Field of Science


Cooler Than Your Environmental Club: An Interview with My Little Sister about the Adirondack Youth Climate Summit

Teenagers who want to cause a disruption don't have to ride a skateboard anymore; these days they can do it on a bike generator. Earlier this November a crowd of students came together in Upstate New York to share ideas about greening their schools and addressing climate change on a small and large scale.  My youngest sister, Leigh, is a senior in high school and was at the conference for her second year. I asked her what they did there, and she told me about energy efficiency, celeriac soup, and how her generation is going to do things differently. (I never did get a straight answer about some Facebook photos, though.)


Hi Leigh! So who attends the Adirondack Youth Climate Summit?

There were about 150 students representing 27 colleges and high schools around New York, mostly from the Adirondack region. Each school could send 5 to 6 students along with a teacher chaperone. Students at my school had to write an essay explaining why they wanted to go to the summit and what interest they had in climate change. (Most students I talked to were shocked that my school had been so selective because their schools just brought their entire environmental club.)

By the way, I hope email is OK. Would I have more generational cred with you right now if I were conducting this interview via SnapChat or something?

I have to say, I much prefer the transfer of information through text bubbles containing less than 140 characters attached to a picture I can only view for 10 seconds on a 4-inch screen...but I guess this will do.

What kinds of workshops did you go to?

I got to attend three different workshops of my choice on the first day, splitting up with my school group so that we could cover more ground. I attended the three that were geared towards successfully sustaining a school garden and implementing younger students into climate action, because that's what I've been focused on at school the past couple years. The rest of my team attended workshops about composting, green teams, energy efficiency, biofuels, and recycling.

I hear the food was a highlight.

The food was absolutely delicious! All the meals and snacks were provided by local farms and vendors. They had vegetarian, vegan and gluten-free options, and Ben & Jerry's (a major sponsor of the summit) provided ice cream the second day. I caught myself enjoying kale chips and even tried parsnip and celeriac for the first time in a delicious soup that a Culinary Arts professor from Paul Smith's College made. (See recipe below.)

As weird as it sounds, I think the presence of wholesome, fresh, unprocessed food really boosted everyone's brain power for a few days.

And there were speakers too?

Brian Stillwell of Alliance for Climate Education kicked off the summit with a catchy, motivating presentation about climate change and the science behind it, followed by Brother Yusef Burgess of Youth Ed-Venture and the Children & Nature Network, who spoke about using the power of nature to transform and educate youth. Later in the afternoon Dr. Susan Powers, the Associate Director for Sustainability at Clarkson University, presented to us the outcomes of climate change in both our best and worst case scenarios.

Mark and Kristin Kimball, who own Essex Farm in the Adirondacks, hosted the dance party, fed us freshly harvested carrots, and encouraged our generation to be the driving force of the climate movement—and, more importantly, to have fun doing it. They made the point that these days, things like smoking cigarettes or dumping gasoline into a lake are considered "socially unacceptable," but that took time. Now, it is our time to make not caring about the environment be socially unacceptable.

Was it valuable just interacting with the other kids there, from different kinds of schools? Were you learning and getting ideas from each other?

YES. The second day, there was a 2-hour poster session where all the schools displayed posters of their current "green" efforts and plans for the future. I had a chance to talk to so many different schools and share ideas about outdoors clubs, gardening problems, recycling efforts and cafeteria food. I had conversations with a high school that was having trouble even starting an environmental club due to the lack of support from administration, and on the other end of the spectrum, I talked to a school that had livestock and taught all their science classes on a farm.

We also had the amazing opportunity to Skype with Finland, where they were holding a similar youth climate summit modeled after ours in the Adirondacks. Despite the sound lag and language barrier, it was still inspiring to see that kids our age halfway around the globe are facing the same problems we are.

It looks like you guys had a lot of fun at this dance party. In your Facebook photos I observed electric guitar, someone crowdsurfing, a guy in a sailor hat juggling fire, and what appeared to be people using ropes to move a large rock. Are these the elements of a good party for the young environmentalist crowd?

I think these are the elements of any good party, actually. Moving the rock could have been a metaphor for how teamwork can move the world or something, but it was really just for the fun of moving a rock. We were told that our generation will make it through this difficult time in climate change only if we have fun in the process.

What sorts of ideas or projects did you bring back from the summit to use at school?

The second day of the summit, all the teams were given 2 hours to create their school's "Climate Action Plan" and a detailed timeline to present to the rest of the schools at the end of the day. Our team decided to focus on 4 major projects in the coming year: improving the school garden, building a bike generator for the lobby, holding a bi-annual school-wide locker clean-out to donate gently used school supplies and teach proper recycling, and finding places to cut the school's phantom energy usage (a.k.a. the wattage used by electronics when they're turned off but still plugged in).

You may not know this, but back when I was at your school I belonged to an "environmental club" too. This meant that a couple of us would go to all the classrooms after school and pull trash out of the blue bins, because otherwise the maintenance guys refused to recycle. Is it fair to say things have come a long way?

Simply put, yes. We have a recycling bin in every classroom, our cafeteria serves vegetables from a number of local farms, quarterly grades and comments are now only available online, our drinking fountains are now water-bottle filling stations, and we have a garden that brings vegetables to the salad bar. We have solar panels on one building and another LEED-qualified building, with another one in the construction phase.

I think we're also a little cooler than your environmental club, because now we are the "Green Avengers," equipped with a logo and a Facebook page.

Are you optimistic about climate change? Do you come back from an event like this feeling like you're part of a group of people who will actually make a difference, whether it's through school-level projects now, or after college as policy makers? Or are we pretty much screwed?

Both times going to the summit I came back incredibly high in motivation, but I knew if I didn't write down all my ideas and get acting quickly, I would lose my energy. Spending time around so many like-minded people definitely makes me excited to get out there and make change.

It also reminds me we have to be able to work on our own and not rely on the work of others because that's part of the attitude that brought us to this predicament in the first place. As Dr. Powers told us, even in the earth's "best-case scenario," we'll still experience rising global temperatures. It's just up to my generation to slow the acceleration of carbon dioxide emissions and provide the optimistic attitude.

Celeriac and Parsnip Soup
Yields 18-24 servings (reduce if you're not feeding a youth summit)

5 pounds cubed celeriac root
5 pounds chopped parsnip
6 tablespoons olive oil
15 cups vegetable stock
1 bundle thyme
1/2 teaspoon salt
1/2 teaspoon ground black pepper

Preheat the over to 400°F. Toss the celeriac and parsnip with the olive oil. Arrange the vegetables in a single layer on a foil-covered baking sheet. Roast them 35-45 minutes, flipping once, until they are tender and golden brown. Combine the caramelized vegetables with the stock and other ingredients in a pot over medium-high heat. After bringing to a boil, let the soup simmer for 15 minutes. Put all the food through a blender or food processor until smooth and serve hot.

Images: The Wild Center (top); Leigh Preston (bottom).

The Shambulance: Put Down the Bananas! There's No Such Thing as a Mono Meal

The Shambulance is an occasional series addressing bogus products and overhyped health claims. The chief tactical officer onboard is Steven Swoap.

While you're enjoying a full Thanksgiving plate this Thursday, you might take a moment to be thankful that your meal isn't a single melon with a spoon stuck in it. Or a stack of plain lettuce. People who eat "mono meals" insist that having only one type of raw fruit or vegetable per mealtime makes their digestive process more natural and virtuous. In reality, it just takes the fun out of salad.

Not to be confused with the noodle soup eaten by college students who are sick with mono, a mono meal is something eaten by healthy people who can afford to buy a lot of produce every week. It's an especially orthodox version of the "high carb raw vegan" diet—or maybe it's a sect of the "80/10/10" diet (which dictates that 80 percent of one's calories should come from carbs, and 10 percent each from fat and protein).

However the eating style evolved, Buzzfeed recently claimed mono meals are a "new diet trend." While it's hard to tell how many mono mealers are out there—they're hardly mainstream—it's true you can search Instagram, Pinterest or Twitter and find photographs of people's thirteen-tangerine breakfasts with a side of hashtags (#801010 #monomeal #fruit!).

An especially zealous group of high-carb raw vegans populates a website called 30 Bananas a Day, although some of them choose to eat their fruits and veggies mixed together, rather than individually. (I spent some time on this site looking for answers about what motivates the mono diet, and instead found several surreal items: a claim that the flavor of raw okra is delicious; a suggestion to blend dates into "dateorade"; a GIF of someone's stomach bloating and un-bloating, mesmerizingly.)

Other sites are more explicit about the point of mono-ing your meals. It's all about simplifying digestion, they say. "If too much activity is happening in the digestive tract," according to Carla Golden Wellness, "enzymes can cancel each other out causing food to rot...With so many different kinds of foods going in at one sitting, our body can get VERY tired trying to sort out the different enzymes and digestion times for all these various foods."

When I sent these claims to Steven Swoap, a physiologist at Williams College, he was pretty efficient about tearing them down.

"You can't have too much activity in the digestive tract," he says flatly. Our bodies use different enzymes to digest proteins, carbohydrates and fats, and "there is no canceling each other out." These processes have evolved to happen at the same time with no stress to our organs—not the stomach or intestine, where digestion occurs, and not the pancreas, which cranks out the enzymes. "The pancreas multi-tasks as well as the best of them," Swoap says.

Mono meal advocates say it's healthier to make things easy on your digestive system by eating just one thing. "When only one food is eaten at a time at a meal, the process of digestion is made to be extremely efficient," says the website Nature's Pilgrim. "The body must only focus on breaking down and absorbing one particular compound."

"Not only is this garbage, it can actually be critically wrong," Swoap counters. Eating a heap of bananas for dinner doesn't make digestion happen faster—and we wouldn't want it to. "Nutritionists agree that taking a longer time is much better for you," he says. Absorbing carbohydrates quickly causes a spike in blood sugar, followed by a spike in insulin. The more sharply a meal raises your blood sugar, the higher its "glycemic index" (GI), a score given by nutritionists.

A plain baked potato, for instance, has a high GI because we can very easily break down its starches into sugars and absorb them. But there's a way to slow things down and avoid the blood sugar spike: add some fat or protein. A dollop of sour cream or butter slashes the GI of that baked potato.

So a mono mealer's goal of mainlining carbs is actually a bad idea. Eating a lot of high-GI foods has been linked to diabetes and heart disease. Luckily, though, a pile of fruit doesn't fit the bill.

"If you each just one naturally occurring food (like a banana or a green pepper or a cucumber)," Swoap says, "this is inherently a meal that is mixed—mixed with carbs, protein, and fats." Every living cell contains fats in its outer membrane and proteins that drive its activities. Additionally, something like an apple or banana has plenty of fiber that slows down your body's absorption of its sugars.

That pile of kiwi fruits, then, won't make anybody's digestion quicker or cleaner than usual. And that's a good thing; your body is happier with slow-and-steady. (A meal that does have a high glycemic index? Juice.)

If you enjoy cantaloupe or plain vegetables enough to eat them exclusively for your meal, it probably won't hurt you. If you really enjoy them, you might become like 30 Bananas a Day user Jared Six. "I have NEVER enjoyed the taste of food more than I do now after 6 months of eating this way," he gushes. "People look at me like there is something seriously wrong for me for being so happy eating something like a meal of just lettuce."

Just make sure those 30 bananas a day don't turn into 36 bananas in one sitting, because that's enough to cause dangerously high potassium levels in your blood—something for which you won't feel thankful.

Image: Elaine Vigneault (via Flickr)

Bees Can Smell How Much Sex Their Queen Has Had

Just because girl talk between bees is wordless doesn't mean it lacks for intimate details. When sister honey bees gather around their queen, they can tell from her pheromones whether she's mated—and how much. What they learn may determine whether they let her live.

The queen honey bee doesn't do much day-to-day ruling, but she does lay nearly every egg in the hive. Her daughters become worker bees, who keep the colony running. Pheromones that the queen and the workers emit—then spread through the hive as they touch antennae and clamber over each other's bodies—carry the signals that maintain order. Among other laws, the queen's pheromones tell workers not to lay eggs of their own.

When the queen's egg-laying prowess starts to fade, though, her workers will replace her without sentimentality. They prepare special queen egg chambers and feed royal jelly to the chosen larvae (who will battle once they emerge, leaving only one queen standing). Then the workers sting the old queen to death. "It can take up to 6 weeks for the new queen to produce a new cohort of workers," says Elina Niño, an entomologist at Pennsylvania State University. So the process harms the hive's productivity, in addition to the dispatched queen herself.

Along with colleagues at North Carolina State University (where she worked at the time) and Tel Aviv University, Niño investigated whether the queen honey bee is honest when she sends pheromone messages to her workers. If the queen could fake the pheromones that say she's in great shape, it would keep her colony loyal for longer. To find the answer, the researchers set about artificially inseminating some bees.

New queens mate just once in their lives, in a sex spree that involves lots of males (called drones). They store all that sperm and use it, a little bit at a time, to fertilize the eggs they lay for their remaining years. The scientists gathered groups of queen bees who had not yet mated with any drones. Then they simulated sex in several ways: Some queens had a needle inserted into them to mimic the physical aspect of mating. Some received actual semen (mixed from the contributions of multiple bachelor bees), in either a large or small volume. Others were pumped with a large or small volume of salt water.

Several days later, the unfortunate queens were offed. The researchers extracted the contents of two pheromone glands, one at a queen bee's mouth and the other near her stinger. Chemical analysis showed that in the pheromones from the bees' back ends, there was a difference between queens who'd been inseminated (or faux-inseminated) and those whose insides were still empty. The pheromones from the jaw gland seemed to carry even more specific information: each group of queens (inseminated for real or with salt water, holding a large or a small volume of whatever it was) had a distinct chemical signature.

But how would worker bees respond to these signals? The scientists put their pheromone extracts onto glass plates and set them down by groups of worker bees. They hoped to take advantage of a bee behavior called the "retinue," in which workers cluster around a queen while licking her and touching her with their antennae.

The worker bees treated the pheromone puddles like real queens. But not all queens were equal. The researchers saw that workers were most attracted to pheromones from queens who were full of semen, rather than salt water. They also preferred pheromones from queens with a larger volume of semen stuffed inside of them.

"Colonies headed by multiply mated queens are more productive, more resistant to diseases and more likely to overwinter successfully," Niño says. In other words, queens that have mated with lots of drones produce hives that are healthier, because they're more genetically diverse. So it would benefit worker bees to be able to sniff out their queen's sexual history and "act accordingly," Niño says. This might mean ousting a queen who hasn't gotten around much, and gambling on a new queen instead.

For beekeepers, the results add new importance to having a healthy queen. Just because a queen is laying eggs, Niño points out, doesn't mean she can keep her subjects loyal. Workers that don't like the smell of their queen's pheromones, perhaps because she hasn't mated with an adequate number of drones, may execute her. Beekeepers who want to avoid that drama should make sure their queen has plenty of partners—because when she talks to her workers about her sexual past, she won't be able to lie.

Image: by Dude-K (via Flickr)

Niño EL, Malka O, Hefetz A, Tarpy DR, & Grozinger CM (2013). Chemical Profiles of Two Pheromone Glands Are Differentially Regulated by Distinct Mating Factors in Honey Bee Queens (Apis mellifera L.). PloS one, 8 (11) PMID: 24236028

You Might Have Outgrown Synesthesia as a Kid

Feeling smug because your normal brain doesn't insist on coloring all its 2's blue and M's purple? Not so fast: you might have been a child synesthete. Some elementary schoolers have associations between colors and letters or numbers that fade as they age. Others' associations expand to take over the whole alphabet, leading them toward a rainbow-hued adult life.

Studying kids with synesthesia is tricky, because first you have to find them—and at a young age, kids don't know the word, or that their perceptions aren't standard. University of Edinburgh psychologist Julia Simner screened 615 kids for synesthesia back in 2009. Starting with six- and seven-year-olds, Simner and her coauthors sat the kids in front of a computer screen and told them to play a game: they'd see a letter or number next to a set of colors, as above, and should choose the "best" color for each one.

After the computer ran through every letter and numeral in random order, it paused for several seconds, then did the entire test a second time. Forty-seven of the kids were significantly consistent in their choices between the two tests—which meant either that they were synesthetic, or that they had a good memory for colors they'd picked at random. The moment of truth came a year later, when those 47 kids sat down and took the test again. People with synesthesia should be consistent not only over a few minutes, but over years. That's because it's not really a test of memory for them; color is simply a quality that a letter or number has, like being even or a consonant. (For rarer types of synesthesia, people might experience colors with sounds, or tastes with words.)

In 2009, Simner found eight girls and boys who passed her tests. For a new study published in Frontiers in Human Neuroscience, Simner and coauthor Angela Bain returned to these patient elementary schoolers—now 10 or 11 years old—and did the test a third time.

They wondered whether any kids' synesthesia would have faded over the intervening years. Anecdotally, some adults say they remember having synesthesia as a child and growing out of it. The researchers started with not just their eight synesthetes, but 39 of the kids who had been classified as near misses in the first go-around—they had been consistent over 10 seconds, perhaps, but not over a year, or their performance had been just shy of statistically significant. Another 40 average kids served as controls.

This time, six kids passed the test. They were consistent both within two trials and compared to their original tests four years earlier. On testing day, these synesthetes made consistent color choices for about 26 out of the 36 letters and numerals they saw. Non-synesthetes were consistent for only 6 or 7.

Five of the children were from the original batch of synesthetes, and the sixth had been a near miss originally. The other three original synesthetes were no longer significantly outperforming their peers in choosing consistent colors. This may be evidence of "synesthetic demise," the authors write.

Young synesthetes losing their colors over time would fit with a popular theory about synesthesia, which says that it comes from an overly connected brain. "All very young children have hyper-connected brains," Simner says; the neurons branch out indiscriminately between different areas. As we grow, the unneeded connections are pruned away, a process that continues throughout childhood. "It may be that synesthetes escape the pruning, so to speak," Simner says. All kids might start out with some degree of synesthesia, which fades away with normal development.

It's also possible, Simner says, that the "near-miss" kids actually had synesthesia that was developing more slowly than their peers'. She found that synesthetes add more and more colored characters to their rosters as they age. When synesthetes were six or seven years old, they had consistent colors for only about a third of letters and numbers. In another year that number had risen to almost half, and at age 10 or 11 over 70% of letters and numbers had fixed colors. Adult synesthetes have consistent colors for 80 to 100% of letters and numbers.

So for people who don't lose their synesthesia as they age, it becomes steadily more consistent. Now that Simner's subjects are 14 and 15 years old, she says, "we very much hope" to test them again. The teenagers may be happy to learn that at least one thing about their lives is becoming less chaotic.

Image: Simner & Bain 2013.

Julia Simner, & Angela E. Bain (2013). A longitudinal study of grapheme-color synesthesia in childhood: 6/7 years to 10/11 years. Frontiers in Human Neuroscience DOI: 10.3389/fnhum.2013.00603

Citizen Scientists Dig Up the Truth about Decomposing Dung

The amount of cow dung plopped into the world every day is almost unthinkable, but Tomas Roslin is thinking about it.

"We can regard it as either an immense waste problem or an enormous ecosystem service," he says. He means that what starts out as a turd in a field turns into a wealth of nutrients for plants—assuming it can make its way below ground. So understanding how dung gets broken down can help us ensure an ecosystem is running smoothly. To address such a messy, large-scale question, Roslin recruited a big mess of young volunteers.

Roslin is an ecologist at the University of Helsinki, and he found his citizen scientists through the Finnish 4H Federation. In all, 79 volunteers signed up, ranging from 10 to 27 years old (most were under 20). They agreed to sample 82 cattle farms that spanned Finland nearly from end to end.

From each farm, the volunteers collected 20 liters of "fresh dung" in late spring or early summer. They divided their dung into 15 pats (using an official dung measurer that had been provided to them) and put the pats back onto cow pastures. Some of the manmade cow patties were left open to the air, while others were covered with cages of coarse or fine mesh to keep out certain insects.

Roslin and his coauthors were especially interested in large dung beetles called dor beetles. In some cases they prevented dor beetles from burying the dung (as the beetles enjoy doing) by putting mesh underneath the patty, and in other cases a full wire cage kept dor beetles from getting into the dung at all. Smaller insects were kept out with finer mesh cages, and earthworms were blocked from the dung by putting a layer of cloth underneath it.

Volunteers weighed the dung piles periodically over the next two months to see how much was left of them. As the summer went on, the patties dried out and were broken down by whatever insects could reach them, as well as by microbes that couldn't be kept out. (Only 73 farms were left in the final analysis, since a few sites were lost to "lack of sufficient commitment by the volunteer" and others to "cows trampling on the experimental pats.")

The results showed that 13 percent of dung decomposition is done by insects. Microbes and rainstorms take care of the rest. The farther north you are in Finland, the more slowly your dung will disappear, perhaps because cooler weather slows bacterial growth.

Each added barrier around the dung made it decompose a little more slowly, showing that all the groups of insects were helping to break it down. But the biggest contribution came from dor beetles. This was in line with what previous, small-scale research had shown—but his network of citizen scientists let Roslin confirm that dor beetles are equally important all across Finland.

It matters because "our dor beetles are not doing that well," Roslin says. Out of three species in Finland, one has gone regionally extinct and another is on the decline. Knowing how important the dor beetle is to healthy farms gives Finland more reason to keep it alive.

Additionally, Roslin says, "just figuring out the basics of how the system works" is critical. In the United States, most cattle waste goes into manure lagoons, where beetles or ecosystems don't really enter the equation. But when waste is returned to the soil, Roslin says, "we need to understand who is behind it." He points out that cattle were initially brought to Northern Europe in part to fertilize the fields.

"We love citizen science," Roslin declares. He and his lab have previously organized citizen investigations of dung beetles and gall-wasps, and they're now working with volunteers to study the hermit beetle Osmoderma barnabita. "The volunteers involved have come to appreciate completely new aspects of their own environment," he says.

There are some drawback to the approach, of course —experiments have to be kept simple, and sometimes a volunteer loses interest or flattens a cow patty. But by pairing small-scale lab research with large citizen projects, Roslin says, "we have managed to collect scientific data sets unachievable by relying on professional biologists."

Riikka Kaartinen, Bess Hardwick, & Tomas Roslin (2013). Using citizen scientists to measure an ecosystem service nationwide. Ecology DOI: 10.1890/12-1165.1

Images: top Timo Marttila/Satakunnan Kansa; bottom Riikka Kaartinen.

Found: A Rotten-Smell Button in the Brain

Window or aisle? Hamburger or hot dog? Bouquet of flowers or rotting flesh? Not all your preferences are up to you—some have been hammered into your genes by evolution.

If you're an average human, you avoid the smell of decay. It signals unsafe food and the threat of infection or disease. Other animals run toward the stench of a stale carcass, maybe because they're flies and it signals a place to lay their eggs.

Whether they love it or hate it, animals identify the scent of rot from two signature molecules. German doctor Ludwig Brieger discovered these molecules in the late 1900s; in English, they're rather cutely named "cadaverine" and "putrescine." Bacteria create the two culprits by breaking down down amino acids in animal bodies. Not solely the sign of a rotting carcass, cadaverine and putrescine also show up in urine and bad breath.

Despite the importance of these smells (or avoiding these smells) in animals' lives, no one had found receptors for these molecules—that is, the locks to which the molecules are keys. Scent receptors are attached to one end of a neuron inside the nose (or whichever body part an animal smells with); when a certain chemical wafts up the nose and latches onto the receptor, a signal travels along the neuron to the brain at the other end. Researchers at the University of Cologne in Germany and Harvard University think they've found one of those receptors for rot.

The authors, led by the University of Cologne's Ashiq Hussain, studied zebrafish, which are commonly used to model the sense of smell in vertebrates. First they checked to make sure zebrafish respond to the smell of decay. When they put putrescine and cadaverine into a tank, zebrafish swam to the other end, showing they feel the same way we do about these smells. When the authors plugged the zebrafishes' little nostrils with glue, the fish were no longer bothered by the odor.

The researchers searched for a receptor in a family of proteins called TAARs (trace amine-associated receptors). Related receptors in rodents are thought to detect other unpleasant odors that come from living things. Zebrafish make 112 different kinds of these receptors, but the molecules that attach to them hadn't been found yet.

After testing 93 smelly chemicals on representative zebrafish TAARs, the authors found a match: cadaverine turns on a receptor called TAAR13c. But could the receptor detect cadaverine in real life, and not only when it was dripped on in purified form by a scientist? To test it, the researchers used an extract of dead fish. When exposed to liquid made from a recently deceased zebrafish, the receptors didn't respond. Liquid from a week-old, rotten fish carcass, though, easily activated the receptor—even when diluted to 1 part in 1,000.

Finding a receptor for cadaverine means scientists now understand a little bit more about how the vertebrate brain responds to awful smells. The receptor protein itself "will not be similar in humans, because mammals do not have close relatives of this zebrafish receptor," says Sigrun Korsching, the paper's senior author. Still, she adds, "There are very few cases where you can show activation of a single receptor leads to a behavioral response." Studying how the zebrafish's neurons respond to cadaverine could lead to a better understanding of how animals process all kinds of odors, whether they enjoy them or not.

Image: by Bill Gracey (via Flickr)

Ashiq Hussain, Luis R. Saraiva, David M. Ferrero, Gaurav Ahuja, Venkatesh S. Krishna, Stephen D. Liberles, & Sigrun I. Korsching (2013). High-affinity olfactory receptor for the death-associated odor cadaverine. PNAS DOI: 10.1073/pnas.1318596110

Note: This post has been edited from an earlier version.

Fungus-Farming Beetles Start Tending Their Crop as Babies

Inside the stems of Japanese bamboo plants, tiny farmers are working in secret. They tend to their crop of fungus, growing it in plump white clusters on their walls for eating, all while sealed safely away from the rest of the world. They begin farming the day they hatch—and when they retire, tuck some of their crop into their pockets to pass on to the next generation.

The farmer is Doubledaya bucculenta, a species of lizard beetle. Many social insects (those that live in colonies) are well-known farmers. Leafcutter ants, for example, cut up all those leaves to feed to their own fungus crop. But farming in nonsocial insects, like the loner lizard beetles, is more mysterious.

Wataru Toki of the University of Tokyo has been gradually uncovering the farming habits of D. buccalenta. Last year, Toki and other researchers announced that the beetle grows a certain kind of yeast (which is a fungus) inside bamboo plants. Each spring, female beetles come to bamboo stems, chew a hole through their hard walls, drop a single egg inside, and then seal the cavity back up. Bamboo stems have hollow sections separated by solid nodes. Inside this protected home, the egg hatches into a larva. The walls of its home end up covered in white fungus, which the larva eats.

Once it's grown into an adult, the beetle chews its way back out of the bamboo and into the world. But female beetles, the researchers found, carry a little bit of their yeast crop with them. They store it in a kind of pocket built into the ends of their abdomens. Is this stash somehow passed on to the next generation of eggs?

To find the answer, Toki and others carried out a number of experiments, including slicing bamboo stalks in half and videotaping the egg-laying process from the inside. After the mother beetle hacks into the plant (she has an asymmetrical head, which Toki suspects somehow helps her crack the tough bamboo), she turns around and sticks an organ called her ovipositor through the hole. She extrudes a single long, tubular egg, then makes several squeezing motions with her ovipositor before sealing the hole back up with bamboo fibers.

This squeezing action seems to deliver the yeast from the mother's pocket into the bamboo plant. The researchers found yeast cells concentrated on the end of the egg and at the sealed-up bamboo hole. Left alone, this yeast can grow into a meager colony. But when the egg hatches, the larva emerges from the yeasty end of the egg and begins to wriggle around its home. Soon, lush yeast colonies sprout in its path.

In other words, "The larvae actively spread the yeast," Toki says. Mothers pass down the crop to their offspring, and larvae start nurturing it as soon as they hatch. For the beetles, farming is a family business.

Toki says it's still not known how mother beetles collect yeast in their pockets. "However, it is clear that they get the yeast before they leave the home—bamboo cavity—where they grew up." Next, Toki hopes to figure out how D. buccalenta prevents other microorganisms from invading its yeast farms. They may not be social, but the beetles have plenty to tell us.

Image: Toki et al.

Wataru Toki, Yukiko Takahashi, & Katsumi Togashi (2013). Fungal Garden Making inside Bamboos by a Non-Social Fungus-Growing Beetle. PLOS ONE DOI: 10.1371/journal.pone.0079515

Schrödinger's Turtle: How Observing Ocean Animals Can Harm Them

We rely on roving ocean creatures to fetch us all kinds of data we couldn't get otherwise. Carrying cameras or GPS units or sensors glued to their bodies, marine animals collect data for human scientists about the health of ocean ecosystems or how their own species migrate. Yet lugging our equipment through the sea may be harder for these creatures than we realize. By tagging them, we might be slowing down or even harming the same species we're trying to preserve.

When scientists tag birds, the authors of a new paper in the journal Methods in Ecology and Evolution explain, they follow the "five percent rule": any transmitters they attach to a bird must be less than five percent of its body mass. This ensures the animal can still take off and fly without trouble. But underwater, heaviness doesn't matter as much. Everything gets a boost from buoyancy. What matters more, the authors say, is drag.

To study how drag from tags affects marine animals, NOAA scientist T. Todd Jones and his coauthors put turtles into a wind tunnel. They chose turtles because they're popular—more than 50 published studies per year involve sticking some kind of device to a turtle. Some sea turtle species migrate across entire oceans, so they may carry these devices for hundreds or thousands of miles. And most are endangered.

Instead of propping up live endangered animals inside their wind tunnel, the researchers built fiberglass models. These were casts of 11 types of turtle bodies, minus the front flippers, made from frozen or stuffed carcasses. (The carcasses themselves were too heavy to mount in the wind tunnel.) The researchers also compared a fiberglass cast to a real turtle carcass in water, to make sure the shell materials themselves didn't cause different amounts of drag.

Turtles, of course, don't fly. "Air and water are both fluids," Jones explains; by matching the Reynolds number—a measurement representing turbulence—of the wind to that of water, the scientists could simulate a swimming turtle. Wind speeds of 8 to 20 meters per second corresponded to turtle swimming speeds of 0.5 to 1.3 meters per second.

Attaching seven different kinds of tags to their fake turtles, the researchers saw that most devices increased drag on adult turtles by 5% or less. With a young turtle and a bulky tag, though, it's possible to double the normal drag on the animal. The authors provide charts that other scientists can use to estimate how much drag they're adding to a turtle, based on the animal's size and species as well as the size and shape of their equipment.

It's nearly impossible to tell how tagging equipment affects animals in real life, thanks to a Schrödinger's-turtle paradox: we can't follow the long-term activities of ocean animals that aren't tagged in some way, so we can only compare tagged animals to other tagged animals. However, Jones worries that putting a lot of extra drag—or even a little extra drag—on an animal like a sea turtle could be harmful. These species may burn through every last bit of their energy as they make long-distance migrations, so any extra burden could hurt their odds of surviving and reproducing. (The added brake on their swimming speed might also make them more vulnerable to predators.)

"By following our guidelines, researchers can minimize the drag effects to their study organism," Jones says. This should help keep animals as safe as possible, and keep scientists' results in line with natural conditions for the animals. "However," Jones adds, "sometimes the guidelines will suggest that a certain tag simply should not be used on a particular animal."

Since sea turtles sometimes carry barnacles on their shells, which also add drag, Jones recommends that researchers take the time to pry off a few barnacles while they're gluing on equipment. That way they can make up for some of the extra burden on the turtle, and perhaps alleviate their own guilt about replacing one pest with another.

T. Todd Jones, Kyle S. Van Houtan, Brian L. Bostrom, Peter Ostafichuk, JonMikkelsen, EmreTezcan, Michael Carey, Brittany Imlach, & Jeffrey A. Seminoff (2013). Calculating the ecological impacts of animal-borne instruments on aquatic organisms. Methods in Ecology and Evolution DOI: 10.1111/2041-210X.12109

Images: top, USGS/photo by Kristen Hart; middle, T. Todd Jones.