A Poop-Loving Moss Discovered Living on Poop-Eating Pitcher Plants

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Poop mosses are strange to say the least. They hail from the family Splachnaceae and most live out their entire (short) lives growing on poop. Needless to say, they are fascinating plants. Recently, one species of poop moss known to science as Tayloria octoblepharum was discovered growing in Borneo for the first time. As if this range expansion wasn’t exciting enough, their growing location was very surprising. Populations of this poop-loving moss were found growing in the pitchers of two species of poop-eating pitcher plants in the genus Nepenthes!

The pitcher of  Nepenthes lowii  both look and function like a toilet bowl.

The pitcher of Nepenthes lowii both look and function like a toilet bowl.

The wide pitcher mouth of  Nepenthes macrophylla  offer a nice seating area for visiting tree shrews.

The wide pitcher mouth of Nepenthes macrophylla offer a nice seating area for visiting tree shrews.

The pitchers of both Nepenthes lowii and N. macrophylla get a majority of their nutrient needs not by trapping and digesting arthropods but instead from the feces of tree shrews. They have been coined toilet pitchers as they exhibit specialized adaptations that allow them to collect feces. Tree shrews sit on the mouth of the pitcher and lap up sugary secretions from the lid. As they eat, they poop down into the pitcher, providing the plant with ample food rich in nitrogen. Digestion is a relatively slow process so much of the poop that enters the pitcher sticks around for a bit.

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During a 2013 bryophyte survey in Borneo, a small colony of poop moss was discovered growing in the pitcher of a N. lowii. This obviously fascinated botanists who quickly made the connection between the coprophagous habits of these two species. On a return trip, more poop moss was discovered growing in a N. macrophylla pitcher. This population was fertile, indicating that it was able to successfully complete its life cycle within the pitcher environment. It appears that these two toilet pitchers offer ample niche space for this tiny, poop-loving moss. If this doesn’t convince you of just how incredible and complex the botanical world is, I don’t know what will!

Pick up your very own Shrew Lew Sticker here!

Photo Credits: [1] [2] [3] [4] [5]

Further Reading: [1]




The Peculiarly Tiny World of Buxbaumia Mosses

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Bug moss, bug-on-a-stick, humpbacked elves, elf-cap moss… Who knew there could be so many names for such tiny mosses. Despite their small stature, the mosses in the genus Buxbaumia have achieved something of a celebrity status to those aware of their existence. To find them, however, you need a keen eye, lots of patience, and a bit of luck.

Buxbaumia aphylla

Buxbaumia aphylla

Buxbaumia comprises something like 12 different species of moss scattered around much of the Northern Hemisphere as well as some parts of Australia and New Zealand. They are ephemeral in nature, preferring to grow in disturbed habitats where competition is minimal. More than one source has reported that they are masters of the disappearing act. Small colonies can arise for a season or two and then disappear for years until another disturbance hits the reset button and recreates the conditions they like.

Buxbaumia viridis

Buxbaumia viridis

I say you must have a keen eye and a lot of patience to find these mosses because, for much of their life, the exist on a nearly microscopic scale. Buxbaumia represents and incredible example of a reduction in body size for plants. Whereas the gametophytes of most mosses are relatively large, green, and leafy, Buxbaumia gametophytes barely exist at all. Instead, most of the “body” of these mosses consists of thread-like strands of cells called “protonema.” Though all mosses start out as protonema following spore germination, it appears that Buxbaumia prefer to remain in this juvenile stage until it comes time to reproduce.

Buxbaumia viridis

Buxbaumia viridis

Considering how small the protonemata are, there has been more than a little confusion as to how Buxbaumia manage to make a living. Early hypotheses suggested that these mosses were saprotrophs, living off of nutrients obtained from chemically digesting organic material in the soils. However, it is far more likely that these mosses rely heavily on partnerships with mycorrhizal fungi and cyanobacteria for their nutritional needs. It is thought that what little photosynthesis they perform is done via their protonema mats and developing sporophyte capsules.

Buxbaumia viridis

Buxbaumia viridis

Speaking of sporophytes, these are about the only way to find Buxbaumia in the wild. They are also the source of inspiration for all of those colorful common names. Compared to their gemetophyte stage, Buxbaumia sporophytes are giants. Fertilization occurs at some point in the fall and by late spring or early summer, the sporophytes are ready to release their spores. The size and shape of these capsules makes a lot more sense when you realize that they rely on raindrops for dispersal. When a drop impacts the flattened top of a Buxbaumia capsule, the spores are ejected into the environment and with any luck, will be carried off to another site suitable for growth.

Buxbaumia viridis

Buxbaumia viridis

I encourage you to keep an eye out for these plants. It goes without saying that data on population size and distribution is often lacking for such cryptic plants. Above all else, imagine how rewarding it would be to finally cross paths with this tiny wonders of the botanical world. Happy botanizing!

Photo Credits: [1] [2] [3] [4] [5] [6]
Further Reading: [1] [2] [3]


Glacier Mice

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At first glance the surface of a glacier hardly seems hospitable. Cold, barren, and windswept, glaciers appear to be the antithesis of life. However, this assumption is completely completely false. Glaciers are home to an interesting ecosystem of their own, albeit on a smaller scale than we normally give attention to.

From pockets of water on the surface to literal lakes of water sealed away inside, glaciers are home to a myriad microbial life. On some glaciers the life even gets a bit larger. Glaciers are littered with debris. As dust and gravel accumulate on the surface of the ice, they begin to warm ever so slightly more than the frozen water around them. Because of this, they are readily colonized by mosses such as those in the genus Racomitrium.

The biggest challenge to moss colonizers is the fact that glaciers are constantly moving, which anymore today means shrinking. As such, these bits of debris, along with the mosses growing on them, do not sit still as they would in say a forest setting. Instead they roll around. As the moss grows it spreads across the surface of the rock while the ice rotates it around. This causes the moss to grow on top of itself, inevitably forming a ball-like structure affectionately referred to as a "glacier mouse."

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Because the moss stays ever so slightly warmer than its immediate surroundings, glacier mice soon find themselves teaming with life. Everything from worms to springtails and even a few water bears call glacier mice home. In a study recently published in Polar Biology, researcher Dr. Steve Coulson found "73 springtails, 200 tardigrades and 1,000 nematodes" thriving in just a single mouse!

The presence of such a diverse community living in these little moss balls brings up an important question - how do these animals find themselves in the glacier mice in the first place? After all, life just outside of the mouse is quite brutal. As it turns out, the answer to this can be chalked up to how the mice form in the first place. As they blow and roll around the the surface of the glacier, they will often bump into one another and even collect in nooks and crannies together. It is believed that as this happens, the organisms living within migrate from mouse to mouse. The picture being painted here is that far from being a sterile environment, glaciers are proving to be yet another habitat where life prospers.

Photo Credit: [1] [2]

Further Reading: [1]

Growing Camouflage

A garden on the back of a weevil living a humid Chilean rainforest.

A garden on the back of a weevil living a humid Chilean rainforest.

Lots of us will be familiar with organisms like decorator crabs that utilize bits and pieces of their environment, especially living sea anemones, as a form of camouflage and protection. Examples of terrestrial insects attaching bits and pieces of lichens to their body are not unheard of either. However, there are at least two groups of arthropods that take their camouflage to a whole new level by actively growing miniature gardens on their bodies.

Little is known about these garden-growing arthropods. To date, these miniature gardens have only been reported on a few species of weevil in the genus Gymnopholus as well as a species of millipede called Psammodesmus bryophorus. Coined epizoic symbiosis, it is thought that these gardens serve as a form of protection by camouflaging the gardeners against the backdrop of their environment.

Bryophytes on a  Psammodesmus bryophorus  male.

Bryophytes on a Psammodesmus bryophorus male.

Indeed, both groups of arthropods frequent exposed areas. What is most remarkable about this relationship is that these plants were not placed on the carapace from elsewhere in the environment. Instead, they have been actively growing there from the beginning. Closer inspection of the cuticle of these arthropods reveals unique structural adaptations like pits and hairs that provide favorable microclimates for spores to germinate and grow.

The plant communities largely consist of mosses and liverworts. At least 5 different liverwort families are represented and at least one family of moss. Even more remarkable is the fact that even these small botanical communities are enough to support a miniature ecosystem of their own. Researchers have found numerous algae such as diatoms, lichens, and a variety of fungi growing amidst the mosses and liverworts. These in turn support small communities of mites. It appears that an entire unknown ecosystem lives on the backs of these mysterious arthropods.

FIGURE 39. Elytral base of Gymnopholus (Niphetoscapha) nitidus with exudates. FIGURES 40a–b. Gymnopholus (Niphetoscapha) inexspectatus sp. n., live specimen with incrustrations of algae and lichens; photographs M. Wild, Mokndoma.  [SOURCE]

FIGURE 39. Elytral base of Gymnopholus (Niphetoscapha) nitidus with exudates. FIGURES 40a–b. Gymnopholus (Niphetoscapha) inexspectatus sp. n., live specimen with incrustrations of algae and lichens; photographs M. Wild, Mokndoma. [SOURCE]

There is still much to be learned about this symbiotic relationship. Although camouflage is the leading hypothesis, no work has been done to actually investigate the benefits these arthropods receive from actively growing these miniature gardens on their backs. Mysteries still abound. For instance, in the case of the millipede, gardens are found more frequently on the backs of males than on the backs of females. Could it be that males spend more time searching their environment and thus benefit from the added camouflage? Only further research will tell.

Photo Credits: [1] [2] [3]

Further Reading: [1] [2] [3]

An Ancient Hawaiian Moss

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The cloud forests of Kohala Mountain on the island of Hawai'i are home to a unique  botanical community. One plant in particular is quite special as it may be one of the most ancient clonal organisms in existence. Look down at your feet and you may find yourself surrounded by a species of moss known as Sphagnum palustre. Although this species enjoys a broad distribution throughout the northern hemisphere, its presence on this remote volcanic island is worth closer inspection. 

Hawai'i is rather depauperate in Sphagnum representatives and those that have managed to get to this archipelago are often restricted to growing in narrow habitable zones between 900 to 1,900 meters in elevation as these are the only spots that are cool and wet enough to support Sphagnum growth. Needless to say, successful colonization of the Hawaiian Islands by Sphagnum has been a rare event.  The fact that Sphagnum palustre was one of the few that did should not come as any surprise. What should surprise you, however, is how this particular species has managed to persist. 

Mounds of  S. palustre  in its native habitat. 

Mounds of S. palustre in its native habitat. 

Hawaiian moss aficionados have long noted that the entire population of Kohala's S. palustre mats never seem to produce a single female individual. Indeed, this moss is dioicous, meaning individuals are either male or female. As such, many have suspected that the mats of S. palustre growing on Kohala represented a single male individual that has been growing vegetatively ever since it arrived as a spore on the island. The question then becomes, how long has this S. palustre individual been on Kohala?

To answer that, researchers decided to take a look at its DNA. What they discovered was surprising in many ways. For starters, all plants were in fact males of a single individual. A rare genetic trait was found in the DNA of every population they sampled. This trait is so rare that the odds of it turning up in any number by sheer chance is infinitesimally small. What this means is that every S. palustre population found on Kohala is a clone of a single spore that landed on the mountain at some point in the distant past. Exactly how distant was the next question the team wanted to answer. 

A lush cloud forest on the slopes of Kohala.

A lush cloud forest on the slopes of Kohala.

The first clue to this mystery came from peat deposits found on the slopes of the mountain. Researchers found remains of S. palustre in peat deposits that were dated to somewhere around 24,000 years old. So, it would appear that S. palustre has been growing on Kohala since at least the late Pleistocene. But how long before that time did this moss arrive?

Again, DNA was the key to unlocking this mystery. By studying the rate at which mutations arise and fix themselves within the genetic code of this plant, they were able to estimate the average rate of mutation through time. By sampling different moss populations on Kohala, they could then use those estimates to figure out just how long each mat has been growing. Their estimates suggest that the ancestral male sport arrived on Hawai'i somewhere between 49,000 and 50,000 years ago and it has been cloning itself ever since. 

A large mat of  S. palustre

A large mat of S. palustre

As if that wasn't remarkable in and of itself, their thorough analysis of the genetic diversity within S. palustre revealed a remarkable amount of genetic diversity for a clonal organism. Though not all genetic mutations are beneficial, enough of them have managed to fix themselves into the DNA of the moss clones over thousands of years. The DNA of S. palustre is challenging long-held assumptions about genetic diversity of asexual organisms.

Of course, no conversation about Hawaiian botany would be complete without mention of invasive species. As one can expect at this point, Kohala's S. palustre populations are being crowded out by more aggressive vegetation introduced from elsewhere in the world. Unlike a lot of Hawaiian plants, however, the clonal habit of S. palustre puts a more nuanced twist to this story. 

Because Sphagnum is spongy yet durable, it has often been used as packing material. Packages stuffed with S. palustre from Kohala have been sent all over the island and because of this, S. palustre is now showing up en masse on other islands in the archipelago. Sadly, when it starts to grow in habitats that have never experienced the ecosystem engineering traits of a Sphagnum  moss, S. palustre gets pretty out of hand. It's not just packages that spread it either. All it takes is one sprig of the moss stuck on someone's boot to start a new colony elsewhere. The unique flora elsewhere in the Hawaiian archipelago have not evolved to compete with S. palustre and as a result, escaped populations are rapidly changing the ecology to the detriment of other endemic Hawaiian plants. 

Photo Credits: [1] [2] [3] [4]

Further Reading: [1] [2] 

The Tallest Moss

For all the attributes we apply to the world of bryophytes, height is usually not one of them. That is, unless you are talking about the genus Dawsonia. Within this taxonomic grouping exists the tallest mosses in the world. Topping out around 60 cm (24 inches),  Dawsonia superba enjoys heights normally reserved for vascular plants. Although this may not seem like much to those who are more familiar with robust forbs and towering trees, height is not a trait that comes easy to mosses. To find out why, we must take a look at the interior workings of these lowly plants. 

Mosses as a whole lack the vascularization of more derived plants. In other words, they do not have the internal plumbing that can carry water to various tissues. Coupled with the lack of a cuticle, this means that mosses are quite sensitive to water loss. For most mosses, this anatomical feature relegates them to humid environments and/or a small stature. This is not the case for Dawsonia. Thanks to a curious case of convergent evolution, this genus breaks this physiological glass ceiling and reaches for the sky. 

Unlike other mosses, Dawsonia have a conduction system analogous to xylem and phloem. Being convergent, however, it isn't the same thing. Instead, the xylem-like tissue of these mosses is called the "hydrome" and is made up of cells called "hydroids." The phloem-like tissue is called the "leptome" and is made up of cells called "leptoids." These structures differ from xylem and phloem in that they are not lignified. Mosses never evolved the ability to produce this organic polymer. Regardless of their chemical makeup, Dawsonia vascular tissue allows water to move greater distances within the plant.

Another major adaption found in Dawsonia has to do with the structure of the leaves. Whereas the leaves of most mosses are only a few cells thick, the leaves of Dawsonia produce special cells on their surface called "lamella." These cells are analogous to the mesophyll cells in the leaves of vascular plants. They not only function to increase surface area and CO2 uptake, they also serve to maintain a humid layer of air within the leaf, further reducing water loss. 

All of this equates to a genus of moss that has reached considerable proportions. Sure, they are easily overtopped by most vascular plant species but that is missing the point. Through convergent evolution, mosses in the genus Dawsonia have independently evolved an anatomical strategy that has allowed it to do what no other extant groups of moss have done - grow tall. 

Photo Credits: Wikimedia Commons, Doug Beckers, and Jon Sullivan

One Badass Moss

Badass and moss are two words that don't find themselves in the same sentence very often, if ever. Today I would like to introduce you to one moss that is certainly worth such a description. Meet Ceratodon purpureus, sometimes referred to as "fire moss." This lowly bryophyte is tough as nails and enjoys a global distribution because of it. From fires and heavy metal pollution to living in our most densely populated urban areas, this moss is a survivor. What's more, its ecology is absolutely fascinating.

Fire moss is truly cosmopolitan. It can be found on every continent and may only lose ground in the tropics where it is replaced by its close relatives. Though we often think of mosses as delicate denizens of shaded forest floors, fire moss is anything but. This is a disturbance-loving species. It gets the name fire moss for its habit of turning up in profusion following wildfires. Cleared of its competition, fire mosses growth can be quite explosive.

Being able to grow on a variety of substrates means that fire moss is equally at home in man-made habitats. It can be found growing in and along sidewalk cracks, old roofs, depressions in asphalt, and on wooden structures. What's more, it can tolerate pollution levels that would normally kill most mosses. One study found that moss grown on mine soils contaminated with toxic levels of heavy metals showed absolutely no decrease in fitness. In fact, they were indistinguishable from moss grown on clean soils.

This moss' lifecycle is ephemeral. Because it needs disturbance to persist, natural succession usually causes it to disappear from a site after a decade or two. Its spores, however, can remain viable for upwards of 16 years in the soil until fire, bulldozer, or any other large-scale disturbance opens the land again.

One of the strangest aspects of this fire moss is how it reproduces. Like all mosses, male gametophytes produce sperm that must make their way to the female gametophyte. They do this by swimming. Whereas moss species living in wet environments can let rain do the work of uniting the sex cells, fire moss has evolved a strategy more familiar to the flowering plants.

It was found that fire moss emits complex volatile scents. What's more, these scents are produced at different rates in the different sexes with females producing much more scent than males. It was found that microarthropods, specifically springtails, are attracted to these scents. Close investigation revealed that springtails significantly increased the fertilization rates in fire moss, hinting at quite a specific reproductive relationship between these organisms, both of which are representatives of some of the first organisms to ever make it onto land.

If this story has not convinced you that fire moss is one badass bryophyte I don't know what will. It is amazing to think that such an incredible organism is probably living out its life a stones throw away from where you are sitting right now.

Photo Credit: Ian Sutton (http://bit.ly/1LqqpMY)

Further Reading:
http://www.publish.csiro.au/?paper=BT9650303

http://www.nature.com/nature/journal/v489/n7416/full/nature11330.html

http://bit.ly/1U4lE2G