Wednesday, November 27, 2019

Society meeting highlights risks of ignoring science

We ignore science, including the study of insects, at our own peril.  This was an underlying message in session after session of the 2019 Annual Conference of the Entomological Society of America.

This year's ESA conference, just a few minutes' walk from the iconic St. Louis Arch, was my first business visit to the the city where I spent most of my growing up years. Out for a jog on the first day of the meeting I remembered as a kid watching workers fit last shiny aluminum triangle into place at the top of the Arch shortly after my family arrived. I admit I felt a little old when I realized the Arch turned 55 this year.

Glorious flies

As glorious as technology can appear to the human eye, I was quickly reminded that insects are just as cool, and have been around a lot longer than any arch.  The plenary session speaker was Janet McAlister, British author of the book The Secret Life of Flies.  With a generous dash of humor, McAlister breezed through story after story of amazing flies.  One in ten living species on the planet is a fly, she said, with 17 million individual flies for every living human. Flies are also beautiful when you get close enough.

We can thank the fruit fly, Drosophila melanogaster, a pest of kitchens and hospitals around the country, for its contributions to our modern understanding of genetics and the genes associated with diseases like Alzheimer's and Parkinson's.

Flies are important pollinators too. A type of biting midge is also the sole pollinator of Theobroma cacao, our plant source for chocolate. No flies?  No more chocolate.

And as McAlister pointed out, at times even crime fighters depend on flies.  The first murder solved with the assistance of insects was the strange case of  Dr. Buck Ruxton in England in 1935. Ruxton was convicted of murdering his wife and servant after the fly maggots found in his victims' decaying bodies were used to estimate the approximate time of the murder.  And as any fan of television's CSI shows will tell you, flies are used for the same purpose today. For some fantastic images of flies, check out Gil Wizen's photography page (featured in many of McAlister's slides).

The coming Insect Apocalypse?

It's not too often that I see reference made to the Bible in a scientific paper, much less a meeting; but this year's buzz-phrase for many attendees was "insect apocalypse."  One of the better attended symposia was devoted to Insect Decline in the Anthropocene (the Anthropocene is a scientific term for the man-dominated biological/geological era we are in today).  While I missed several talks in this session while darting between papers, the central message was clear.  Something is happening to insect populations around the world, and it's not good.

Among concerns of attendees are declines in many kinds of
wild bees, sometimes referred to as a "Beepocalypse"
Hans deKroon, from Radboud University in the Netherlands reported on the results of a 27 year study of insect densities in 63 German nature preserves.  Using the same sampling method and places for sampling in relatively unchanged parklands between 1989 and 2016, the researchers documented a 76% decline in the total weight of insects (biomass) caught in traps over this time.  The surprising thing was that declines were seen across all sites with all kinds of insects--not just a few.  The authors attribute some of the decline to land fragmentation (sites were often close to agricultural land), but also possibly pesticides and climate change.

David Wagner, University of Connecticut, reported a similar 70% decline in moths of pristine New England forests.  The decline, he said, averages 1-2% per year and is across a large region.  The only explanation is some kind of broad external cause(s). Beyond increasing global temperatures, possible causes for loss of moths and butterflies include nitrification, light pollution, exotic insects, and car strikes.

So what are the consequences of such large declines in insect biomass?  I mean shouldn't we be rejoicing in fewer insects if this means fewer pests?  Absolutely not. In addition to entomologists, all sorts of biologists and nature lovers should be concerned by these numbers. Insects are keystone (ecologically very important) species in many environments.  They help decompose dead organic matter, keep potentially invasive plants under control, and feed fish and birds and many, many other types of wildlife. Indeed, one especially depressing study in the Science journal this year reports a 29% decline in bird numbers in the U.S. since 1970 (click here to see the paper in full). While the reasons for bird decline are complex, losing an important food source is not good for birds or bird lovers.

Tim Showalter, Louisiana State University, cautioned attendees to take care in drawing hasty conclusions, and in careless interpretation of apocalyptic data.  In a cautionary paper, he noted that a 2018 paper on supposed food chain collapse and a 60% decline in insect populations due to climate change in a Puerto Rican rain-forest garnered attention in the press, but was ultimately based on faulty data.  A change in positioning of temperature stations, misinterpretation of different survey databases, and impacts of multiple hurricanes led the authors to erroneous conclusions.  The food chain is NOT collapsing in Luquillo, Puerto Rico, he said. A rebuttal to the paper is now posted on the journal website.

Showalter's paper illustrates the imperfection, yet self-correcting nature of science.  It also illustrates how easy it can be for interpreters of science to cherry-pick data to reinforce a given point of view. We all need to be critical readers of science; however, this doesn't mean we can't trust scientists.  Certainly the majority view of entomologists is that something alarming is happening to many kinds of insects in many locations around the world. We should not ignore this issue or the scientists raising fair warning.

Learning from History

Rocky Mountain locust, Melanoplus
spretus, ca. 1870s, Minnesota. 
As I get older, history gets more interesting.  The ESA is fortunate to have among its membership a significant number of scientists with an interest in the historical roots of entomology. For example, I learned from Jeffrey Lockwood, University of Wyoming, that the first recorded time our government called on science to solve a political problem involved entomology. Between 1874 and 1877 the Rocky Mountain locust caused staggering crop damage in Kansas, Nebraska, Minnesota and Missouri. While inventors and hucksters of the day promoted a variety of solutions for locusts, little was really known about the biology and life cycles of these insects. For example, many farmers believed that locusts were so diabolically destructive because they were led by kings and queens (not true).

In 1876 a new governmental group known as the Entomological Commission was authorized by Congress to study the problem. The team quickly recognized that the key to the locust's destruction lay in identifying its true identity, its breeding grounds and the conditions that led to outbreaks (sounds a lot like an IPM program).  Also a collection of natural enemies was identified. While this information would have ultimately been useful in developing long-term control measures, Rocky Mountain locust swarms were already in decline by 1877--something for which the entomologists were happy to take credit. It turns out that by the 1880s the swarms all but ceased, likely because of the loss of the great buffalo herds which, by reducing food in the permanent breeding range, and pulverizing the soil with their hooves, would trigger the buildup of migratory locust swarms.

Entomologists were pragmatists in the locust wars, arguing against those who ascribed the swarms as evidence of God's judgement due to a general lack of morality and repentance.  Rather than promoting a day of prayer, however, entomologists insisted that farmers would be better served by looking to science to discover the causes and solutions to the plagues.  Today the Rocky Mountain locust is extinct, following the path of all organisms that cannot adapt to a changing environment.

Insects and Health

Like it or not insects are important factors in human health. Insects and indoor health was the theme of one session I attended.  Respected researcher Felicia Rabito, Tulane University, pointed out that asthma remains relatively poorly understood, despite its public health significance. One in 12 children in the U.S. suffer from asthma, a chronic inflammatory disease of the airways. In her studies 73% of homes have elevated levels of one or more environmental triggers of asthma (e.g., smoke, pet dander, particulate air pollution, and pest derived allergens).  Cockroach allergens remain one of the strongest promoters and triggers, and appear to cause four times the hospitalization rate of other allergens. Her research with a relatively small sample size showed that even a single IPM intervention (bait only) could have significant positive health outcomes for kids living in treated homes. Their team plans to redo the study with a larger (300 household) sample size.

A co-researcher with Rabito, and one of the most original and thought-provoking urban entomologists today, Coby Schal, North Carolina State University, gave an interesting talk on reducing cockroach allergens simply through cockroaches baiting.  He argued that the comprehensive IPM approach, such as advocated by the National Institute of Allergy and Infectious Disease, starting with improving sanitation, use of non-chemical tactics, biological control and (perhaps) chemical control may be too slow and expensive in most cockroach infested homes (think public housing).  His data suggests that IPM and health specialists should lead with cockroach baiting because it is the fastest and least expensive way to reduce indoor allergens. It remains alarming to me the number of pest control companies that still rely primarily on sprays to control German cockroaches, when baits have time and again been shown more effective in controlling cockroaches and improving public health.

Bed bugs remain a topic of interest in these meetings, though not to the level of 5-10 years ago.  Jonathan Sheele gave two papers on bed bugs from a doctor's perspective. In the Ohio Emergency Room where he previously worked, he noted that when bed bugs were found on a patient, that room would be out of use for cleaning and pest control an average of 20 hours. This would happen every 2-3 days on average. His hospital spent $30,000 annually on IPM costs associated with infested patients. Patients with bed bugs were more likely to suffer anemia, Staphylococcus infection, and use an inhaler than patients without bed bugs. In a separate paper, Sheele reflected on the potential for a future pill that people could take to kill bed bugs. In lab studies, both spinosad and fluralaner (Bravecta®) provided excellent control of bed bugs; however neither drug is yet approved for use on humans.  Abamectin is another antiparasitic agent that does have human approval, however tests on its effectiveness in humans against bed bugs have not been conducted. Such an innovation could be a big boon, especially for low income families suffering from bed bugs.

Stephane Perron, National Institute of Public Health in Quebec, Canada, looked at bed bugs in public health and reported that bed bug infestations often result in prolonged stress for patients. Some of the mental health impacts of bed bugs include fear, sense of lack of control, physical discomfort, sleep deprivation, financial stress, property loss, stress over preparing a home for treatment, conflicts with neighbors, the stigma associated with bed bugs, fear of insecticides, and exacerbation of prior mental health issues.  On the flip side, a recent study she conducted showed that anxiety and depression could decline when bed bugs were successfully controlled--a real benefit pest management companies can take pride in.

Zach DeVries, University of Kentucky, noted that the bed bug's status as only "a nuisance" is coming to an end. Again, public health professionals, decision makers and politicians need to take cockroaches, bed bugs, mosquitoes and other urban pests seriously.

Odds and Ends

Again I felt a little old during this meeting when I realized how different students are today. Grad students at the meeting are more diverse and more attuned to social media than ever before. As such they represent many of your younger pest control customers.

Striving to keep up, I attended a session on using social media.  I found myself in a group fellow laggards who did not understand some of the basics of the Twitter platform.  While I do use Twitter (@mikemerchant), I realized I still didn't understand some of the basics of the app and Twitter platform.  I learned how to better use hashtags, and that I need to follow more people if I want to expand my personal Twitterverse (I have a difficult-enough time with the regular Universe) #oldfashioned, #luddite, #booklover.  I reflected that if we fail to learn from these young professionals we risk ending up like the Rocky Mountain locust.

Joe DeMark, Corteva AgriScience, gave a paper on a new termiticide caulk formulation in the works. The caulk provides another above-ground option for treating termite tubes.  It could, I envision, replace the somewhat clunky (though effective) AG bait stations.  Caulk has an advantage of being flexible enough to inject into infested trees, or placed directly on an exposed termite foraging tube.  It has the same active ingredient as Sentricon, noviflumuron and is applied with a regular caulk gun.  In studies conducted in New Orleans against Formosan termites, tree infestations were consistently eliminated in about 2.5 months.  Control of termites in homes was accomplished in 30-90 days.  If it should ever become a product, DeMark does not expect it to be commercially available until after 2020.

The Asian longhorn tick is now present in 11 states since its discovery in 2017.  A first human bite was recorded this year, which was significant because of its ability in other countries to carry disease to both livestock and humans.  In a talk by Ryan Smith, Iowa State University, I learned that a 2019 study showed that the tick could pick up Lyme disease from an infected mouse (bad). But the same study showed it could not maintain the disease through molting. This is good news, because it means this tick is unlikely to transmit Lyme disease in the wild.  Nevertheless, there are other diseases of concern and the increasing number of exotic pests being introduced into the U.S. continues to threaten both ecological and human health

Lastly, the ACE Associate Certified Entomologist program hosted by the ESA continues to grow. As of this writing there are 1251 active ACEs.  ESA estimates that there will be 1,272 ACEs by the end of year (lots of new applicants currently), representing 13.5% growth since December last year. The ACE program is unique in that it is the only individual-oriented certification program. It can provide potential customers with assurance that your company has qualified staff, and allows you to attend meetings like the St. Louis conference at discounted rates.

If you think you're interested in becoming an ACE, check out the ESA Certification Corporation website.  And consider attending one of the upcoming Texas prep classes in Dallas or in College Station.  The class is an excellent way to either begin studying, or as a last-minute confidence builder before taking the test.

Each of us has a unique role to play in service to our society. But we only do our jobs well when we commit ourselves to lifelong learning. As is clear from these meetings, knowledge is expanding rapidly.  I hope each of you keep following the science behind the pest control profession (as you already are by reading to the end of this post) and continue to avoid the perils of unfounded opinion.

Science is the father of knowledge, but opinion breeds ignorance. Hippocrates