Five things everyone should know about… Sloths

1) A sloth is not a sloth. There are two types of tree sloths that diverged roughly 20 million years ago—two-toed and three-toed sloths, so named for the number of digits on their forelimbs. They differ greatly in what they eat, when they’re active, the trees they use, how far they move and even their mating systems. In a nutshell, two-toed sloths are generalists, using a wide variety of habitat types and resources, while the three-toed sloth is much more specialized, eating leaves from just a few species of trees, and even spending the majority of their lives in just a few individual trees.

2) They are extremely low-energy. Both types of sloths have slow metabolisms, but the three-toed sloth has the lowest energetic needs of any mammal ever recorded. Sloths achieve this by not moving very much, and also by letting their body temperatures fluctuate with outdoor temperatures. In terms of calories, a single potato is all a three-toed sloth would need each day to survive (if sloths actually ate potatoes).

3) Constipation is a way of life. Sloths consume plenty of fiber in the form of leaves (three-toed sloths) and a variety of leaves and fruits (two-toed sloths). Yet these foods are digested so slowly that sloths need to pass feces and urine only about once a week. Three-toed sloths climb down to defecate at the base of their host trees—practically the only time they leave the canopy.

4) The sloth is a miniature ecosystem. And understanding that ecosystem helps clarify sloths’ odd bathroom behavior. Sloths host a dedicated species of algae in their fur as well as scores of flightless “sloth moths” that depend on the sloth’s defecation descent for reproduction. The moth lays eggs in the sloth’s dung and then returns to the sloth’s fur. After the eggs hatch, the caterpillars feed on the dung, become moths, and the moths find—during the only brief moment in their lifetime that they can fly—another sloth to live on. When the moths die, their bodies are decomposed by fungi and bacteria in the sloth’s fur. The products of this decay, nitrogen in particular, provide fertilizer for the algae, which the sloths eat—thus adding nutrients to their diet.

5) Made for the shade. As tropical forests in Central and South America are cleared for agriculture and other uses, sloths (like many other species) need to find or adapt to new habitats in order to survive. Our team studied sloth populations at a large shade-grown cacao plantation in Costa Rica. With its diverse overstory of native trees, the plantation provides suitable habitat for sloths—especially two-toed sloths—and seems to point the way to at least one kind of farming that can benefit sloths and other native tropical animals.

Jonathan Pauli and Zach Peery, professors of forestry and wildlife ecology, have studied sloths in Costa Rica since 2009.

PHOTO: Jonathan Pauli watches after releasing a two-toed sloth in Costa Rica
Photo courtesy of Jonathan Pauli

Antibiotics Off the Beaten Path

As more antibiotic-resistant “superbugs” emerge, it’s clear that we desperately need new antimicrobial drugs. Yet, over the past couple of decades, antibiotic discovery has largely been stagnant.

“The reality is there’s almost no new antibiotics that are developed. And that’s because pharmaceutical companies have decreased their investment—in part because of the rediscovery issue,” explains bacteriology professor Cameron Currie.

The “rediscovery issue” refers to the fact that soil has historically been the prime source of new antibiotics—but it seems to be tapped out. When scientists screen soil microbes for new antibiotics, they keep finding the same compounds over and over again.

Currie is part of a team that is looking elsewhere.

Currie and his colleagues have been focusing their efforts on microbes that are associated with insects, plants and marine life from all around the United States, funded by a $16 million grant from the National Institutes of Health that was awarded in 2014.

“One of the major hurdles is finding new compounds, and that’s where we’re really excelling,” says Currie, a co-principal investigator on the grant. His partner is David Andes in the UW–Madison School of Medicine and Public Health.

At the front end, the work involves some good old-fashioned bioprospecting. Currie’s group, which is in charge of the terrestrial sphere, has gathered more than 2,000 flies, aphids, caterpillars, bees, ants and other insects, as well as mushrooms and plants, from locales near and far, including Alaska, Hawaii and Wisconsin’s Devil’s Lake.

Back at the lab, things get high-tech pretty quickly. Microbes are isolated from the samples and tested for antimicrobial activity. Promising strains undergo genetic sequencing that allows Currie’s group to determine how likely they are to produce novel antibiotic compounds. From there, other scientists involved in the grant go on to test the most promising compounds in a mouse model of infection. This approach has already yielded some exciting drug candidates.

“We have 9,000 strains to screen, and we have already found some new compounds that are effective at combating infections in mice and have low toxicity,” says Currie.

With so many samples to process, Currie’s group adopted bar code technology to help them keep track. They have a bar code reader—like you’d find in a grocery store— connected to a lab computer that they use to scan petri dishes, look up samples and add new data. For each microbial strain they’ve isolated, the database has photos of the “host” insect or plant, GPS coordinates for the collection site, assay results, genetic sequence and much more.

At this point, Currie feels confident that the project will pay off, and he’s eager to see one of the group’s compounds go into human clinical trials.

“If you find one new antibiotic that gets used in treatment, it’s a major success. You’re saving people’s lives,” Currie says.

Five things everyone should know about … The Future of Agriculture

1 l Apps are critical to ag. Farmers use mobile technology for many things, including turning irrigation and other equipment on or off, maintaining pest counts from field scouting, identifying bugs, checking field records, reviewing soil types, ensuring site-specific planting or production and keeping track of pest control operations. These apps often link directly to computers, allowing farmers to maintain a complete record of everything that happens on the farm and make critical long-term comparisons.

2 l Big data is helping agriculture. Data is being collected on all aspects of production, and big data analysis can improve our decisionmaking and increase productivity. Ultimately, this big data approach can bring regional and even global improvements to food production, resource conservation and environmental stewardship.

3 l Drones and satellites will help manage farmland as we move forward. Much of the commercial market for drones will be in agriculture. Drones are affordable and can boost productivity and cost-efficiency in agriculture as they scout fields, identify areas of concern, take photos and assist data collection. Satellite imagery and remote-sensing technologies are also on the horizon, allowing growers to identify and gather data pertaining to field-related questions and concerns long before the human eye can see the problem.

4 l Genetically modified organisms and cis-genetics will expand the abilities of plant breeders to create agricultural varieties for specific production and management needs. We have already seen the rapid expansion of genetic manipulation in developing plant varieties with new traits from other plants (GMOs), or having plants with traits that are enhanced and/or silenced to aid in some aspects of the plant’s growth and production. We are now on the threshold of a new technology—cis-genetics, where only the genetic material of the host plant is used to create desired characteristics. While many still question the role of these technologies, there is little doubt they will play a role as agriculture faces future challenges.

5 l RNAi technology will take pest management to the next level. We’re moving toward completely biologically based technology that uses RNA (ribonucleic acid) to turn off specific enzymes in target pests and silence genes that are essential to the pests’ life processes. This RNAi (ribonucleic acid interference) technology will take out only pests that are specifically targeted and will have no impact on other organisms—a truly innovative and safe approach for our next generation of pest management.


Deana Knuteson and Mimi Broeske are with the CALS-based Nutrient and Pest Management Program. Jeffrey Wyman is an emeritus professor with the Department of Entomology.

The Road from Farm to Market

Consumer demand for regionally produced food is on the rise. But transportation and distribution logistics for mid-size shippers, distributors and farmers can be tricky. These supply chain partners are looking for ways to more efficiently move products from Wisconsin’s farms to markets, while upholding many of their customers’ sustainability values.

That’s where the CALS-based Center for Integrated Agricultural Systems (CIAS) comes in. CIAS is working with university and private-sector partners to bring regionally grown food to urban markets while growing rural economies and addressing the environmental impacts of food freight.

“When people think of local food, they think of farmers markets and community-supported agriculture,” says Michelle Miller BS’83, associate director of programs for CIAS. “While these direct markets are the gold standard for connecting us with the people who grow our food, they don’t address the need to get more high-quality regional products into grocery stores, restaurants and schools.”

Consumers tend to believe that food is more sustainable if it travels a short distance from farm to table. However, a USDA study found that compared to direct markets, the large truckloads and logistical efficiencies found in the conventional food system sometimes use less fuel per food item transported.

Helping mid-size farmers move full truckloads of their products into wholesale markets is one way to build a more resilient regional economy. However, farmers face numerous challenges when shifting from direct to wholesale marketing. Product aggregation is one major hurdle, as wholesale public markets for assembling farmers’ wares have largely disappeared from the landscape.

The Wisconsin Food Hub Cooperative (WFHC), founded in 2012, helps fill that gap by providing sales, marketing and logistical support for its 37 farmer-owners, with sales of $1.7 million in 2015 and anticipated sales of $2.5 million in 2016.

CIAS helped WFHC implement retail product quality specifications and food safety requirements. Access to CALS expertise in those areas has made a big difference for their business, according to WFHC development director Sarah Lloyd.

“Most retail outlets require growers to obtain voluntary food safety certifications,” says Lloyd. “The help we’ve received in working through this maze of regulations has been critical.”

According to Miller, much more work is needed to help Wisconsin growers move their products into regional metro markets. CIAS is investigating fair trade strategies to provide equitable compensation for farmers. The center is working closely with city, county and regional partners to increase food processing and related food systems economic development in southern Wisconsin. CIAS is also researching more sustainable truck fleets using alternative fuels, hybrid electric engines and day cabs.

“We can gain efficiencies across the food system, at the farm level and in the way we move food to markets,” says Miller. “Ultimately we want to make it easier for consumers to support Wisconsin farmers.”

Tara Roberts-Turner, a founding farmer and business manager of the Wisconsin Food Hub Cooperative, loads fresh produce onto a truck bound for Chicago.

Photo credit – Tara Roberts-Turner 

Five Things About Daylight Saving Time

1. A Founding Father was an early advocate. In 1784 Benjamin Franklin observed that during summer months, people slept during the daylight hours of morning and then burned candles at night for illumination. Thus adjusting schedules to begin earlier in the day during summer months would substitute free sunlight for costly wax. Though Franklin advocated changing schedules, he did not propose changing the clock. This idea was first suggested in Britain in 1907, and it was implemented in warring nations in 1916 as an energy-saving measure.

2. Farmers were not. The notion that farmers pushed for daylight saving time to give them more time in the field is a myth. In fact, farmers consistently came out against a peacetime daylight saving time, which was not implemented in the U.S. until 1966. Losing an hour of morning light meant an early rush to get crops to market. And dairy farmers noted that cows respond poorly to changes in their schedule.

3. The health effects of DST are a mixed bag. More time spent pursuing outdoor activities and increased exposure to vitamin D can be beneficial. However, studies have found increases in such maladies as workplace accidents, heart attacks, headaches and even suicides at the start and end of daylight saving time, attributable to the negative effects of disrupted sleep rhythms. This is particularly so for people with mental health problems.

4. It’s good for business—except when it’s not. Outdoor sports facilities (think golf courses), the grill and charcoal industries and retail groups have long argued that DST is good for business—and for theirs, it is. Less fortunate: airlines that have to scramble to keep international flights running smoothly during the time changes, and television networks that lose prime-time viewers to the extended daylight.

5. The biggest argument for DST is questionable. The idea that daylight saving time saves energy has been the most formidable argument for its implementation and extension. Most recently, the U.S. Energy Policy Act of 2005 extended DST in 2007 by three weeks in the spring and one week in the fall. But studies by economists in 2008 and 2011 suggest that DST leads to the same amount of electricity use, but shifts it to different parts of the day, or even increases energy use slightly if people engage in additional energy-intensive activities (examples: driving and using air-conditioning).

Daniel Phaneuf is a CALS professor of agricultural and applied economics.

Stay Longer in the Kickapoo

The Kickapoo Valley is a picturesque area of western Wisconsin that attracts many visitors during the summer. But to improve economic development throughout this rural region, many residents and business owners want to lengthen the tourism season—and CALS/UW–Extension researchers are helping them make plans to do so.

“We’re fairly busy in the peak season, but tourism drops off in the shoulder months,” says Sadie Urban, the events coordinator for the Kickapoo Valley Reserve, an 8,500-acre natural and recreational area. “There’s still a lot to do in the area during those times, but we don’t really see the tourists then.”

To form a plan of action to attract new visitors, the Kickapoo Valley Reserve applied for funding help from the Kickapoo Valley Reforestation Fund, also known as the Ralph Nuzum Fund. The fund supports projects that enhance the ecological, economic and social well-being of Kickapoo Valley residents.

As part of the grant, Urban and her colleagues needed a University of Wisconsin partner—and Bret Shaw, a CALS professor of life sciences communication, was the right fit for the project.

“I’m interested in the intersection of tourism, sustainability and economic development, so this project was right in my wheelhouse of market research and helping rural communities,” says Shaw, who also has an appointment with UW–Extension as an environmental communications specialist.

Shaw started work in the valley by talking with stakeholders and identifying the goal of attracting tourists during the shoulder months. He and graduate student Heather Akin then surveyed Kickapoo Valley visitors and wrote a report about tourist demographics, behaviors and feelings. The full report is available at http://go.wisc.edu/kickapoo.

Community organizations in the Kickapoo Valley are using Shaw’s findings to influence their marketing materials and plan new events. Research indicated that excitement, adventure and food-related experiences would attract visitors. An immediate response was the Kickapoo Reserve Tromp and Chomp, a new trail run held in May featuring post-race meals by local chefs and growers. Urban says the event brought at least $6,400 tourist dollars into local economies—and that it will be held annually.

In addition to consulting on new events, Shaw is involved in the Ralph Nuzum Lecture Series, which introduces valley residents to experts on topics such as agriculture, wildlife and sustainability. Shaw also helped establish an Extension video channel to share those lectures with a broader audience and showcase the valley in general. Videos are available at http://uwexvideochannel.org/.

Shaw is optimistic that these ongoing collaborations between UW–Madison, UW–Extension and the Kickapoo Valley Reserve will produce the desired increase in tourism and economic development.

“Each time we attract a new visitor, that person spends around $140 if they stay overnight, so we’d like to see these events continue to help local businesses and residents,” Shaw says.

PHOTO—Natural beauty: A rock bluff along the Kickapoo River, one of the area’s many draws for tourists.

Five Things Everyone Should Know about … Nutmeg

1 It’s not a nut. Nutmeg is the seed kernel inside a yellow fruit of the nutmeg tree, an evergreen native to the Molucca Islands (sometimes called the Spice Islands) of Indonesia. Whole nutmeg seeds are oval, brown and about an inch long, with a nutty aroma and taste—but they don’t pose a risk to people with nut allergies.

2 This beloved holiday spice can be dangerous. But only in fairly large amounts. It takes two tablespoons or more to produce symptoms of nutmeg poisoning, toxicologists say. Those symptoms may include acute nausea, dry mouth, dizziness and a slowdown of brain function to the point where victims experience blackouts. Higher doses can cause shock and hallucinations.

3 That’s due to the nutmeg’s essential oil. Myristica, as the oil is called, contains myristicin, a narcotic that functions in the plant as a natural insecticide. Nutmeg also—as do its frequent recipe companions, cinnamon and clove—acts as an antibiotic.

4 Nutmeg has other medicinal properties as well. Consumed in small doses, nutmeg can serve as a digestive aid in reducing flatulence and indigestion, and can also help treat nausea and diarrhea as well as lower blood pressure. Applied topically, it can offer pain relief and has been used for rheumatism, mouth sores and toothache.

5 Nutmeg was more valuable than Manhattan. By the 16th century, nutmeg—coveted as a flavoring, hallucinogen, alleged aphrodisiac and deterrent to the plague—was being sold by European traders at a 6,000 percent markup. The Dutch soon wrested control of all the nutmeg-producing Moluccas except for a tiny island called Run, which was controlled by the British. At that time, Run seemed more valuable than Manhattan, then under Dutch control as New Amsterdam. In order to seal their nutmeg monopoly, the Dutch gave the British New Amsterdam in exchange for Run. It seemed like a good idea.

Johanna Oosterwyk, a faculty associate in the Department of Horticulture, is manager of the DC Smith Greenhouse, a facility that provides plant-growing space for the instructional needs of departments and programs of the College of Agricultural and Life Sciences.

Five things everyone should know about . . . Unmanned Aerial Vehicles (aka “Drones”) in Agriculture

1 Agriculture is poised to become the biggest market for unmanned aerial vehicles (UAVs). Up to 80 percent of the commercial market for UAVs will eventually be for agricultural uses, predicts the Association for Unmanned Vehicle Systems International. Industry analysts expect more than 100,000 jobs to be created and nearly half a billion dollars in tax revenue to be generated collectively by 2025, much of it from agriculture.

2 UAVs have great potential use in monitoring crop health. During the growing season, producers spend time and resources scouting crops to identify issues that might impact growth or yield. Such monitoring is done mostly through manned planes, satellites—or, very often, a good old-fashioned walk through the field. But data collected through these methods can take a long time to process, making it hard for farmers to address problems in a timely, cost-effective manner. UAVs can allow producers to cover and analyze a greater area in more detail and in less time.

3 Ag UAVs can be loaded with game-changing technology. UAVs may be equipped with infrared cameras, vegetative indices sensors and other technology, collecting all manner of relevant data (presence of insects or disease, amount of water or dryness, location of livestock). Farmers also can use UAVs to tailor their use of such inputs as pesticides or fertilizer based on how much is needed at a specific point in a field, a process known as variable rate application. This practice can save the grower money while maintaining yield and also reducing the amount of potential runoff into nearby streams or lakes.

4 But simpler and less expensive models can be very helpful as well. Utilizing a UAV with a visible light camera (what we use for normal pictures and/or video) can give producers a bird’s- eye view of what is happening in their fields. Anomalies such as color variations in the crop canopy, winter kill areas and animal damage can be seen from the air. Once identified, these damaged areas can be verified on the ground more easily.

5 Wisconsin UAV interest is high. Most grower and commodity group presentations I have given with UW–Extension in the past year have been about UAVs and their uses. From the perspective of crop management and spatial variation management, our ability to collect data has been somewhat limited to the beginning of the growing season (spring soil sampling, for example) and the end of the growing season (yield monitoring). Any further data collection would require walking the field or extra passes over the field with equipment. UAVs have the potential to allow us to collect data about the health of the crop over the entire growing season.

Brian Luck is a CALS assistant professor of Biological Systems Engineering and a Machinery Systems/Precision Agriculture educator with UW–Extension. His UAV research focuses on applied uses of current UAV technology for production agriculture.

Five things everyone should know about … Stevia

  1. It’s not just a sweetener. The plant genus Stevia includes more than 200 species of herbs and shrubs native to South America and mexico. Yet only two species, Stevia rebaudiana and Stevia phlebophylla, produce steviol glycosides in their leaves. These glycosides are the source of the plant’s sweet compounds.
  2. But as a sweetener, it’s nothing new. Stevia rebaudiana has been used for more than 1,500 years by various indigenous peoples in South America both to treat diabetes, obesity and hypertension and to provide a sweetening effect for food and drink. Commercial use of stevia took off when sweeteners such as cyclamate and saccharin were identified as possible carcinogens. Japan became the first country to introduce commercial use of stevia in the early 1970s and still consumes more of it than any other nation. Stevia has been available for several decades in natural food stores but in recent years has increased greatly in popularity as a sweetener for processed foods. Today, stevia can be found in many u.S. supermarkets under a variety of brand names, such as Truvia and PureVia.
  3. Why use stevia instead of sugar or other sweeteners? Stevia is significantly sweeter than table sugar, and comparable in sweetness to products such as aspartame, saccharin and sucralose, but it is metabolized differently. Stevia is perceived as sweet but does not cause a rise in blood glucose like sugar, making it a promising food for diabetics. It is a natural rather than an artificial sweetener.
  4. How is stevia processed within the body? The glycosides in stevia are primarily known as rebaudioside (or rebiana) and stevioside. They have some bitterness associated with them and can be blended with other compounds to minimize this effect. Once consumed, the glycosides break down into steviol, which is simply excreted; and glucose, which is used by intestinal bacteria and does not go into the bloodstream. So eating foods sweetened with stevia means a sweet taste without added calories.
  5. Can I grow stevia in Wisconsin? Stevia plants are not adapted to cold conditions but may be grown as annual plants in temperate regions (including in Wisconsin). However, growing plants from seed as an annual crop generally does not result in satisfactory results. Stem cuttings from mature stevia plants may be rooted and used to propagate stevia for growth in spring and summer.

Irwin Goldman is a professor and chair of the Department of Horticulture.

Five things everyone should know about . . . Milkweed

1. It is the stuff of life for monarch butterflies. Monarchs lay their eggs on milkweed, and milkweed leaves serve as nearly the sole food of monarch caterpillars. But many species benefit from the bounty of milkweed. Milkweed flowers produce nectar that other kinds of butterflies, honey bees, native bees and other pollinators enjoy. Hummingbirds line their nests with floss from milkweed seed pods.

2. It’s both medicine and poison. Milkweeds—there are more than 100 species—belong to the genus Asclepias, named after the Greek god of medicine and healing. Milkweeds have been used in medicine for thousands of years because their tissue contains cardiac glycosides, which increase the heart rate and in a purified form are useful in treating such conditions as cardiac arrhythmia and congestive heart failure. As a crude extract, cardiac glycosides are toxic and have been used as poison. Monarch larvae retain the toxins they consume in milkweed leaves and as butterflies remain toxic to predators.

3. Its presence is dwindling, along with the monarchs. The first decade of this century saw a 58 percent decline in milkweeds in the Midwest, according to a 2012 study—a time when we’ve also seen a whopping 81 percent decrease in monarch production. Factors often cited for milkweed’s decline include loss of habitat as grasslands and conservation reserves have been converted to farmland for corn and soybeans as well as increased use of herbicides on those crops.

4. There’s a growing movement to bring it back. Researchers at CALS and elsewhere have noted an increase in biodiversity, pollination and other ecosystem services that come from establishing or maintaining a mix of perennial native plants near cropland—and milkweed, they say, should be part of it. Vigorous efforts are taking place throughout the Midwest to plant large areas of milkweed along the monarchs’ migration path to Mexico, where they spend the winter.

5. Milkweed will enliven and beautify your garden—but keep your gloves on when handling. The toxins that protect the monarch can harm humans. Make sure the sap doesn’t get into your eyes, and if it does, seek medical attention as it can cause significant damage. While not all milkweeds are equally toxic and some kinds can be eaten, great care must be taken when selecting and preparing it.