I realized after my interview last weekend that I had never actually covered Japanese Beetle Bags on my blog! That omission must be remedied!
I’m sure you’ve seen them–they are for sale all over. The sad truth is that they don’t work.
Sure, they fill up the bag-o’-death in a really satisfying way, but they also attract many, many more beetles into the area that don’t get caught. As long ago as 1985, there was pretty clear evidence that putting the bags out actually made the damage from the beetles worse.
Beetle bags contain a combination of lures–the bright yellow color mimics flowers, there’s a feeding attractant, and also a female sex pheromone. It is the buggy equivalent of a giant flashing neon sign advertizing a message equivalent to “FREE SEX ORGY AND ALL YOU CAN EAT BBQ WINGS + BEER”.
A lot of beetles come to the trap–but less than 25% of the beetles attracted actually go into it.
Here, look at the data.
That’s from a 2009 study that looked at the specific behavior of beetles attracted to the trap. They concluded that it’s not a problem with trap design; it’s a problem with beetle brains. Scarabs are notoriously poor fliers; a few will probably bean you at top speed if you stand around outside long enough in the summer.
Their braking strategy is about the same as the one I use on rollerblades–find a large object, smash into it, and hang on.
So, Japanese beetles fly into the area where the trap is and most of them miss it. They hang around the trap–because they know that orgy must be around here somewhere–and eventually hook up and start eating. Outside the trap.
Some of them do eventually find their way into the bag later on, but the total catch is still pretty dismal. And you just paid money to bring all these pest insects into your yard. Oops.
One recommendation that’s commonly made, since the traps do work, just not the way we want, is to buy them and give them to the neighbor you hate the most. Then their garden will be gobbled up, and your beetles will all fly over there.
Sounds great, right? Except. Here is where the Karma comes in.
One of the reasons these beetles are so evil is they have a 1-2 punch. No only do they eat your fruit and veg, they lay their eggs in your yard. And eat your grass from the roots.
So, if you send all your beetles over to your neighbor’s yard with the traps…they will lay thousands of eggs over there. And even more beetles will come right back when the grubs emerge from his/her yard. Payback is a bitch.
So how can you control them? Honestly, I have had the best success with a Mason jar full of soapy water. Find a small kid and tell them you’ll give them a penny for each beetle in the jar. Problem solved.
You might also enjoy this video about Japanese Beetle Control created by the University of Maine. Ayup!
Switzer, P., Enstrom, P., & Schoenick, C. (2009). Behavioral Explanations Underlying the Lack of Trap Effectiveness for Small-Scale Management of Japanese Beetles (Coleoptera: Scarabaeidae) Journal of Economic Entomology, 102 (3), 934-940 DOI: 10.1603/029.102.0311
Gordon, F. C., & D. A. Potter (1985). Efficiency of Japanese beetle (Coleoptera: Scarabaeidae) traps in reducing defoliation of plants in the urban landscape and effect on larval density in turf. J. Econ. Entomology, 78, 774-778
Wired has a very nice article on the controversy over the use of LBAM pheromone in an urban area in California, in which they do an excellent job balancing both science and public reaction. From Wired:
“Since material safety data sheets can make even the most benign molecules sound terrifically dangerous, vigilant citizens will express their concern about rather innocuous substances — damaging their credibility with the scientists who should listen to their objections — and making it hard to sort out any real threats.”
Rather predictably, the comments have a high level of burning stupid:
“All of you posts supporting the collusion and concentration of power by a wealthy few big ag/chem corporations better get informed or stop writing without revealing your ties to these corporations. IT IS NOT A PHEROMONE, it is synthetic in hugely, hugely unnatural concentrations with lots of carcinogenic and mutagenic inerts. The spray is inhaled deep into lungs like silica and asbestos. We got sick. Animals died. Some of us are still sick. Has one person been contacted who filed a pesticide related health complaint? – NO! Isn’t that enough for you doubters? Don’t you respect the people,or do you just respect and believe the CDFA/USDA, who are nothing more than propaganda machines for big corporate interests.”
I really just don’t get the conspiracy thing.
I have a lot of friends that work for USDA, and they are just some of the nicest folks around. This is also true of friends that work for agrochemical companies. None of these people would go along with a massive plan to cause harm or defraud the public.
This is also true of the people I worked with when I was employed by a pharmaceutical company, the other “big corporate interest” that gets a lot of blame. They all worked at that company because they believed they could truly create change with their work, and make lives better.
Are companies profit motivated? Sure.
But nearly every big company that has behaved badly has been brought down by an insider. You might be able to get a few people corrupt enough to misbehave, but they will be found out. (To get an entire corporation to lie, it apparently takes a Vice President.)
The other thing I hear a lot is that the USDA, college faculty, and state employees are getting rich by working with the agrochemical industry.
Sure, we take money from companies, in the form of grants and contracts. And you would not believe what a pain in the ass grants and contracts are. Right now, if I buy a centrifuge using the money from Grant A, I am not supposed to use it for work on Grant B. Every dime is strictly accounted for. In a rather crazy, counterproductive way, actually.
You can do some consulting work, but the total amount of time you spend on different projects is tracked. If you try to dip into too many pots, you will get a phone call that you won’t enjoy.
This is not a lucrative job. I’m not poor, but I’m not rolling in dough and shilling for agrochemicals either.
I have almost 20 years of experience, I am in a senior leadership role at a large research station, and I have never made more than $55,000/yr in my entire life. Comfortable, yes. Rich, no.
Being a scientist, especially an agricultural scientist, is not a fast track to riches and fame.
But I digress.
Back to the article.
I liked these comments:
“This pheromone has to be labeled as a “pesticide” simply because the end result of using it is the destruction of a pest. If water is sprayed and used to destroy a pest, then it too will have to be labeled a pesticide.”
“What would you suggest? I like to ask this of people who whine and criticize, because they never have the answer. Think on it for a while, and when you come up with the solution to the problems that span 6,000,000 square miles and encompass 300,000,000 people, by all means, let us know what it is.”
An amusing letter arrived earlier this week:
My name is Margot and I’m the webmaster of http://www.best-pheromones.com. I wanted to know if you could do a paid UNBIASED review of our product/site. Please let me know if you are interested.
Margot [name and email removed]
I was especially intrigued by the capitalization of “unbiased.” After I got done laughing, I sent back a response:
I am an entomologist, and I write about insect pheromones, and the way they are used in agriculture.
I will not be linking to your commercial website, nor accepting cash to write about what I think (here’s my UNBIASED opinion) is a crock of BS. Human pheromones have little documentation in the scientific literature.
For the record, Margot sent me a very polite thank-you back. Point to Margot.
Now, there are a few human chemicals that do seem to meet the definition of a pheromone. You can read a nice introduction to what is known about human pheromones in this APA article. The pioneer in human pheromone research is Martha McClintock, who first isolated and showed that a pheromone was responsible for synchronizing women’s menstrual cycles.
This is probably not the compound for sale at the commercial website. At least, I hope not–I really don’t think a guy dousing himself in that compound will get the response he wants.
There are some other compounds that do seem to induce changes in human physiology. The compounds that have been studied most are steroid musks (androstenol and related compounds) produced by glands in men’s underarms. Yummy!
However, the physiological changes that have been reported are not the “do me now!” that is sold by human pheromone companies. I think this bit from a peer-reviewed paper’s abstract is important:
“Although this is additional evidence that androstadienone may be a pheromone, it is yet to be determined whether humans exude concentrations into the air adequate for social communication or process this chemical information within natural social contexts.”
Translation: we can make a chemical, and we can measure that it’s doing something. But we don’t know if this actually happens in day-to-day human life.
I think it’s significant that another peer-reviewed study found a chemical could affect women’s mood, but not their behavior. From the abstract:
“The results showed that exposure to a non-detectable amount of androstadienone modulated women’s psychophysiological arousal and mood in a positive direction but did not change attention performance or rating of facial attractiveness. Moreover, mood effects were only evident when an experimenter of the opposite sex conducted the testing. This suggests that social context is important for mood effects of androstadienone exposure in women. “
Interestingly, the results were the same in a different study when they tested a proposed female pheromone on men–the sex of the interviewer affected the action of the test compound. My inference from this is that as humans, we respond primarily to the person interviewing us, rather than how they smell. Which is pretty logical, given that we are a highly visual and social animal.
I also was intrigued by this study looking at the effects of a proposed human pheromone on marketing–men exposed to a male pheromone felt more manly, but it had no effect on women.
If the results are so mediocre, why are so many researchers working on the issue of human pheromones? Just how much money is being made on human “pheromones,” anyway? One company (traded under stock symbol EROX) reports revenues of 1.2 million bucks. And that’s just one company of the many, many companies in on this snake oil that supposedly gets you laid.
I suspect that most human pheromones sold would fail a chemical test comparing what chemicals are actually in them with what’s claimed to be in the bottle. And, given that the cheapest human pheromone I’ve seen was $25/ounce, that’s a highly profitable ripoff.
Lastly, there is also a larger ethical question in play here.
WTF makes someone pay large sums of money–usually over the internet–to buy a mystery liquid that claims to make them irresistible? If some of the claims of these companies were true, they are essentially selling a date-rape drug. Which would make the person buying this stuff pretty despicable, IMHO.
Symposium: On the nature of mammalian and human pheromones
The McClintock paper in Nature, demonstrating menstrual synchrony
The other likely human pheromone: a review of mother-baby physiology and behavior
The Crazy, it Burns. You might remember me mentioning a dust-up over pheromone spraying in California a couple of weeks ago. Now the spray date has been advanced, and even more paranoia has set in:
“They have apparently moved their spraying date up from August to June First–and seem to be moving ahead despite widespread public protest against the spraying. The spray (much like the ‘chemtrails’ that people worry about…but undeniably real) which they will aerosol-spray on millions of sleeping people on more than one occasion, contains more than the pheromone–it contains nine other ingredients, many of them quite toxic.”
Here is an even more hysterical version:
People of the world, the US Government is planning to poison more than two million people, in California, using an untested biological “pesticide” this summer….There are many who believe that this spray is not directed at the moth population which the government says is the goal of the spray, but rather that it is directed at humans. There is a growing body of evidence to support this claim, considering that the moth itself does not cause any crop damage….
The LBAM infestation is a monumental hoax designed as a cover for an operation of devious goals to expose people to dangerous chemicals over several years.
Unfortunately, these posters also alerted me to the fact that some of the anti-pheromone paranoia is sponsored by a company I do business with–Credo, my wireless and long distance phone company. Credo claims that Checkmate is a pesticide, which is flat-out WRONG. Frustratingly, there is no obvious place to contact Credo to tell them just how wrong, in the giant universe of wrongness, they are.
Sigh. This is a biological control method. It is species-specific. It is applied in very tiny amounts. It doesn’t kill anything, and it isn’t a pesticide.
It is what all the environmentalists IN CALIFORNIA have been screaming for for decades.
I guess they just didn’t want it implemented in their backyards.
Yesterday, I posted a new episode in the “Ask an Entomologist” series. My regular readers (we’re up to 8!) were probably thinking “Gosh, why is Bug-girl writing this long post? Isn’t she hugely overworked at her new job?”
The answer is yes, I am very stretched right now. (Urk!)
I finished that post on pheromones (it had been a draft since last fall) because something silly annoyed me very, very much. I wrote that post to provide the background to the smack I’m about to deliver today.
What motivated me? There is a huge outcry in California…because they are planning to spray pheromones for light brown apple moth (LBAM).
“Officials claim no “adverse” effects are expected when aerial dissipation of vast quantities of CheckMate OLR-F and LBAM-F will be sprayed over the Bay Area beginning as early as June. Tell that to hundreds of residents of Santa Cruz and Monterey counties who have reported health problems from last years coating.”
Errr..what? Pheromones are about as safe as you can get! They are naturally occurring compounds that are used in insect sexual communication. Most consider them a type of biological control.
As I explained yesterday, insect sex pheromones are used in tiny amounts (0.0001 microlitres still gets a rise out of my males). The application rate for CheckMate is 0.65 fluid ounces per acre. I’ll say that again:
Less. Than. One. Ounce. Per. Acre.
So, rather than using broad-spectrum pesticides, the state is using unique natural compounds specific to two pest species. And this is grounds for a petition and multiple protest sites? Their reaction can be best summarized as “OMG there are chemicals!!”
Interestingly, the very same blogger that sounds the alarm above, 6 months earlier, detailed the threat to California agriculture:
“The state’s agriculture industry faces $100′s of millions in losses if this interloper gets a more serious foothold in the agricultural zones of the Central Valley, and already nursery stock & cut flowers from 8 Bay Area & Northern California counties are quarantined and not allowed to ship interstate. “
What will be the consequence if this spray is halted? As mentioned in the quote above, LBAM, an introduced species, could become permanently established in California, and cause a lot of people to loose a lot of money. And then REAL pesticides will be used, in considerably larger quantities than this pheromone spray.
Have we really progressed to a point where any chemical use at all is suspect? I’m afraid so: Dihydrogen oxide is a good example. I’m sure it’s totally a coincidence that it was also in California that a county almost banned this compound in 2004:
“The city councillors of Aliso Viejo in Orange County, California, are well-meaning, socially responsible people. And when they came across the huge threat posed to their constituents by dihydrogen monoxide they did what any elected official should do: they took steps to protect their community. A motion due to go before the city legislature proposed banning the potentially deadly substance from within the city boundaries.”
This backlash to pheromone use reminds me very much of individuals refusing to be vaccinated for selfish (and unfounded) reasons, and harming a larger group.
California is a very, very strange place. I will now resort to the stereotypical Midwestern comment:
As tiny animals that live widely dispersed, finding a partner of the proper sex and species to reproduce with is a problem for insects. How do they arrange a hook up?
Insects have solved that problem in a variety of ways, but sexual pheromones are one of the most common solutions. Pheromones are “chemicals emitted by living organisms to send messages to individuals of the same species.” The message transmitted doesn’t have to be about sex–there are lots of different kinds of pheromones–it’s just more appealing to human prurient interest when sex is involved
By making a species-specific blend of chemicals and releasing it into the air, insects are able to communicate over great distances. With sex pheromones, the message is usually from the female, and has the content “I’m here and ready to get it on, big boy!”
So, how do insect sex pheromones work?
Male moth antennae are exquisitely sensitive to even individual molecules of a female sex pheromone. (You can see an animation of what happens neurologically in a moth antenna when pheromone hits a receptor here, courtesy of UC Davis. Davis also has a movie of how male silk moths react to pheromone in a commonly used test apparatus.)
Reception of the pheromone triggers a series of behaviors in the receiver (male), leading to the two insects meeting and, hopefully, reproducing.
My illustration shows a theoretical situation.* The female (on the right) emits her pheromone from a gland, and the wind disperses it. Think of each pixel of color as an individual pheromone molecule. The more concentrated the pheromone, the darker the color.
Males fly upwind following a pheromone concentration gradient, and eventually find the female. (animation version here). Moving into of an area of lower pheromone concentration is a signal to turn, to try to follow the concentration as it increases.
This model makes a lot of assumptions–that the female is a stationary point, for example–but it’s a pretty good description of how the system generally works.
In fact, this simple system has been used in robotics to develop a robot that follows a smell to the source of a chemical leak!
How do synthetic pheromones muck up this process and provide insect control?
Many types of biological control in the last few decades have developed out of identifying and using an insect’s natural biochemistry and metabolism against itself. Insect sex pheromones are commonly marketed for control or monitoring of insect pests.
There are several ways that synthetic pheromones are used for insect control, but the one I’m interested in today is mating disruption. The theory is that if you saturate an area with pheromone, the males will be unable to follow a chemical trail, and will be unable to find the females. Males will also be attracted to the synthetic pheromone dispensers, and try to mate with them–with predictably unsatisfactory results for the male. Sometimes synthetic pheromone dispensers are combined with traps to kill the male insects, and really make sure no mating goes on.
No male + female = no eggs = no pest insect reproduction. It’s a type of insect birth control.
The beauty of the system is that it is specific to one species. A problem with pesticides or biological toxins are “off target” effects. You spray to kill the bollworms, and also kill all the predators that would help you out by eating the bollworms. Oh, and any butterflies and pollinators that happened to be in the area, too. Bummer.
Mating disruption involves very small amounts of a chemical, released in a small area, that results in lots of horny males and frustrated females of one species, and no fertilized eggs. Because males are so sensitive to the pheromones, micrograms are used, not pounds of active compound/acre. When it works, it’s been pretty awesome–pink bollworm and tomato pinworm are two success stories.
The problem is, mating disruption doesn’t always work 100% of the time. (What does, really, in any biological system?)
This is usually because while synthesizing a species’ pheromone is relatively easy with new molecular tools, understanding the complexity of a species’ behavior and ecological dynamics isn’t that simple. As we learn more about insects and their population dynamics, we continue to get better at figuring out why this works well on some insects, and not others. Entomologists also have seen evolution in action, as it’s turned out that insects have variation in their chemical blends, and are not as chemically monolithic as the model suggests.
All in all, it’s a fascinating system, and I’ll talk more about it tomorrow.
For additional info:
- Read a whole textbook chapter on sex pheromones!
- Visit the UC Davis chemical ecology site, and look at more cool movies and research
- A National Academy online book about pheromone communication in insects
*Disclaimer: the graphics and examples used here are for illustration only. Females don’t emit pheromone in a rectangle, and males are not a blue blob. If you can’t deal with this much abstraction in the purpose of communicating with lay readers, get a life. Or, make the graphics for me :p