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The Return Of Bed Bugs – Smarter Ones January 13, 2010

Posted by Mrs Weird Scientist in Animals, Evolution, Insects, Tough Stuff.
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Your mattress may be home to more than your pillow or favorite stuffed animal. It could be the home of bed bugs!

The title reads like a horror movie but for those who have battled it out with bed bugs, it makes a lot of sense. Others might think that ‘don’t let the bed bugs bite’ was just some bedtime line their parents used as a cute joke.

In fact, let’s see now who knew that bed bugs really existed. Try out the poll below (be honest!).


Bed Bug Basics

Bed bugs are small, reddish brown insects that feed on human blood, which engorges them and makes them bigger. They are from the insect family Cimicidae and common bed bugs are formally called Cimex lectularius. They tend to be most active at night, coming out of the cracks in walls or bed frames and other hiding places to get their bloody grub. They can travel in suitcases, so hotels are a hot spot for bed bugs as well as other places that see plenty of people coming and going. Cornell University has an ace fact sheet to give you the lowdown on bed bugs. You can also have some fun playing around on Pest World for Kids, a website created by the National Pest Management Association (NPMA). But let’s get back to finding out why these wee pesky critters have returned and what makes them smarter today.

Gone But Not For Long

Here we have a bed bug hiding in a wood bed frame. The bed bug looks like it's having a Sunday snooze but I bet it's getting rest so it can hunt for fresh blood! Image credit: Thomas Oldani

Bed bugs were once nearly destroyed in our modern environment, where the use of chemicals such as dichlorodiphenyltrichloroethane – otherwise more easily known as DDT – kept these beasties at bay. DDT is a pesticide that is either very useful or very toxic, depending on who you ask or what journal study you read. Ultimately though, it was banned.

The Good And Bad Of DDT

DDT was used to keep mosquitoes under control, mostly because they spread malaria. It was used to keep lice numbers down too. So what happened when it was banned? As somewhat of a side effect of its use, DDT had kept bed bug numbers down. After it was banned, a bunch of other chemicals were used to treat bed bug infestations. The bed bugs, however, got smart and developed resistance to some of these chemicals. That resulted in a big UH OH for society as bed bug infestations are now on a major rise! Scientists from the University of Massachusetts Amherst and Korea’s Seoul National University decided that it would be important to find out more about resistant strains of bed bugs in New York. The work was published in the Journal of Entomology. Let’s see what they discovered, shall we?

When researchers got busy observing bed bugs in New York, they found these pests had mutations in their nerve cells. What does this mean? It means they are resistant to the chemicals used to kill them. Where the chemicals would previously have paralyzed and killed the bed bugs, the mutations mean that bed bugs are now outsmarting their opponents – us!

Let The Bed Bug Collecting Begin!

To get the scoop on bed bug resistance, researchers took a sample of easily controllable ones from Florida and compared these to ones from New York that were harder to deal with. So just how resistant were these little bugs?

Look at this partially engorged bed bug. It probably looks similar to the bed bugs in Milan after they feasted on my blood. Oh, and a fun fact of the day: the Italian word for bed bugs is cimice dei letti.

Researchers found that the bed bugs in New York had up to 264 times the resistance to the modern chemical used to kill bed bugs – deltamethrin. If we picture a nerve cell, it has these little sodium channels on the outer membrane bit. This is where the flurry of nerve impulses come to life. In the New York bed bugs, this nervous system mutation means they can keep feeding long after those Florida ones have been exterminated.

Grossaroo

When I was in grade 3, I made up the word ‘grossaroo’ to describe anything yucky. This word is fitting in the case of what happened to me recently when I was working at an agency in Milan. After a few nights at what seemed to be a nice corporate flat, I began to get loads of itchy, inflamed red bites. I awoke one night to find a flattened-looking bug moving across my otherwise clean, crisp white sheets.

I yelped and quickly squished it with my slipper, only to see it turn into a smattering of blood, which it just took from its recent feeding of my body! Just after, I saw another one. By morning, my bed looked like a crime scene with all those splats of blood and bugs. Eeek! Fortunately, I got moved to a new place and had everything washed. Hopefully, those Milan bed bugs weren’t too hard for the building owners to get rid of, unless they’re resistant beasts like those New York ones.

Bed Bug Warrior To The Rescue

So now you know (if you didn’t already!) that bed bugs do exist. Not only that, but they’re continually evolving to get smarter, doing so in ways that make it harder to get rid of them. For now, you can be smart by being extra cautious when traveling. Always check for signs of bed bugs around the mattress and furniture. Since not everyone shows bites from these little pests, prevention will remain the best line of defense. And while it’s not necessarily smart, it sure is fun when checking for bed bugs to yell “YOU’RE GOING DOWN!” If your parents ask what you’re doing, you can explain that you’re the self-appointed family warrior here to protect everyone from bed bugs.

Image credits: Unless otherwise specified, images courtesy of the National Pest Management Association.

The Recipe For A Perfectly Sticky Web May 31, 2009

Posted by Mrs Weird Scientist in Animals, Brain Power, Evolution, Insects, Tough Stuff.
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Have you ever tried to bake a cake, only to find out that when it came out of the oven, it was dry and hard? Maybe you realized that you’d put in too much sugar. Or, maybe you cooked it for too long. Would you believe that spiders have a similar challenge when it comes to spinning their webs? Too much of a good thing can actually leave a web that’s far from perfect.

For this web to catch its prey, it needs to have just the right amount of stickiness and strength.  If all goes well for the spider, dinner will soon be served!

For this web to catch its prey, it needs to have just the right amount of stickiness and strength. If all goes well for the spider, dinner will soon be served!

For a spider to catch its prey, the web needs to be sticky but still remain strong. If the balance isn’t right, the web won’t catch a bug and it’ll be one hungry and grumpy spider!

A Killer Web Evolves

If you’re a spider, you’ve got your work cut out for you! To catch your prey, you want a web sticky enough that the bug gets caught inside but strong enough that the web doesn’t break from its struggles. With such a fine balance needed, spiders have evolved to get it just right.

Let the Construction Work Begin

To build those impressive webs we see, spiders start by putting down lines of dry silk. Then, they weave spirals of sticky silk to nab their prey. But, spiders of yesteryear didn’t build their webs in quite the same way.

Millions of years ago, spiders would lay down a coating of dry adhesive on these spirals. Rather than stick to the web, a bug would be entangled by these dry spirals. As a cool fact you can throw out at your friends, there are still some spiders today that weave their webs with this dry adhesive – we call them deinopoid spiders.

Yet things began to change, with orb weaving spiders evolving to make webs that were more effective at catching prey. Rather than continue to use this dry adhesive, spiders started to go the sticky route by using wet drops of a glue-like substance. When you think of glue, it seems that the sticker the glue, the better. Not for spiders though!

Curious Scientists Start Investigating

Some scientists started to wonder about these sticky webs – is stickier always better? To find out, Ingi Agnarsson of the University of Puerto Rico in San Juan and Todd Blackledge of the University of Akron in Ohio went on a mission to check out a lot of different spiders. They observed 17 species of orb weaving spiders. You’d have to like spiders quite a bit to watch so many different kinds! The full study results are in the Journal of Zoology.

It’s All About Force

The researchers tested the strength of the strands and the stickiness of them too. How’d they do that? Well, they stuck a piece of sandpaper in the web and then measured how much force was required to remove it.

To break a strand on the web, a specific amount of force is needed. When the researchers put the web to the test, they found that by using anywhere from 20% to 70% of this force needed to break the web, the sandpaper was released.

So, a stickier web might hold the insect but as it continues to struggle, the force would ultimately break strands of the web, causing the insect to be released. Yet, with the glue being a bit less sticky, the insect could pull away from a single strand, but it would get caught by the next one. Since the strands don’t break, they can continue to stick to the bug, making its fight a much harder one.

Spiders Are Impressive

It’s actually really impressive and cool when you think about the work that goes into creating a web with just the right balance of stickiness and strength. As for me, I’ll leave the bug-catching to those smart spiders. I think I’ll just stick to making cakes instead. Pun fully intended! Now if only there was a recipe for making good jokes…

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Hairy Frogs Have An Unusual Defense June 2, 2008

Posted by Mrs Weird Scientist in Animals, Tough Stuff.
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When I think about frogs, I usually picture the cute, little ones hopping around the lake near my house. Well, there are many types of frogs and one in particular is almost the stuff of nightmares! Not only is it a super duper hairy creature but it has a peculiar defense mechanism that has intrigued scientists.

Hairy Frog

Credit: Gustavocarra for Wikimedia Commons. Check out the claws on this bad boy! If the hairy frog feels threatened, he will bring forth his dangerous claws through the toe pads on his hind legs. Hmmm. I have a feeling that unlike dogs, throwing him a treat won’t make him like me!

Trichobatrachus robustus – as the frog is formally named – breaks its own bones to create special claws that force their way through the frog’s toe pads. It’s thought that this action is performed when the frog is threatened. While we already know that salamanders do something similar by pushing their ribs through the skin to create spiky barbs, the frog’s maneuver is unique! Not only that, but the closest action we’ve seen from other frogs involves bony spines that stick out from the wrist. The difference, however, is that the bones project out naturally, which is different from the hairy frog where the claws force their way out as a form of defense.

Beware The Claw

David Blackburn from Harvard University has studied these interesting frogs; the work is published in the journal Biology Letters. Blackburn found that when at rest, the frog’s claws are sheltered in a bunch of connective tissue. A piece of collagen joins the sharp bit of the claw and a bone found at the tip of the frog’s toe. At the other end of the claw is an attached muscle. Blackburn thinks that when the frog is threatened and under attack, it will contract the muscle, which causes the claw to be pulled downwards. Then, the sharp bit tears away from the bony end and pokes through the toe pad. The end result is a contraption that looks really intimidating. But wait, there’s more to the hairy frog than just these claws! They also have some other neat features. When they breed, male frogs produce long strands of skin and arteries that resemble hair. While researchers aren’t totally sure why the hair exists, they think it might be to bring in more oxygen through the frog’s skin.

Feeling Hungry

In some parts of the world, these hairy frogs are cooked and eaten. Yes, you did just read that correctly – food! The people who hunt the frogs have to be careful not to get hurt by the frog’s claws, so they use spears and similar weapons to capture the creatures. Now, I’m all one for trying new foods but in this case, I think I will pass, thank you very much!

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Secrets Of Climbing June 1, 2008

Posted by Mrs Weird Scientist in Animals, Environment, Evolution, Think About It.
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Treetops

Ever had a favorite tree in your yard that you liked to climb once in a while? You probably scurried up the tree and maybe hung out for a bit before carefully making your way down to your abode on the ground. We all know that some creatures like to live up in the trees but what makes the trees such a cool place to inhabit? Scientists may have found some clues as to why early primates liked to make their home in the forest canopy. It’s all about size!

Apes and monkeys – ancestors of humans – might have ended up in the trees because of their small size. Researchers have been curious for a while now about why early primates happily lived up in the trees. Why so curious? It’s because they thought that climbing used up more energy than walking. When it comes to walking, for example, smaller animals use up more energy in comparison with larger animals. Generally, we would expect the animals to live in a way that conserves energy. So, it has been somewhat of a confusing question as to why primates would make a transition to the trees if it meant that their energy efficiency was compromised.

Using A Treadmill To Investigate

Mongoose Lemur

You’re probably reading the word ‘treadmill,’ and wondering to yourself what I’m talking about! Well, treadmills can be useful for many things – not just for us humans to use as exercise equipment. In this case, researchers from Duke University in North Carolina observed primates as they walked and climbed on a special treadmill that was designed for the study. The results were surprising!

The researchers found that there was no difference in how much energy was consumed for small primates whether they walked or climbed the treadmill. This means that climbing didn’t have a higher energy consumption. In this way, the small primates could make good use of the treetop environment without compromising their energy. These early primates would have been approximately the size of a very big rat. The results were published in the journal Science and the information gives us some clues about how the ancestors of these primates ended up in the trees approximately 65 million years ago.

Yummy Food

You might be wondering what was so great about the trees? Well for early primates, moving into this new environment provided them with an abundance of tasty insects and fruits. On top of that, evolutionary changes then occurred, which means that the primates developed characteristics to help them better adapt to this new environment. For these mammals, the changes included the development of nails instead of claws. Jandy Hanna, a Duke graduate student at the time of the study, created the treadmill apparatus and measured primate activity and energy consumption. She explained:

We assumed it would be more energetically expensive for all of them to climb than to walk, so this finding was unexpected. What we have shown is that they could have made this shift into a rich environment with insects and fruits without increased energetic cost.

Ultimately, the small size of the primates meant that they could make the transition into the trees to enjoy the goodies up there. From the perspective of energy consumption, heavier animals had less incentive to climb than walk, so it was the smaller primates who had the competitive edge. Still, even if it does take more energy for humans to climb – that sure never stopped me when I was a kid and I liked climbing the tree to my playhouse.

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Bye Bye Bats February 28, 2008

Posted by Mrs Weird Scientist in Animals, Think About It.
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Bat in a Tree

You probably don’t give a lot of thought to bats, maybe because they don’t tend to be particularly visible creatures to most of us. Biologists in North America, however, are giving a lot of thought to bats right now. In fact, they are extremely perplexed and confused about bats. Why? A very mysterious illness is killing off bats in enormous numbers.

Bat Illness Strikes

In New York state last winter, the illness was identified in two caves, where it killed off almost all of the bats. What is particularly worrisome now is that it has spread to Vermont, where it has afflicted bats in New England’s biggest bat cave – Aeolus cave.

White-nose Syndrome

It’s called white-nose syndrome, which leaves a bat emaciated and with a white fungus on its nose. While the fungus isn’t the actual cause of their death, the combination of changes that occur do lead to the bat’s death. These changes include abnormal hibernation patterns and weight loss, leaving the bats unusually thin and suffering from related problems. Biologists still aren’t sure exactly sure how this illness gets transmitted. They also don’t know what causes it – if it’s the result of something happening in the bat’s environment or perhaps another cause entirely. For now though, officials are recommending that people avoid caves in the affected area for the next few months because by then, we will all hopefully know more about this mysterious illness.

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