Silicon Bed Bug Weaponry

May 4, 2015

BED BUGS CAN be spiked and trapped by tiny spears like leaf hairs, and can become dehydrated or dessicated and rendered harmless by certain forms of silicon, the second most abundant element in planet Earth’s crust (28%) after oxygen (47%). That silicon can be the bane of bed bugs is indeed odd when one considers that silicon permeates our world from beach sands, opals, agates and quartz crystals to sandpaper, semiconductors, glasses, ceramics, optical fibers and cosmetic products. Indeed, the famous French scientist and silkworm entomologist, Louis Pasteur, whose name has become synonymous with the germ theory of medicine, predicted silicon’s eventual service in human medicine; though Pasteur was probably not thinking along the lines of silica gels and desiccant diatomaceous earth dusts as remedies for the 21st century’s worldwide medical plague of bed bugs.

Despite its commonness in nature and the human environment and potential uses in human medicine, the use of silicon products comes with caveats to users, who might want to wear sufficient protective clothing and respirators to avoid inhaling the products. Strangely enough, that much maligned metabolic waste product, carbon dioxide, which along with sunlight is essential to photosynthesis and life on planet Earth, is perhaps a safer component (e.g. as a lure or attractant) when integrated into bed bug traps. Food grade diatomaceous earth made from freshwater diatoms is considered relatively nontoxic; whereas filtering grade diatomaceous earth (e.g. the type used for swimming pool filters) is a crystalline form with inhalation toxicity.

“Louis Pasteur (1822-95) said that silicon would prove to be a treatment for many diseases and in the first quarter of the twentieth century there were numerous reports by French and German doctors of sodium silicate being used successfully to treat conditions such as high blood pressure and dermatitis,” wrote British chemist John Emsley in his superb compendium, Nature’s Building Blocks (An A-Z Guide to the Elements). “By 1930, such treatments were seen to have been in vain and the medication fell out of favor. So things rested, until the discovery that silicon might have a role to play in human metabolism, and then followed suggestions that it could have a role in conditions such as arthritis and Alzheimer’s disease, but no new treatment based on these suggestions has yet emerged. Meanwhile, silicon continues to be linked with a disease of its own: silicosis. Miners, stone-cutters, sand-blasters and metal-grinders develop this lung condition which is a recognized occupational disorder caused by the inhalation of minute particles of silica…” Symptoms include coughing, wheezing and shortness of breath; a more aggressive form of silicosis associated with certain types of asbestos can develop into lung cancer and has been a rich source of litigation for occupational exposure in the USA.

While silica products should be used sparingly (a caution that should also apply to most sprays) or not at all by some people (e.g. existing respiratory problems; perhaps seek a medical opinion before using), they might prove for many others the tipping point for winning the bed bug war as part of an integrated approach that controls bed bugs (many of which are pesticide resistant) using a multiple arsenal of weapons including herbal oils, clutter reduction, heat, sealing crack and crevice harborages, traps, pheromones, carbon dioxide, vacuuming under baseboards, etc.

At the 2014 Entomological Society of America (ESA) annual meeting, Kyeong-Yeoll Lee of South Korea’s Kyungpook National University (Daegu) reported that silica in the form of diatomaceous earth (Perma-Guard(TM) or Fossil-Shell(R)) acted as a synergist when heat (hot air) fumigations substituted for chemical fumigants such as methyl bromide. Though the test insect was Indian meal moth, a worldwide pest of stored grain and many other packaged agricultural products, it would not be surprising to find that heat treatments combined with silica products like diatomaceous earth will also prove efficacious and perhaps also synergistic against bed bugs. Indeed, heat treatments may induce bed bugs to move around more, which could hasten contacting diatomaceous earth and water loss.

At the same 2014 ESA meeting, Virginia Tech (Blacksburg, VA) researcher Molly Stedfast provided some impressive results via the time-consuming process of first educating apartment residents about bed bugs and then painstakingly vacuuming along baseboards to suck up as many bed bugs as possible before applying the silica products under the baseboards to further reduce bed bug populations. This integrated (IPM; integrated pest management) approach required quite a bit of manual labor, as furniture had to be moved to gain access to the baseboards before vacuuming and then applying silica gel or dust products.

Stedfast tested two silica products, Mother Earth(TM) D, a highly-absorptive desiccant dust made from 100% freshwater diatomaceous earth, and CimeXa(TM) Insecticide Dust, a 100% amorphous silica gel. The silica dust or gel injures the insect cuticle (outer protective “skin”), letting water leak out and leading to dehydration (providing relative humidity is not extremely high, above 81%; and free water is unavailable). Both the diatomaceous earth and silica gel products were “very effective at killing bed bugs even at 10% of the label rate.” Going above the label rate was a waste of resources, as only so much product can contaminate the bed bugs. Bed bugs can die within 24 hours of contacting the silica products, but air currents that blow the dusts around can be a problem; also the products need to stay moist and not dry out to be effective. Among Stedfast’s biggest headaches is the application equipment, which was not very robust.

The patent literature reveals that inventors such as Roderick William Phillips in Vancouver are working on improved spray apparatuses for applying diatomaceous earth: “There is disclosed a spray apparatus for holding contents comprising diatomaceous earth and a compressed propellant for propelling the diatomaceous earth. There is also disclosed use of diatomaceous earth to control a population of bedbugs…diatomaceous earth, a naturally occurring siliceous sedimentary rock that includes fossilized remains of diatoms. However, known methods of applying diatomaceous earth can be cumbersome. For example, known methods of applying diatomaceous earth may undesirably require handling the diatomaceous earth, for example to transfer the diatomaceous earth from a container not having an applicator to a separate applicator apparatus. Also, known applicator apparatuses may apply diatomaceous earth unevenly, which may be wasteful or ineffective. In general, known methods of applying diatomaceous earth may be sufficiently complex so as to require professional involvement, which may undesirably add to cost and delay of bedbug treatment. Also, numerous types of diatomaceous earth are available, and different types of diatomaceous earth vary widely and significantly from each other. It has been estimated that there are approximately 100,000 extant diatom species…and may vary widely and significantly in size and shape across a very large number of diatom species…”

At the University of British Columbia (Vancouver), Yasmin Akhtar and Murray Isman demonstrated that both diatomaceous earth and herbal or botanical compounds such as neem, ryania and rotenone are to varying degrees transported by adult bed bugs and contaminate other adults and younger bed bug nymphs. “Our data clearly demonstrate horizontal transfer of diatomaceous earth and botanical insecticides in the common bed bug,” said Akhtar and Isman. “Use of a fluorescent dust provided visual confirmation that contaminated bed bugs transfer dust to untreated bed bugs in harborage. This result is important because bedbugs live in hard-to-reach places and interaction between conspecifics can be exploited for delivery and dissemination of management products directed at this public health pest…This result is important because bedbugs live in hard-to-reach places (cracks, crevices, picture frames, books, furniture) and as such interaction between the members of the colony can be exploited for delivery and dissemination of control products.”

At the 2014 ESA annual meeting, Akhtar suggested protecting travelers and suppressing bed bug transit by building diatomaceous earth into luggage, mattresses and fabrics. Diatomaceous earth provided 96% repellence; bed bug mortality was zero at 24 hours, but 93% after 120 hours. Diatomaceous earth could also be applied to box springs, dressers and headboards, and under carpets and inside drywall. A diatomaceous earth aerosol provided 81% bed bug mortality at 30 days, and was still active and being transferred from dead bed bugs to live bed bugs.

Diatom species mined for diatomaceous earth are stunning in their architectural variety and beauty. Ultimately, the silicon secrets of living diatoms has the potential to transform “the manufacture of siloxane-based semiconductors, glasses, ceramics, plastics, elastomers, resins, mesoporous molecular sieves and catalysts, optical fibers and coatings, insulators, moisture shields, photoluminescent polymers, and cosmetics,” wrote UCSB marine scientist Daniel E. Morse. “The manufacture of these materials typically requires high temperatures, high pressures or the use of caustic chemicals. By contrast, the biological production of amorphous silica, the simplest siloxane [(SiO2)n], is accomplished under mild physiological conditions, producing a remarkable diversity of exquisitely structured shells, spines, fibers and granules in many protists, diatoms, sponges, molluscs and higher plants. These biologically produced silicas exhibit a genetically controlled precision of nanoscale architecture that, in many cases, exceeds the capabilities of present-day human engineering. Furthermore, the biological productivity of siloxanes occurs on an enormous scale globally, yielding gigatons per year of silica deposits on the floor of the ocean. Diatomaceous earth (composed of the nanoporous skeletons of diatoms) is mined in great quantities from vast primordial deposits of this biogenic silica.”

Advertisements

Termites: Good Medicine (Antibiotic Alternatives)

January 2, 2015

[Note to Search Engines: This is Not Another Termite Poop Story.]
Antibiotic-Resistant Bacteria Beaten by Termite Innate Immune System (the science part)

Antiseptic procedures and germ theory, stuff now routine like doctors and nurses washing their hands to avoid contaminating patients, entered modern medicine via 19th-century applied entomology aimed at solving a mysterious silkworm population decline baffling Italy’s Agostino Bassi and France’s Louis Pasteur (See blog, The Mysteries of Colony Collapse). Today, Pasteur might be looking over the shoulder of Yuan Zeng in Xing Ping Hu’s Urban Entomology Lab at Auburn University, wondering how termites make themselves more robust and immune to disease. After working with silkworms and formulating modern germ theory, Pasteur realized that “the exclusive emphasis on the germ theory of contagious disease” was a very incomplete view of reality in need of modification; a radical notion that would be opposed by many in modern medicine even today, as germ theory has attained the status of orthodoxy and relegated the alternatives to the fringes.

Pasteur told colleagues that if he had the chance to go back to silkworm entomology again he would focus on nutrition, the environment and physiology (e.g. immunity) to increase robustness, vigor and disease resistance. Stuff that would be cutting edge in the 21st century. Stuff like termite entomologist Yuan Zeng’s study of how termite “innate immune systems” overcome MultiDrug Resistant (MDR) bacteria infecting over 2 million people annually in the USA. MDR bacteria in the USA annually kill over 23,000 “because they are untreatable with today’s drugs,” Zeng told the Entomological Society of America (ESA) annual meeting. MDR bacteria are also becoming “a significant global health threat.” An excellent YouTube video of Yuan Zeng describing her Auburn University research on termites defeating MDR bacteria is now available.

Zeng’s previous research with powdered extracts of Eastern subterranean termites (Reticulitermes flavipes) against bacteria causing human gastric distress lends credibility to traditional folk medicines containing insects. “Our previous research on disease resistance in R. flavipes workers showed that the crude extract of naive termites constitutively displayed a broad-spectrum antibacterial activity including agents responsible for human gastric infections,” Zeng told the ESA annual meeting. The logic behind using termites as medicines or drugs is that subterranean termites forage and nest in soil loaded with pathogenic microbes, making them a “source for novel antimicrobial discovery because they have evolved effective innate immune systems in confronting various harmful microorganisms.”

If a termite species is both pest and medical cure, then might an alternative to chemical fumigation be to harvest (e.g. trap or vacuum) the termites and sell them as a medicinal crop? That is a question that rarely, if ever, is asked. “Science has already proven the existence of immunological, analgesic, antibacterial, diuretic, anesthetic, and antirheumatic properties in the bodies of insects,” wrote Brazilian researcher Eraldo Medeiros Costa-Neto in an article titled ENTOMOTHERAPY OR THE MEDICINAL USE OF INSECTS. “Since early times, insects and the substances extracted from them have been used as therapeutic resources in the medical systems of many cultures. Commonly considered to be disgusting and filthy animals, many insect species have been used live, cooked, ground, in infusions, in plasters, in salves, and as ointments, both in curative and preventive medicines.”

Florida is the place where all the termites of the world seem to be coming to live. The Palm Beach, Florida, TV news recently warned of a Caribbean invasion of conehead or tree termites, known scientifically as Nasutitermes corniger. Conehead termites avoid competing with subterranean termites by building “beach-ball size” nests above ground and “brown tubes up the outside walls of houses,” and according to the TV make wood look like “shredded wheat.” Even “aggressive spraying” dating back to 2001 failed in its goal of eradication, and 100 million conehead termites nesting in 120 colonies amongst 42 properties were sprayed in 2012. Conehead termites, which are “distributed from southern Mexico to northern Argentina and the West Indies,” are “commonly used in traditional medicine in Northeast Brazil,” say scientists in Brazil. No doubt the coneheads will turn up again and again in Florida until they are finally accepted as residents. That is the nature of invasive insects.

Perhaps instead of chemical eradication programs, these termites should be harvested and exported to Brazil and elsewhere for medical use. “With the increase in microbial resistance to antibiotics, the use of natural products represent an interesting alternative for treatment,” wrote Henrique Coutinho and his Brazilian colleagues in an article titled “Termite usage associated with antibiotic therapy.” Crushed and powdered conehead termites mixed with a conventional antibiotic drug (which was failing, due to bacterial resistance) produced “a new weapon against the bacterial resistance to antibiotics” via a termite-drug synergy. In other words, mixing powered conehead termites with the drug made for a more powerful antibiotic medicine than using the antibiotic drug alone. At least the coneheads are good for something.

Yuan Zeng told the ESA and YouTube that she fed subterranean termites “sublethal concentrations of MultiDrug Resistant (MDR) pathogens, Methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa (PAOl),” which induced “an alternation of protective proteins” produced by the termite’s innate immune system. “The composition changes of proteins following the feeding of MDRs significantly inhibited the growth of P. aeruginosa and MRSA,” said Zeng. “The results of this research could be a significant breakthrough for developing novel effective drugs” to fight human disease pathogens resistant to multiple antibiotic drugs. Worldwide, millions of people stand to benefit.

Known termite immune proteins include termicin, spinigerin, lysozome, tGNBPs, and “two unidentified proteins from several termite species with potent antibacterial and antifungal activities.” However, Zeng’s termite antimicrobial compounds are different; though there is still much scientific work to be done.

In the journal “Recent Patents on Biotechnology,” Japanese researchers Toru Matsui, Gaku Tokuda and Naoya Shinzato from University of the Ryukyus in Okinawa discussed patenting termite genes for alternative energy and drug production. “Although termites are regarded as harmful because of the ability to decompose cellulosic materials such as houses made of wood,” said Matsui et al. “Termites and/or their symbionts are potentially good resource of functional genes for industrial applications…for biomass utilization, environmental remediation, and fine-chemicals production.” Several termite genes have already been patented for biofuel (cellulase) and fighting infections (antimicrobial peptides).

A fungus-growing termite, Pseudacanthotermes spiniger, is notable for producing termicin, an antifugal peptide, and spinigerin, an anti-bacterial and antifungal peptide. “These peptides and the corresponding cDNAs have been patented as useful for protection of plants from pathogenic fungi or medical purposes,” said Matsui et al. “Similarly, some chemical antibiotic compounds isolated from termites have also been patented for the use of treating a microbial infection or disease.”

“Although entomotherapy is an ancient practice, it is still relatively unknown in the academic world,” wrote Costa-Neto. “In fact, as Holt already stressed in 1885, the advance of medical science and the suppression of folk knowledge swept away belief in the medicinal qualities of insects.”

Insect species outnumber plant species 16-fold, according to an article in The Indian Journal of Traditional Knowledge: “Yet very few researchers have concentrated on the medically useful properties of insects. Most research with insects revolves around getting rid of them.”

Medical Botany refers to plants used for medical or health purposes. But there is no entomological equivalent. Medical Entomology addresses arthropods as medical or pest problems; and by analogy is like Weed Science to Botany. Insects as medicinal cures or health enhancers are outliers, orphan science, folk healing curiosities; perhaps supermarket tabloid fodder alongside celebrity scandals and UFO abductions.

In South India winged subterranean termites (Odontotermes formosanus) are traditionally roasted in earthen pots and consumed for three evenings to treat asthma. But their anti-bacterial qualities have not been explored, “mainly because of the difficulty in harvesting large numbers.” Memo to South India: An abundance of potentially medicinal subterranean termites are ready for harvesting and roasting for export in south Florida, Hawaii, New Orleans, Auburn, Mississippi, etc. Perhaps in some distant future a doctor will say, “Take two powdered termites and some Vitamin C, and call me in the morning.”


The Mysteries of Colony Collapse

May 15, 2014

COLONY COLLAPSE DISORDER (CCD) of honey bees is one of the lingering mysteries of early 21st Century science in more ways than one: from its microbial, immune system and genetic components to an amorphous almost Orwellian terminology as imprecise and ambiguous as climate change (a slogan wide enough to encompass warming up, cooling down, and even staying the same temperature while the numbers fluctuate around the mean or average). The ambiguous language says both nothing and everything simultaneously, though underlying CCD is a quest for as yet unknown changes in insect rearing circumstances that will produce non-collapsing honey bee colonies. During the 19th century (1800s), a century marked by worldwide famines in the the old colonial empires and phylloxera-ravaged wine-grape vineyards collapsing in France, a revolution in modern medicine was being birthed in the mysteriously collapsing silkworm colonies. Fortunately for lovers of silk fabrics, fashion and textiles, 19th century silkworm farmers had the services of the real-life scientific Sherlock Holmes of the era, the famous French freelance scientist and sometime entomologist, Louis Pasteur.

Pasteur had a knack for solving applied problems like fermentation (beer, wine, vinegar) and silkworm colony collapse, and then using the results to develop broader theories like germ theory, which taught modern doctors to wash their hands and sterilize their instruments so as to stop spreading the germs that commonly killed their patients. How Pasteur almost single-handedly accomplished so much more than whole scientific institutes seemed able to do in the 20th century was the subject of an illuminating mid-20th century book, Louis Pasteur Free Lance of Science, by French-borne microbiologist Rene Dubos. “Toward the middle of the nineteenth century a mysterious disease began to attack the French silkworm nurseries,” wrote Dubos. “In 1853, silkworm eggs could no longer be produced in France, but had to be imported from Lombardy; then the disease spread to Italy, Spain and Austria. Dealers procuring eggs for the silkworm breeders had to go farther and farther east in an attempt to secure healthy products; but the disease followed them, invading in turn Greece, Turkey, the Caucasus–finally China and even Japan. By 1865, the silkworm industry was near ruin in France, and also, to a lesser degree, in the rest of Western Europe.”

“The first triumphs of microbiology in the control of epidemics came out of the genius and labors of two men, Agostino Bassi and Louis Pasteur, both of whom were untrained in medical or veterinary sciences, and both of whom first approached the problems of pathology by studying the diseases of silkworms,” wrote Dubos, who between World Wars I and II worked at the League of Nations’ Bureau of Agricultural Intelligence and Plant Diseases as an editor of the International Review of the Science and Practice of Agriculture. “A disease known as mal del segno was then causing extensive damage to the silkworm industry in Lombardy. Bassi demonstrated that the disease was infectious and could be transmitted by inoculation, by contact, and by infected food. He traced it to a parasitic fungus, called after him Botrytis bassiana (since renamed Beauveria bassiana, a widely used biocontrol agent)…An exact understanding…allowed Bassi to work out methods to prevent its spread through the silkworm nurseries. After twenty years of arduous labor, he published in 1836…Although unable to see the bacterial agents of disease because of blindness, Bassi envisioned from his studies on the mal del segno the bacteriological era which was to revolutionize medicine two decades after his death.”

Chemist Jean Baptiste Dumas, Pasteur’s mentor, prevailed upon the reluctant free lance scientist to head a mission of the French Ministry of Agriculture. “Although Pasteur knew nothing of silkworms or their diseases, he accepted the challenge,” wrote Dubos. “To Pasteur’s remark that he was totally unfamiliar with the subject, Dumas had replied one day: ‘So much the better! For ideas, you will have only those which shall come to you as a result of your observations!’”

A way of life was also at stake. As described in 19th century France by Emile Duclaux, Pasteur’s student and intimate collaborator (in Dubos’ book): “…the cocoons are put into a steam bath, to kill the chrysalids by heat. In this case, scarcely six weeks separate the time of egg-hatching from the time when the cocoons are carried to market, from the time the silk grower sows to the time when he reaps. As, in former times, the harvest was almost certain and quite lucrative, the Time of the Silkworm was a time of festival and of joy, in spite of the fatigues which it imposed, and, in gratitude, the mulberry tree had received the name of arbre d’or, from the populations who derived their livelihood from it.”

“The study of silkworm diseases constituted for Pasteur an initiation into the problem of infectious diseases,” wrote Dubos, who was influenced by the famous Russian soil microbiologist, Serge Winogradsky, who favored studying microbial interactions in natural environments rather than in pure laboratory cultures. “Instead of the accuracy of laboratory procedures he encountered the variability and unpredictability of behavior in animal life, for silkworms differ in their response to disease as do other animals. In the case of flacherie (a disease), for example, the time of death after infection might vary from 12 hours to 3 weeks, and some of the worms invariably escaped death…Time and time again, he discussed the matter of the influence of environmental factors on susceptibility, on the receptivity of the ‘terrain’ for the invading agent of disease. So deep was his concern with the physiological factors that condition infection that he once wrote, ‘If I had to undertake new studies on silkworms, I would investigate conditions for increasing their vigor, a problem of which one knows nothing. This would certainly lead to techniques for protecting them against accidental diseases.’”

“Usually, the public sees only the finished result of the scientific effort, but remains unaware of the atmosphere of confusion, tentative gropings, frustration and heart-breaking discouragement in which the scientist often labors while trying to extract, from the entrails of nature, the products and laws which appear so simple and orderly when they finally reach textbooks and newspapers,” wrote Dubos. “In many circumstances, he developed reproducible and practical techniques that in other hands failed, or gave such erratic results as to be considered worthless. His experimental achievements appear so unusual in their complete success that there has been a tendency to explain them away in the name of luck, but the explanation is in reality quite simple. Pasteur was a master experimenter with an uncanny sense of the details relevant to the success of his tests. It was the exacting conscience with which he respected the most minute details of his operations, and his intense concentration while at work, that gave him an apparently intuitive awareness of all the facts significant for the test, and permitted him always to duplicate his experimental conditions. In many cases, he lacked complete understanding of the reasons for the success of the procedures that he used, but always he knew how to make them work again, if they had once worked in his hands.”

Though famed for disproving the spontaneous generation of life, immunization via attenuated living vaccines and the germ theory of infectious disease: “Pasteur often emphasized the great importance of the environment, of nutrition, and of the physiological and even psychological state of the patient, in deciding the outcome of the infectious process,” wrote Dubos. “Had the opportunity come for him to undertake again the study of silkworm diseases, he once said, he would have liked to investigate the factors which favor the general robustness of the worms, and thereby increase their resistance to infectious disease…A logic of Pasteur’s life centered on physiological problems is just as plausible as that which resulted from the exclusive emphasis on the germ theory of contagious disease.”

The 21st century is riddled with insect colony conundrums and mysteries. For example, why among the social insects are honey bees plagued by Colony Collapse Disorder, while “Colony Expansion Disorder” prevails for other social insects in the USA. Rather than collapsing, USA colonies of Argentine ants are forming “super-colonies,” and red imported fire ant colonies are growing stronger by the day and annually expanding their North American geographic range; this despite being deliberately dosed with pesticides and attacked by biocontrol organisms (perhaps even more so than the beleaguered honey bees). And quite independently of mortgage rates and housing sales, Formosan subterranean termite colonies damaging billions of dollars of USA housing stock are happily munching away at both live trees and “dead-tree” wooden housing assets with little collective danger of colony collapse, though individual colonies come and go.

Perhaps beekeeping and crop pollination would be easier if Colony Collapse Disorder were an actual “disorder” as defined by the Diagnostic and Statistical Manual of Mental Disorders (DSM), and honey bees were endowed with sufficient consciousness and behaviors amenable to bee psychology or psychiatry.

The very real plight of honey bee colonies or hives is still in what Dubos would call the “atmosphere of confusion, tentative gropings, frustration.” At the most recent Entomological Society of America annual meeting, roughly a century and a half after silkworm colony collapse was eliminated by better more sanitary rearing practices, honey bee health was still puzzling. Honey bee colony loss in Virginia increased to 30% from 5-10% in recent years, possibly due to disease pathogens, pesticides and immune system suppression, say Virginia Tech researchers (e.g. Brenna Traver) studying glucose oxidase (GOX), an indicator of immunity in social insects. Honey bee social immunity is complex, involving factors as diverse as pheromones and grooming, and honey bee production of hydrogen peroxide (H2O2), which sterilizes food for the colony.

Nosema ceranae, a global gut pathogen, was seen all around the USA in 2007 at the same time as Colony Collapse Disorder. Black queen cell virus is another culprit, along with deformed wing virus, which is spread among honey bees by varroa mites. Then it is hard to overlook that over 120 different pesticides and their metabolites have been found in honey; including common beekeeper-applied pesticides such as coumaphos, fluvalinate, chlorothalonil and the antibiotic fumagillin. At the University of Puerto Rico, Gloria Dominguez-Bello is testing oxytetracycline and other commonly used antibiotics for their effects on honey bee microbes similar to those known to affect everything from obesity and brain function to organ transplants.

Those familiar with Pasteur’s entomological research on silkworm colony collapse in the 1800s would have experienced a sense of deja vu at the most recent Entomological Society of America meetings listening to Gloria DeGrandi-Hoffman, a research leader at the USDA-ARS Carl Hayden Bee Research Center in Tucson, Arizona. Nutrition, stress and pesticides may indeed be involved, but more focus is warranted for honey bee microbial health and gut microbes. Honey bee nutrition and microbiology is complicated by seasonal variations with changing food sources. According to DeGrandi-Hoffman, a lack of beneficial microbes may set honey bees up for infectious diseases like chalkbrood.

For example, pesticides used for Varroa mite control and potent beekeeping antibiotics like thymol and formic acid can affect the Lactobacillus microbes bees need for digestion and preservation of pollen as beebread, said DeGrandi-Hoffman. When bacterial plasmids found in high numbers in beebread are plated with the pathogen Aspergillus flavus, the pathogen rapidly loses virulence.

It is likely honey bees rely on beneficial microbes to protect from harmful pathogens, as honey bees have among the fewest immune system genes of any insect. Thus, when California almond growers spray fungicides, insecticides and miticides, a side effect could be fewer beneficial microbes in honey bee guts and in beebread. Thus, the honey bees would be less healthy and more susceptible to diseases like chalkbrood. Probiotic supplements designed to add beneficial microbes to honey bee diets are being tested in some California orchards. No doubt a familiar concept to those shopping for probiotic yogurts.