a bit like the writer was grasping at straws by choosing many random stories and trying to tie them in with vampire culture.
Still, there are heaps of fun tales and facts that kept the book interesting right to the end. I did shudder at some of the gory bits but in a sense, this is part of the appeal when it comes to vampires. People like to be afraid and they like the intrigue of the unknown.
Can You Handle It?
Who will like this book? Well, it’s not a book for my younger readers and even then, will probably only interest a select group of my teen readers. The graphic prose and macabre tales are gruesome at times. But for those who perhaps truly do fear vampires, this book brings that fear to a much less frightening reality. We learn how events that are most definitely of the human kind fueled the myths and fantasy that make up vampire culture today. While the book didn’t give much of a vampire bite, it left some strong human tooth marks. Ironically, I think readers may be left fearing humans far more than vampires.
How To Be An Assassin February 21, 2010Posted by Mrs Weird Scientist in Animals, Brain Power, Insects, Think About It.
Tags: assassin bug, prey, spiders
Credit: Video generously provided by Anne Wignall of Macquarie University.
Imagine you’re a hungry insect. To get your next meal, you need to be a true assassin, using stealthy tactics to capture your prey. Well if you were an assassin bug, then your plan might read like this:
1. Slowly approach your prey
2. Tap the web before each step
3. Bounce around a bit
4. Grab some web strings
It might sound like a strange plan but it works! The assassin bug does all these bizarre movements to trick the spider into thinking it has an insect caught in its web. Once the spider is sure that it has its next meal, it scurries over to the assassin bug. But too bad for the spider, it will now become a tasty meal for this sneaky insect. To find out more about this peculiar bug, I chatted with Anne Wignall of Macquarie University in Sydney, Australia, who had some of her recent work published in the Journal of Ethology. Anne already knew that some bugs would hunt down spiders but she wanted to find out just how they did it! Anne explained to me:
When I heard that there was a bug that seemed to lure spiders toward them, I was instantly fascinated because it seems like such a crazy thing to do, when spiders are such dangerous predators themselves.
In fact, there is actually one more step in the assassin bug’s plan, which could come in at number six. Once the assassin bug grabs the spider, it sometimes will tap the spider with its antennae. Researchers think this might be a way to hypnotize the spider, making it harder to escape.
A World Of Assassins
The assassin bug in the video above is a species known as Stenolemus bituberus. But if you thought it was the only one, think again! Anne describes just how busy our world really is when you get outside:
There’s also lots and lots of other assassin bug species and insects that use stalking, deception, luring and other cool tactics to hunt other invertebrates, and we’re finding more all the time.
So this means there are way more bugs out there with incredible, assassin-like tactics to capture their prey. For example, Todd Blackledge of the University of Akron in Ohio has been investigating how wasps hunt spiders. He found that adult female wasps will capture spiders and sting them. Ouch! But that isn’t all. The wasp then lays an egg on the spider, which allows the wasp larva to eat the spider, helping it grow into an adult.
Your Garden: A Battleground For Bugs
Now that you’ve checked out the video above, you might actually be able to find one of these creepy crawlies in your garden. Anne suggests that if you live along the east coast of Australia, you should explore the trees and webs in your garden, where you might find an assassin bug battling it out with a spider. Just be glad that while those hungry bugs fight it out, you don’t have to go through anything quite so dramatic when you want to have lunch. In fact, make yourself a nice sandwich, grab your camera, then see what you can find in your backyard!