Springtime Symbiosis: Trout Lilies and Superhero Ants

troutlily_webJML

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.

The Corpse Flower Opens – and Stinks!

corpseflower_fri

Many flowers use insects to transfer pollen from one plant to another. Some flowers attract bees or butterflies. The corpse flower, though, uses carrion beetles and flesh flies. What attracts these pollinators? The color of decaying flesh, putrid scents, and the warm temperature of a freshly dead body. Lovely.

While we humans tend to focus on color, beetles and flies who pollinate the corpse flower may be more attracted to the scent and temperature. Angioy et al. (2004) showed that certain insects have the abilities to “see” temperatures and are attracted to heat. The heat generated by the spadix of the flower is unusual in the plant kingdom. Not many plants expend tons of energy to warm up to around 100 degrees Fahrenheit. Those few that do are called “thermogenic plants.” It’s generally accepted that the heat increases the range of the odors (Barthlott et al. 2009), which is true of course. But wouldn’t all plants benefit by increasing scent ranges? Yet this mechanism is found in plants that only mimic carcasses to attract pollinators – plants like the skunk cabbage and voodoo lily.

While most flowers give their pollinators a reward of some kind (think nectar), the corpse flower seems to just take, take, take. The plant mimics carrion, where pollinators normally lay their eggs, yet gives the pollinators no food or reward. Or could it?

I personally found it interesting that the spathe of the corpse flower closed back up after it bloomed. It’s probably protecting the developing fruit. Yet the fruit takes 6-9 months to mature. At the Chicago Botanic Garden, the spathe of their corpse flower wilted after about 3 months, exposing yet unripe fruit. Could the flower serve as protection for the developing carrion beetles? Is there any food supply for those youngsters when they hatch? Or is it just a dead end (pun intended)?

FYI: while other arums smell like corpses too (my personal favorite is the “pig-butt arum”), some species of Amorphophallus smell like bananas or carrots.

  1. Angioy AM et al. 2004. Function of the heater: the dead horse arum revisited. Proceedings of the Royal Society Biological Sciences. 271(3) S13-15.
  2. Barthlott W et al. 2009. A torch in the rain forest: thermogenesis of the Titan arum (Amorphophallus titanium). Plant Biology 11. 499-505.

The Corpse Flower, a Botanical Marvel

corpseflower_lupin_thuIt’s rare to see a corpse flower bloom. If you ever have the opportunity, take it… especially if you get to visit Sumatra. Lucky for me, a corpse flower (Amorphophallus titanium) blossomed in the greenhouse next to my office last weekend at NC State University (https://cals.ncsu.edu/corpse-flower-at-nc-state/).

It took the corpse flower, dubbed Lupin, 13 years to save up enough energy to bloom.  It’ll probably be another five years before it does so again. So corpse flowers are rather special. Actually, fewer than 200 cultivars have been recorded since 1889. But now’s your opportunity. For some yet unknown reason, a bunch are flowering at once (1).

Lupin grew six feet tall in under two months! That tall, purple-grey phallic structure is called a spadix. At its base are about 700 vibrant orange and purple female flowers and thousands of male flowers (2). When the one giant petal (actually a bract known as a spathe) opens, the spadix releases a stench to attract carrion beetles and flies who pollinate all those female flowers.

So actually, the corpse flower isn’t a flower at all. It’s over a thousand flowers wrapped into one giant, stinky, gorgeous inflorescence.

corpseflowerfemales

  1. http://www.sciencealert.com/no-one-really-knows-why-but-america-s-corpse-flowers-are-all-blooming-at-once
  2. Gandawijaja, D, S. Idris, R. Nasution. 1983. Amorphophallus titanium Becc.: a Historical Review and Some Recent Observations. Ann. Bot. 51:269-278.

Wildflower Stories: The Final Chapter (Horsenettle)

ATwildflowers_horsenettlePlants are masterful chemists when it comes to defending themselves. Turns out, some plants build fortifications too. And these armories may even store deadly microbes for use as biological weapons.

Major defensive structures of plants include thorns, spines and prickles. Did you know they’re different? Thorns, officially, grow from the stem or shoot of the plant. They’re like miniature, pointy branches. Hawthorns and lemon trees, for example, have thorns. Spines grow from leaf tissues. Some leaves develop spinous points; some leaves fully convert into spines (like on cacti). Prickles grow from the plant’s outer surface of cells (the epidermis). Since the epidermis is found all over a plant, prickles can pop out of anywhere. “Thorns” on roses are actually prickles. And the spikes growing all over the leaves of this horsenettle (Solanum carolinense) are… prickles.

horsenettleBut these defensive structures may be more prickly (or thorny?) than we ever imagined. Preliminary research indicates that harmful (even deadly) microorganisms inhabit thorns, spines or prickles and cause further injury to herbivores who dare to challenge the awesome power of plants (1).

  1. Halpern M, Raats D, Lev-Yadun S. The Potential Anti-Herbivory Role of Microorganisms on Plant Thorns. Plant Signaling & Behavior. 2007;2(6):503-504.

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.

clover_bee

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.