Pitcher plant port-a-potty for the tree shrew

A pitcher plant (courtesy of Wikimedia Commons)

Timeline, 2009: As humans, we are a bit limited in our imaginations. For example, we’d probably never consider climbing onto the edge of a toilet seat and licking the sides while…um…employing the toilet for standard uses. Perhaps one reason—among many obvious choices—is that we’re not tree shrews living in the wilds of Borneo in Southeast Asia.

If you’re now envisioning tree-dwelling rodents enjoying the civilized development of having their own toilet, you’re not too far off. Borneo is home to a number of unusual relationships between species, but none may be stranger than the one that has developed between the tree shrew and the pitcher plant. The pitcher plant is carnivorous, and as its name implies, has a pitcher-shaped structure that it uses to trap its food.

The many uses of the pitcher plant

Normally, a pitcher plant growing on the ground is the perfect trap for hapless animals drawn to its minimal nectar output. For some species, they’re not a death trap but a place to brood offspring—one frog uses the pitcher plant to lay its eggs, where trapped, digested insects may provide some nourishment. The insects fall in because the funnel-shaped pitcher part of the plant has a slippery lip that acts as a deadly superslide for any insect that alights on it. Unable to gain a foothold, the animal slides helplessly into the plant’s interior, landing in a pool of digestive enzymes or bacteria that slowly break it down.

What does a pitcher plant do with digested insect? It does what any organism, plant or otherwise, does with its food—it extracts nutrients from it. One primary nutrient that plants (and everything else) require is nitrogen. This element is part of life’s important building blocks for DNA and RNA and the amino acids that make up proteins. Thus, to grow and reproduce, organisms must acquire nitrogen from somewhere. Some plants form a partnership with bacteria to get their nitrogen. Pitcher plants digest insects for it.

Unless no insects are available. While ground-growing pitcher plants in Borneo can subsist on available ants and other crawly critters, some pitcher plants grow on vines and trees, where ants are largely unavailable. In addition, mountainous environments are not known for harboring lots of ants, so the pitcher plant needed a new plan for getting its nutrients.

Nectar for nitrogen

The plan, it seems, was selection for making more nectar, reducing the slippery factor, and behaving like both a toilet and a food source for an abundant animal in the Borneo mountains, the mountain tree shrew. Using video cameras, researchers based at a Borneo field station captured one of the most unusual mutually beneficial relationships in nature: the tree shrew, while enjoying the abundant nectar uniquely produced by these aerial pitcher plants, also poops into the pitcher plant mid-meal. The plant, perfectly shaped for the tree shrew to park its rear just so while it eats, takes up the feces and extracts nitrogen from it. In fact, these pitcher plants may derive up to 100 percent of their nitrogen from the tree shrew poop.

Researchers think that this friendly relationship must have been in the making for a very long time. The pitcher plant opening is perfectly shaped and oriented so that the nectar collects just at the lip and the shrew must orient while eating so that the funnel-like pitcher collects any poop that emerges. The plant also has developed sturdier and thicker structures that can support the weight of a dining/excreting tree shrew, which isn’t much at less than half a pound, but quite a bit for a plant to support.

As odd as this adaptation may seem, it’s not unique. Ground-dwelling pitcher plants have formed similar mutually beneficial relationships with insect larvae that help themselves to some of the insect pickings that fall in. These larvae excrete any leftovers, and the plant harvests nutrients from these excretions. Interestingly, the tree shrew itself dines on insects, so the pitcher plant is still indirectly deriving its nitrogen from insects even when it uses tree shrew poop. It’s just getting it from the tail end of a rodent intermediary instead.

Can animals sense disaster?

Animals head for the hills when natural disaster looms

People living and working in national parks where the devastating 2006 tsunami hit made a startling observation within a few days of the disaster. They had found no animal carcasses of any kind. It appeared that animals had somehow managed to avoid the killer waves that resulted in the deaths of tens of thousands of people.

In Yala National Park in Sri Lanka, people flying over the area in helicopters observed horrible devastation—uprooted trees, cars upended, cars in trees—everywhere the waves had roared over the 391-square mile preserve. But one thing they didn’t see were the bodies of dead animals. The park is home to Asian elephants, crocodiles, buffalo, monkeys, and leopards, and every animal appeared to have made for the hills before the waves swamped their habitat.

Some turtle carcasses have washed ashore, but they seem to be the only notable wildlife deaths in the region. At an elephant trekking center in Thailand, two elephants named Poker and Thandung suddenly went nuts, broke their chains, and headed for the hills, carrying four lucky Japanese tourists on their backs. The elephants and the tourists survived the waters that flooded over the area five minutes after the elephants broke free.

A long history of doom-detection

A long, but anecdotal, history of animals’ ability to sense doom underscores the observations from this most recent tragedy. As far back as about 400 B.C., we noted unusual animal activity just preceding a natural disaster. The Greek historian Diodorus observed in 383 B.C. that two days before a destructive earthquake, the rats, snakes, weasels and even worms had decamped from the affected city. Worms—dwelling in the ground and possibly well-equipped with underground sensors—also figured in a mass animal exodus recorded prior to the 1755 earthquake in Lisbon, Portugal, the worst natural disaster on record prior to the recent Asian tsunami.

Dogs bark, geese honk, livestock get bull-headed. In the big Alaskan earthquake of 1964, a rancher could not get his cows to stay in the lowland pastures; the stubborn bovines insisted on grazing in the hills. Later that day, a huge earthquake hit, triggering a tsunami that wiped out coastal Alaskan towns, but the cows survived on their hillsides.

Are humans missing a vital organ?

Animals appear to know something’s coming possibly because they have what one researcher has described as sensory organs to detect tiny changes leading up to a big event. We, unrefined creatures that we are, do not detect these micro-changes and live in ignorance until the disaster hits. But proving that animals have something we don’t in this regard is a bit difficult because we can’t recreate earthquakes or tsunamis in the lab. Sure, we could shake a table or wash water over a false beach, but it’s the signals leading up to the events that we strive to understand. Since we cannot detect them, we don’t know what they are, and we can’t re-create them.

Our only chance of gaining some experimental insight into this phenomenon is to rely, as so many scientists do, on solid preparation for sheer chance. A marine biologist on the U.S. east coast has done just that, and in the process has become the first scientist to acquire actual proof that animals respond to impending disaster.

Sharks reveal a bit of the secret

The biologist, Michelle Heupel, had been radiotagging sharks off the coast of Florida when Tropical Storm Gabrielle approached. Six hours before the storm made landfall, all 14 sharks she was monitoring suddenly evacuated their nursery site. She and others believe that the sharks registered the drop in barometric pressure that preceded the storm. The drop made depths feel shallower, and the sharks instinctively swam en masse for deeper waters. Heupel got another chance to monitor this movement when Hurricane Charley swept onto the east coast. Again, the sharks she was monitoring all rapidly exited the area hours before the storm moved in.

Chinese winemaking aged 9000 years

Tracking ancient alcohol production is tough

The fermented grain has been the centerpiece of much of the development of human civilization. According to archaeologists, wines and beers contributed to the formation of religious practices, commerce, social interactions, and community structure. So it’s only natural that we would want to find out how and when we began purposely making such beverages to imbibe.

But alcohol evaporates easily, and being a liquid, isn’t usually preserved for archaeologists to discover thousands of years after the fact. Yet scientists have managed to get lucky and to apply a little smarts to figuring out the mysteries of ancient alcohols, and some of the best information on such beverages is now coming out of China.

The dawn of “real” human civilization?

In China, there is a famed Neolithic archaeological site where some of the oldest musical instruments and Chinese pictographs have been found. The Neolithic age, or New Stone Age, dates back to about 8000 or 9000 years, and this particular site in northern China has yielded abundant resources for investigations into the period, often viewed as the dawn of real human civilization.

Among these resources are pieces of pottery from vessels used to hold liquids. Researchers determined that these pots probably held fermented beverages because they were so similar to vessels from later periods that were known to have stored wines. To investigate their ideas, they collected pieces from the bottoms of 16 different vessels from the northern China site. The bottoms of the pots, they reasoned, would have absorbed more of the liquid and precipitates than the sides, and would thus yield more information.

Archaeo-chemists identify fine old vintage

Using various methods to identify the chemical makeup of the residues on the pots, the archaeo-chemists, as they are called, determined that the vessels once held wines made of rice or millet and flavored with tree resins, honey, and flowers. The methods they used, which included gas and liquid chromatography and mass spectrometry, pinpointed the flower residues as hawthorn or wild grape. One key component they identified was tartaric acid, which is the primary organic acid in grape wine.

At the same time they were performing these analyses on pot fragments from a 9000-year-old village, the scientists were also investigating the evidence from another lucky find. They had discovered some vessels that were part of a burial site for elite individuals living during Shang and Western Zhou dynasties, from about 1250 to 1000 B.C. These vessels had become tightly sealed as their lids had corroded and formed a barrier around the top. Perfectly preserved inside were the liquids they held, probably intended as accompaniments for the dead on their way to the next world, or possibly used in burial or visitation rituals.

Truly ancient Chinese recipes

The archaeo-chemists analyzed the contents, which looked and smelled very like the rice and millet wines that are still made today in China. They found that the vessels contained wines made of the very same components as those identified in the 9000-year-old pot fragments from the Neolithic village. The recipes appear to have been used for millennia.

The finds also indicate that the people who made the wines had a sophisticated understanding of the fermentation process. They used cakes made of various molds to break down the carbohydrates in rice or millet into simple, fermented sugars. They appear to have known that substances like wormwood—which was found in the Shan/Western Zhou analysis—would enhance the fermenting activity of the yeast considerably.

A Chinese record–for now

China now holds the record for the world’s oldest known human-directed fermentation. Iran held the previous record, based on wines found in two jars at a Neolithic site dating to 5400 B.C. The oldest known reference to a fermented beverage recipe comes from Iraq, where a clay tablet mentions how to brew beer as part of a hymn to the goddess of brewing.

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