Wednesday, November 10, 2021

Do flies really throw up on your food when they land on it? Most of the over 110,000 known fly species have no teeth, so they cannot chew solid food PUBLISHED ON November 8, 2021


A fly regurgitating digestive juices. (Carlos Ruiz, CC BY-ND)

WASHINGTON — “Do flies really throw up on my food when they land on it?” asks Henry E., age 10, Somerville, Massachusetts, in the most recent edition of The Conversation’s Curious Kids. You may want want to wait until after breakfast to find out the answer!

Imagine you’re at a picnic and just about to bite into your sandwich. Suddenly you spot a fly headed your way, homing in on your food with help from its compound eyes and antennae. It manages to escape your swatting, lands on the sandwich and then seems to throw up on it!

It can look kind of gross, but the fly might be just airing out its own digested food, or spitting on yours.

Most of the over 110,000 known fly species have no teeth, so they cannot chew solid food. Their mouthparts are like a spongy straw. Once they land on your food, they need to release digestive juices to liquefy it into a predigested, slurpable soup they can swallow. In short, some flies are on a liquid diet.

To fit more food in their stomachs, some flies try to reduce the liquid in what they have already eaten. They regurgitate food into vomit bubbles to dry it out a bit. Once some water has evaporated they can ingest this more concentrated food.

Human beings don’t need to do all this spitting and regurgitating to get nutrients out of our food. But you do produce a digestive juice in your saliva, an enzyme called amylase, which predigests some of the sandwich bread while you chew. Amylase breaks down starch, which you can’t taste, into simple sugars like glucose, which you can taste. That’s why bread gets sweeter the longer you chew it.

Did you know flies can taste food without their mouths? As soon as they land, they use receptors on their feet to decide whether they’re on something nutritious. You may have noticed a fly rubbing its legs together, like a hungry customer getting ready to devour a meal. This is called grooming – the fly is essentially cleaning itself, and may also clean the taste sensors on the bristles and fine hair of its feet, to get a better idea of what is in the food it has landed on.

Should you trash food a fly’s landed on?

When a fly touches down on your sandwich, that’s probably not the only thing it’s landed on that day. Flies often sit on gross stuff, like a dumpster or decomposing food, that’s full of microbes. The germs can hitch a ride and, if the fly stays put long enough, hop onto your meal. This is much more dangerous than their saliva because some of the microbes can cause diseases, like cholera and typhoid. But if the fly doesn’t stay longer than a few seconds the chances of microbes transferring are low, and your food is probably fine.

To keep insects from landing on your food, you should always cover it. If your house is infested with flies, you can use simple traps to get rid of them. Carnivorous plants can also eat the flies and help control their population.

Are flies good for anything?

Spitting on food and spreading diseases sounds disgusting, but flies aren’t all bad.

Watch closely the next time you’re outside and you might be surprised by how many flies visit flowers to get nectar. They’re an important group of pollinators, and many plants need flies to help them reproduce.

Flies are also a good source of food for frogs, lizards, spiders and birds, so they’re a valuable part of the ecosystem.

Some flies have medical uses, too. For example, doctors use blow fly maggots – the young, immature form of flies – to remove decomposing tissue in wounds. The maggots release antiviral and antimicrobial juices, and these have helped scientists create new treatments for infections.

More importantly, the fruit flies you may have seen flying around ripe bananas in your kitchen have been invaluable in biological research. Biomedical scientists from all over the world study fruit flies to find causes and cures for diseases and genetic disorders. And in our lab, we study what the world looks like to insects, and how they use their vision to fly. This knowledge can inspire engineers to build better robots.

So, although it’s a nuisance to shoo flies away from your sandwich, maybe you can spare a few bits of your lunch?

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

–Ravindra Palavalli-Nettimi
Postdoctoral Research Associate
Florida International University
and Jamie Theobald
Associate Professor of Biological Sciences
Florida International University

Thursday, October 14, 2021

USDA launches first phase of soil carbon monitoring efforts New initiative will sample, measure, and monitor soil carbon on Conservation Reserve Program acres PUBLISHED ON October 13, 2021


“These CRP Climate Change Mitigation Assessment Initiative projects will survey, sample and measure the climate benefits of land enrolled in CRP conservation practice types over time,” said Zach Ducheneaux, Administrator of USDA’s Farm Service Agency (FSA). “This data will help USDA better target CRP practices to achieve continued climate wins across environmentally sensitive lands while strengthening our modeling and conservation planning resources for all producers.” (USDA, Public Domain)

WASHINGTON — The U.S. Department of Agriculture (USDA) is investing $10 million in a new initiative to sample, measure, and monitor soil carbon on Conservation Reserve Program (CRP) acres to better quantify the climate outcomes of the program. CRP is an important tool in the Nation’s fight to reduce the worst impacts of climate change facing our farmers, ranchers, and foresters. This initiative will begin implementation in fall 2021 with three partners. Today’s announcement is part of a broader, long-term soil carbon monitoring effort across agricultural lands that supports USDA’s commitment to deliver climate solutions to agricultural producers and rural America through voluntary, incentive-based solutions.

“These CRP Climate Change Mitigation Assessment Initiative projects will survey, sample and measure the climate benefits of land enrolled in CRP conservation practice types over time,” said Zach Ducheneaux, Administrator of USDA’s Farm Service Agency (FSA). “This data will help USDA better target CRP practices to achieve continued climate wins across environmentally sensitive lands while strengthening our modeling and conservation planning resources for all producers.”

These models include the Daily Century Model, or DayCent, which simulates the movement of carbon and nitrogen through agricultural systems and informs the National Greenhouse Gas Inventory. Data will also be used to strengthen the COMET-Farm and COMET-Planner tools, which enable producers to evaluate potential carbon sequestration and greenhouse gas emission reductions based on specific management scenarios.

USDA partners will conduct soil carbon sampling on three categories of CRP practice types: perennial grass, trees, and wetlands.

Perennial grasses: In consultation with USDA, Michigan State University will sample and measure soil carbon and bulk density of CRP grasslands (including native grass plantings, rangelands, and pollinator habitat plantings) at an estimated 600 sites across the U.S. with a focus in the central states during this five-year project. This information will be used to model and compare the climate benefits of CRP. Partners include the University of Wisconsin-Madison, the University of Arkansas at Pine Bluff, Deveron, an agriculture technology company, and Woods End Laboratories.

“Our interdisciplinary team is excited to work with FSA on assessing, monitoring, and modeling the climate benefits of CRP,” said Professor Bruno Basso, Michigan State University. “Our proposed integrated system for sampling and modeling soil organic carbon accrual and ecosystem services in CRP lands aims to maximize climate outcomes to mitigate the deleterious effects of climate change on our planet”.

Trees: Mississippi State University will partner with Alabama A&M University to collect above and below ground data at 162 sites across seven states documenting CRP-related benefits to soil and atmospheric carbon levels. Information will help further calibrate the DayCent model. This five-year project will focus within the Mississippi Delta and Southeast states.

“There are hundreds of thousands of acres of trees planted under the CRP program in Mississippi and neighboring states that make a substantial contribution to climate change mitigation, but we don’t have a good idea how large that contribution is,” said Austin Himes, assistant professor at Mississippi State University. “This incredible team of partners will use a mix of traditional forestry measurements and state of the art technologies to get an accurate estimate of those benefits, which in turn can help policy makers incentivize tree planting. Additionally, we get to train students to collect all that data, providing them hands-on experience.”

Wetlands: Ducks Unlimited and its partners will collect data on carbon stocks in wetland soils as well as vegetation carbon levels at 250 wetland sites across a 15-state area in the central U.S. Data will support the DayCent and additional modeling. Partners for this five-year project include: Migratory Bird Joint Venture, Intertribal Research and Resource Center at United Tribes Technical College, Clemson University, Kenyon College, Lincoln University, Pennsylvania State University, the University of Missouri, and the University of Texas at Austin.

“We’ve long known wetlands offer many ecosystem services that have an outsized benefit for wildlife and people” said Dr. Ellen Herbert, DU’s Ecosystem Services Scientist. “This study will help improve our understanding of the potential of CRP restored wetlands to mitigate the effects of climate change, improve water quality and provide habitat. We believe the data gathered from this study will ultimately help demonstrate the effectiveness and overall values of CRP. And, we greatly appreciate USDA for selecting DU to partner in this project.”

CRP Monitoring, Assessment, and Evaluation Projects

These three Climate Change Mitigation Assessment Initiative projects are funded through FSA’s program to work with partners to identify Monitoring, Assessment and Evaluation (MAE) projects to quantify CRP environmental benefits to water quality and quantity, wildlife, and rural economies.

Applications for projects were welcome from all organizations, including public, private, nonprofit institutions, and educational institutions including historically Black colleges and universities, Tribal colleges and universities and Hispanic-serving institutions or organizations.

For more details on the all the awarded MAE projects, visit the FSA Monitoring Assessment & Evaluation webpage.

About the Conservation Reserve Program

CRP is one of the world’s largest voluntary conservation programs, with an established track record of preserving topsoil, sequestering carbon, reducing nitrogen runoff and providing healthy habitat for wildlife.

In exchange for a yearly rental payment, agricultural producers enrolled in the program agree to remove environmentally sensitive land from production and plant species that will improve environmental health and quality. In general, land is enrolled in CRP for 10 to 15 years, with the option of re-enrollment. FSA offers multiple CRP signups, including the general signup and continuous signup, as well as Grassland CRP and pilot programs focused on soil health and clean water. In 2021, producers and landowners enrolled more than 5.3 million acres in CRP signups, surpassing USDA’s 4-million-acre goal.

Earlier this year, USDA announced updates to CRP including higher payment rates, new incentives for environmental practices, and a more targeted focus on the program’s role in climate change mitigation. This included a new Climate-Smart Practice Incentive for CRP general and continuous signups that aims to increase carbon sequestration and reduce greenhouse gas emissions. Climate-Smart CRP practices include establishment of trees and permanent grasses, development of wildlife habitat, and wetland restoration. Download the “What’s New” fact sheet  to learn more about CRP updates.

More Information

Under the Biden-Harris Administration, USDA is engaged in a whole-of-government effort to combat the climate crisis and conserve and protect our nation’s lands, biodiversity, and natural resources including our soil, air, and water. Through conservation practices and partnerships, USDA aims to enhance economic growth and create new streams of income for farmers, ranchers and private foresters. Successfully meeting these challenges will require USDA and our agencies to pursue a coordinated approach alongside USDA stakeholders, including State, local, and Tribal governments.

USDA touches the lives of all Americans each day in so many positive ways. In the Biden-Harris Administration, USDA is transforming America’s food system with a greater focus on more resilient local and regional food production, fairer markets for all producers, ensuring access to healthy and nutritious food in all communities, building new markets and streams of income for farmers and other producers using climate smart food and forestry practices, making historic investments in infrastructure and clean energy capabilities in rural America, and committing to equity across the Department by removing systemic barriers and building a workforce more representative of America. To learn more, visit

USDA is an equal opportunity provider, employer and lender.

Thursday, July 15, 2021