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.