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Fall bug season is upon us, and this summer’s warmer than usual weather left behind an exploding insect population. You can expect to see more mosquitoes, stink bugs and yellow jackets until the weather cools. And bugs are more than just a nuisance this year — the U.S. is dealing with its most serious outbreak of mosquito-borne West Nile virus to date. “Bug Guy” Mike Raupp helps explain what you’re seeing, and how to protect yourself from insects that bite, sting or stink.
- Michael Raupp "Bug Guy" and Professor of Entomology, University of Maryland
Mike Raupp shows how to take a bite out of mosquitoes and keep your house pest free by using the right clothing, cleaning out standing water and other techniques.
Mike Raupp shows us the best ways to keep the infamous brown marmorated stink bug from invading your home.
FAQ: Mosquito Repellents
From the University of Florida, a study on how mosquito repellents work and the average protection time of different repellents on the market.
MR. KOJO NNAMDIYou're not imagining it. That is the voice of Michael Raupp, the Bug Guy in the background, and there were more flying, buzzing, stinging, crawling creatures around this summer. Fall bug season is upon us, and this summer's warmer than usual weather left behind an exploding insect population. So you can expect to see lots of mosquitoes, stink bugs and yellow jackets until the weather cools.
MR. KOJO NNAMDIAnd bugs are more than just a nuisance this year. The U.S. is dealing with its most serious outbreak of mosquito-borne West Nile virus to date. Bug Guy Mike Raupp helps explain what you're seeing, and how to protect yourself from insects that bite, sting or stink. He is a professor of entomology at the University of Maryland. Mike Raupp, good to see you again.
PROF. MICHAEL RAUPPKojo, it's always wonderful to be here. Thank you so much for having me.
NNAMDISo we're probably not imagining that there were more bugs this summer. We've had exceptionally warm weather, until very recently at least. How does warmer weather affect the insect population?
RAUPPWell, for a lot of these species, Kojo, there's a direct relationship between temperature and the rate at which insects develop. They're literally cold-blooded. The warmer it is, the faster they can develop. So for, let's say, mosquitoes, when...
NNAMDILet's not -- no, go ahead, please.
RAUPPWhat we have to -- I'm sorry to take us there right off the bat. But for things like our culex mosquitoes, these are the rascals that carry the dreaded West Nile virus. At 70 degrees, it may take them about two weeks to go from egg to adult mosquito. But when we hit 90 degrees, the generation time is going to reduce to about half that, about one week.
RAUPPSo when we had these exceptionally warm springs and the warm summer, what it means is there's simply many more generations of these mosquitoes which can then vector the diseases. So for many of our insects, things like stink bugs included, if they have multiple generations, the warmer it is, the more insects we're going to see per unit time.
NNAMDIAnd you mentioned the culex which -- the culex, as my understanding, are the main species in our region that carry the West Nile virus, the culex pipiens or something called culex tarsalis, which apparently like heavy rains. What disturbs me is that you say the culex are so small, they can come through your window screens.
RAUPPWell, this is called the little house mosquito. And over the past several weeks, I've noticed that these guys have appeared in my house in the evening. My screens are all in pretty good shape. I have a couple of the little squares in there that might be just a tiny bit larger than originally designed. And these mosquitoes are so tiny, you can see them here. I've put some in. They're only slightly larger than, I don't know, would you say, maybe the letter L on a sentence.
RAUPPSo these guys are really quite clever. And if you have the tiniest of rends in your screen, these guys can come in. The other thing, Kojo, is they're very crafty. When I'm out on my patio dining in the evening, and that's when these guys are often very active, I notice they'll kind of hover near me, and when I come indoors, they will simply follow me in before I can close that screen door. And now I've got more little culex pipiens flying around my home. So they really are quite clever getting in and...
NNAMDII am fascinated by how small they are. These insects squeeze through...
RAUPPThey're amazing, yes.
NNAMDIWell, if you'd like to join the conversation, if you have questions for Mike Raupp, 800-433-8850. What flying, buzzing, crawling creatures have you noticed recently? How do you protect yourself and your family from mosquitoes and other bugs? 800-433-8850. You can send us email to firstname.lastname@example.org. We're not only talking about heat, Mike. We're also talking about severe droughts which some areas also saw. How does that affect bugs?
RAUPPThis is a little counterintuitive to me, Kojo. But a wonderful study done of the West Nile virus and some of the associated environmental factors found that the two strongest predictors of the West Nile epidemic were above average temperatures and a period of drought particularly early in the season. So these are exactly the conditions I think we saw in places like Texas and across the Gulf Coast where they had a period of prolonged drought then followed by rains.
RAUPPThis seems to be the key. Now, there have been several hypotheses advances to why drought. It seems counterintuitive because we know that these mosquitoes have to have water to breed.
RAUPPBut, apparently, certain species of mosquitoes, some of these container-breeding mosquitoes, like the culex pipiens, as the habitat, in general, dries down, in urban landscapes, in particular, where we have things like catch basins, bird baths, swimming pools and containers, as these waters concentrate and become foul, they're the perfect situation for these container-breeding, foul water-breeding mosquitoes, like culex pipiens, to multiply. We also find that certain birds may be concentrated near these areas where there are water.
RAUPPAnd that combination of birds, which are the reservoir for the West Nile, and elevated populations of mosquitoes near these water sources basically provide the recipe for these outbreaks of West Nile virus. They saw similar outbreaks following periods of drought in places like Romania and also Israel. So this is not uncommon to see this quite unusual pattern.
RAUPPThen when we get the rains, the monsoons, as we saw and continue to see down through our southern states along the Gulf, it opens the door for a whole another realm of mosquitoes, mosquitoes like culex tarsalis which is another important vector. So it's this kind of constantly changing landscape, wet and dry, that creates the habitat for these very, very opportunistic mosquito species.
NNAMDIWell, just a few facts about West Nile virus, there's no vaccine for humans nor any specific treatments. Seniors and children tend to be the most vulnerable. Eighty percent of people infected will not develop any illness at all. Around 20 percent will develop what's known as West Nile fever with headache, tiredness, body aches. The most severe type of infection can cause inflammation of the brain or around the spinal cord. The number of cases of West Nile are expected to increase through October. Mike, does that mean mosquitoes will still be biting?
RAUPPYeah, absolutely. I was out wandering the neighborhood the day before yesterday, and I found a little pool, a very, very small puddle in a container. And there were probably, oh, 30 or 40 very young, in other words, what we call early instar mosquito larvae. So the breeding season is, by no means, over. Last year, in the winter that didn't exist. I had little house mosquitoes biting me indoors in December. So we're, by no means, out of the woods in this.
RAUPPAnd, again, as long as we have this continuation now of above normal temperatures, and we will throughout the Southern states and central portion of the country and even here in the northeast, and ample rainfalls so there are containers for these container-breeding mosquitoes to breed, we're going to see a continuation. So we're not really out of the woods yet. And people need to be aware of this and take steps to avoid being bitten by mosquitoes.
NNAMDIWell, because mosquitoes are biting you, does that necessarily mean they'll be biting me? Some people are convinced that they are mosquito magnets and that they get bitten far more than those around them. Is there any truth at all to that?
RAUPPKojo, are you a magnet?
NNAMDINo. I don't consider myself a mosquito magnet. I really don't get bitten a lot.
RAUPPRemember that it's only the females that bite, Kojo. Are you sure you're not a mosquito magnet?
NNAMDINo. Maybe I am now that I'm thinking about it.
RAUPPOK. Well, the deal with this is that, believe it or not, humans emit more than 100 different chemical signals, that is, volatile chemicals that come off their bodies. Some of the kinds of things that mosquitoes are attracted to include carbon dioxide, of course, lactic acid and certain other compounds. Nonanol is one. This is an alcohol that's highly attractive to mosquitoes, and it's also a compound that's produced by birds. That's maybe part of the reason for the attraction of some of these culex mosquitoes to birds and humans.
RAUPPSo the answer -- short answer to your question is absolutely. It's that unique blend of chemicals that come from the surface of a person that makes one person an attractor and another not. My wife is an attractor, and, whenever I go into the field, I always take her with me.
NNAMDIBecause she is a mosquito attractor. Mike Raupp, he is the bug guy. He's a professor of entomology at the University of Maryland who says that since most mosquitoes that do the biting are females and I don't get bitten a lot, I can disqualify myself as a babe magnet. Here is Kathy in Alexandria, Va. Kathy, you're on the air. Go ahead, please.
KATHYThanks for taking my call. I've seen in our area these huge wasps. I think they're wasps. They're like a inch-and-a-half long. I was just curious where they come from, if any one else has seen them what they are.
NNAMDII'm looking at them right now even as we speak because Mike Raupp is holding them up for me. Exactly what are those, Mike?
RAUPPThese exactly are the cicada killer wasps. This is one of nature's most interesting and curious and, in many cases, dramatic kind of creatures that we see buzzing around our lawns throughout the summertime. What these little rascals do is, early in the season, the males appear, and they stake out a territory.
RAUPPSo if you walk out in your backyard, you'll see the males buzzing around, and what they're doing is defending their turf because shortly thereafter, the females will emerge, migrate to these areas and begin to set up shop. What the female cicada does is she flies into the tree and she hunts our annual cicada, the dog-day cicada.
RAUPPShe stings it, paralyzes it, then flies it back to a gallery which she makes in the ground. She stuffs it down the hall while it's still paralyzed. And, Kathy, this is gruesome, so you may not want to listen to this next part.
RAUPPShe lays an egg on the cicada. The egg hatches, and her baby devours the cicada while it's still alive. Now, here's the interesting part of the story. Kojo, can you see? The one on the left is the female.
RAUPPThe one on the right is the male. Notice the male is about half the size.
NNAMDIHalf the size of the female, yes.
RAUPPIn the ultimate exercise of gender control, if she wants to make a son, she will catch a single cicada, stuff it down the hall and lay a male egg. If she wants a daughter, she will capture two cicadas because it takes twice as many cicadas to make a daughter. And she will lay a female egg which will then develop into a daughter cicada killer.
NNAMDISo you are saying she makes the choice even before she devours the cicada of the gender of the offspring that she wants?
RAUPPHow about that? Now, humans have been trying to do this for 300 years, and we don't have it right yet. But, by golly, these cicada killers are quite clever.
NNAMDIThat's some kind of skill, a scary skill, but a skill nevertheless. Cathy, thank you very much for your call. We move on to Jean in Annapolis, Md. Jean, you're on the air. Go ahead, please.
JEANHi. Thank you. It's kind of two questions. I know everybody is seeing more and more bugs we don't want to see, like mosquitoes. But it seems to me, in my yard, I'm seeing way less diversity of insects like dragonflies, butterflies, bees, a lot less of those. And I was wondering what your guest thought of that, and also about organic farming and how we've heard it's not good for your health or any better for your health. But what does it do to all of the pests and -- that aren't treated by all those pesticides?
NNAMDIFirst, lack of diversity in our insects.
RAUPPYeah. There's a -- basically, these are great questions, Jean, and not simple answers. But basically, the diversity of insects that we see in our landscapes is often tied to the diversity of plants. So as we reduce the diversity of our plants in our landscape through the process of urbanization, in other words paving over habitat -- in many cases, we often replace native plants with exotic plants -- this changes the balance of nature, shall we say, because some of these exotic plants simply don't serve as food sources for some of our native insects, particularly butterflies.
RAUPPThe same thing, again, with the widespread use of chemicals. This certainly has taken a toll on things like our pollinators, some of our natural and native pollinators, which are also susceptible to the loss of biodiversity in the flowering plants and such. I think one of the big drivers over the past couple of years, again, has been unusually dry periods of time, particularly in early summer when some of these pollinators are depending on abundant nectar and pollen from the flower sources.
RAUPPHowever, this year, I think in my particular small slice of the world, it was rather a good year for butterflies. Actually, this is one of the better years for butterflies that I've seen in the past several years. And my bees did quite well in addition to that. And regarding the organic farming, I've kind of paid little attention to this conversation. And I guess at the crux of this argument is the fact that, you know, the pesticides that are used to produce our food crops, in many cases, are applied at rates that are so low that really the human health concern is minimal here.
RAUPPBut I think you're right in raising this question about the broad-scale use of insecticides posing a threat to many of our native pollinators in particular. And I think that there is a point of concern here, and we certainly have to try to reduce the use of those pesticides whenever we can to help support these beneficial insects.
NNAMDIJean, thank you very much for your call. We're going to take a short break. When we come back, maybe a few recommendations for what people can use to protect themselves from mosquitoes, gnats, stink bugs and other insects. 800-433-8850. I'm Kojo Nnamdi.
NNAMDIWelcome back. Our guest is Mike Raupp, the Bug Guy. He's a professor of entomology at the University of Maryland. We're taking your calls, of course, at 800-433-8850. Have you had problems with ants or stink bugs? How did you deal with it? And speaking of stink bugs, Mike, we got an email from Don, who says, "I live in Hyattsville, Md. and have only seen a few stink bugs all year as opposed to the thousands last year. Where did they go?"
NNAMDIIt is, indeed, the season of the stink bug. We also got a tweet, asking, "What is this? It's a grey bug that looks like it has a suit of armor on." We're all talking about the same thing here, aren't we?
RAUPPWe are. These -- that little image we have, they look medieval or prehistoric. They look like a shield. They're cloaked in armor, and they have that sword-like beak that they're going to jam in the plant. So, Don, keep your powder dry. Just wait. The stink bugs are lurking. I was out in Keedysville the day before yesterday in Western Maryland, and in the span of about half an hour, I caught about 500 stink bugs in the soybean patch and on the Paulownia tree.
RAUPPSo I think they're just amassing. The difference here is that in the late autumn of 2011, we had a lot of cool, wet weather, and the second generation of stink bugs never really got off the ground. That put a dent in that first generation of 2012, but they've had a pretty spectacular summer and spring. And I'm not going to be at all surprised if we don't begin to hear squawks and squeals up and down the East Coast over the next several weeks as these massive stink bugs try to find their way in.
NNAMDIIts official name is the brown marmorated stink bug.
NNAMDIThey, of course, don't bite. But for some reason or the other, you have brought with you here today what looks amazingly like a praying mantis. What does that have to do with this conversation?
RAUPPWell, this is a fascinating story. The Chinese praying mantis, which is the very large green or brown mantis that we see this time of year, was first discovered...
NNAMDII'm looking at him here now. He's not alive, and he's still scary. He's that large.
RAUPPOh, they're gorgeous creatures, Kojo.
RAUPPThey were first discovered in -- just outside of Philadelphia, Pa., back in the 1880s, and apparently they came into Meehan's nursery on a shipment, perhaps, of Japanese red maple. Now, the curious thing is, with the importation of the brown marmorated stink bug from Asia into Allentown, Pa., less than 60 miles away, we've had an old reunion of sorts between old friends. And now we see the Chinese praying mantis inviting the stink bug over for dinner.
RAUPPOh, really? Yes. And my little mantis was able to devour about 12 of these stink bugs in the span of about 12 minutes. So they really chow down on those stink bugs.
NNAMDIThey really like them.
RAUPPIn fact, I had a grower call me last year and said he had an outbreak of praying mantises in his cornfield that were devouring the stink bugs.
NNAMDISo there you have it. If you collect praying mantises, then they'll work on your stink bugs for you. We have several callers. Here is Joanna in Washington, D.C. Joanna, you're on the air with Mike Raupp. Go ahead, please.
JOANNAI'm very excited because just a few minutes ago, I saw the most amazing creature. It was like a caterpillar or a centipede, about 4 inches long, green, about half an inch in diameter, with yellow dots or sort of raised bumps, four big ones near the head and then small ones in a parallel line down the body. You know what it is?
RAUPPThis is the larva or the caterpillar of one of our beautiful silk moths, perhaps something like polyphemus or cecropia, oh, but you were lucky. This is a fortunate day indeed, Joanna, because these things are relatively rare, especially in our urban environment. It's -- it is nice that we have Rock Creek Park in the C&O Canal that penetrate deep into Washington, D.C., so we can have some of these beautiful, beautiful silk moths.
RAUPPBut I'm quite certain that this is the caterpillar, and it's getting ready now to spin its cocoon. So in a few short weeks, it's going to finish munching on a twill of Poplar tree or wherever you found it, spin a cocoon and emerge as a gorgeous, gorgeous silk moth early next spring. So congratulations.
NNAMDIJoanne, thank you very much for your call. We move on to Pat in Hyattsville, Md. Pat, your turn.
PATA question about mosquitoes. Am I imagining that they love my ankles more than any other body parts?
RAUPPWell, Pat, they would actually love your feet more than your ankles. It turns out that -- and no offense here. Please don't take this the wrong way because they love my ankles, too. It turns out that there are certain types of microbes that are commonly found on our feet. And these particular microbes make volatile compounds that are simply irresistible to mosquitoes. This is one of the way they find us.
RAUPPSo, no, your observation is 100 percent correct. That's where I get my bites. That's where most people get their bites. And, in fact, if you take some dirty socks and sneakers and put them out there, you'll see the mosquitoes homing in on those things as well. So maybe give that a try.
NNAMDIWhat advice do you have for Pat and others to protect themselves from mosquitoes?
RAUPPYeah, this time of year, what we really need to do is we need to basically try to prevent your exposure to mosquitoes, and by this I mean avoid working out at the times of the day particularly dusk when some of these culex species are most active. Be sure to wear long clothing, long sleeve shirts and pants. This will reduce the number of bites. And if you had exposed skin, of course, use an insect repellent.
RAUPPThere are several good products on the market. DEET, of course, is the gold standard. There's an alternative to DEET called Picaridin. It works quite well. And there are a number of botanically based mosquito repellents that will be very, very effective for a couple of hours, this is fine. The other thing to do is repair those screens and, of course, eliminate standing water sources. Dump the bird bath. Dump the wheel barrel. Unplug that clog drain. Get rid of all standing water.
RAUPPAnd if you can't drain, let's say, a little puddle, you can always get the insecticide, the larvicide. It's called Bti, bacillus thuringiensis israelensis. It comes formulated. It looks like a donut. You toss it in that standing water, and it will kill those mosquito larvae.
NNAMDIDEET is apparently the most effective, but quite a few people don't want to use DEET. And they find, however, that herbal insect repellents on the markets just don't work. You also recommend that people read labels of all insect repellents because repellents, for instance, containing DEET should not be under your clothing. We've got a link at our website, kojoshow.org, with information about a number of common bug repellents. But read the label huh, Mike?
RAUPPAbsolutely, and especially this is the case with your children. Don't leave it to the kids to put on these mosquito repellents. Always help children apply mosquito repellents and read those labels because several of these compounds will contain cautionary warnings about use with children.
NNAMDIOn to Melanie in Woodbridge, Va. Melanie, you're on the air. Go ahead, please.
MELANIEHi, thank you. I have a question about the intelligence of bees. I've loved bugs since I was a kid, so I'm always watching bugs do their thing. And we planted lavender here, French lavender, and the bees seem to love that. But each spring, there seems to be a new group of bees or maybe they're their families, I don't know. But they come, and I can swear they're hovering in front of us, looking at us.
MELANIEAnd the other thing that makes me question also is I've kind of developed where I sit on the porch, and I can watch them. And I can get pretty close to them. And I noticed that one day, I came out on the porch, and there was this really scary hornet coming at me. I can swear to you the bee chased that hornet away. And that's all I have...
NNAMDISo the bees are both observing and protecting you, it would appear.
MELANIEI don't know. Maybe it's all in my head, but they seem very intelligent. They...
NNAMDIThe bee security brigade at Melanie's house.
RAUPPYes, Melanie must be a bee charmer. Melanie, congratulations on that. So, now, I'm going to question you. Are you still on, Melanie?
RAUPPYeah. Now, are some of these bees rather large bees, almost bumblebee-type bees...
MELANIEYeah, they're huge.
RAUPPYes. You've kind of hit the nail the head. Basically what you're looking at here, especially early in the spring, aren't necessarily bumblebees. We will have many bumblebees especially on lavenders. But there's another bee called the carpenter bee which you may be familiar with. And they emerge very early from their over-wintering site, which is probably a hole in your deck or something like that, and begin to forage on the mints and lavenders early in the season.
RAUPPThey disappear in midsummer because this is when the larvae of the carpenter bees are developing inside the gallery in your deck. What we'll see in this time of the year is a resurgence of brand new carpenter bees that will come again and forage on your mints and your lavender. And they -- the chasing around that you note here is actually the male carpenter bee defending his territory.
RAUPPHis territory may be your deck or a railing or your siding, and what he's defending that wood for is the eventual arrival of his mate, the female carpenter bee, which he will then proceed to wed. And she will then make a hole in your deck or your siding, so that's why that male is chasing you about.
MELANIEI thought -- uh-huh?
NNAMDIWell, if you choose to decide that he is there to personally protect you, that is also your choice.
MELANIEI'm a little heartbroken.
RAUPPOh, it is a guy, though.
NNAMDIThank you very much for your call, Melanie. We move on to Ed in Frederick, Md. Speaking of bees, Ed, you're on the air. Go ahead, please.
EDGood day, Kojo. I'm a bee keeper in Frederick, Md. We spoke before. Anyway, this year, typically, I get a couple, three swarms each year that, you know, get called for swarms. This year, I caught over 30. Because of the lack of winter, we -- the bees just went crazy this year in swarms. I'm concerned that now we have some feral bees out and about, and that's all well and good. But I'm concerned that if we get a bad winter, we have a whole bunch of weak hives now, 'cause they kept splitting two and three times, that the feral hives will now die.
EDSo that's one concern. I've also been noticing these green -- about a month ago, I had a whole bunch of green caterpillars -- excuse me, green beetles. I thought that they were the ones that were from -- I thought there was a beetle that were in the trees, the...
RAUPPEmerald ash borer?
RAUPPMm hmm. Yes.
EDBut they weren't. I looked at the picture. They weren't that. But I don't know what they were. And we had lots of them. I mean, hundreds of them, and they take my -- get my peach tree...
NNAMDIOK, we're running out of time. Allow me to have Mike Raupp respond to you, Ed.
RAUPPYeah. Ed, you're absolutely right. It really -- the warm spring really pushed the swarms on our domestic honeybees this year. We just have to keep our fingers crossed that they might stay down, and some of these feral colonies actually take hold and are able to survive the winter. There are a number of green beetles. Of course, the emerald ash borer is one. This is the one that's attacking and killing our ash trees.
RAUPPBut there are other green beetles. One of the most common is the six-spotted green tiger beetle which is a highly beneficial predator that we often find on the ground. So I'm not exactly sure where you saw your green beetles, but there are several species of green beetles, many of which are beneficial. So this may not have been a bad thing actually, Ed.
NNAMDIThank you very much for your call, Ed. We only have about 30 seconds left, but we got a tweet, "How much does the depletion of the bat population due to the white moss fungus affect the increase in mosquitoes?"
RAUPPYeah. It's a great question. I don't think anybody knows the answer. Certainly the bats do take a bit of a toll on mosquitoes particularly these corpuscular ones, the ones that are flying about the time that the bat starts. So this can't be good...
RAUPP...I think, is the short answer.
NNAMDI...there's another tweet you might want to know about it. It comes from someone named Brian who is tweeting, "That's my dad on 'The Kojo Show.'"
RAUPPHey, Brian. How are you doing? I hope you have your insect repellent on today. That's all I can say to you, young man.
NNAMDIMike Raupp is Brian's dad. He's also the Bug Guy. He's a professor of entomology at the University of Maryland. Mike, always a pleasure.
RAUPPMy pleasure, Kojo.
NNAMDIAnd thank you all for listening. I'm Kojo Nnamdi.
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