School of Life Sciences | Ask A Biologist

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A Matter of Scale

A Matter of Scale

By CJ Kazilek
Illustrated by Dr. Biology

show/hide words to know

  • Billion: a number represented as 1,000,000,000, or 109, also equal to thousand millions.
  • Matter: the stuff that makes up the things we see. At the smallest level, matter is atoms, which are made of protons, neutrons and electrons.
  • Nano: a unit of measure that is a billion times smaller than a meter, also billionth the size of a meter, or 10-9.
  • Nanotube: a hollow cylindrical molecule, like a straw. Nanotubes are made of one element, usually carbon atoms.
  • Scale: is used to describe the size differences between objects, or how large or small an object is.
  • Spectator: someone who looks or watches something.

You may not think about it, but size does matter. It is especially true when talking about the very tiny things that exist in the nano world. Things in this tiny and often violent place no longer play by the same rules as the things we can see. They don’t even behave the same as things we can see with a light microscope.

Feather Biology

How birds use their feathers header

Feather Biology

By CJ Kazilek
Illustrated by Sabine Deviche

show/hide words to know

  • Anatomy: parts of the body and how they fit and work together... more
  • Envy: a desire to be like someone or have something others have. You could envy a person's new iPod, or to be able to run as fast as your friend.
  • Iridescence: bright rainbow-like colors that can change depending on the angle you look at them or the angle light hits them.

Flights of Fantasy

Almost everyone has wished at one time or another to be able to fly like a bird. Just the thought of soaring above your city or town without any mechanical device gives us a reason to envy these feathered animals.




How Do Beetles Reproduce?

beetles header image

How Do Beetles Reproduce?

By Jenny Drnevich
Illustrated by Dr. Biology

show/hide words to know

  • Life Cycle: the sequence of all stages through which an organism passes - going from egg to adult.
  • Offspring: babies, kids.
  • Reproduce: to make more individuals of your species... more

How Beetles Reproduce

Adult Beetle

Every living species is somehow involved in reproducing and making offspring. Most of us are familiar with how humans and mammals make babies, but do all creatures reproduce in the same way?


collection image


By Edward Birge

show/hide words to know

  • Decompose: to break down dead material.

Decomposition in action

Grass ClippingsGet yourself a large pile of grass clippings (best results are a foot or more wide and a foot deep) and a thermometer (the kind with a probe at the end of a wire is the best).

Air Pollution

collection image

Air Pollution

By CJ Kazilek

The Phoenix metropolitan area, like many large cities, has problems with air pollution at certain times of the year. You can do a simple experiment to determine some of the factors that affect air pollution.

Ant Farm

Ant Farm

By Rebecca Clark
Illustrated by Sabine Deviche

show/hide words to know

  • Colonies: a group of the same kind (species) of plants or animals living together... more
  • Nocturnal animal: animal that is active at night... more
  • Rotund: round and large.

What's an Ant Farm?

Fish bowlFarming... ants? Who ever heard of such a thing? Sure, humans farm corn and tomatoes, but ants!

What's the buzz about bees and the bee genome?

Listen in on a fun filled interview as Dr. Biology finds out what's buzzing around ASU School of Life Sciences Professor Gro (Grew) Amdam's laboratory.

Content Info | Transcript

MP3 download | 11MB

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Topic Time
Bee facts - how fast, how far, how many in a hive, and how many to make one pound of honey 00:44
Bee News / Africanized Bees “Killer Bees” 01:45
Are Africanized Bees Dangerous? 01:55
Are Africanized Bees Replacing European Honeybees? 02:48
Do Africanized Bees Perform the same ecological functions as European Honeybees? Pollination 04:23
Bee sense of sense of smell 05:00
Bee communication 06:00
Bee dance 06:27
Genome (what is a genome?) 07:41
Bee genome and a new theory of social evolution 09:09
Do you like to write and the writing process? 10:46
Bee aging - aging and the ability to turn it on and off 11:10
Aging switch 13:06
Genome and aging research 13:52
Differences between the Norwegian and U.S. systems 14:52
Control Freak 16:36
Radio host in college 17:50
Wanted to be a Veterinarian 18:40
What would you be if you were not a biologist? 20:36
Advice for young scientists 21:25
Have you ever been stung by a bee? 21:46

Transcript - (PDF)

Dr. Biology: This is "Ask a Biologist", a program about the living world. I'm Dr. Biology.

My guest today is Assistant Professor Gro Amdam, who is a faculty member in the School of Life Sciences, and also a member of the Center for Social Dynamics and Complexity.

Her research involves honeybees. She has published research articles in important journals such as "Nature", and the "Proceedings of the National Academy of Sciences", and is part of a large group of scientists responsible for mapping the genome of the honeybee. We'll be talking about that work later in the program.

Welcome to the show, Professor Amdam.

Gro Amdam: Thank you, Dr. Biology.

Dr. Biology: Doing my reading, I found that bees are really pretty amazing insects. Before we get to the importance in biology and research with bees, I thought I would talk about a few bee facts.

Honeybees can fly 15 miles per hour, which sounds pretty good, but we can actually run up to 30 miles an hour, so you could outrun a bee if you had to. But what's more impressive is that while they're flying along, their wings beat at 180 times per second, which is pretty darn fast. If you think of just blinking your eye is that fast.

On an average trip, a trip, a single bee visits at least 50 to 100 flowers. And to make that favorite sweet, golden honey that we like, one pound of it, a honeybee hive, which is about 60,000 bees, they have to fly, collectively, 50,000 miles, which is like flying around the Earth two times.

While flying the 50,000 miles, honeybees visit at least two million flowers, just to make that one pound of honey. And all of this has been going on for 10 to 20 million years.

So, let's see what the buzz is about bees. Bees often are in the news, but mainly about European honeybees, and Africanized honeybees, which we often hear them called as "killer bees".

One of my questions for you, is, are Africanized bees really dangerous?

Gro: Well, Dr. Biology, cars are dangerous too. It really depends on the context. Africanized bees are more defensive than European bees. And that implies that if you walk close to their nest and you act in a threatening way, their response will be much stronger. They will send out many more bees to attack you, than what the European bees will do.

A person can take a couple of hundred bee stings. It's very rare that European bees will send that many stinging workers after you, but the Africanized bees will. And therefore, if you're attacked, you have a considerable risk going on. So yes, in that sense they are dangerous.

Dr. Biology: Well, along that line, I also read that the Africanized honeybees are replacing European honeybees, as they migrate up through the United States. Is this true, and what concerns should we have?

Gro: Well, another interesting thing with Africanized bees is, they produce more colonies per year, so they have more children colonies than what the European honeybees do. Therefore, they can rapidly spread and take advantage of the natural nesting sites, than the European bees can. This is the reason for the replacement that you're talking about, and yes. It's going on.

A larger and larger proportion of the colonies out there are African. They produce a large number of drones, males, that can interbreed and cross their aggressiveness into the European bees. So there's also this hybridization going on, one thinks, that is also causing the number of gentle European bees that are out there to decrease.

This is a concern from the perspective of probability. Because if you're out there, and you're walking along the trail, and there's a honeybee colony that you happen to stumble upon. Because of this replacement, it's now much more likely that that colony will be Africanized, and that it will attack you and then we're back in the danger zone and what might happen to you next.

Dr. Biology: OK. So I'm going to be careful where I'm walking, and try not to be aggressive around these possibly Africanized honeybees.

Gro: That's a very good idea.

Dr. Biology: Are there some other issues with them? For example, do they still, do the Africanized honeybees provide the same functions and the same roles as European bees, such as pollination?

Gro: Yes. There's, to the best of our knowledge, no decline in the efficiency of the natural tasks that the bees perform, with this replacement. The Africanized bees still pollinate flowers, and are probably also an important nutritional source for many predators of bees.

Dr. Biology: OK. Well, that gives the Africanized bee a little bit of a break in the press, I suppose.

I've also read that honeybees have an unusually sensitive sense of smell. So just how sensitive are honeybees to smell?

Gro: Well, they're obviously better than a couple of other insects, like mosquitoes and flies. But I believe they are not as good as dogs. So there were some suggestions made by other researchers earlier this year that maybe bees could be used for similar tasks like what you use dogs for, like smelling tumors in people, which is a new thing. Also bomb detection.

But bees have fewer sensory cells dedicated to smell than dogs. And probably, their ability to discriminate between smells is not so good. So we might have to stick with the dogs for some of those purposes still.

Dr. Biology: Well, that's one of the things that I was really curious about. That really helps. It also means that my dog is safe right now, for that task.

So sense of smell, they're better. Do they use that to communicate? Or do they use some other method of communication?

Gro: Well, smell is very important inside the nest of bees, because it's dark. The larvae, for example, use pheromones, or odors, they send out to the adult bees to communicate if they're hungry and how things are.

But bees also have one other very interesting means of communication inside the dark nest. This is a dance that the foraging bees perform when they come back to the nest. It's been referred to as a dance language. And the discoverer of this language, Karl von Frisch, got the Nobel Prize in 1973 for this discovery.

What bees do, bees that are foraging, when they come back to the nest, they will perform a dance that tells other bees the direction and the quality of the food that's out there. They provide direction by transposing the angle of the sun using gravity, instead of the sun, because it's dark inside the nest.

They use the duration of a certain waggling they do with their bodies to communicate the distance, and also the quality.

Dr. Biology: Marvelous.

As I mentioned at the beginning of the program, you're part of a very large group of biologists that have recently mapped and published the genome of the honeybee in the Journals "Nature" and "Science". It seems that these are exciting times for researchers with bees. We often hear the word "genome" used, such as the human genome, the Drosophila, or as we might call it, the fruit fly genome.

Before we talk about how the bee genome can tell us some more about what we want to know in biology, can you tell us what a genome is and why it is important to know about the genome of different animals and plants?

Gro: Well, a genome is often referred to as the "blueprint". It's the "blueprint" from which you can build a form of life. The genome is a sequence of DNA that codes for various genes that are translated into proteins. Proteins are what build up our bodies and govern many of the processes that happen to us. And this is general property of every living form.

The reason why it's important to know about the genomes of different animals and plants is that, of course, many of these principles are general. There are also differences. We are different than the plant. And we are different from apes. And bees are different from us. And how do these differences emerge from a genome? And how can changes occur in evolutionary time, to change a being from something to something else?

One thing that was kind of a poster child idea for sequencing the honeybee genome was that it could tell us something about how you become social. One thought was that you could compare the honeybee genome to the genome of the fly and the fly has a simple solitary lifestyle, lives alone. And maybe when you look at the difference between the two genomes, you could say, "Well, hey, these genes are in the bee, but not in the fly. So maybe they're responsible for social behavior and maybe the stance language and a lot of other exciting things that bees do."

The surprise came when the genome was mapped out and they saw it was smaller than that of the fly, meaning it had fewer genes.

Dr. Biology: How much smaller is it?

Gro: It's missing, I believe, a couple of thousand genes.

Dr. Biology: OK.

Gro: And this actually makes sense. In the context of work I've done here at ASU with the founding director of the School of Life Sciences, Robert Page, we launched a new theory for social evolution about two years ago.

We are claiming that social life isn't something new and exciting that has relied on new social genes that only the bee would have, and not the fly. But that social evolution is built on all genes. It's an exploitation of old evolutionary inventions and it builds something, it appears to be new, but that in truth, is very old.

Dr. Biology: Is that published in "Nature"?

Gro: This work was published first in "Proceedings of the National Academy of Sciences, USA". And new work was published in "Nature' in January of this year.

Dr. Biology: Do you like writing?

Gro: Yes. I like it very much.

Dr. Biology: Is it kind of a combination of all the work you do in the lab and the research? Is it a nice way to get it out at the end?

Gro: One thing is how everything comes together, but another thing is how your ideas unfold on paper and how you would like to tell other people your story. And that's what I like.

Dr. Biology: Very good.

Well, it brings me back to one of the first times I met you. You came to my office and you brought in this really wonderful photograph. And it had these bees that are standing on top of an old-fashioned pocket watch. It's just a marvelous picture in itself, but there's a story behind that. I'd like to know a little more.

Gro: Well, the clock under the bees represents time and the context of this time with bees is their aging pattern, which appears to be fundamentally different from a lot of the other organisms that researchers use to understand aging.

Popular organisms for understanding aging are the fly, also mice, and a little worm called Caenorhabditis. All of these organisms are characterized by progressive aging, meaning that you're born, it moves along, you get older, and you age.

In bees, it's different. Bees have a division of labor between bees that are inside the nest, that we call nurses because they take care of the larvae, and foragers, that are outside collecting nectar and pollen.

And a bee can be a nurse for anything between a week and a year, and while she is a nurse, she doesn't appear to age. But as soon as the bee becomes a forager, independent on whether this happens the first week of life or up to a year, then aging starts.

We have several markers for this aging, it's a buildup of protein damaging the brain and the loss, for example, of learning performance of its loss of immune function, which also characterizes human aging.

And the fact that bees have this plasticity, so it's not progressive aging, but it's more an aging switch.

Dr. Biology: Like you can turn it on and turn it off.

Gro: Turn it on. And "off" is a key word here because what we can do with bees, that I don't think any other organism can be used for, is to reverse aging. And this implies that we can take bees that are foragers and that show signs of aging, and we can put them inside the nest and give them larvae, and then remove all of the normal nurse bees. And what will happen to these foragers is that many of them will become nurses again.

And this is linked to a rejuvenation of their physiology and, seemingly, a negative rate of aging. So, becoming younger again.

Dr. Biology: That's fabulous. This ties us back to the genome again. This becomes really important for you, because I'm assuming you're going to use that as a map as you compare these different bees and their different aging.

Gro: Yes. What we're doing is we're doing large scale kind of finger printing of the genes and proteins that are expressed differently in these different types of bees: the aged bees, the young bees, and the reverted, or newly become-young-again bees.

And for these large scale finger printing experiments we need to know genomic information, of course. And it will allow us to pinpoint more specific candidates, meaning candidate genes and candidate proteins, for understanding what is going on with these bees and how they can have this amazing plasticity of their aging.

Dr. Biology: I'm actually going to shift gears a little bit here. You've been at ASU for a little over a year now, maybe two years.

Gro: One year.

Dr. Biology: One year?

Gro: Mmm hmm.

Dr. Biology: OK. Well, when good things are happening, it goes really fast. Before you joined the faculty there at State University in the School of Life Sciences, you were a researcher in Norway. Actually, you still conduct research in Norway and, in fact, you grew up in Norway.

So what I was curious about, for some of our young scientists. Do you notice a difference between the two schools, the cultures, or the way things are done?

Gro: Yes. I'm Norwegian. I grew up in Norway. The Norwegian school and research system is based on a different philosophy, in many ways, than the US system. It is not a system where it's perceived that excelling in something is a virtue on its own. It's much more a society of equality. This you see at every level of social organization.

But in the research area, it implies that most researchers get an OK amount of money to work with. Nothing spectacular. Even if they do really, really good research, it's difficult to build a big lab and truly excel at an international level.

Not many researchers can hope to do that, because if you become too big, there will be restraints in the system saying, "Please, There are others not as fortunate as you, and you will have to share your resources with them."

Now, I'm not the sharing kind of person, and I do like the US system better, where there are opportunities to excel, and where excellence is rewarded.

Dr. Biology: That leads me off in another, slightly different area. I was reading about you a little bit, and one quote I got out of this little story, which I found interesting, is that you admit to being a control freak. So I want to make sure. Is this true?

Gro: Yes. This is true. And it probably affects my ways of doing things.

Dr. Biology: So is this a good quality in your research area, or in scientists in general? Do you advise this for the young scientist? Or is it just the way you are, and you flow with it?

Gro: I think you should go with your personality. This is one of my features, and it works for me, because I can channel it into productivity, right? So my control freakiness makes me really anal about the quality of the work I do. And it makes me supervise my lab efficiently.

And also, in a way, I hope, it helps my young people in my lab. It makes them see how they can systemize the work they do, and how they can achieve to take their ideas from the level of a desk to the level of experiments and to the level of publication.

Dr. Biology: So with this, some people might think that that's all you've ever done. You've only been a scientist. That's all you think about. But I also heard that you were a radio host in Norway. I was curious what got you started in radio, and what was the program about?

Gro: This was actually a university type of radio, maybe much like what we're doing here now. We were primarily presenting to students, once a week, an hour-long program about what was going on at the university: social issues, political issues, concerts. We were interviewing guests, artists, also directors and political figures in the context of the university and how education was conducted.

Dr. Biology: So were you getting your degree in science at the same time?

Gro: Yes.

Dr. Biology: Oh, that's great.

These are three questions I always ask everybody on the show. One of them is, when did you first know you wanted to be a scientist or a biologist?

Gro: That's an interesting question, because I realized first that I wanted to be a veterinarian. It was all I could think about. I decided when I was five years old, because I loved animals. And all of my basic training up until undergraduate level, was based on getting into vet school and becoming a veterinarian.

Luckily, I must say, after enrolling at the vet school, before classes started, I had to do a six month internship with a veterinarian. This was part of the training program. I realized, as I knew already, that I really loved working with the animals. I loved figuring out what was wrong and prescribing treatments, and bringing the solution to the owner.

But what I hadn't factored in, and what no one had really told me, was that the owner didn't necessarily have to agree with me.

Dr. Biology: [laughs]

Gro: I could have this perfect solution to the issues at hand, and the owner might say no. And within a couple of weeks only, I realized I couldn't live with this. It was absolutely not acceptable not to have people doing what I knew was right.

And so I quit. I enrolled in a conservation biology program. I was very much without direction. I enrolled because my father and mother and both grandfathers and whole family had been at this university, doing similar things.

It took a couple of years before I found my direction. And it was basically a very, very interesting lecture given by a professor that worked with social insects and mathematics. That was where I started.

Dr. Biology: OK. I know you wouldn't be a veterinarian. But if you weren't a biologist, what would you be?

Gro: Oh, this question has tormented me. Because, especially in graduate school, I think, many young scientists feel this way. It's a lot of pressure, and it's tough, and you stay up at night, and you're worried about your experiments and what might blow up the next day in the lab.

And you think, isn't there anything else? Anything? Anything that can make me as happy and engaged? And I was struggling with this. I wanted to find an answer to this question. At least I would know I had some kind of alternative. I never succeeded in finding one.

Dr. Biology: You didn't?

Gro: So if I were not a biologist, what would I be? I would be miserable and unhappy.

Dr. Biology: [laughs] Well, we'll keep you on as a biologist, without a doubt. I guess I would like to leave it with one more question, and actually one after that.

What advice would you have for young scientists?

Gro: My best advice is, don't get too caught up into what other people say. Think about what you want, and do it.

Dr. Biology: That's very good. The other question I had, and it's more particular to you, of course. Have you ever been stung by a bee? Or maybe I should ask, how many times have you been stung by a bee?

Gro: I can't give you any specific numbers. But I can guarantee you that after a couple of stings, you get really, really good at wearing protective gear. And duct tape your suit closed, so no bees can ever come in.

Dr. Biology: No bees.

Well, Gro Amdam, thank you for visiting with us.

Gro: Thank you for having me.

Dr. Biology: You've been listening to "Ask a Biologist", and my guest has been Assistant Professor Gro Amdam, from the ASU School of Life Sciences.

The "Ask a Biologist" podcast is produced on the campus of Arizona State University. If you'd like to contact us about this program or would like to ask a biology question, you can visit our website at

I'm Dr. Biology.

Transcription by CastingWords

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What's the buzz about bees and the bee genome?

Audio editor: Charles Kazilek

Tiny Tigers

Dr. Biology chases down Research Professor David Pearson to learn about his work with some cool insects called tiger beetles.

Content Info | Transcript

MP3 download | 7MB

You are missing some Flash content that should appear here! Perhaps your browser cannot display it, or maybe it did not initialize correctly.

Topic Time
Do tiger beetles run so fast that they go blind? 00:20
Title of Field Guide for Tiger Beetles 00:50
World map and the travels of David Pearson 01:15
How many languages do you speak? 01:45
Functions of Tiger beetle colors and patterns 02:15
Camouflage 03:02
Color mimicry (looking like other animals) 03:12
Temperature control 03:34
Where can you find tiger beetles? 04:32
How many species of tiger beetles have been discovered? 04:32
The answer to the question - do tiger beetles run so fast they go blind? 05:23
How fast can a tiger beetle run? 05:23
What is it like to be hunted by a tiger beetle? 05:46
What got you started studying tiger beetles 06:43
What are other uses for studying tiger beetles? 07:15
Bioindicators 07:46
Do you have any interesting stories from all your travel? 08:54
Guinea worm (Fire Worm) 09:09
When did you first know you wanted to be scientist? 09:58
If you were not a biologist, what would you be? 10:41
Ecotourism 11:17
Play-by-play of being hunted down by a tiger beetle. 12:17
Advice for young scientists 13:31

Transcript - (PDF)

Dr. Biology: This is Ask-a-Biologist, a program about the living world, and I am Dr. Biology. Imagine being chased down by one of the world's fastest animals. If you are unfortunate to be caught and grabbed by their large, strong mandibles, well, the rest of the story would not be a pretty sight. Luckily, if you're not the size of a quarter, you have nothing to fear, because the animal I'm talking about is the tiger beetle, one of the best hunters and fastest animals in the world.

How fast are tiger beetles? I've heard they can run so fast that they go blind. We'll learn more about these colorful animals and their amazing speed from our guest scientist, David Pearson. Dr. Pearson is a research professor in the School of Life Sciences at Arizona State University, and an expert on tiger beetles.

Pearson is also a world traveler, and author of numerous books and travel guides. He recently co-authored a book titled "A Field Guide to Tiger Beetles in the United States and Canada," which is published by Oxford University Press. This latest book provides both experts and people new to the study of tiger beetles a wonderful collection of information about these insects, and includes a large collection of color photo illustrations detailing over 200 tiger beetle species out of North America.

Welcome to the show, David.

Professor David Pearson: It's fun to be here, Dr. Biology.

Dr. Biology: When I first walked into your office--and this is a couple of years back--the first thing I noticed was this wonderful, large world map, and it was filled full of these pushpins. Can you tell me about that map and the pushpins?

David: Well this is a way that biologists get to brag about their travels. It also helps the students who come in get interested in something I'm doing, and breaks the ice on helping us talk about a lot of things besides just biology. Those pins indicate places I've been, study sites I've been to around the world.

Dr. Biology: The other thing I was curious about, as a world traveler, one of the tools that you'd have is, you speak languages other than English. How many languages do you speak?

David: Well I'm not sure exactly about the definition of speaking well. I can communicate pretty well and teach courses in about five languages, and get in trouble in maybe three or four other languages.

Dr. Biology: Well what's your favorite language.

David: Oh I'd have to say Spanish is probably, after English, Spanish is probably my favorite language.

Dr. Biology: We're talking today about these tiger beetles, and the tiger beetles, when I look at your book, it has this large collection of just amazing images of the tiger beetles. And what's amazing about them are the colors. Some of them look like they've been chrome-plated, some of them look like they have an expensive paint job that you might see on a car; other tiger beetles have these patterns to them, which might be where they got their names. I'd like to know a bit more about the coloration and their importance to the tiger beetle.

David: The color of the tiger beetles, in the first place, is something that has attracted a lot of amateurs and professionals to study them. They're much like butterflies in some ways. They're more subtle, and you have to look harder to see them, but once you know, these colors help keep your interest up, especially if you're just beginning.

But the colors that we've found have several functions. One, of course, is that they help camouflage. We find that most species of tiger beetles have a color that very closely matches the background or the ground on which they run. Other species of tiger beetle have a color that is not quite so obviously camouflage, and as a matter of fact stands out like a sore thumb in being so bright, and we've found that these species of tiger beetle appear to be mimicking or looking like other, more dangerous, things like wasps and ants, and they are cheating more or less, but they take advantage of fooling the predators.

Also, we find that some colors actually help, light colors and dark colors, especially in making sure that these beetles can control their temperatures inside. If they're very dark, they can stand out in the sun and absorb the sun faster, or if they're very white they can reflect some colors that occur in some very hot areas by reflecting those waves of energy coming from the sun.

Dr. Biology: When I saw the map and all those pins, I couldn't help but believe that you can just about find tiger beetles anywhere in the world. Is there anyplace you can't?

David: In some ways it's kind of an excuse, it's a fun excuse to have to be able to run off to any part of the world, because tiger beetles occur everywhere except Hawaii, Antarctica, and a group of islands called the Maldives off the southern tip of India, and Tasmania. Sometimes wondering why they don't occur in these places is a little hard, but they do appear everywhere else. We have found them as high as 13-to-14,000 feet elevation, and as low as -200 feet elevation.

Dr. Biology: Wow. So how many species of...

David: Well right now--well, we're finding new species every year, but right now it's around 2, 600 species. So it's a fun number, because it is not overwhelming, it's a manageable number; on the other hand it is enough to actually use them to do some fairly sophisticated studies and comparisons especially.

Dr. Biology: I was curious. I was doing some reading, of course, before we got to sit down and chat today. One of the things I read is that the tiger beetles can run so fast they go blind. Is that really true?

David: That's maybe a little bit of an exaggeration, but actually they do run fast enough that the neural system in their eyes, trying to interpret the signals coming from them, coming too fast--they run that fast. And as a matter of fact, the tiger beetle has to stop and reorient itself because it has run beyond its ability to see where it was going.

Dr. Biology: So how fast can a tiger beetle run?

David: Well, tiger beetles actually now have been clocked as, for their size, being the fastest-running insect in the world. If they were the size of a horse, and you were able to extrapolate the size and speed from that, they'd be running probably 200 or 300 miles per hour. So they are very, very fast.

Dr. Biology: If they can run that fast, what is it like for something that they are hunting?

David: They are totally predacious. They feed on other insects--ants and spiders, and there are numerous other types of insects running on the ground. Part of the name--tiger--comes from the fact that they do visually pursue these other organisms, and pounce on them, and tear them apart with their mandibles.

Dr. Biology: When they pounce on them, the descriptions I've heard are somewhat--since it's Halloween--gruesome; but how do they actually...

David: Well if you're a tiger beetle it's not gruesome, but sometimes watching it... They have these very large, long, thin mandibles that are almost like swords with little teeth sticking out of them, and they grab the prey item--an ant or a small spider--they start to crush it and tear it apart, and then they spit up their saliva, which helps to digest these insects outside their body even before they start to suck in the juices of the insect they're chewing on.

Dr. Biology: Well I can see how you got, or at least remain, interested in tiger beetles, but what got you started?

David: Well, I got started with tiger beetles back in Minnesota. I was actually a boy birdwatcher when I was very young, and in the middle of the day the birds would become very, very slow, hard to find, because they were becoming inactive in the heat of Minnesota, if you believe that. It is exactly that time when these tiger beetles become active, so it was a good way to fill in that hiatus in the middle of the day when the birds weren't active. After a while, the tiger beetles became more interesting than the birds.

Dr. Biology: As you have been studying the tiger beetles, besides understanding how and where they live, and how they eat, do they have other functions? Do they have some other story to tell us, so to speak?

David: A big part of why we're using the tiger beetles is because we do know so much about them. We know more about tiger beetles than most any other group of species, for instance in a tropical rainforest. There are 1000's and 1000's of species. We know a little bit about the birds and the butterflies and some of the plants, but still tiger beetles are still amongst the best known of all those groups. So we can use as what we call 'bio-indicators'. We can use them to understand the rest of the forest when there's not enough time to learn about the other species that are much harder to observe or are less well known.

Dr. Biology: You say 'bio-indicators'. What are they indicating to you then?

David: The bio-indicator is used in several ways. For instance, on a study in Madagascar, we were asked by the government of Madagascar to determine the boundaries of a border in the northeastern part of the island, using tiger beetles as one of the indicators to maximize the number of species that could be preserved given the boundaries of the parks. So we drew the boundaries of the park using tiger beetles, and in this case, butterflies, birds and lemurs as a way to have the smallest park still covering the most number of species. Again, because they're so well known, they could indicate for all the other species: the frogs, the orchids and the other animals and plants for which we didn't have enough information, and we would probably be assured that the park would maximize their numbers as well.

Dr. Biology: Since you've done, it looks to me like from your biography, and also from some of your publications, a lot of traveling, a lot of it in the rainforest, one of the things that I'm always curious about is if you have any interesting stories or events that occurred on some of your trips.

David: I've got lots of stories. I like to sometimes use these stories, especially with big classes because they are kind of gross. For instance, I'm apparently one of the only North Americans to ever come back from India with a worm called the 'guinea' worm, or 'fire' worm. It's the largest roundworm in the world; it's a meter long. It gets under your skin, and I could actually feel it like a piece of undercooked spaghetti when I was taking a shower against my ribs. What they do is release an enzyme that eats away at the exterior under the skin, and they then control human behavior. Every time that female worm wants to lay eggs, she releases that burning sensation, which is relieved immediately by water. So she tells you when she wants you to put your arm or leg in the water, and she keeps doing that for six weeks until all of her eggs are gone.

Dr. Biology: I'm hoping you're worm-free now.

David: I am worm-free now, but it was still a great experience.

Dr. Biology: Switching just a little bit, because we're talking to usually young scientists, when did you first realize you wanted to be a scientist or a biologist?

David: Well I was very lucky. I don't know what it was: having the right teachers, right parents, right genes. I'm not sure what it was. I knew when I was about six or seven years old that I wanted to grow up to be a birdwatcher. And I told my parents and my teachers this is what I wanted to do. Of course, they told me right away that I couldn't make any money doing that so I could think of that as a hobby. But again, I had to decide fairly soon that it was my life, and if I made a mistake, at least it's my mistake.

Now they pay me to travel around the world. Maybe not watching birds so much, but doing much of that same kind of thing. I also understand that there was a lot of luck involved there, of getting the right people to encourage me to pull out what talents I do have.

Dr. Biology: If you weren't a biologist, would there be something else you would like to be?

David: I think that if I weren't a biologist, I'd probably make my living being a photographer; maybe nature photographer that would be really fun. I think also perhaps being a travel agent or a tour guide, that would be kind of fun as well.

Dr. Biology: That probably comes from these travel guides that you've been writing for so long.

David: Yeah, part of it. I can see the downside too. I think I prefer doing it the way I do it, but I could probably lead a tour every once in awhile and have a lot of fun, especially depending on how excited the people were that I was able to share this information with.

Dr. Biology: Do you have any concerns with eco-tourism?

David: Yeah. I've worked a lot with eco-tourism around the world, from Africa, Southeast Asia to South America. What we've found is that there's a fine line between eco-tourism and eco-terrorism. A lot of people who claim that they're running lodges in a very 'green' way, and that they're very concerned about the ecology, it ends up that the green is more the color of the money. Eco-tourism is probably one of the only ways that I've seen that really works, especially in rainforests, of using the rainforests for a long term, in a solid, economic way that doesn't destroy the forest - if it's done right. But in many cases, people become greedy and selfish, and they can even destroy the forest using eco-tourism.

So we've worked a lot in trying to get a good balance there between solid economic returns, but for the long-range and having some kind of control either through the people who own the lodges or the tourist themselves, empowering them to be able to comment to the lodge owners what does and does not work for maintaining good eco-tourism.

Dr. Biology: Again, since this is our Halloween edition, and our first edition, one of the things I'd like you to do is give a play-by-play view of what it would be like if you're getting hunted down by a tiger beetle and the final moments of the prey.

David: That would be pretty, pretty grim. There actually was a movie back in the 1950's; I think it was called 'Them'. It featured tiger beetles as enlarged marauding insects invading civilization. First of all, they can run probably 10 to 20 times faster than you can, at least. They've got very good eyes. Probably the only way you can escape them is by standing stalk still and not moving because they don't perceive still things; they perceive movements more than anything else. That would be very difficult seeing that thing coming at you with these big monstrous mandibles and big eyes and be able to stand still, but if you learned to do that you could probably escape them.

Otherwise, you can anticipate being grabbed by those large mandibles and spat upon, those enzymes breaking you down and being torn apart very quickly.

Dr. Biology: Well I'm glad I'm not small enough to be lunch for a tiger beetle. I have one more question. To young scientists out there, what advice do you have for them?

David: What I've learned, especially in teaching non-majors here for the last 10 or 15 years, is that I believe that virtually everybody has got a talent lying inside them - a passion, an obsession. And very often, the problem is pulling that out, discovering what it is. How someone discovers what their passion, what their obsession or talent or interest is sometimes difficult, and you never know what's going to do it. It could be a class you took, a teacher you had, a book you read, a movie you saw, someone you talked to, a radio program, or a TV program. I encourage students to try and expose that obsession and bring out that passion. The sooner they can do it the better they are. And if they could end up having someone to pay them to do, for the rest of their lives, something they do as a hobby anyway, just think about what kind of fun they would have and how much fun they rest of the world would be.

Dr. Biology: Well David Pearson, I'd like to thank you for visiting with us.

David: Thank you for inviting me. I've enjoyed it.

Dr. Biology: You've been listening to Ask-a-Biologist, and my guest has been research professor, David Pearson, from the ASU School of Life Sciences. The Ask-a-Biologist podcast is produced on the campus of Arizona State University. And even though our program is not broadcasted live, you can still ask your questions about biology using our companion website. The address is, or you can just Google the words "Ask a Biologist." I'm Dr. Biology.

Transcription by CastingWords

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Tiny Tigers

Audio editor: Charles Kazilek

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