Springtime Symbiosis: Trout Lilies and Superhero Ants

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Trout Lilies (Erythronium americanum) pop up from the forest floor, tiny harbingers of warm weather to come. This little lily is a spring ephemeral – a flowering plant that takes advantage of that tiny window of time between the last frozen days of winter and the heyday of spring, when the forest canopy selfishly soaks up all the sun’s rays. During those few weeks, the Trout Lily breaks through a ceiling of dead leaves, and slurps up sun and nutrients to store for the rest of the year in its underground bulb. If that’s not enough, that brief time is also used to flower, produce seeds, and make sure the next generation is safely on its way. No wonder this little plant needs a rest for the remainder of the year!

Given the time limitation, the Trout Lily can’t mess around with seed distribution. It has to be done right and done quickly. Call in the ants.

Many spring ephemerals, like the Trout Lily, produce an incentive for ants to take their seeds, move them a distance away, and plant them in a safe, nutrient-rich location. Each seed has a dollop of yumminess on its outer surface, like icing on a seed-shaped cupcake (officially the “icing” is called an elaiosome, a mixture of fats and protein). Ants carry the seeds back to their nests, feed the yumminess to their larvae, and dispose of the seeds in a waste area which just happens to be a wonderfully fertile location for young seedlings to begin their lives.

Not only do ants spread seeds to new locations and give them a fertile spot to grow, they also protect the seeds from predators like mice. Ruhren and Dudash (1) placed seeds in four scenarios on the forest floor: (a) accessible to both ants and mice, (b & c) accessible to either mice or ants, and (d) inaccessible to mice and ants. The researchers found that ants secured the seeds before the mice, saving the little plants’ lives. In locales where these superhero ants have vanished, spring ephemeral populations drop 70% (2).

Want to learn more about the superhero ants (a.k.a. winnow ants)? Visit School of Ants.

  1. Ruhren, S. and M. R. Dudash. 1996. Consequences of the Timing of seed release of Erythronium americanum (Liliaceae), a deciduous forest myrmecochore. American Journal of Botany 83(5):633-640.
  2. Rodriguez-Cabal, M., K.L. Stuble, B. Guenard, R.R. Dunn, N.J. Sanders. 2012. Disruption of ant-seed dispersal mutualisms by the invasive Asian needle and (Pachycondyla chinensis). Biol. Invasions 14:557-565.

A Poinsettia by any other name… the cuetlaxochitl

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Politics was different in the early 1800s. You didn’t even have to run for office to be elected. Joel Poinsett’s friends nominated him to the South Carolina House of Representatives, and he won. By that time, he’d already completed years of travel through Europe, Russia, the Middle East, and South America where he’d met with foreign ministers, consuls, an empress, and many other political figures.

Within a few years, Poinsett became a U.S. congressman and then the first foreign minister in Mexico. That’s where he saw that plant that would later carry his name. He sent cuttings back to his greenhouses in Charleston and introduced the United States to a beautiful Mexican plant. Unfortunately, Poinsett got in a bit of trouble over his political views in Mexico (the word “poinsettismo” was coined as a result of his intrusive meddling) and was recalled from his post. Poinsett went on to cofound the National Institute for the Promotion of Science and the Useful Arts, later known as the Smithsonian Institution.(1)

Of course, the Poinsettia was well-known in Mexico long before Joel Poinsett. The plant is called cuetlaxochitl (pronounce), and grows as a shrub in Mexico City. The blood-red bracts are symbolic of sacrifices and creation.(2)

  1. To learn more about Joel Poinsett, read “Joel R. Poinsett: Versatile American” by J. F. Rippy
  2. Lots of interesting information about Poinsettias can be found at http://extension.illinois.edu/poinsettia/

Bee Bandits

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Flowers need bees. A bee’s job is to move pollen from one bloom to another; plants pay for the bee’s service with sweet nectar. Cunningly, some bees have found a way to get a paycheck without the work.

Carpenter bees (Xylocopa sp.) exhibit a behavior called “nectar theft.” Rather than reaching the base of the flower through its opening (and getting a pollen dusting in the process), robber bees bite a hole in the base of the flower to slurp up nectar, bypassing the pollen-yielding anthers entirely.

We can’t necessarily blame them though, as it may be the plant’s own darn fault. Flowers with long tube-like bases are more likely to get robbed since the brawny carpenter bees can’t reach the nectar any other way (1). This relationship may even keep the flower tubes shorter over evolutionary time, since short flowers are more likely to be pollinated (and less likely to be robbed).

In order to deter break-ins, some flowers have evolved thicker flower walls, new toxins, or even special relationships with animal “special forces.” Some tropical flowers produce extra nectar in a special chamber for ants, who act like police in stopping the robber bees (2).

P.S. The bees I watched for this sketch were upstanding citizens – no thievery going on here!

P.S.S. It’s a girl! This bee’s got a black face. Males have a large patch of white on their faces. (http://www.uark.edu/ua/arthmuse/carpbee.html)

  1. Navarro L and R Mendel. 2009. Relationship between floral tube length and nectar robbing in Duranta erecta L. (Verbenaceae). Biological Journal of the Linnean Society. 96 (2) 392-398.
  2. Gerling D, HHW Velthuis, and A Hefetz. 1989. Bionomics of the Large Carpenter Bees of the Genus Xylocopa. Annual Review of Entomology. 34:163-190.

 

Wildflower Stories: Ast(er)ounding!

asters_ATlFavorite flower? Daisy (an Aster, like these).
Not only is it humble and cute, it’s a bargain. For each daisy you buy, you get hundreds of flowers. The disk part of each “flower” is actually a composite of scores of tiny flowers. Look close – you’ll see.

aster_closeAnd the “petals” of a daisy? Each one is actually a whole flower too! The single petal plucked for “loves me” or “loves me not” is actually 5 petals fused over evolutionary time. If you look at the tips, you can still see some divisions.

Here’s another example of an aster – purple coneflower!

Educational Activity: dissect an aster and see all the mini-flowers for yourself!

Wildflower Stories: Part 4 (Minty-fresh poop?)

ATwildflowers_mintBee Balm (Monarda sp.) is a member of the Mint Family – a group of aromatic plants that includes basil, lavender, rosemary, salvia and oregano.

How can you identify a Mint? Of course, the smell is a dead giveaway. That odor is actually a deterrent for herbivores. If a mouse eats a bit of mint, that mint scent will overpower the rodent’s sense of smell. So the mouse won’t be able to pick up a cat’s scent later on.

Some beetles have evolved to resist the essential oils of Bee Balm. When they eat the plant, oils condense in the beetles’ poop. They form the poop into a “shield”, waving it at any potential predators.mint_flower

Wildflower Stories: Part 3 (Red Clover Symbiosis)

ATwildflowers_cloverImagine the extreme thirst of being stranded at sea, encircled by water you cannot drink.  Air is like that. Our bodies need nitrogen desperately to survive – and we’re surrounded by air full of Nitrogen (N2). But it’s all unusable. N2 needs to be converted to NO2 for us to use. Only bacteria can do that.

So what do bacteria and nitrogen have to do with this unassuming little plant? Red Clover (Trifolium pretense) is a member of the Legume Family of plants. Legumes cooperate with soil bacteria, giving them sugars and, in return, receiving “fixed nitrogen” (NO2). This fixed nitrogen inserts itself into all the living structures of the plant and, when eaten, passes the usable nitrogen on to animals.

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Until the early 1900s, the only way we could get nitrogen in our bodies was through this route. Then, the Haber-Bosch process was developed. Not only did it save us from mass starvation (yay!), it served as a resource for making bombs (hiss!) and ultimately intensifying World War II.

For an AWESOME read about the Haber-Bosch process, read “The Alchemy of Air” by Thomas Hager. Now if someone would just write an exciting, gut-wrenching saga about legumes and soil bacteria.

Wildflower Stories: Part 2 (Tall Bluebell)

Bluebell_ATwildflowerslSee that Tall Bluebell (Campanulastrum americanum) flower? Is it red or is it blue?

Believe it or not, it’s kind of both!

The color pigment in plants that makes red is called anthocyanin. The pigment normally reflects red light waves. But if you raise the pH and add a couple metal atoms to anthocyanin, it changes the light waves reflected – and poof – blue!

bluebell_flower

Turns out, blue is a pretty rare color in nature. Dr. David Lee wrote a whole book about how colors in nature come to be, including the fairly complex steps to making blue in “Nature’s Palette: The Science of Plant Color”.

If you’d like to check out the color pigments in the flowers around your home, visit Scientific American for an easy, do-it-yourself pigment experiment.