Natural Nicotine Heals Honey Bees

January 23, 2017

NEONICOTINOID INSECTICIDES (e.g. thiamethoxam, imidacloprid, clothianidin) developed at Bayer Japan as safer alternatives (e.g. to human spray applicators) to the natural nicotine once widely used by farmers and gardeners, is now suspected of contributing to honey bee health problems like learning disorders and colony collapse. In contrast, natural nicotine, found in honey produced by bees working tobacco fields, as well as in pollen, nectar, leaves and other plant parts, is a nutrient and medicine helping to heal weak honey bee colonies, said Susan Nicolson of South Africa’s University of Pretoria at “Entomology Without Borders,” a joint meeting of the International Congress of Entomology (ICE) and the Entomological Society of America (ESA) in Orlando, FL.

Natural nicotine, even if produced organically in a sustainable recycling sort of way from tobacco waste products, is mostly shunned in organic farming and gardening. “Over 120 million sites will be returned on a web search on tobacco, but most will not be associated with plant science,” wrote USDA-ARS researcher T.C. Tso in Tobacco Research and Its Relevance to Science, Medicine and Industry. “Many plant scientists in academic institutions cannot obtain grant support for projects using tobacco as a research tool. Some even have to avoid tobacco because of the applying of ‘political correctness’ to academic research. The tobacco plant has served as a valuable tool since the dawn of plant and biological sciences, so it is indeed a great loss to scientific progress that a research tool already invested with so many resources and about which there is such abundant knowledge and such great potential for new advancement is now being wasted.”

Honey bees readily consume bitter alkaloids such as nicotine mixed in sugary plant nectars. Adult honey bees excel at detoxifying alkaloids such as nicotine, which should not be surprising, as survival depends on it. Younger, larval honey bees have fewer enzymes to detoxify nicotine, but also survive quite well even when their royal jelly contains high levels of nicotine. Honey bees and insects immune to nicotine, such as green peach (peach-potato) aphids, transform nicotine into less toxic butanoic acid. A knotty question naturally arises: If natural nicotine heals honey bees, why are synthetic neonicotinoids so terribly different? Are natural compounds like nicotine inherently more beneficial and their synthetic analogs (e.g. neonicotinoids) inherently bad, perhaps due to subtle differences in molecular structure? If bees and other pollinators are a major concern, perhaps natural product restrictions on nicotine need to be relaxed to provide competition to the synthetic neonicotinoids.

“Alkaloids, especially in the nicotine family, have been the main focus of tobacco research because alkaloids are the characteristic product of tobacco,” writes Tso. Dozens of other tobacco molecules are relatively overlooked, including sugar compounds providing least-toxic botanical insect and mite control. Anabasine (neonicotine), an alkaloid found in tobacco and other plants, has also been widely used as a natural insecticide. Strangely enough, anabasine is also an insect attractant and a poison gland product of Aphaenogaster ants. In a strange urban twist to the wild bird practice of lining nests with medicinal herbs emitting essential oils counteracting parasites: Researchers in Mexico discovered urban birds lining nests with cigarette butts to similar advantage. In times past, organic gardeners soaked cigarette butts in water to get a nicotine spray brew. Historically, most commercial nicotine insecticide used on farms and gardens was a sustainable tobacco waste extract.

There are 60-80 described tobacco or Nicotiana species, some available in seed catalogs and grown as ornamentals. Most Nicotiana species grow wild in the Americas, with some in Australia and Africa. “Tobacco plants are easy to grow and have a short growing period,” writes Tso. “Each tobacco plant may produce 14 g or about 150,000 seeds which may provide seedlings for 2 to 5 acres (1–3 ha) of field tobacco, depending on the type.” In Europe, oil extracted from tobacco seeds is being explored for an alternative bio-diesel fuel industry, with dry leftovers as animal feed.

Native American Nicotiana species are being integrated into China’s ancient agricultural interplanting tradition. When tobacco is interplanted in vineyard rows, tobacco roots and grape roots intermingle. Perhaps some sort of biological soil fumigation occurs. Whatever the mechanism, vineyards are cleansed of soil-dwelling phylloxera aphids, a pest that almost destroyed wine grape growing in France in the 1800s and is still a worldwide problem. According to the journal Chinese Tobacco Science, intercropping tobacco with sweet potato also alleviates soil and other pest problems, maximizing profits per unit area of land. Burley tobacco is intercropped with cabbage and other vegetable crops, according to the Journal of Yangtze University (Natural Science Edition).

Neonicotinoids are soluble in water and absorbed systemically by plants, and some are sprayed on urban lawns and landscapes. However, over 80% of synthetic neonicotinoids are applied to seeds prior to planting hundreds of millions of acres of corn, soybean, sunflowers and other crops. In Canada’s Ontario and Quebec provinces, 100% of corn seed is treated with neonicotinoids, said Nadejda Tsvetkov of Toronto’s York University at “Entomology Without Borders.” Though neonicotinoids were seldom found in corn pollen samples, somehow, perhaps by water transport, neonicotinoids are finding their way into clover and willow tree pollen far from corn fields.

“For a lot of farmers it is hard to get seeds untreated, especially corn,” as commercial seed is routinely treated with neonicotinoids regardless of need, said the University of Maryland’s Aditi Dubey at “Entomology Without Borders. In Maryland and other mid-Atlantic USA states where low pest pressures are the norm, neonicotinoid seed treatments are both unneeded and counterproductive. In 3-year Maryland rotations with double-cropped soybeans, winter wheat and corn, sowing seeds treated with thiamethoxam or imidacloprid reduced beneficial predatory ground beetles and increased slug damage to crops. Mid-Atlantic USA farmers typically apply 4 unnecessary prophylactic seed treatments every 3 years. Besides reduced biocontrol and more pest damage, soil accumulation over time is a disturbing agro-ecosystem possibility.

Alternative seed treatments include natural plant hormones such as salicylic acid and methyl jasmonate, which induce a natural immunity called induced systemic acquired resistance (SAR). Crops such as lettuce and argula (rocket) grown from seed treated with salicylic acid and methyl jasmonate also release volatile gases repelling pests such as sweet potato whitefly, a major worldwide pest, said Ben-Gurion University’s Mengqi Zhang at “Entomology Without Borders,” a gathering of 6,682 delegates from 102 countries. Numerous botanical materials and microbes have also been investigated around the world as alternative seed treatments.

A proactive approach to honey bee and bumble bee health includes a diversified landscape sown with herbs and medicinal botanicals for self-medication, not just natural nicotine from tobacco nectar or other sources. Thymol, an essential oil found in thyme and many other plants, is already sprayed in hives by beekeepers to combat Varroa mites. At “Entomology Without Borders,” North Carolina State University’s Rebecca Irwin reported laboratory choice tests where bumble bees rejected nicotine. In field tests, bumble bees were given a choice of different colored flowers each with a different botanical such as thymol, nicotine, anabasine and caffeine. Bumble bees only selected flowers with thymol to self-medicate. Interestingly, thymol and other herbal essential oils also synergize nicotine, boosting effectiveness against disease pathogens and perhaps also minimizing the likelihood of colony collapse.

Landscapes and hedgerows sown with medicinal plants such as thyme, sunflower and foxglove minimize bumble bee disease transmission, said Lynn Adler of the University of Massachusetts, Amherst. The current USA farm bill will actually pay farmers to plant bee-friendly sunflower edges or hedgerows around canola fields. Antimicrobial and medicinal honeys derived from sunflower, bay laurel (Laurus nobilis), black locust, etc., also effectively combat bee diseases like chalkbrood and foulbrood, said Silvio Erler of Martin-Luther-Universität in Halle, Germany at “Entomology Without Borders.”

Bee pharmacology is also useful in human medicine. In Oaxaca, Mexico gangrene is stopped and wounds are healed by combining maggot therapy and honey, reported Alicia Munoz. Maggot therapy uses sterilized (germ-free) green bottle fly maggots to disinfect and cleanse wounds by eating unhealthy tissues and secreting antibiotics, allowing healthy pink tissue to grow back under honey-soaked gauze. This cost-effective approach reduces hospital stays, lowers morbidity and can eliminate the need for surgery. It may sound yucky, but for diabetics and patients with bed sores or wounds where surgery is medically impossible, a few maggots and a little honey is preferable to amputating wounded or infected limbs.

Cancer-fighting bee propolis products were touched upon at “Entomology Without Borders” by Chanpen Chanchao of Chulalongkorn University in Bangkok, Thailand, where hives of stingless bees are reared like conventional honey bees. Cardol, a major component of propolis from the Indonesian stingless bee, Trigona incisa, causes early cancer cell death by disrupting mitochondrial membranes and “producing intracellular reactive oxygen species (ROS).” ROS are essential to energy, immunity, detoxification, chemical signaling, fighting chronic and degenerative diseases, etc. Cardol “had a strong antiproliferative activity against SW620 colorectal adenocarcinoma,” killing colon cancer cells within 2 hours, followed by complete cell necrosis within 24 hours. Thus, cardol is an “alternative antiproliferative agent against colon cancer.”

Sunflower Power & Health

October 10, 2016

WITH PERHAPS 25 MILLION ha (62 million acres) of sunflowers grown for seed oil worldwide, sunflower diseases and pests and their remedies have a global impact. “Sunflower oil can be used as an alternative or additive to diesel fuel to create biodiesel, a clean-burning alternative fuel produced from a renewable resource,” wrote G.J. Seiler, one of many worldwide contributing authors to the Compendium of Sunflower Diseases and Pests, a book produced by the American Phytopathological Society (APS), a scientific group whose essence includes plant doctoring, discerning what makes for healthy versus diseased plants. “Use of the product may decrease farmers’ dependence on petroleum fuels by substituting ‘farm-grown’ fuel for use in diesel engines. For use in diesel engines, sunflower oil requires more extensive purification, including removal of waxes and gums. Minor engine modifications, such as improved fuel filters, are also necessary to burn any vegetable oil. Since the energy content of sunflower oil is less than that of diesel fuel, consumption is greater and power output is less.” However, the high-protein residues leftover from sunflower oil extraction have the right amino acid balance to mix with soybean meal to grow healthy chickens and livestock, a virtuous ecological cycling of sunflower plants.

Indeed, in Argentina’s southern Pampas, if you get the planting times right, sunflower and soybean are compatible as intercrops. Working in agriculture, I observed sunflower border rows or perimeters around conventional crop fields attracting pollinators and natural enemies providing biological control of pests. However, sunflowers are so attractive to beneficial insects that they do not want to leave. Thus, sunflower stalks need vigorous shaking to get green lacewings and natural enemies of aphids and other pests to take flight into adjacent crops needing protection. At the moment, fields of GMO canola producing high quality cooking oil are displacing sunflower fields in many areas. But the APS sunflower Compendium awakened my love for sunflowers, as even the diseases afflicting the plants have a certain beauty under the microscope. So, I can see the APS sunflower Compendium serving as an outstanding library reference for biology teachers and students looking for projects in sunflower-growing areas.

R.M. Harveson opens the APS sunflower Compendium with a brilliantly concise narrative chronicling the journey of sunflower seeds from their native North America to Russia, where innovative plant breeders painstakingly created the first modern sunflower seeds high in oils, providing the platform for today’s worldwide sunflower industry. The Mennonites, an anti-violence religious group migrating from Germany (Prussia) and a war-plagued Europe to Russia in the 1780s for free farm land promised by Catharine the Great, pioneered commercial sunflower oilseed farming in a harsh landscape long thought unsuitable for even subsistence farming. Their descendants were lured to Saskatchewan and Manitoba, Canada to create North America’s sunflower industry. During World War II, when “securing the fields of Ukraine was a major objective of Adolf Hitler’s war on Russia,” sunflower oil was a superior antifreeze, lubricating World War II weapons that froze with conventional gun oils. Joe Pappalardo’s excellent and entertaining book, Sunflowers: The Secret History: The Unauthorized Biography of the World’s Most Beloved Weed (Overlook Press) adds color and specifics, and is cited in Harveson’s “Selected References” in the APS Compendium.

Personally, I love the feel on my head and hair of a shampoo blending organic sunflower oil, citrus oils and herbs; and organic sunflower seeds at breakfast supply trace minerals like zinc, which is often deficient in produce grown in local California soils. Sunflower sap, which occasionally has been used medicinally, contains terpenoid compounds that show potential as alternative botanical pesticides. As ingredients in traditional medicines, wild sunflowers have been used for everything from wound healing and rattlesnake bites to combating infection and pain relief. Modern medical uses include topical oil formulations with sunflower oil to improve skin health, fight fungal infections, relieve inflammation and itchy, dry skin, and in dentistry to improve the gums.

Seed hulls of certain sunflower varieties are traditional sources of yellow, ruby red, purple, and black dyes or colorants (e.g. anthocyanins) useful in body painting, cosmetics, foods and textiles. Indeed, some plant breeders are working on a sunflower seed that would be high in oil and have a ruby red husk or hull that could be extracted to replace commercial synthetic red food dyes. Other researchers see the hulls as useful absorbents for wastewater reclamation. But by far, sunflower seed oils (e.g. NuSun for cooking) are the main sunflower item of commerce, and even trade on the commodities futures markets. Sunflowers seeds like Mammoth Russian for eating and snacking or adding to birdseed blends are important crops, but minor compared to the large acreages of sunflower oilseeds grown worldwide.

For various reasons, sunflowers have not become commercialized as a biotech GMO (Genetically Modified Organism) crop, which makes life easier for organic growers. Though perhaps better known from Van Gogh canvases, sunflowers were experimental subjects on the USA’s Apollo space missions. And “sunflowers have been successfully used as vehicles for the phyto-remediation of soil contaminated with heavy metals and radioactive materials (e.g. following the Chernobyl disaster),” wrote Harveson. In March 2011 after the Great East Japan Earthquake and Fukushima Daiichi Nuclear Power Plant accident, sunflowers and sunchokes were among the “alternative technology” plantings to concentrate and remove from soils radioactive cesium, which emits gamma rays and has a 30-year half life.

Sunchokes or Jerusalem artichokes, perennial sunflowers grown for edible tubers high in inulins, are sometimes recommended for diabetes and cardiovascular diseases, being associated with lowering blood sugar and cholesterol. Indeed, Jerusalem artichoke chips have been tested as a snack food alternative to potato chips for diabetics, being almost devoid of starch and fats. Several dozen other sunflower species are known, including one that is 92% pure natural rubber. Most likely sunchokes and other sunflower species including backyard ornamentals are subject to pests and diseases similar to those described in the APS Compendium.

To prevent pests and diseases, as a kind of insurance, perhaps 95% of commercial sunflower seeds are coated with neonicotinoid pesticides (e.g. thiamethoxam, clothianidin) at planting time, according to Michael Bredeson of South Dakota State University in Brookings at the 2015 joint meeting in Minneapolis of the Entomological Society of America (ESA), the American Society of Agronomy, the Crop Science Society of America, and the Soil Science Society of America. Bredeson studied 11 commercial sunflower fields, and found that “the seed treatment failed to improve yield or decrease herbivores.” In other words, quite apart from whatever effects on honey bees and beneficial organisms higher in the food chain, the neonicotinoid seed treatments are mostly a waste of resources and money. Though perhaps they do buy peace of mind for commercial sunflower growers, much like any insurance policy.

But the peace of mind bought by unnecessary early-season pesticide seed treatments may bring ecological food chain effects that cost sunflower growers more money and crop loss later in the season. The neonicotinoid pesticides may enter the food chain via plant nectar, plant tissues and predator consumption of tainted prey. Indeed, Pablo Gontijo and colleagues (2015) reported that sunflower seeds treated with thiamethoxam poisoned minute pirate bugs (Orius insidiosus), which are major predators of aphids, caterpillars, spider mites and other pests. Part of the problem is that the beneficial bugs, besides eating pests, also suck moisture directly from plants and thereby become poisoned by systemic pesticides used as sunflower seed treatments.

Likely the poisoned pirate bugs are only the tip of the proverbial iceberg. At the 2015 ESA meeting, Sirilak Lankaew from RYFCRC in Rayong, Thailand reported that cassava cuttings treated preventively with thiamethoxam provided 1-2 months cassava mealybug protection at the cost of food chain effects on beneficial insects via poisoned cassava nectar. Specifically the wasp Anagyrus lopezi, a cassava mealybug natural enemy, feed on the poisoned cassava nectar and “experience acute mortality for up to 21 days after treatment, and have significantly reduced lifespan for at least 42 days after treatment.” With 8 million farming households in Thailand growing cassava and 70% of Thailand’s small-scale farmers using neonicotinoid pesticides, there is a need for alternative technologies “fully compatible with (naturally-occurring and cost-free) biological control.” In sunflower, something like the APS Compendium to identify the potential problems is a good first step towards minimizing unnecessary pesticide treatments and developing alternative technologies.

One approach to developing sunflower soils that are disease-free and avoiding seed treatments is the opposite of crop rotation. Namely growing the crop repeatedly in the same soil so that disease organisms build up and then are destroyed by natural biological agents. It is like the predator and prey cycle, where pests buildup to high levels and even cause some damage before being opportunistically exploited and knocked down by their natural enemies. This approach, known as building a disease suppressive soil, can take a few years; and is perhaps best suited to patient organic growers with the wherewithal to weather those tough early years, and possessed of a confidence, hope or faith that the natural cycles will eventually play out. Likely the Mennonites whose experiences Joe Pappalardo recounts in his book took this route in turning the barren Ukraine, Russian and Canadian lands into productive agricultural fields in the era predating intensive chemical agriculture.

Another interesting alternative technology with ancient roots is interplanting, the idea of mixing different crops in the same fields. In Pakistan, sunflowers are being considered as a healthful alternative for local cooking oil shortages via interplanting sunflowers with the staple mungbean crop. In Florida, sunflower strips have been proven to attract honey bees and a variety of predators and parasitoids supplying natural biological pest control to adjacent organic vegetables. In China, parts of Asia and Africa, and even the Americas, sunflowers are viewed as an alternative technology to reduce herbicide use. Sunflowers provide natural weed control via shading the ground and natural herbicidal compounds (allelochemicals) toxic to some of the world’s worst weeds, such as dodder and barnyard grass. Multiple benefits if you can get rid of a weed patch, produce beneficial insects and pollinators, and harvest some seeds at the same time.

The health benefits of sunflowers will likely be a key driver for this crop in the future, though medicinal sunflower benefits are far from the cutting edge of agriculture and medical research in the genomic era. Broader medical applications may involve anti-inflammatory and cardiovascular benefits, bone health, detoxification, skin protection (e.g. from light & anti-aging) and anti-cancer effects. Applied to the skin, sunflower oil formulations may reduce bacterial and fungal infections, and are touted by some for premature newborns. In Cuba a product called Oleozon, sunflower oil treated with ozone gas, was registered in 1999 to treat fungal skin diseases (tinea pedis); and can stop bacteria and viruses resistant to multiple drugs.

Interestingly, researchers in Iran writing in the Journal of Food Science and Technology like the idea of infusing highly unsaturated oils like sunflower seed oil with raspberry or related Rubus species (e.g. blackberries) as a GRAS (Generally Recognized As Safe) alternative to preservatives like BHA and BHT. Rubus leaves add other medicinal properties to sunflower oil, “including as astringent, hypoglycemic, anti-diarrhea, anti-inflammatory agents for mucous membrane of oral cavity (mouth) and throat.” Many other oils and herbs may have medicinal value when combined with high linoleic acid sunflower oil. Time will tell.

The whole idea of plant medicines may yet return to modern medical practices for a variety of reasons. “Extended life expectancy is accompanied with an increase in age-related pathologies that include cardiovascular and neurological diseases, obesity, and cancer, conditions that are inflicting an immense pressure on health care costs and quality of life,” write researchers Andrea Doseff and Erich Grotewold at The Ohio State University and Arti Parihar in Ujjain, India, in the book, Pigments in Fruits and Vegetables (Springer, 2015). “Thus, there has been an increased interest in recognizing and understanding the mechanisms of action of active nutritional compounds with health benefits, or nutraceuticals, for the prevention and treatment of various diseases.”

The researchers in India and Ohio note that over 8,000 flavonoid chemicals beyond vitamins have been identified, including a range of anthocyanins like those in sunflowers, “which are responsible for providing colors to fruits and vegetables, and have dietary value as color additives with potential health benefits.” Over 10,000 tons per year of anthocyanins from black grapes alone are consumed every year, and this whole general category of plant pigment compounds has “uses in the prevention and treatment of inflammatory diseases including cardiovascular diseases, obesity, and cancers.” Who knows what concentrated research into sunflowers would reveal?

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.

Pollinator-Friendly Lawns: Flowers or No Flowers?

April 28, 2013

TURF is a $25 BILLION USA INDUSTRY, said Nastaran Tofangsazi of the University of Florida (Apopka, FL), a sex pheromone researcher looking to complement biocontrols like beneficial Beauveria bassiana fungi and Steinernema carpocapsae nematodes to control the browning and uneven grass growth caused by tropical sod webworm (Herpetogramma phaeopteralis) in Florida’s $9 billion worth of turfgrass. Also at the Entomological Society of America (ESA) annual meeting, Auburn University’s R. Murphey Coy noted that the USA’s 164,000 km2 (63,320 square miles) of turf is the USA’s most irrigated crop. Turfgrass irrigation consumes 300% more water than corn; plus 4.5 pounds (2 kg) of nitrogen per 1,000 square feet (93 m2).

Alabama is among the top USA turfgrass-producing states, and Auburn University researchers are looking to reduce turfgrass water, nitrogen and iron inputs by colonizing grass seeds and roots with easy to apply sprays of plant growth promoting rhizobacteria (PGPR). Blends of PGPR species such as Bacillus firmis, Pseudomonas and Rhizobium in turfgrass and cotton induce systemic resistance to pestiferous Fusarium fungi and triple parasitic wasp biocontrol of the caterpillar larvae of moth pests like fall armyworm (Spodoptera frugiperda).

Not everyone is a fan of turfgrass lawns, and before the modern chemical era lawns were more like fragrant flowery meadows. “Agricultural experts and agribusiness are bound by the idea that even land that has lost its natural vitality can still produce crops with the addition of petroleum energy, agricultural chemicals, and water…considering this form of agriculture to be advanced,” wrote Japanese agriculturist and philosopher Masanobu Fukuoka in the book, Sowing Seeds in the Desert (edited by Larry Korn).

“When I suggested that it would be a good idea to plant fruit trees to line the streets in towns and cities and to grow vegetables instead of lawns and annual flowers, so that when the townspeople were taking a walk, they could pick and eat the fruit from the roadside, people were surprisingly enthusiastic,” said Fukuoka. “When I suggested that it would be good to scatter the seeds of clover and daikon on the existing lawns so that in two or three years the clover would overcome the lawn and the daikon would take root amid the ground cover, interestingly, it was the Asian people and Asian-Americans who said they would try it right away. Most Americans would just laugh and agree with the theory, but they were cautious about putting it into practice. The reason, I believe, is that it would challenge their adherence to ‘lawn’ culture. If they cannot overcome this prejudice, there will be a limit to the growth of family gardens in the United States.”

“It seems that the main goal in the life of the average American is to save money, live in the country in a big house surrounded by large trees, and enjoy a carefully manicured lawn,” wrote Fukuoka. “It would be a further source of pride to raise a few horses. Everywhere I went I preached the abolition of lawn culture, saying that it was an imitation green created for human beings at the expense of nature and was nothing more than a remnant of the arrogant aristocratic culture of Europe…Because residential lots are large in the United States, a family vegetable garden can provide for all the food needs of a typical family, if they are willing to do the work. In Japan, a residential lot about a quarter acre would be enough to allow near self-sufficiency and provide a healthy living environment, but I learned—to my envy—that in many suburban and rural areas of the United States, people are not allowed to build houses on small lots.”

On closer inspection, modern American lawns are more often a biodiverse mixture of turfgrass and flowering plants like clover and dandelions. Kentucky bluegrass lawns may be 30% white clover, which favors native pollinators like bumblebees. Clover and dandelion flowers attract honey bees, bumble bees, parasitic wasps that kill pests, hover flies (syrphids) that eat aphids, and carnivorous rove and ground beetles eating snails, slugs, caterpillars and other pests. Nonetheless, tons of herbicides go onto USA lawns to eradicate clover and dandelions as weeds, often as part of fertilizer and insecticide mixtures.

Turf biodiversity is all well and good, but only as long as the clover and dandelion flower nectar is pure and uncontaminated by pesticide cocktails. Lawns laden with clover and dandelion flowers provide bees and beneficial insects with “a big gulp of nectar,” the University of Kentucky’s Jonathan Larson told the ESA annual meeting in Knoxville, Tennessee. When those “big gulps of nectar” are laced with certain neonicotinoid pesticides, the effects can ripple through the ecological food chain.

When turfgrass pesticide labels say, ‘Don’t treat flower heads,’ “Follow the label to the letter of the law” to avoid poisoning pollinators, said Larson. Or get rid of the flowering plants in the lawn by mowing the turf before spraying. Or delay pesticide sprays until after clovers, dandelions and other lawn flowers have finished flowering. Clover control in lawns using herbicides is difficult, and usually not feasible, Larson told the ESA. Hence, mowing is the preferred strategy for removing flowering lawn weeds before spraying pesticides.

In enclosure experiments with tents confining bees in the turf, mowing the turf before pesticide treatment mitigated the problem, resulting in more bees and more honey. In 2012, bees were tented on clothianidin-treated turf for 6 days and then moved for 6 weeks to a Lexington, Kentucky, horse ranch with unsprayed turf. Clothianidin reduced the rate of bumble bee weight gain, but at the end of 6 weeks the bees were starting to catch-up. But overall, the 6-day pesticide exposure still resulted in reduced bumble bee weight gain, less foraging and reduced queen and hive reproduction several weeks later. Chlorantraniliprole, which has a different mode of action (muscular), did not produce these adverse effects. Larson also told the ESA that clothianidin, a widely used neonicotinoid turf pesticide, also reduces decomposers (detritivores) like soil-dwelling earthworms and springtails more than chlorantraniliprole.

Besides supporting more soil life, more biocontrol organisms, and healthier crops of pollinating bees, you get a healthier turfgrass lawn if you do not need pesticides and do not have to mow so often. “Mowing height is an easily manipulated cultural practice that can have an impact on ecological conditions,” Samantha Marksbury from the University of Kentucky, Lexington, told the ESA. “Taller grass usually supports a more diverse ecosystem and increases natural enemies. Increasing cutting height stimulated deeper roots, yielding a healthier turf with less need for insecticide. Higher mowing height decreases need for irrigation and the canopy prevents water loss.”

Taller turf (raised mowing height) also tends to be more robust and more tolerant of white grubs. Nevertheless, about 75% of turf is lush residential monocultures (mostly one grass species) that is heavily fertilized, dosed with chemical herbicides and frequently mowed, Emily Dobbs of the University of Kentucky, Lexington, told the ESA. However, the ecology of grass cutting or mowing gets quite complex and has seasonal variations. In May, turf with a low mowing height (2.5 inches; 6.4 cm) was hotter, drier, and had the most predatory ground beetles, rove beetles and spiders. Later in the season and Sept/Oct, turf with a higher mowing height (4 inches; 10.2 cm) was cooler, wetter, and had the most predators.

Historically, in the Middle Ages in England, going back many centuries (even before Chaucer) before the age of chemical farming and gardening, lawns were “flowery meads” with roses, violets, periwinkles, primroses, daisies, gillyflowers and other colorful, fragrant flowers interplanted right into the turf. The idea of planting a lawn with one species of grass made no sense, though a camomile lawn or plot came into being for infirmary gardens in England after 1265, as this medicinal aromatic plant helped other plants growing nearby in poor soils and grew faster the more it was trodden.

“There were no flower-beds of the sort familiar to us,” wrote Teresa McLean in her 1981 book, Medieval English Gardens. “The simplest type of flower garden was the flowery mead, wherein low-growing flowers were planted in turf lawns, sometimes walled, sometimes left open, to make a beautiful domestic meadow. The flowery mead was the locus amoenus of God’s beautiful world.”

“Trees were often planted in raised turf mounds, surrounded by wattle fences, which doubled as seats,” wrote McLean. “Medieval lawns, unlike modern ones, were luxuriously long, and full of flowers and herbs; they were fragrant carpets to be walked, danced, sat and lain upon. What modern lawn could find a poet to write about it as Chaucer wrote about the one in the Legend of Good Women?

Upon the small, soft, sweet grass,
That was with flowers sweet embroidered all,
Of such sweetness, and such odour overall…”

Native Bees Pick Up Pollination Slack (Combating Colony Collapse)

May 3, 2012

HONEY BEE COLONY COLLAPSE Disorder (CCD) is a murky headline catch phrase, a scientific-sounding term that is almost a euphemism, to describe a population decline. In other words, there are fewer honey bees than there used to be, which is bad for agricultural crops dependent upon these domesticated insects for pollination.

Why a population decline is called a “disorder” is a bit beyond me, though it sounds almost clinical or medical. Perhaps that is the point; and calling it a disorder makes it a more respectable object of study and aids in obtaining funding and public support for research and finding a remedy. The declining human populations in Russia, Italy, Germany, Japan and other developed countries are not called a disorder; which perhaps implies an underlying value judgment. Might be nice to discover a Bed Bug Colony Collapse Disorder (BBCCD) to give cause for celebration. Though the acronym BBCCD in the Google search engine would confusingly yield CDs from the British Broadcasting Corporation (BBC).

Wikipedia makes it sounds like honey bees are being kidnapped: “Colony collapse disorder (CCD) is a phenomenon in which worker bees from a beehive or European honey bee colony abruptly disappear. While such disappearances have occurred throughout the history of apiculture, the term colony collapse disorder was first applied to a drastic rise in the number of disappearances of Western honey bee colonies in North America in late 2006…” If such occurrences have been happening throughout history, then the “disorder” sounds more like normality. In any case, times are tougher for those relying upon domesticated honey bees for crop pollination.

The interesting flip side of honey bee colony collapse disorder is the almost metaphorical return of the natives: Really a rediscovery and new appreciation of overlooked native pollinators like North American squash bees, digger bees, miner bees, sweat bees, bumble bees, and syrphid flies.

Whether you call it a disorder or a population decline: Nature abhors a vacuum or an empty ecological niche, like an absence or paucity of pollinating honey bees in a flowering agricultural ecosystem. Niches tend to get filled in nature, though the process may take years. With fewer honey bees (Apis mellifera is an introduced species in the Americas) in the fields, native bees hitherto ignored or overlooked are taking over the pollination chores on certain crops, according to research presented at Entomological Society of America (ESA) meetings.

“Nearly 4,000 species of native bees are found in North America,” said the University of Kentucky’s Amanda Skidmore. Integrated Pollination Management (IPM) or Integrated Crop Pollination, jargon phrases that sometimes popup at meetings, refers to managing crop ecosystems as habitats for native pollinators.

“In order to best utilize bees as pollination service providers, agro-ecosystems must be managed to attract and sustain them based on their natural history biological requirements,” Skidmore told the ESA. These habitat requirements include “energy (nectar), larval food proteins (pollen), and protected nesting sites (i.e. untilled earth, nesting boxes, dead plant matter).”

Native long-horned bees (Melissodes bimaculata) take up some of the slack from depleted honey bee populations in Kentucky by pollinating squash, melon and vegetable crops. Sweet alyssum (white-flowered variety), a flower interplanted in agricultural crops to promote biological control of pests by natural enemies, was heavily favored by the native pollinators; along with bee balm (Monarda didyma) and wood sage (Teucrium canadense). The idea is to plant a succession of flowering resources, including native wildflowers, shrubs and trees, to sustain native pollinators from very early season to late season. Research on habitat plantings is on-going.

Native North American sweat bees (Halictidae) and digger or mining bees (Andrenidae) are abundant pollinators of Michigan’s important blueberry crop in some locales, Michigan State University researcher Rufus Isaacs told the ESA. Nearby meadows “grow” sweat bee populations that move into blueberries to provide pollination services. Well-drained soils mean more nesting habitat for digger or mining bees that also pollinate blueberries. Several dozen wild native annual and perennial plants with varied bloom periods are being test-grown near Michigan blueberries to determine which best boost native bee populations and reduce the need for honey bee pollination.

Similar strategies for adding habitat for native pollinators are also being researched in crops as diverse as apples, cherries, squash and watermelons in regions as far-flung as Florida and California.

Earthworm Compost, Medicinal Honey & Fewer Hive Sprays Avert Bee Collapse

April 4, 2012

HONEY BEE COLONY COLLAPSE DISORDER and subtle learning and memory pesticide effects were among Biocontrol Beat topics detailed in Feb. 2011 (Honey Bees, 24-Hour Surveillance Cameras & Pesticides). For many attendees of Entomological Society of America (ESA) annual meetings, the two reports on pesticide effects on honey bees and bumble bees in the 30 March 2012 issue of Science magazine were just two more data bits, nothing particularly surprising; albeit good headline news fodder and a bit troubling. Perhaps a slight feeling of déjà vu for those familiar with Rachel Carson and her book of more than half a century ago, Silent Spring.

To imbibers of energy-boosting, nervous system stimulants like coffee, tea, and the many other caffeinated beverages flooding the marketplace, the idea that a common natural (e.g. botanical) or synthetic chemical might affect behavior is almost a no-brainer, though not necessarily self-evident. Caffeine has gone from fruit fly studies to mosquito control remedy recently. Natural nicotine from tobacco family plants has had almost an opposite trajectory, having once been widely used (e.g. burned as a fumigant) and recommended (e.g. soaking cigarette butts in water) for pest control in agriculture, greenhouses, and organic gardens; and now shunned because of its toxicity to humans and beneficial insects.

Neonicotinoid pesticides, like the widely used imidacloprid, had their design inspiration in natural nicotine molecules; but are safer to humans and other animals. But perhaps not totally without adverse effects, if indeed it is possible to have a substance that is toxic and yet totally safe. The Science reports associate neonicotinoid chemicals like imidacloprid with reduced bumble bee colony size and queen production, as well as lower honey bee survival and foraging success.

Though the scientific data will be subjected to further debate and future studies may confirm or refute the results, Science magazine writer Erik Stokstad, in an accompanying news and analysis, marshaled a stunning statistic to go with the reports: “In the United States alone, 59 million hectares of crops are protected by systemic pesticides. Seeds are treated with these neurotoxins before planting, and the poison suffuses the tissues, pollen, and nectar…”

Nonetheless, as ESA annual meeting habitués may know: genetics, pathogens, parasites, and beekeeper practices apparently also figure into the still mysterious honey bee Colony Collapse Disorder (CCD). Perhaps aptly for a confusingly mysterious disorder, CCD, the acronym for Colony Collapse Disorder, is confusingly the same as the Community College of Denver, charged-coupled devices (like those capturing images in digital cameras), Confraternity of Christian Doctrine, and The Convention Centre Dublin, to mention but a few highly-ranked “CCD” terms in Google.

Those who put their faith in scientific panels, better testing, and more government regulation will be heartened to know that Stokstad says more is on the way in Europe and the USA. Those wanting to do something practical right now to help the honey bees and native bumble bees pollinating their backyards and fields might find more encouragement in some of the presentations coming out of the Entomological Society of America (ESA) annual meetings.

For example, North Carolina State University soil ecologist Yasmin Cardoza, who has shown that earthworm compost produces plants more resistant to caterpillar pests and aphids, more recently told the ESA that amending a cucumber soil (model system) with earthworm compost (vermicompost) helped bumble bees and other native pollinators become heavier, healthier, and more fecund.

Cucumber plants grown in soils amended with earthworm compost had flowers (pollen, nectar) with significantly more protein and a bit more sugar. These more nutritious flowers grown with earthworm compost attracted more bumble bees and native pollinators. Plus the bumble bees had more and larger ovary cells and egg tubes (i.e. an indication of enhanced reproduction), weighed more, and had fewer disease pathogens. Whether earthworm compost can reverse or prevent Colony Collapse or create Colony Expansion would make for an interesting study.

Beekeeping methods also take a hit for exacerbating honey bee problems; and are illustrative of how mites, insect pests and pesticides make for the type of challenging problem that in previous centuries were solved by privately-funded freelance scientists like Louis Pasteur. Pasteur’s freelance entomological endeavors included almost single-handedly rescuing the nineteenth-century silk industry from a similar mysterious collapse of silkworm colonies (insect colonies seem particularly prone to epidemic collapse when you want them; but resistant to collapse when you would rather be rid of them, like termite and fire ant pests). Rene Dubos’ account in his 1950 book, Louis Pasteur Free Lance Of Science, is well worth reading for free on the Internet (pdf, Kindle versions). By early twenty-first century standards, Pasteur seems almost like a Rambo of science, accomplishing with a few assistants what would seem impossible today.

Even if the cause of honey bee colony collapse is still mysterious, like silkworm colony collapse was prior to Pasteur, there is no doubting the reality of the problem.

“In Virginia, the number of managed honey bee colonies have declined by about 50% since the late 1980s due to the introduction of parasitic mites,” Virginia Techie (Blacksburg, VA) Jennifer Williams told the ESA. “Excessive reliance” on fluvalinate (a pyrethroid miticide) and coumaphos (an organophosphate miticide) have “been implicated in numerous problems to honey bees, including impaired reproductive physiology, reduced ability of colonies to raise queens, reduced sperm viability in drones (males), and increased queen failure and loss.” Often these miticides are found in combination with imidacloprid (systemic insecticide), chlorothalonil (broad-spectrum fungicide), and the broad-spectrum antibiotics oxytetracyline and streptomycin used by beekeepers to combat American foulbrood disease in honey bee hives.

Fluvalinate, coumaphos, coumaphos-oxon, and chlorothalonil are found in almost half of North American honey bee colonies at ppb (parts per billion) levels that can be acutely toxic. Combining miticides, pesticides, and antibiotics is a toxic cocktail recipe boosting honey bee mortality 27-50%, according to Williams. In other words, it is a vicious circle in which beekeeping practices (e.g. miticides, antibiotics, substituting sugar water for honey) may have deleterious effects offsetting curative effects on already weakened and mentally confused bees feeding on plants treated with pesticides rather than healthy composts like those being studied by Cardoza.

As if honey bees did not have enough health problems, the small hive beetle (Aethina tumida) is now part of the mix. “In their native range in South Africa, these beetles cause relatively little damage,” Natasha Wright of the University of Arkansas told the ESA. “However, they can be destructive to honey bee colonies in the United States and Australia. The adults and larvae feed on bee brood and bee products. They also cause honey to ferment, which results in unsellable honey. Little is known about the biological control agents.”

“Identifying new mechanisms that support honey bee health will be pivotal to the long-term security and productivity of American agriculture,” Emory University’s Lydia McCormick told the ESA. “Hydrogen peroxide is a potential natural defense/stress response to small hive beetle,” a pest which can devastate a honey bee colony in weeks or months. Not to knock beekeepers, who have enough problems already, but their practice of feeding bees sugar water rather than honey laced with hydrogen peroxide may be part of the problem. Honey bees produce more hydrogen peroxide in their honey to combat stressors like the hive beetle.

“Extremely low concentrations of hydrogen peroxide in sugar-water fed samples may represent a problem in this common method of hive management,” said McCormick. “Honey bees may selectively regulate higher brood honey hydrogen peroxide as a strategic oxidant defense. Given that brood cells contain honey bee larvae, high honey hydrogen peroxide may help protect against pests.” Indeed, small hive beetle survival is lower with hydrogen peroxide in the honey.

Honey containing hydrogen peroxide has been marketed for its antibacterial, wound healing, and skin care potential; and prescriptions for medical-grade honey are a possibility. New Zealand professor Peter Charles Molan published an interesting historical review on honey for wound healing in 2001. Besides hydrogen peroxide, honey may have healing botanical compounds (phytochemicals). Perhaps the bee’s loss is humankind’s medical gain. Though if the bees are lost as pollinators in the process, it is not a sustainable practice in the longer-term.

Moth-Eye Reflections

September 8, 2011

“ANTI-REFLECTION MOTH-EYE ARRAYS are now widely applied in panels of instruments, like cellphones and in window panes,” wrote Doekele G. Stavenga of the Department of Neurobiophysics at the University of Groningen (The Netherlands) in Functional Surfaces in Biology -Little Structures With Big Effects, Volume 1. The editor, Stanislav Gorb of the University of Kiel (Germany), thanked senior publishing editor Zuzana Bernhart (Plant Pathology and Entomology; Springer, Holland) for her “belief in this topic and her personal help.” Bernhart said that a big dose of the inspiration for the two book volumes came from what have become regular symposia on insect-inspired innovations at the Entomological Society of America (ESA) annnual meetings.

At nanotechnology events, insects and entomology are acknowledged frequently as inspiration. For example, at the California NanoSystems Institute on UCLA’s campus, Tomohide Takami, a researcher visiting from the Division of Quantum Phases and Devices at Konkuk University (South Korea), said “we have fabricated a bio-mimetic probe called ‘nano-mosquito’…to explore nano-world.” In a prior lecture Xiaodong Chen visiting from Nanyang Technological University (Singapore) noted: 1) energy storage devices, lightweight aerospace materials, and self-assembly inspired by diatoms and honey bee honeycombs; 2) Singapore’s waterfront Esplanade Theatres on the Bay is an architectural shape perhaps inspired by fly eyes and tropical fruit (durian); 3) moth eyes that are anti-reflective (so enemies do not see the glint of their eyes) and provide better vision at night and in fogs inspire solar cells that harvest more light.

“Anti-reflective moth-eye arrays could produce up to 12% more energy than those employing single layer anti-reflective coatings,” via “a reduction of up to 70% of the light reflected from the surface,” said Stuart Boden and Darren Bagnall of the University of South Hampton (UK) in their poster display (“Bio-mimetic nanostructured surfaces for near zero reflection from sunrise to sunset”). Via electron beam lithography and dry etching (subwavelength): “We have fabricated a range of moth-eye arrays in silicon. Reflectance measurements confirm the low reflectivity of these arrays over the visible and near infra-red wavelengths, making them excellent candidates for reducing reflection on solar cells.”

“Insects have facetted, compound eyes, consisting of numerous anatomically identical units, the ommatidia,” wrote Doekele Stavenga and his colleagues in the Proceedings of the Royal Society B (22 March 2006. 273(1587):661-667), a journal whose roots date back over 200 years to London in 1800. Back in the 1960s, researchers discovered that the outer surfaces of moth eyes had “an array of cuticular protuberances termed corneal nipples” which reduce light reflection to 1%. Thus, moth night vision is improved by allowing 99% of light to enter moth eyes. Fewer reflections or less glint from the eyes makes moths harder for predators to detect. [Moth defenses against bat echo-location is another story, for another time]

“Moths thus realize a much higher light sensitivity than butterflies, allowing a nocturnal instead of diurnal (daylight) lifestyle,” wrote Stavenga et al. “A moth with large, glittering eyes will be quite conspicuous, and therefore its visibility is reduced by the eye reflectance decreasing… The insight that nipple arrays can strongly reduce surface reflectance has been widely technically applied, e.g. in window panes, cell phone displays and camera lenses.”

Moth-eye antireflection coatings (ARCs), “which are inspired by the grainy microstructures on the corneas of moths consisting of a non-close-packed hexagonal array of conical nipples, can suppress reflection over a broader range of wavelengths and wider angles of incidence than traditional multilayer dielectric ARCs,” wrote Chih-Hung Sun and other chemical engineering colleagues at the University of Florida, Gainesville, in an article titled “Large-scale assembly of periodic nanostructures with metastable square lattices.”

Moth-eye ARCs, reported Sun et al., “are widely utilized in eliminating the “ghost images” for flat-panel displays, increasing the transmittance for optical lenses, improving the out-coupling efficiency of semiconductor light emitting diodes, and enhancing the conversion efficiency of solar cells.”

“Since all biological structures are multifunctional, it makes them even more interesting,” wrote Stanislav Gorb in his introduction to the Springer book, Functional Surfaces in Biology. “Small surface structures at the micrometer and nanometer scales (i.e. very very small) are often vitally important for a particular function or a set of diverse functions…Because of the structural and chemical complexity of biological surfaces, exact working mechanisms have been clarified only for some systems.”

Some other possible innovations from the micro-world described in the Springer book: Protective slime coatings that protect seeds from rotting (e.g. pathogens) and stimulate or inhibit seed germination as needed. Water-repellent hairs have been “invented” by spiders. Water bugs can inspire waterproofing, anti-submersion fabrics, and surfaces promoting water runoff. Self-cleaning plant surfaces that cause water to form spheres and roll off are inspiration for water-repellent surfaces that might also trap air underwater for breathing. The plant world’s system of water transport pipes (xylem) can yield ideas for water transport systems. Feather microstructures could inspire aerodynamic innovations to complement lessons learned from insect flight.

We have barely scratched the surface of the ingenious natural world that we inhabit and share.