The Stinging Tree, or, Australia Hates Mammals

Can’t Touch This
(via: anhs.com.au)

Common Name: Stinging Tree, Gympie-Gympie

A.K.A.: Dendrocnide moroides

Found: Rainforests of Northeastern Australia

It Does What?!

Australia, which was apparently intended only for the very bravest of human beings, is home to many of the world’s most poisonous snakes, spiders, and scorpions. Even the surrounding ocean is exceptional for the number of ridiculously venomous species it contains. Still, a person could be forgiven for thinking that, so long as they stay out of the water and keep away from the creepy-crawlies, they’ll be okay. Ha ha ha… nope. In Australia, everything is out to get you.

Meet Gympie-Gympie, the Stinging Tree (or to be more accurate, stinging shrub). Growing in rainforest clearings and along creek edges- anywhere the canopy is broken- this two metre (6.5ft) high plant has large, heart-shaped leaves and juicy purple fruit. And every square centimetre of it, from the soil on up, is covered in tiny, poison-filled hypodermic needles. These hollow silicon needles are delicate enough to break off at the slightest touch, leaving them embedded in the skin of whatever creature was unfortunate enough to do so. The skin will often then close over them, making the needles nearly impossible to remove. The substance they’re filled with is a very potent neurotoxin with a very long shelf life- herbarium specimens of the plant collected in 1910 are still able to cause pain. And since the body is unable to break down silicon, this all adds up to a very long punishment for a very small mistake.

Go on, I dare you.
(Photo by Melanie Cook)

A brief brush against a stinging tree produces intense pain that peaks after about half an hour, but can literally take years to subside completely. Numerous dogs and horses have died because the pain was so intense. There is even one official record of a human having died- a Dutch botanist of the 1920s. Oddly enough, no actual tissue damage is done by the neurotoxin- death due to the plant is attributed to heart failure due to the shock of the pain, described by one researcher, Dr. Marina Hurley, as “like being burnt with hot acid and electrocuted at the same time.” An ex-serviceman who fell right into one of the trees while crossing a creek in the 1940s describes having had to be tied down to his hospital bed for three weeks because the discomfort was so intense. One intrepid/insane researcher actually purified the neurotoxin and injected himself with it, suffering terribly and thereby proving that the toxin, rather than the needles, causes the majority of the pain. But not all of it… simply standing near a gympie-gympie for an extended period can cause allergic reactions and nosebleeds as the needles are shed in the wind.

“I eat neurotoxins for breakfast.”
(Via: Billabong Sanctuary)

So this must be just about the best herbivore-defence system ever, right? Amusingly, no. The trees still undergo heavy damage due to hungry spiders, ants, snails, and especially beetles, all of which can avoid its defences. The tree is even prey to one species of marsupial, the red-legged pademelon, which is either immune to the neurotoxin or has enormous pain tolerance. So why develop this extensive arsenal if it’s completely ineffective? One expert has suggested that it may have evolved to protect the plants from the now long-extinct giant Diprotodonts which once inhabited the Australian rainforest, making it one more dangerous relic of a long-ended war. You win, stinging tree, you win.

[Fun Fact: The best way to attempt to remove some of those poisonous silicon needles embedded in your arm?  Wax hair removal strips, according to the Queensland ambulance service.]

Says Who?

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A Shellfish Goes to the Dark Side (Sacculina carcini)

The crab barnacle, hitchin’ a ride.
(Image by Hans Hillewaert)

Common Name: Crab Barnacle, or the charmingly descriptive Dutch term “krabbenzakje,” meaning “crab bag”

A.K.A.: Sacculina carcini (and other Sacculina species)

Found: In the coastal waters of Europe and North Africa

It Does What?!

Most barnacles, those almost quaint crusts seen decorating old piers and ships, live their lives by cementing themselves to a hard underwater surface and using their arm-like limbs to pull passing bits of food into their mouths all day. Not so for the crab barnacle, who decided that all that arm-waving was for chumps and set about evolving into the ultimate free-loader.

Normal, hardworking barnacles, for the sake of comparison…
(Image by Michael Maggs)

In its immature larval form, Sacculina has a similar body plan to other barnacles and is able to swim about freely; however, rather than finding a surface to settle down on, it finds itself a crab. Typically, this will be a green crab, species Carcinus maenas. The female barnacle (more on the males later) crawls along the surface of the crab’s shell until she comes to a joint – a chink in the armour – where she turns into a sort of hypodermic needle, injecting herself into the crab and leaving her limbs and shell behind. Now nothing more than a tiny slug-like mass, she makes her way to the crab’s abdomen and proceeds to grow rootlike tendrils throughout her host’s body, drawing nutrients directly from the bloodstream.

If that wasn’t disturbing enough, consider Sacculina’s mode of reproduction. In addition to its internal root system, the parasite forms an external sac (hence the nickname ‘crab bag’) where the female crab normally keeps her fertilized eggs. This is where the male barnacle comes into play. Upon finding a crab already infected by a female, the male will do the same needle trick, injecting himself into the external sac and living for the rest of his life as a parasite inside the female’s body. Fertilization takes place and the sac is soon full of microscopic Sacculina larvae.

In case you needed a closer look.

Since the barnacle infection has rendered the host sterile, and because crabs aren’t very bright, the crab will now care for this sac of larvae as if they were her own young. But what if the infected crab was male, you ask? No problem. The parasite is able to interfere with his hormones to such an extent that, in addition to changing his body shape to that of a female, he now actually behaves like, and even carries out the mating gestures of, a female crab.

Now, this may not seem so bad from the point of view of the crab; I mean, it doesn’t know it’s carrying around evil changeling spawn, right? But it’s a bit worse than that. Wanting to keep all the available energy for its own use, the parasite prevents the crab from moulting its shell or re-growing lost claws, as crabs normally do. This leads to a variety of secondary infections which, coupled with malnutrition, leads to the premature death of the crab. But nature isn’t without a sense of fair play… research has now found that Sacculina sometimes succumbs to viruses and yeast naturally present in the crab’s body, via infection of its rootlets. Take that, bloodsucking barnacle!

Says Who?

  • Powell & Rowley (2008) Diseases of Aquatic Organisms 80: 75-79.
  • Zimmer (2000) “Do parasites rule the world?” Discover Magazine (August issue).
  • Russell et al. (2000) Journal of the Marine Biological Association of the U.K. 80: 373-374.
  • Mouritsen & Jensen (2006) Marine Biology Research 2: 270-275.
  • Goddard et al. (2005) Biological Invasions 7: 895-912.

The Plight of the Spheroid Seaweed (Aegagropila linnaei)

Everyone’s Favourite Freshwater Pet
(via: http://commons.wikimedia.org/wiki)

Common Name: Lake Balls, Marimo

A.K.A.: Aegagropila linnaei

Found: Japan, Iceland, Scotland, Estonia, Germany

It Does What?!

Sure, you’ve had dogs and cats as pets, maybe even fish or lizards… but what about a big ball of algae? Probably not, but if you live in Japan, this idea won’t seem so odd.

Lake balls, or marimo, as the Japanese refer to them, are a rare and unique growth form of the filamentous green algae species Aegagropila linnaei. They occur in only a few isolated habitats worldwide because, unlike most algae, the species lacks a desiccation (dryness) resistant life stage which would allow it to be carried to distant bodies of water. The balls are formed from a densely-packed clump of algal strands which grow outward in all directions, and can reach up to 25cm (10 inches) in diameter. New balls can form from the free-floating form of the same species, or from the breakup and re-growth of an old ball. Found in shallow lakes with sandy bottoms, gentle wave action rolls the clump around, forming a near-perfect sphere and allowing all sides of the ball to receive light for photosynthesis. Seen rolling lazily around the lake bottom, and even rising and falling on columns of warm water, the marimo can almost seem sentient.

It is this bizarre movement and their strangely beautiful appearance which have made marimo so popular in Japan, where they are protected as a “natural monument” and even appear on postage stamps. Unfortunately, it has also been their downfall. Because the algae reside in fresh water and are adapted to low light conditions, they are easily cared for, leading many people to collect them and keep them in their homes. The Japanese believed that a healthy, well looked-after marimo would make the owner’s wishes come true. Lake balls eventually became so rare, due to both human collecting and pollution, that in the early 1950s, a campaign was launched asking Japanese citizens to return their beloved marimo to the lakes from which they had been taken. Impressively, people did so, and in large numbers. In honour of their selflessness, the first annual marimo festival was held, and has continued ever since. Today, the lake ball has become an important environmental symbol in Japan, and children even have their own stuffed marimo toy character, Marimokkori, to play with.

Japanese kids have the best toys, no?

Says Who?

  • Boedeker et al. (2010) BioScience 60(3): 187-198
  • Soejima et al. (2009) Aquatic Ecology 43: 359-370
  • www.marimoballs.com

Every Day is a Crappy Day for the Bird-Dropping Spider (Celaenia excavata)

Celaenia excavata
(via: http://commons.wikimedia.org/wiki)

Common Name: The Bird-dropping Spider

A.K.A.: Celaenia excavata

Found: Eastern and Southern Coastal Australia

It Does What?!

Quick, what’s the first thing that comes to your mind when someone says “disgustingly inedible” ?

If you said “Why, poop, of course!”… congratulations, you think just like Celaenia excavata. And if the thing you’re trying to look inedible to is a bird, naturally, you go with bird poop. Such is the evolutionary reasoning behind the politely-named Bird-Dropping Spider. And while remaining motionless is a must, looking the way it does allows the spider to sit comfortably atop a leaf all day, secure in the knowledge that spiders’ main predators, birds and wasps (who apparently aren’t into eating bird poop either), won’t take an interest.

“Nobody here but us droppings.”
(Thanks to Ron Atkinson at http://www.findaspider.org.au)

But the mimicry doesn’t end there for this sneaky little guy- by day it sits inactive and gross-looking, but by night, it hangs upside down from a leaf and releases the mating pheromones of a female moth. When some unlucky male moth comes looking for a good time, the spider snatches it right out of the air with its powerful front legs and wraps it up for dinner. The moth may be eaten right away or, if its capturer isn’t feeling hungry quite yet, be hung under a leaf next to the spider’s egg sacs, which, oddly enough, look like nuts (see top photo).

Believe it or not, Celaenia excavata isn’t the only spider out there masquerading as merde. Another such trickster is Mastophora cornigera, a North American species which is part of a group known as the Bolas Spiders, or Fishing Spiders. Not content to hope their prey wanders into arm’s reach, bolas spiders release pheromones to attract male moths, then dangle a line of silk with a sticky blob on the end. Once a moth gets close enough, the spider swings its line and –yoink– rips the poor thing right out of mid-air. Whoever thought up Spiderman’s web-slinger clearly had a bolas spider in mind.

So there you have it, the leisurely lifestyle of a successful spider: pile of poo by day, upside-down fisherman by night.

Says Who?

The Curious Case of Turritopsis nutricula

Turritopsis nutricula

Common Name: The Immortal Jellyfish

A.K.A.: Turritopsis nutricula

Found: Tropical and temperate oceans around the world

It Does What?!

Ever been under a lot of stress and found yourself longing for the simplicity of childhood? What if, by force of will, you could actually turn back into your childhood self? And once you’d re-grown up, you could do it again. And again, and again… Welcome to the unusual lifestyle of Turritopsis nutricula, the so-called immortal jellyfish.

Jellyfish, also known as medusae (singular: medusa), are the mature life stage of Phylum Cnidaria, Subphylum Medusozoa. They start off as a bottom-dwelling structure that looks a lot like a series of plants connected by stolons (like strawberry plants… translucent, underwater strawberry plants). These “pseudo-plants” are called polyps, and when they mature, they bud and release many tiny medusae into the ocean, like a plant releasing pollen.

The polyp stage of Turritopsis nutricula

In most species, these medusae go off and live the jellyfish version of the good life- swimming, eating plankton, releasing sperm or eggs to be fertilized and form polyps for the next generation, and finally dying at the ripe old age of anywhere from a few hours to six months, depending on the species. Not so for the Immortal Jellyfish.

Reaching a size of only 4.5mm across, when Turritopsis nutricula becomes stressed, whether due to aging or a change in its environment, it can begin a process called transdifferentiation. First, its tentacles (80 to 90 of them in adults!) shorten and are re-absorbed into the body. The medusa becomes unable to swim and settles onto the bottom. It there transforms into a blob-like mass of cells and, within two or three days, forms a new polyp. In about a month, new jellyfish are ready to be released.

In theory, T. nutricula can pull this trick any number of times, which would effectively make it immortal. However, as scientists point out, these little guys frequently die from disease or predation before they can regenerate (Whovians, insert your own Doctor Who joke here), keeping the population under control. Not entirely under control, though, apparently- one researcher describes the spread of T. nutricula through the world’s oceans as a large-scale, “silent invasion.”  Beware the Immortal Jellyfish.

Says Who?

  • Miglietta & Lessios (2009) Biological Invasions 11: 825-834
  • Piraino et al. (2004) Canadian Journal of Zoology 82: 1748-1754

[Thanks to The Marine Biology Image Database for the use of these images: Migotto AE, Vellutini BC (eds). 2011. Cifonauta: marine biology image database. Available at http://cifonauta.cebimar.usp.br/ ]

Smells like death, looks like… an Amorphophallus?

Amorphophallus titanum

Common Name(s): Corpse Flower, Titan Arum

A.K.A.: Amorphophallus titanum

Found: Sumatra, Western Indonesia

It Does What?!

Looking like something from an Enterprise away mission, this is a plant you won’t soon forget. For those who imagine that biologists don’t have a sense of humour, the scientific name of the Corpse Flower is Amorphophallus titanum, which is Latin for ‘giant misshapen penis.’ And it’s not a bad description; the plant produces a… well, vaguely penis-shaped bloom that grows up to three feet tall and, as if we needed more to snicker about, produces pulses of heat which move from the base to the tip, reaching temperatures of over 36 degrees Celcius (97 Fahrenheit).

It happens to every Amorphophallus at some point…
(Via: plantae.ca)

It’s actually a bit of a misnomer to call this phallic monstrosity a flower- it’s really an inflorescence, a structure on which smaller, individual flowers grow. In the case of Amorphophallus, that cone in the middle is called a spadix (think calla lilies or jack-in-the-pulpit… same plant family), and holds upwards of 900 tiny flowers, of which about half are male and half are female.

Naturally, all those tiny little flowers need to get pollinated in order to create more giant-penis-plants, and the pollinators of choice for Amorphophallus are carrion beetles and blowflies. How to attract the attention of your favoured pollinators in a busy Sumatran rainforest? You give them what they want – the stench of rotting flesh. Those pulses of heat I mentioned before actually serve a purpose; they work like a convection oven, throwing off a foul odour which rises above the canopy as the warmer air rises. This allows the scent signal to be carried over greater distances. And how bad does it smell? Researchers of the plant note that a principal chemical component of that funk is known to also be the main source of the delicate bouquet that is rotting human flesh. Mmm… For another overly-vivid mental picture, be sure to check out a close relative of the Corpse Flower, Helicodiceros muscivorus, a.k.a. Dead Horse Arum.

Says Who?

  • Barthlott et al. (2009) Plant Biology 11: 499-505.
  • Shirasu et al. (2010) Biosci. Biotechnol. Biochem. 74(12): 2550-2554.