Posts Categorized: Science You’re Super

Science, You’re Super: Bees!

Bee_EvanSowder

By Aryn Henning Nichols • Photo by Evan Sowder
Originally published in the Summer 2015 Inspire(d)

There’s always been a buzz around bees.

Okay…it’s a bad pun. But, really, bees are pretty darn amazing. They fly their slightly cantankerous (especially for the bumble bees) bodies around, pollinating flowers and crops across the world – in the U.S., alone, their work is worth an estimated $10 billion. (3)

Some even say bees are responsible for one out of every three bites of food we eat. Most crops grown for their fruits (like squash, cucumber, tomato, eggplant), nuts, seeds, fiber (such as cotton), and hay (alfalfa grown to feed livestock), require pollination by insects. Pollination is “the transfer of pollen from the male parts of a flower to the female parts of a flower of the same species, which results in fertilization of plant ovaries and the production of seeds.” According to Michigan State University’s entomology department, the main insect pollinators, by far, are bees. There are hundreds of species of bees that contribute to the pollination of crops. (5)

So where do these little super heroes come from and how do they know how to do their jobs?

Scientists believe that both bees and flowering plants evolved around 100 million years ago during the Cretaceous period. Before this, many plants released seeds and pollen using cones (think pine trees, but both big and small cones). The wind brought the pollen and cones together, thus fertilizing them. But some plants began to reproduce using flowers, and they needed the help of insects and other animals to achieve pollination. (2)

Around the same time, bees were evolving from their wasp-like ancestors. Prehistoric wasps were carnivores that lay their eggs in the bodies of their prey. After flower reproduction happened, bees became herbivores, eating pollen and nectar from the plants and pollinating flowers as they went. (2)

To further enhance pollination, a bee’s body is covered in fuzzy hair that collects pollen, and its legs are built for specific pollen-collecting tasks. The body has three sections – the head, the thorax and the abdomen – much like other insects. The abdomen houses the stinger, and the crop, or honey stomach, where the bees store nectar. A bee has five eyes – three simple eyes, “orocelli”, and two compound eyes made of lots of small, repeating eye parts called “ommatidia” that specialize in seeing patterns. This allows bees to detect polarized light – a super-power humans do not possess! (2)

Bees can be solitary – living mainly alone – or social – living in colonies. Less than 15 percent of bees are social, even though many people are most familiar with social bees since they produce things like honey and beeswax, and will pollinate in large groups in orchards and gardens. (2)

Two of the most advanced social bees are honeybees and bumblebees. Each colony has a single queen, many workers, and – at certain stages in the colony cycle – drones. A commercial – human provided – honeybee hive can contain up to 40,000 bees at their annual spring peak (but it’s usually fewer). (1)

Although honeybees and bumblebees are both social, their societies are quite different. Honeybee colonies are perennial – a nest will last generations. Bumblebees, on the other hand, have annual nests. (2) But no matter how they live, most bees have a similar approach to mating. In nearly every species, a male bee’s only job is to mate with a female. After the female mates, she either retreats to a shelter for the winter or returns to her nest to lay eggs. A female solitary bee lays only a few eggs in her lifetime, but a queen honeybee lays thousands! (2)ScienceYoureSuper_Logo

Honey, let’s Dance

Bees have an acute sense of smell, and can recognize symmetry and patterns, such as colors or shapes. This helps bees find and recognize flowers and food. Honeybees communicate food’s location with a special bee language: dancing.

When a scout finds food, she uses two known tools to remember its location. 1. A solar compass that helps her calculate where things are in relation to the sun. The bee’s ability to see polarized light (remember the ommatidia eyes) tells her where the sun is even if it’s a cloudy day. 2. An internal clock that tells her how far she has flown.

When the scout returns to the hive, she distributes nectar samples, then performs a dance on the hive “dance floor.”

If the food is nearby, the scout does a “round dance,” making loops in alternating directions.

When the food is far away, she does a “waggle dance”. She runs in a straight line while waggling her abdomen, then returns to the starting point by running in a curve to the left or right of the line. The straight line indicates the direction of the food in relation to the sun. (3)

Then, the sisters head out to forage. They make up to a dozen trips back and forth between the hive and the food; each bee can carry half her weight in pollen or nectar!

Inside the hive, the worker bees transform the nectar into honey. Nectar is 70 percent water compared to honey’s 20 percent. Bees evaporate the extra water by regurgitating the nectar over and over, and also fan their wings over the honeycomb.

While doing all this foraging for nectar and pollen, bees inadvertently pollinate nearly 100 crops. All told, insect pollinators contribute to one-third of the world’s diet. (3) (Super heroes!)

Bees themselves gather enough honey to survive winter. During winter, bees leave their hives only to go to the bathroom. Inside, they take care of the queen and heat the hive by vibrating their wing muscles, similar to humans’ shivering. To control the temperature in the summer they circulate air with their wings and sprinkle the honeycomb with water. (3)

The length of a female honeybee’s life is usually only a few weeks. A queen, though, can live three to five years!

There has been a major decline in commercial honeybee numbers over the past 50 years – and even more so since 2007 – called Colony Collapse Disorder (CCD). The cause hasn’t been pinpointed yet, but researchers say reasons could include parasites and bacteria, environmental stress, like a lack of pollen, and, very likely, pesticide usage.

What can we do to help? Here are three easy ideas:

  1. Plant a Pollinator Garden. See online guide for plantings. (www.pollinator.org/guides.htm)
  2. Reduce your use of pesticides, especially when flowers are in bloom and bees are out foraging
  3. Buy local to help support local beekeepers (4)

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Aryn Henning Nichols was amazed by bees as she researched this story – dancing? Polarized light? Awesome. Let’s work to save the bees! Plant some butterfly weed (and other pollinator garden plants) today!

Extra bee facts:

  • The average American consumes a little over one pound of honey a year.
  • In the course of her lifetime, a worker bee will produce 1/12th of a teaspoon of honey.
  • To make one pound of honey, workers in a hive fly 55,000 miles and tap two million flowers.
  • In a single collecting trip, a worker will visit between 50 and 100 flowers.
  • A productive hive can make and store up to two pounds of honey a day. Thirty-five pounds of honey provides enough energy for a small colony to survive the winter. (3)

Sources:

1. en.wikipedia.org/wiki/Bee
2. animals.howstuffworks.com/insects/bee.htm
3. www.pbs.org/wgbh/nova/bees/
4. www.cnn.com/2015/03/04/living/iyw-5-ways-to-help-bees/
5. nativeplants.msu.edu/about/pollination

Science, You’re Super: Fireflies!

Fireflies

By Aryn Henning Nichols • Photo by Radim Schreiber
Originally published in the Summer 2014 Inspire(d)

You know what’s super magical? Light-up bums.

I’m talking fireflies, of course! A field or dark forest flooded with those little flickering butts is some seriously super science. It’s one of my favorite things about summer. But have you ever wondered how they do it? Or why?

First off, fireflies – or lightning bugs (whichever you prefer) – are neither flies nor bugs. They’re beetles. But lightning beetle just doesn’t have the same ring, does it? (1)

These little beetles produce a chemical reaction inside their bodies called bioluminescence, which allows them to light up. Inside their light organs, oxygen combines with calcium, adenosine triphosphate (ATP), and the chemical luciferin – all while the bioluminescent enzyme luciferase is present. This produces light. (2)

And it’s not just any light. An average electric light bulb gives off 90 percent of its energy as heat, and only 10 percent as light. If fireflies produced that much heat when they lit up, they’d probably not live through it (giving new meaning to “fire”flies). Luckily, fireflies are amazingly efficient light-producers. During bioluminescence, a hundred percent of the energy goes into making light. (1)

The firefly controls the beginning and end of the chemical reaction, and thus the start and stop of its light emission, through oxygen. Insects do not have lungs, but instead transport oxygen from outside the body to the interior cells through a complex series of successively smaller tubes known as tracheoles. When the firefly wants to light up, it adds oxygen to the other chemicals needed to produce light. When there’s no oxygen available, the light goes out. (2)

They appear to light up for a variety of reasons: to communicate their distastefulness to predators, to help identify certain types of species, or, more commonly, to attract members of the opposite sex. Yes, fireflies get right to the point in their short two-to-three-week lifespan. Studies have also shown that some female fireflies like males with high flash rates and/or increased flash intensity. Ooh la la! (2)

Unfortunately for some sad folks in a few sad regions, not all fireflies flash. Fireflies that inhabit the western areas of North America don’t use light signals to communicate. Because of this, many people inaccurately believe that they don’t exist west of the Rockies, since flashing populations are rarely seen there.

But for some lucky folks in a few lucky regions, fireflies synchronize their flashes! It’s rare – in the US, you can see this phenomenon (usually during a two-week window in late spring) at Great Smoky Mountains National Park in Tennessee – but amazing to see. Thousands of fireflies will light up at the same time, over and over, in what’s called simultaneous bioluminescence! Not coincidentally, thousands of people come from all over to witness this amazing show each year. (3)

And now, final interesting firefly fact: Firefly luciferase is also useful in medical research! It can be used as markers to detect blood clots or to tag cells and genes, and to monitor hydrogen peroxide levels in living organisms (hydrogen peroxide is believed to play a role in the progression of some diseases, like cancer and diabetes). Scientists can now use a synthetic form of luciferase – fortunately – as we’d all like to keep those little bums flashing for many years to come. (1)

Sources:

1. insects.about.com/od/beetles/a/10-Cool-Facts-About-Fireflies.htm
2. www.scientificamerican.com/article/how-and-why-do-fireflies
3. www.nps.gov/grsm/naturescience/fireflies.htm

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Aryn Henning Nichols has watched, chased, or caught fireflies every summer of her life. She may also have squished and smeared a few, and feels more than a little guilty about it, especially after writing this Science, You’re Super! Sorry, fireflies. Never again!

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Radim Schreiber, born in the Czech Republic, is an artist/photographer and cinematographer. His passion for photography began while photographing insects during his college years in Iowa. After completing his BFA at Maharishi University of Management, he started working for The Sky Factory, LLC in Fairfield, Iowa, as a nature photographer, cinematographer, and digital artist. Radim has won multiple national and international photography competitions, including the Smithsonian Magazine Photography contest. Radim’s latest project is photographing the bioluminescent glow of fireflies.

 

Science, You’re Super: Compost!

Compost

It’s a dirty Business…but it’s worth it!  Shutterstock photo/ Marina Lohrbach

By Kristine Jepsen • Originally published in the Spring 2015 Inspire(d)

You know you’ve wondered about it – that heap in your neighbor’s yard. Or, maybe your child came home from school and breathlessly told you a classmate had buckets full of garbage-eating worms in her basement. Perhaps you yourself have saved kitchen scraps with the hope of turning them to the ‘black gold’ known as compost, rich and weighty and uniform as it crumbles through the fingers.

It’s not magic, but science! Composting is one of the most transformative and successful processes on the planet. It’s a specific series of biological and chemical events that harvests the raw elements from anything once living – blades of grass, banana peels, wood chips, newspaper – and returns them to their most accessible form: soil teeming with life-giving nutrients. Dust to dust.

So why aren’t more people drinking this Kool-Aid? Well, because watching dead things come back to ‘life’ isn’t pretty. There are mushy, squishy parts and lots of bugs. Composting also takes time – ranging from a few months to a year or more, depending on ambient temperatures and handling. And, if proceeding under less-than-optimal conditions – i.e. without the right ratio of materials or influx of oxygen – it can get stinky. Really stinky.

But it’s totally do-able, even with Midwestern winters as they are. And it could save 25-30 percent of your household waste from the landfill, where organic plant matter has little chance of breaking down organically.

There are three common types of composting: 
Aerobic – in which the microorganisms doing the dirty work require oxygen;
Anaerobic – actually called putrefaction, in which microorganisms go to town in the absence of oxygen, releasing ammonia, methane gas, and hydrogen sulfide; and
Vermicomposting – a subset of aerobic composting where the work is done primarily by species of worms that adore digesting food scraps and fiber waste.

In the aerobic setting – the fastest and most common in nature and most often replicated by humans – the perfect scenario is to feed dry, carbon-rich “brown” ingredients (newspaper, wood chips, leaves, dry-ish coffee grounds) in proportion to wetter “green” ingredients (vegetable scraps, fruit peels) in combinations that result in the total chemical composition of the pile achieving a ratio is 25:1 or 30:1 (carbon:nitrogen).

This ratio exists because the microorganisms – bacteria, bugs, fungi, etc – that metabolize compost use carbon as fuel, oxidizing it and respiring it as carbon dioxide, as well as combining it with nitrogen and other nutrients to make their own cell protoplasm. It does not, however, mean the pile needs 25 parts brown ingredients to 1 green. This is where it gets a little more confusing: Each food source contains some proportion of brown to green as well— it falls into one camp or the other depending on how dry it is when added. So, all told, a good rule of thumb is to add two parts green to one part brown, or even one-to-one. (See resources below for a link to a handy compost “recipe” calculator.)

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As bacteria chow down and oxidize carbon it generates HEAT (photo by Kristine Jepsen)! Under aerobic composting conditions, just one gram of glucose molecules can release up to 484 to 674 kilogram calories (kcal) of heat – enough kilowatts to brew 4-6 pots of java in the average coffee maker. As compost is digested and microorganisms multiply, the pile heats up and those best suited for each range of temperatures – and the changing food supply – take over.

A compost pile both introduces and sustains a wide variety of bacteria, fungi, and actinomycetes (those wispy, branching growths that often form an extensive colony, or mycelium).

Successive waves of bacteria that tolerate the hot-getting-hotter interior of the pile include mesophilic bacteria (50-115 degrees), which give way to thermophilic bacteria (150-160 degrees – by comparison, the average hot water heater is set around 125 degrees.) After the first 10 days, the original materials in the pile lose their definition and the pile shrinks substantially. Beyond 160 degrees, bacteria die off or run out of sufficient oxygen to continue, and the pile starts to cool, requiring stirring or turning to put undigested materials back in contact with remaining bacteria.

By contrast, compost fungi and actinomycetes cannot handle the hotter interior, restricting them to growth within the first 2-6” beneath the surface. There, they break down much of the tougher plant matter in the pile, usually near the end of the composting period or “curing” when the temperatures have begun to drop and they can survive across a larger part of the pile.

Toward the end, mites, millipedes, centipedes, springtails, beetles and earthworms also flourish and add their castings to the nutrient density of the mixture. In fact, the size of the organisms present in the pile can indicate the mixture’s maturity, as the organisms on each level of the food chain keep the populations of the next lower level in check.

Compost – or humus – is ‘done’ when it ‘stabilizes’ and its internal temperature returns to ambient temperature, even when turned or stirred. Most of the original materials should be unrecognizable, though tough, woody items like sunflower stems, corncobs, and avocado pits will still be intact. These can be removed (laden with beneficial bacteria) and incorporated into a new pile for another round. The remaining, sifted compost —reduced to about a third the volume of its original inputs! — should cure or rest for three or more months before use as potting soil, mulch or a soil amendment. It will be deep brown in color, uniform in particle size (small), and smell ‘good’ and earthy – like a forest floor.

turningmushroomcompost

Commercial compost – for sale at garden centers – is regulated by state agencies, says Marty Grimm, who sells bulk commercial compost from his farm east of Decorah through his company, Upper Iowa Organics (pictured above, photo by Kristine Jepsen). His windrow-style piles, centered on his 34 acres, must maintain an internal temperature of 131 degrees or more for 15 consecutive days, measured by a recognized compost thermometer, before it can be ‘screened’ to remove any ‘overs’ (oversize particles). Then it cures for 3-9 months before it’s ready for sale. “That’s the state’s regulation for ensuring harmful pathogens don’t survive,” Grimm explains. “Compost is quantified and classified as a fertilizer, just like the synthetics.”

If you don’t have room or desire to build a bin or pile, vermicomposting is aerobic composting in miniature – where the red wiggler or manure worm (Eisensia foetida) or the red worm (Lumbricus rebellus) chew up the layers of brown and green inputs, leaving rich, uniform castings.

Plastic worm bins need to be perforated with several holes on all sides for ventilation, and a coarse cloth (coconut mat, burlap) should line the bottom of each bin. When a bin is full and castings uniform, the worms can be ‘removed’ by stacking a new bin containing fresh food on top or alongside it. After mere days, the worms will migrate through the ventilation holes to the fresh grub.

“As with most things, worms will thrive if you just pay attention,” says Jim Tripp, an avid gardener and founding member of Decorah Urban Gardens (DUG). “If they’re slowing down, you have to adjust.” Is the air temp colder? Are they not getting through the wetter materials and need another sheet of newspaper laid on top? “Also, no discussion of worm bins should go without stating: ‘Worms LOVE coffee grounds. Love them.’”

Just think about that next time you’re tossing a filter in the trash.

Who knows? You just might find yourself commissioning a scrap bucket to keep under the sink.

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Every windowsill in Kristine Jepsen’s home has at least one plant in it. And she pots up jade starts rather compulsively. It’s time to cultivate compost, too – no more excuses! In addition to writing for Inspire(d), she publishes creative nonfiction and other projects on her site: kristinejepsen.com.

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DO IT AT HOME!
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How to get started with aerobic composting

Choose a well-drained site and a retaining structure, if desired (wooden pallets, for example, or a rotating bin – you can purchase special bins just for composting that are built on a “spit” for easy spinning)

Alternate 2-4” layers of brown and green materials, roughly adding equal amounts by weight (which means adding more of the drier, lighter brown stuff to balance out the heavier green stuff). Some sources propose adding this volume of material and just stirring it uniformly, instead of messing with layers. Water compost lightly as layers are added.

Keep the site 3’x3’x3’ or thereabouts so the work of stirring it or turning it is manageable. ‘Turning’ means removing everything from the bin and putting it back in, moving material from the edges of the pile to the middle, as possible. Keeping the site compact also encourages bacterial activity and keeps the heat from dissipating in cooler temperatures.

Continue to add material to a pile, as warranted by the space, burying food scraps in the center and covering each green addition with a layer of ‘brown’ inputs, such as dry leaves.

To ‘finish’ a pile, stop adding new material and let the compost cure until turning no longer generates bacterial activity (heat).

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Composting gone wrong: Common mistakes and how to fix them

Don’t overwater or overfeed with nitrogen-rich “green” ingredients. The microbes, including worms, can’t keep up. If your pile or bin feels more moist than a damp (not dripping) wash rag, back off on the green stuff and add some dry “brown” stuff to restore order.

Stinky, slimy mess? Turn the pile uniformly or stir the worm bin. Every phase of aerobic composting requires an influx of oxygen. Check your carbon-to-nitrogen ratio of ingredients to adjust for moisture, too. Keep in mind that some ingredients can go either way: Grass clippings are full of nitrogen (green) when they’re fresh and wet. They’re more in the ‘brown’ camp once they’ve dried.

Won’t heat up? The pile likely contains too much carbon (brown ingredients). Mix more green inputs into the pile and aerate thoroughly. If still too dry, water the whole pile and stir again.

Don’t compost pet droppings, bones or meat scraps, which often contain pathogens that aren’t killed in the range of thermic activity in the average home compost pile.

Don’t compost colored paper – the dyes that create the color may contain metals and other chemicals that harm beneficial composting bacteria.

Avoid composting yard waste containing weed seeds, which are also difficult to kill.

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Resources:
Interactive compost recipe calculator

Comprehensive how-to from Texas A&M Extension Service

The chemistry of composting

Florida’s state site for home composting

Guidelines for testing finished compost

Good list of browns and greens — with their carbon:nitrogen ratios

List of ‘greens’ and ‘browns’

Source for vermicomposting worms

Or, ask around town – an active composter might even have worms to share!