Where to find slime mold

Not surprisingly, they fascinate some biologists and amateur naturalists. I am here astraddle the North Carolina-Tennessee border on a spectacular Indian summer day with a team of myxo taxonomists participating in the All Taxa Biodiversity Inventory ATBI , a year effort to identify and catalog as many of the organisms occurring in the square-mile park as possible.

The myxo section is coordinated by Stephenson, who is also a biology professor at Fairmont State College in West Virginia. In December dozens of taxonomists from some 25 universities and research institutions met in Gatlinburg, Tennessee, to launch the survey, set up a nonprofit overseer—Discover Life in America—and start raising funds.

The National Park Service is providing housing, maps, vehicles and other support for the project. Scientists expect to uncover , species in the park, many new to science. The taxonomy of myxos depends on what the fruiting bodies look like: size, shape, color and their "complexion" smooth or warty , as well as microscopic characteristics detected back at a lab. They are found in rotting logs, stumps, bark and similar microhabitats on all continents. A myxo begins life as a microscopic spore.

The zygote devours bacteria found in decaying wood and elsewhere, increases its size by nuclear division, then masses into a blob called a plasmodium. The ideal spot is high enough to catch a passing breeze and dry enough to avoid fungi. Then the whole program repeats itself. We clamber up the steep path to Clingmans Dome, at 6, feet the highest point in the park. Dozens of tourists march along with us, and for the most part, our band would pass without drawing undue attention.

That is, until every so often a myxo team member brandishes his loupe, a magnifying glass slung from a cord about his neck, pulls out a small knife and plunges off the path into the bush. Stephenson charges down a slope intent on a rotting log. Ted Stampfer scrabbles up to pore over a bush. Randy Darrah marches up to a still-standing tree and presses his loupe close to the bark. Put the lids on the tubs and bring them indoors. Now wash your hands! Keep them in the dark, room temperature is fine.

Every few days have a look. You could try leaving one in the light for a few days and see if it makes spores. Although P. This one cell is a master shape-shifter. Biologists first brought the slime mold into the lab more than three decades ago to study the way it moves—which has a lot in common with they way muscles work on the molecular level—and to examine the way it reattaches itself when split.

That thinking has completely changed. In the early s Toshiyuki Nakagaki, then at Hokkaido University in Japan, and his colleagues chopped up a single polycephalum and scattered the pieces throughout a plastic maze. The smidgens of slime mold began to grow and find one another, burgeoning to fill the entire labyrinth. Nakagaki and his teammates placed blocks of agar packed with nutrients at the start and end of the maze. Four hours later the slime mold had retracted its branches from dead-end corridors, growing exclusively along the shortest path possible between the two pieces of food.

This past October Reid and his colleagues published a study revealing that the way a slime mold navigates its environment is even more sophisticated than previously realized.

As polycephalum moves through a maze or crawls along the forest floor, it leaves behind a trail of translucent slime. Reid and his teammates noticed that a foraging slime mold avoids sticky areas where it has already traveled. This extracellular slime, Reid reasoned, is a kind of externalized spatial memory that reminds polycephalum to explore somewhere new.

To test this idea, Reid and his colleagues placed slime molds in a petri dish behind a U-shaped barrier that blocked a direct route to a piece of food.

Because the barrier was made of dry acetate, the slime molds could not stick to it and climb over it; instead, they had to follow the contours of the U toward the food. Ultimately, 23 of 24 slime molds reached the goal. But when Reid coated the rest of the petri dish in extracellular slime before introducing the slime molds, only eight of 24 found the food.

All that preexisting slime confused the slime molds, preventing them from marking different areas as explored or unexplored. Reid thinks that a polycephalum in a labyrinth is similarly dependent on its slime, using it to first map the entire maze and then to remember which corridors are dead-ends.

Navigating a maze is a pretty impressive feat for a slime mold, but the protist is in fact capable of solving more complex spatial problems: Inside laboratories slime molds have effectively re-created Tokyo's railway network in miniature as well as the highways of Canada, the U.

When researchers placed oat flakes or other bits of food in the same positions as big cities and urban areas, slime molds first engulfed the entirety of the edible maps. Within a matter of days, however, the protists thinned themselves away, leaving behind interconnected branches of slime that linked the pieces of food in almost exactly the same way that man-made roads and rail lines connect major hubs in Tokyo, Europe and Canada.

In other words, the single-celled brainless amoebae did not grow living branches between pieces of food in a random manner; rather, they behaved like a team of human engineers, growing the most efficient networks possible. The plasmodium of the many-headed slime mold Physarum polycephalum has been used for solving mazes and even mapping the Tokyo transit system in its quest for food.

Plasmodia are usually clear, white, yellow, orange, or red, and can grow large enough to be visible to the naked eye. Touching a slime mold in this stage feels like touching snot and will leave a slimy residue on your finger.

Eventually, the plasmodium creeps into a drier spot and develops into one or more fruiting bodies, ephemeral structures containing tons of spores, which eventually disperse to restart the life cycle. There are fewer than 1, species of plasmodial slime molds known worldwide. Plasmodial slime molds are in the class Myxomycetes, not to be confused with cellular slime molds or protostelids, which cannot be seen without a microscope.

Most species are cosmopolitan and tend to be common in temperate zones. These species tend to catch observant eyes because of their larger fruiting bodies and brightly colored plasmodia. But if you have the patience to stop and scrutinize a decaying log for a couple of minutes, you may be rewarded with the sight of even smaller slime molds, which are often only a few millimeters tall but no less impressive. Though easily overlooked by humans, slime molds consume bacteria and provide food for ants, slugs, snails, and other organisms.

There are even beetles that feed exclusively on slime molds.