Take a walk in a winter forest and you can’t help but notice beech trees. Silky smooth bark and sand-colored dry leaves stick out like Christmas lights against a dull and gloomy background. While every other leaf drifted to the forest floor months ago, beech leaves hold tight like cat hair on a sweater.
It’s called marcescence – these leaves that just won’t drop – and it’s common in oak and beech (the trees are close relatives). But why keep the leaves? Are these trees just photosynthetic versions of hoarders?
One possible reason may be to protect that bud, the thin tapered structure often described as “cigar-shaped.” Inside the scaly covering are the beginnings of the new year’s growth. Hungry deer can ruin a tree’s plans for spring. But with beech trees, deer tend to get a mouthful of dry leaves whenever aiming for a yummy bud. (1)
What about attacks from smaller enemies? Insects seem to prefer infesting trees with leaves hanging on over winter. R. Karban decided to yank all the leaves off a few dozen small oaks and compare infestation levels of a tree-noshing wasp. (2) His numbers indicate that wasps prefer leaf-hoarding trees three-to-one compared to his denuded ones.
I believe Nature is constantly sending messages of wisdom if we’ll just listen. In this case, perhaps she’s saying “every action has an upside and downside, but with diversity, there’s always hope for a better future.”
- Svendsen, Claus R. 2001. Effects of marcescent leaves on winter browsing by large herbivores in northern temperate deciduous forests. Alces 37(2): 475-482.
- Karban, R. 2007. Deciduous leaf drop reduces insect herbivory. Oecologia. 153: 81-88.
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)
- To learn more about Joel Poinsett, read “Joel R. Poinsett: Versatile American” by J. F. Rippy
- Lots of interesting information about Poinsettias can be found at http://extension.illinois.edu/poinsettia/
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.
- 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.
- Barthlott W et al. 2009. A torch in the rain forest: thermogenesis of the Titan arum (Amorphophallus titanium). Plant Biology 11. 499-505.
It’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.
- Gandawijaja, D, S. Idris, R. Nasution. 1983. Amorphophallus titanium Becc.: a Historical Review and Some Recent Observations. Ann. Bot. 51:269-278.
As agriculture took hold in Middle Eastern societies about 10,000 years ago, archeological evidence of cat domestication appears. When humans began storing grain, any rodent-killing animal was a benefit. But the presence of cats didn’t spread along with agriculture. Egyptians may have revered cats, but other civilizations used weasels or snakes to limit mice. In the painting “Lady with an Ermine” by Leonardo da Vinci, the weasel may symbolize purity or the young woman’s last name (similar to the Greek word for ermine). With all due respect, however, I think the animal may have just been the lady’s pet; weasels were more common pets than cats at that time.
Cats may have been popular in Egypt during the heyday of the Roman Empire, but Greeks and Romans kept weasels as their rodent-killing pets. Cats joined European families around the fourth century but were relatively uncommon until the 1600s (1).
Nowadays, of course, cats are popular pets and internet memes. Their omnipresence is also a major cause of concern to ecologists and bird lovers. In a 2013 research article, Loss et al. estimated our purring pets (and their feral cousins) kill about 2.5 billion birds and 12 billion rodents each year in the U.S. alone (2).
P.s. The adorable cat who posed for this painting is our own 18-year old feline princess, Flea. She’s killed exactly one bird in her life, a fledgling finch who accidentally flew into her mouth. Flea didn’t even bite down; the little bird panicked to death.
- The Oxford Handbook of Animals in Classical Thought and Life. G.L. Campbell. 2014. Oxford University Press.
- Loss, S.R. et al. 2013. The impact of free-ranging domestic cats on wildlife of the United States. Nature Communications 4:1396.
An old Philippine folktale pits a firefly against a troop of apes. One day, an ape asks the firefly why he carries a lantern. The firefly replies that he uses the light to see mosquitoes and defend himself. The ape laughs and calls the firefly a coward. Insulted, the insect challenges the ape (and all his friends) to a fight. The next day, the firefly faces 1000 apes with large clubs, all lined up against him. The firefly lands on the first ape’s nose and the second ape swings his club to squash the insect. But the lightning bug flits away and the ape’s blow kills his companion instead. Then the firefly alights on the second ape’s nose. A club is swung and the second ape is dead. On and on until the firefly reaches the last ape, who piteously surrenders. The folktale ends, “Since that time, the apes have been in mortal terror of the fireflies.” (1)
Despite folktales consistently portraying apes as fools, we all know they’re actually pretty smart. The Philippine tale is one account of why apes avoid fireflies. But could there be a biological reason for this aversion? Maybe it’s because fireflies are noxious.
One firefly can kill a bearded dragon (Pogona sp.), a fairly large lizard that can grow up to 2 feet long (2). For mammals like apes, well, they probably just taste really bad. Most animals that eat fireflies spit them out or throw them up.
Fireflies do try to warn their would-be attackers through their coloration. Light and dark stripes and red markings are examples of aposematic coloration – both are found on this lightning bug. Don’t say he didn’t warn you!
- Millington, WH and BL Maxfield. 1907. Visayan Folk-Tales. Journal of American Folklore. 20(79) 311-318.
- Knight, M et al. 1999. Firefly Toxicosis in Lizards. Journal of Chemical Ecology. 25(9)
With all the beautiful berries available now, I’ve been seeing more fruit flies hanging around the kitchen. Annoying? Yes. Ruining my strawberries? Nope. Fruit flies lay their eggs on damaged or rotting fruit. So they’re only interested in the pieces that are going bad. I’m ok with that.
But consider a fruit fly who lays her eggs on fresh fruit. She’d have the agricultural community freaking out. Just imagine the risk to berry crops. Actually, you don’t have to imagine because scientists have already done the calculations for you: it’s potentially $2.6 billion of risk (1).
Evolution has already dealt this stunning set of cards to Drosophila suzukii, the spotted-wing drosophila (2). The females have an ovipositor (the anatomical structure that deposits eggs) that looks like a serrated knife. Unlike the common fruit fly in your house, this species’ egg-laying parts can cut through the skins of raspberries, strawberries, blueberries, cherries, and grapes.
Want to learn more about the spotted-wing drosophila? IFAS at the University of Florida has a great info page on the little beastie (with horrifically gorgeous pictures, by Martin Hauser, of that ovipositor – if you haven’t seen fruit fly genitalia yet, you are missing out).
p.s. Thanks to Dr. Nadia Singh for introducing me to Drosophila suzukii.
- Walsh, Douglas, M. Bolda, R. Goodhue, A. Dreves, J. Lee, D. Bruck, V. Walton, S. O’Neal, F. Zalom. 2011. Drosophila suzukii (Diptera: Drosophilidae): Invasive Pest of Ripening Soft Fruit Expanding its Geographic Range and Damage Potential. Journal of Integrated Pest Management. 2(1): G1-7.
- Atallah, L. Teixeira, R. Salazar, G. Zaragoza, A. Kopp. 2014. The making of a pest: the evolution of a fruit-penetrating ovipositor in Drosophila suzukii and related species. Proceedings of the Royal Society B: Biological Sciences, 281 (1781)