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Is this a saltwater millipede?

Is this a saltwater millipede?



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I spotted this millipede-like creature in Hervey Bay, Australia at low tide, just kind of hanging out at the bottom of a small saltwater tidepool.

It's several inches long, composed of a large number of segments, each of which appears to sport a pair of legs.

Hard to tell from the photos, but the creature is aquatic and in both instances was observed moving around under about an inch or so of water. No specimens, alive or dead, were observed outside of the water.

They leave obvious trails behind them in the sand at the bottom of the tidepool as they move across it, and I assume they have some ability to burrow into the sand as I saw far more trails than I did creatures.

What are these things?


This is indeed a polychaete worm, and likely a member of the beachworm family Onuphidae.

From the Marine Education Society of Australasia :

Polychaetes are particularly common on and in muddy and sandy shores. Their most obvious feature are the pairs of parapodia appendages. One pair comes from each body segment. These parapodia are used for crawling and swimming. "Para" means "like", and "podia", "pod" or "ped" means "legs". These parapodia are often tipped with hardened spine-like setae or dorsal cirri.

You can find some good informaiton on beach worms here, and information on the distribution, abundance and population dynamics of various species here.

I'm sure a quick message to Dr. Pat Hutchings, the Austrtalian Museum's polychate expert, would prove to be be your best chance to get a species identification.

For those interested in additional polychaete identification, you can download a digital ID key.


The term millipede comes from two Latin words - mil, meaning thousand and ped meaning feet. Some people refer to these critters as "thousand leggers." But both names are misnomers because scientists have yet to find a millipede species with 1,000 legs. Most actually have less than 100 legs. The millipede that holds the record for most legs has a mere 750, far short of the thousand leg mark.

This trait, and not the total number of legs, is what separates the millipedes from the centipedes. Turn a millipede over, and you'll notice that almost all its body segments have two pairs of legs each. The first segment always lacks legs entirely, and segments two through four vary, depending on the species. By contrast, centipedes have just one pair of legs per segment.


The mystery of millipede mating revealed in landmark imaging study

A team of US scientists has just solved a long-standing biological mystery – how exactly do millipedes mate? Using a variety of novel imaging methods, including microscopic ultraviolet photography and micro-CT scanning, the research finally figured out how these tiny creatures get it on.

"This is the first time we've been able to understand these millipedes' mechanism of insertion, how the male and female organs interact with each other,” says Petra Sierwald, from Chicago’s Field Museum and one of the study’s authors. “Before this, we had no idea how he would actually get the sperm into her.”

Millipedes can generally be somewhat shy organisms, so getting them to mate in laboratory conditions hasn’t been easy. The new study focused on a type of small, brown North American millipede called Pseudopolydesmus, known for being more than willing to mate, even in the most exhibitionist situations.

"They will even mate in the lab in the Petri dish under the light,” says Sierwald.

A Pseudopolydesmus millipede, viewed under UV light

Utilizing a number of modern imaging techniques, the research team discovered some unexpected, and previously unknown, details elucidating the millipedes' mating ritual. First, the researchers needed to understand exactly how a male millipede got his sperm into the female.

Millipedes are one of the few organisms that use specialized limbs called gonopods to transfer sperm into females. In the Pseudopolydesmus, the gonopods are notably quite far from its testes. The new research found the millipede releases its sperm from its testes and then contorts itself to cover its gonopods in the sperm, described as a blue-ish liquid.

The male gonopods then enter the female’s vulva using tiny claws to hook into specific ridges on the vulva. This is the first time researchers have described this kind of lock-and-key relationship in the Pseudopolydesmus millipede.

"She has two openings, one on each side between her second pair of legs," says Sierwald. "We had no idea for this entire group, which part is inserted and where it is inserted in the female.”

Another mystery solved by the new study is the source of a strange secretion that seals the sperm inside the female’s vulva. This process functions to concentrate the sperm until the female lays her eggs, subsequently coating the eggs in sperm as they leave her body.

A Pseudopolydesmus vulva, under UV light

"Before this study, we had no idea really where the secretions came from,” explains Sierwald. “I always thought it came from the male, because I thought the male wanted to seal off the female so that she couldn't mate again. But now, having seen the glands inside the female's vulvae through the CT-scanning, I think most of that secretion comes from the female. I don't know whether that is her way of protecting her vulvae or preserving the sperm. Those are interesting fields for further study."

The rigorous imaging study shines a light on a nearly century-old mystery that traditional microscopy simply could not solve. Sierwald says the research is not only important in offering a better understanding of how millipedes are related, but it delivers insights into how different millipede species evolved. And, of course, it answers one burning question many entomologists have been asking for decades – what does a millipede vulva actually look like?

"There are 16 orders of millipedes in the world, and for most of them, we have only faint ideas what the vulvae look like,” says Sierwald.

The new research was published in the journal Arthropod Structure & Development.


If you see a glowing millipede, best not to bite it

If you go down to the woods of California today, you might be in for a big surprise. At night, the forests crawl with sinuous shapes that glow with an eerie greenish-blue colour. They are Motyxia millipedes and they shine brightly whenever they’re disturbed. “If you go to the right forest and you let your eyes get adjusted to the night, then you can see them everywhere,” says Paul Marek from the University of Arizona. Some big oak tress can shelter 1 glowing millipede in every square metre. They look like fields of stars.

There are around 12,000 known species of millipedes, and only the eight Motyxia species glow. Marek says, “[They] would definitely be on my top 10 for my imaginary “millipede biodiversity global tour” (along with the shocking pink millipede in Thailand & the longest millipede in Africa).”

But why do the Californian ones glow? Marek knows the answer. With hundreds of millipedes, some clay, and a bit of paint, he has shown that they light up to ward off predators. You might expect that the light shows would make the millipedes easier to find and eat. In fact, it deters hungry mouths.

The ability to make your own light, known as bioluminescence, has evolved around 40 to 50 times in the history of life. Hundreds of animals can do the same thing, from fireflies to squid to deep-sea fish. They use this ability to attract their prey, to recognise their mates, and to hide from predators. Motyxia millipedes are part of this extensive club, but they’re unusual in one important respect: they’re blind. They can’t see their own glows their light shows are aimed at a different audience.

Marek collected 164 Motyxia millipedes from California’s Giant Sequoia National Monument and painted half of them to cover up their nightly glow. He then tethered them with a gently knotted string to specific places throughout the forest. Marek also built 300 clay millipedes using a bronze cast made by his wife. He covered half of them with the same obscuring paint as the live millipedes, and the other half with a glow-in-the-dark hue. He scattered the fake millipedes throughout the forest just like the real ones, and waited.

The next morning, he found that rodents like grasshopper mice, had savaged around a third of the millipedes. The dull ones took the brunt of the attacks – they had between two and four times as many bite marks as the glowing ones. Nearly half of the dull clay millipedes bore the wounds of a rodent attack compared to just 22 percent of the glowing models. Similarly, rodents had attacked around 18 percent of the painted live millipedes but only 4 percent of the glowing ones.

The experiment showed that the millipedes’ glow repels predators, and the models proved that it’s the light, rather than the smell or taste of the animals, that puts off attackers. The glow sends a clear message: “Don’t eat me. I’m dangerous.” And they are – the millipedes create cyanide in their bodies and secrete the poison through pores along their flanks. They make for an unpleasant and possibly lethal mouthful.

If doesn’t matter that an animal is poisonous if its predators have to bite it to find that out. The predator would get a mouthful of poison, but the prey would incur a serious wound. This is why many poisonous animals advertise their toxic payloads with bright colours.

Many millipedes also have bright colours, but these would be useless to Motyxia species. They spend the daytime buried in the leaf litter, emerging only at night to feed on decaying plants. “Night is an excellent time to do millipede things like eating detritus and mating,” says Marek. When they’re active, predators wouldn’t be able to see bright colours anyway. As such, Motyxia millipedes are a dull orange, and they publicize their defences by glowing in the dark. “I think that Motyxia is better able to exploit this nighttime niche if bioluminescent & toxic,” says Marek.

Now, Marek wants to find out more about how the millipedes got their lights. By analysing the genes of all 8 species, he found that bioluminescence has evolved only once in this group. While many animals glow by harnessing luminous bacteria, the millipedes rely on their own light-producing protein. What that protein is, and how it’s related to those of other glowing animals, is still a mystery.

Reference: Marekt, Papaj, Yeager, Molina & Moore. 2011. Bioluminescent aposematism in millipedes. Current Biology. Current Biology citation tbc.


750-leg millipede

File this under "Things You Don't Want to Step on With Bare Feet:" A white millipede that manages to cram 750 wiggly legs onto its 0.4- to 1.2-inch (1- to 3-centimeter)-long body.

Illacme plenipes is the world-record holder for "leggiest creature." It's found, bizarrely, in only a 1.7 square mile (4.5 square kilometer) area in northern California &mdash doubly odd, because the creature's closest living relative calls South Africa home. The millipedes may have spread out across the globe when most of the land on Earth was part of one supercontinent, Pangaea. When the supercontinent broke apart 200 million years ago, the relatives could have been separated, explaining the long-lost connection. [Image Gallery: The Leggiest Millipede]


Examples of Commensalism

Orchids Growing on Branches

Orchids are a family of flowering plants that grow on trunks and branches of other trees. The epiphytic plants are commonly found in dense tropical forests. Orchids rely on the host plant for sunlight and nutrients that flow on branches. They do not grow to be large plants and do not harm the host tree in any manner. Orchids have their photosynthesis process and do not extract any nutrients from the host plant apart from the water that flows on the outer bark. On the other hand, host plants gain no benefits from the orchards.

Livestock and Cattle Egrets

A typical commensal relationship is between livestock and cattle egrets. The egret is a species of heron that moves along with cattle or horses. Sometimes it can be seen on the back of the animal. Initially, it was believed that the birds fed on ticks and other parasites, but it was later discovered that the birds feed on insects hiding in vegetation, which get stirred when the animals feed. When the birds are not working alongside the animal, they hop on the back for a ride. They are light birds and do not limit the movement of the host.

Sharks and Remora Fish

The remora or suckerfish is a small fish that grows to about three feet. It is a member of the ray-finned fish. The remora forms a commensal relationship with large sea organisms, especially sharks, turtles, and whales. Its specially-designed suckers attach to the fins of the host animals and thus benefit for transportation and protection from predators. It also feeds on the leftover of sharks. The small size of the remora makes it less intrusive, and the shark barely feels its presence.

Beetles and Pseudoscorpions

Pseudoscorpions are tiny scorpion-like insects that grow to about half an inch in length. They are distinguished from real scorpions by a lack of stingers. Pseudoscorpions hide on exposed surfaces of host animals such as fur of mammals, and beneath the wings of bees and beetles. They gain transportation and protection from predators and weather elements. Pseudoscorpions cause minimal intrusion and do not harm the host insect due to their small size. They are also too small to be of any benefit to the host.

Milkweed and Monarch Butterfly

The monarch butterfly is common in North America. During the larval stage, it attaches to a specific species of milkweed that contains toxic chemical cardiac glycoside. The poison is harmful to vertebrates, and most animals avoid contact with the plant. Monarch butterflies extract and store the toxin throughout the lifespan. Birds find monarch butterflies distasteful and thus avoid eating them. Monarch larvae are resistant to the poison and are therefore not affected, and the milkweed is not a carnivorous plant therefore, causes no harm to the developing butterfly.

Birds and Army Ants

The commensal relationship between army ants and birds is unusual since both can prey on the other. Birds trail army ants not to feed on them but to feed on insects escaping the ants as they move across the forest floor. The birds easily catch the prey while the ants remain unaffected. Due to their aggressive nature, painful bites, and poison, birds avoid eating ants.

Burdock Seeds on Animals

Many plants have evolved different dispersal features, including curved spines. Burdock plants are mostly found along roadsides. Their seeds are equipped with long curved spines that attach to the fur of animals and are transported to other areas. Burdock seeds are incredibly light that animals barely recognize their presence while their long hooks are not strong enough to pierce the skin of animals.

Whales and Barnacles

Barnacles are crustaceans that are unable to move on their own. During the larval stage, they stick to other organisms such as whales or attach to shells, ships, and rocks. They grow and develop on these surfaces without negatively affecting the host. Barnacles feed on plankton and other food materials as the whales move. This way, they benefit from transportation and nutrition. They do not feed on blood or flesh therefore, they cause no harm to the whale.

Sea Cucumbers and Emperor Shrimp

The emperor shrimp is a crustacean that is common in the Indo-pacific region. It is often seen attached to sea cucumbers where they benefit from transportation and protection from predators without spending energy. The shrimp get off the host cucumber to feed and attaches to another when it wants to move to a different area. The emperor shrimp is small and light to affect the movement of the cucumber.

Caribou and Arctic Fox

The relationship between the caribou and the arctic fox is an example of commensalism in the tundra. The fox trails the caribou while the reindeer prowls for food. As it digs up the soil to expose lichen plants, subnivean mammals are attracted to the site, making them easy targets for the fox. The fox keeps its distance from the deer to avoid spooking it.


Scottish millipede fossil found to be world's oldest known bug

Researchers at the University of Texas in Austin claim to have identified the world's oldest bug. The specimen is a millipede ancestor found on the island of Kerrera in Scotland, and it dates back 425 million years. The team says that this finding implies that insects underwent a rapid phase of evolution.

“Bug” is a pretty casual term, but in this case, the team says it refers to any insect, arachnid, or any other creepy-crawly creature. That’s quite a wide net, but makes it more impressive that this fossil is the oldest of them all.

The specimen is an extinct millipede species called Kampecaris obanensis. While the fossil itself was discovered as far back as 1899, it’s only just now been accurately dated.

To do so, the team used radiometric dating on zircons in the sediment. Zircons are tiny mineral grains that are incredibly durable, so they survive all kinds of geologic events that deep time can throw at them. That makes them perfect time capsules.

The fossil millipede Kampecaris obanensis was found to be 425 million years old

Using this process, the team dated zircons from three fossil sites in the UK, all of which are known to have some of the earliest millipede specimens. As mentioned, the Kampecaris was found to be the oldest, at 425 million years. Fossils from a second site, Ludlow, were 420 million years old, and others from Cowie were 414 million years old.

The team says that this finding raises some interesting questions about insect evolution. Other fossil evidence shows that bugs were widespread by 407 million years ago, and huge communities of insects and related creatures were thriving in forests by 385 million years ago. That suggests that insects underwent fairly rapid evolution, within about 40 million years.

“It’s a big jump from these tiny guys to very complex forest communities, and in the scheme of things, it didn’t take that long,” says Michael Brookfield, lead author of the study. “It seems to be a rapid radiation of evolution from these mountain valleys, down to the lowlands, and then worldwide after that.”

The fossil of the world's oldest known bug was found on the island of Kerrera in Scotland

Interestingly, the team also believes that the fossils described here are not just the oldest bugs discovered so far – they’re among the oldest bugs, period. They say that older bug fossils have not been found in older deposits that are known to preserve other delicate fossils.

That said, the hypothesis clashes with another method known as molecular clock dating. This technique estimates when types of species arose based on tracing back the rate of DNA mutations. According to the molecular clock, millipedes should be about 500 million years old – 75 million years older than these fossils.

The researchers aren’t declaring themselves irrefutably correct, of course. Instead, they say they’re just setting up hypotheses that can be tested in future work.


Materials and Methods

Diplopod Catalogue

Classification and species diversity data were extracted from a catalogue of the Diplopoda assimilated and archived at the Field Museum of Natural History (Chicago, Il) by P. Sierwald. The taxonomy of each millipede order was recorded using the traditional Linnaean classification ranks – species, genus, family, and order. Other taxonomic levels (subspecies, subgenera, tribes, subfamilies, superfamilies, and suborders) were not included in the analysis due to infrequency of use in millipedes. Species that are not currently assigned to families were included in a single placeholder taxon per order. This assignment decreases the overall average distance between species by reducing the inflation of higher taxa. Many of these unplaced species are of dubious validity and most have not been encountered since they were first described. The data set assimilated spans the time period from 1758–2007. Geographically, the data were not complete for approximately 17% (2,014 of 12,116 nominal species) of taxa.

Taxonomic Distinctness

The taxonomic distinctness metric [2] is the average distance from any species to any other in a phylogenetic tree. The input tree can be created using phylogenetic data or, in the absence of such data, by translating the hierarchical classification scheme in place for a group. The formula is summarized as follows: where ω is the “distinctness weight” (i.e., the distance in nodes when traversing the tree from one species to another) between species i and j, and s is the number of species in the tree. This metric was assessed for each order of millipede in the R [34] package Vegan [35] using the current millipede classification [11]. Due to the lack of a well-resolved diplopod phylogeny with complete taxonomic sampling, the input phylogeny comprised the Linnean hierarchical levels (i.,e., Class, Order, Family, Genus, Species) translated into a tree. The implementation of the taxonomic distinctness metric in Vegan scales the longest path to 0 thus all values reported herein reflect this adjustment. The taxonomic distinctness scores for all orders were plotted against their respective log transformed species totals. A linear regression was fitted to the data using the R command “lm”. Taxonomic data for the non-diplopod orders of the Chilopoda [36] and the arachnid order Pseudoscorpiones [37] were assessed using the same approach. Data points for the Pseudoscorpiones and Chilopoda were added to the plot after the regression analysis for comparative purposes.

Global Species Diversity Estimates

Three analyses were conducted to project estimated millipede species richness. First, we employed the method described by Wilson and Costello [38] that uses a class of thinned temporal renewal models. A non-homogenous Poisson process (NHPP) is extended to the models, and estimates are made using Bayesian inference by a Markov Chain Monte Carlo (MCMC) approach. This method provides estimates of the diversity remaining to be discovered and the amount that will be discovered at any point in the future.

The second approach we employed, that of Bebber et al. [39], examines taxonomic productivity to assess when the rate of species descriptions will reach zero. This is assumed to be the point at which all species have been described. The number of species described at time t was plotted against the cumulative total of species described at time t-1. A local regression was used to assess overall trends in the taxonomic productivity using the locfit package [40] in R. An overall negative linear slope is required to achieve a total species richness estimate. The point at which the overall slope becomes negative was determined and used as the final analysis starting point. This taxonomic productivity approach to estimating global species diversity was carried out in R using a script (provided by D. Bebber). The point at which a linear regression intercepts the x-axis is considered the global species total. This method requires consistent sampling efforts through time. Deviations in taxonomic productivity can be seen as changes in the magnitude and/or sign (+/−) of the initial local regression curves slope through time. As the slope becomes negative and progresses towards an x-axis intercept, the total global diversity is assumed to be nearing complete description. However, an alternate explanation for changes in the slope of the line is inconsistent taxonomic effort.

A final method used to estimate global millipede species richness relies on an ad hoc extrapolation based on taxa whose species diversity is considered nearly completely described (e.g., Mammalia and Aves). The global species diversity of birds [41] and mammals [42] were taken as a ratio of the species richness in the United States and Europe because these taxa are considered nearly fully described. The European data millipedes, mammals and birds were taken from Fauna Europaea [43] to standardize the countries included in the analysis. The resulting values of global species per US species were each multiplied by the US millipede diversity to obtain estimates of global millipede richness. We used US millipede species diversity because it is the most thoroughly described fauna, perhaps equitable to the European fauna, and the data for mammals and birds are considered relatively complete and available.

Geographic Diversity Statistics

The most recent available data for land area (excluding water bodies such as lakes, seas, etc.) and human population for all of the World's countries were downloaded from http://www.geographic.org on 23 August 2010. Only countries having at least one millipede description were included in these analyses. The “lm” command in R was used to carry out linear regression analyses on the species number data per country (i.e., the number of millipede species described from each country) as a function of: land area (km 2 ), human population, and human population (excluding India and China). These analyses were carried out with all countries together and with tropical countries (at least 50% of land area within the tropics) separated from nontropical countries (less than 50% of land area within the tropics). A Welch two-sample t-test was used to compare the average numbers of species in tropical and nontropical countries, and, lastly, the numbers of species per square kilometer were calculated for tropical and nontropical countries.


Shedding light on millipede evolution

As an National Science Foundation (NSF)-funded entomologist, Virginia Tech's Paul Marek has to spend much of his time in the field, hunting for rare and scientifically significant species. He's provided NSF with an inside look at a literal bug hunt, and the fascinating world of bioluminescence.

It is midnight on a winter night in 2013, and I am in the middle of a dark oak forest near San Luis Obispo, Calif. I am here, alone, with my millipede-finding ultraviolet flashlight and wanderlust to explore. My goal is to find millipedes that are bioluminescent—meaning they produce light through a chemical reaction.

As an entomologist who is fascinated by millipedes, I chose this site because back in 1967, two immature, inch-long bioluminescent millipedes were first discovered here. But between 1967 and 2013, this species had not been seen and its biology had remained a mystery.

In hot pursuit of a millipede

Looking for these 62-legged millipedes is an adventure. Their habitats are in giant sequoia forests, coastal live oak groves, and mountain skunk cabbage meadows in the High Sierra of California. Collecting them requires conducting fieldwork from dusk to dawn.

These millipedes not only glow in the dark but also fluoresce—meaning that when they are illuminated with ultraviolet (UV) light, they shine a brilliant green hue. So I search the dark forest with just the purple light of a UV torch, which makes fluorescent creatures glow.

Over by a small bubbling stream, I find one member of this enigmatic species, then two more (which were mating) and then three more. Their green fluorescence shines brightly under the UV light. I switch the light off and the millipede disappears I turn it back on and it reappears as a glowing beacon of lime green.

I excitedly, but gently, scoop up the millipedes to avoid disturbing them, which could cause them to ooze cyanide as a defense mechanism. I must place each of them into a small plastic cup with a bit of soil and leaves that provide moisture.

The millipedes that I seek hold clues about the evolution of bioluminescence and how this trait, which functions as a deterrent to predators, is rare evolutionarily and geographically.

My research team, which is funded by NSF, explores the evolution of bioluminescence in a genus known as Motyxia, the only millipedes in North America that are known to be bioluminescent.

In a previous article for NSF, I explained that Motyxia's "glow means no!" to predators. That is, the green glow of nocturnal Motyxia—which are exclusively found in the Sierra Nevada Mountains of California—wards off nocturnal predators. Motyxia's bright coloring warns predators that when these millipedes feel threatened, they ooze toxins, including hydrogen cyanide, an extremely poisonous gas.

However my recent research indicates that millipedes may not have always used bioluminescence as a defense mechanism. Rather, bioluminescence may have originated in a millipede species named Xystocheir bistipita for an entirely different function and slowly evolved into its current defensive function for Motyxia.

Xystocheir bistipita, which was not known to be bioluminescent, had not been seen in about 50 years until I recently rediscovered this species in the oak forest near San Luis Obispo. When I rediscovered it, I surprisingly found that this species does, in fact, emit a faint glow.

In order to provide a context to the evolution of bioluminescence, my team and I sequenced the DNA of Xystocheir bistipita, and positioned it on an evolutionary tree with other species of Motyxia and their closest relatives. These and other analyses showed that Xystocheir bistipita should now be classified in the genus Motyxia along with other glowing millipedes. So in honor of its family ties, I gave Xystocheir bistipita a new name: Motyxia bistipita.

Our analyses also showed that the faint bioluminescence of the low-lying cousins of Motyxia bistipita—which I'll refer to as simply M. bistipita—represents an older trait than the brighter bioluminescence of their mountain relatives. In addition, millipede species that live at higher elevations exhibit the brightest bioluminescence.

Furthermore, millipedes with brighter bioluminescence have larger cyanide glands, suggesting that millipede toxicity may be linked to the intensification of their bioluminescence.

These discoveries provide the bases for a possible explanation of the evolutionary origins of bioluminescence in millipedes. Over time, bioluminescence gradually escalated from the faintly glowing species of Motyxia that live at low elevations to the brighter and more highly toxic species of Motyxia that live at high elevations.

This evolution might have occurred because millipedes that live at high elevations share their habitat with many more predators than do lower-elevation millipedes. Therefore, they need a brighter glow to advertise to predators the greater toxicity of their cyanide weapon. The more glow, the more emphatic the "No!"

Our analyses of the chemical reaction used by M. bistipita to generate its faint glow suggests that this species might not have originally acquired bioluminescence as a defense mechanism. Rather, it might have acquired its faint glow to help adapt to the dry heat of its habitat—before other Motyxia acquired bioluminescence.

Evidence for this idea includes the particular chemical reaction that M. bistipita uses to create light. This reaction neutralizes potentially harmful chemical byproducts, such as peroxides, which the millipede's body produces when it metabolizes oxygen in hot weather. Bioluminescence by M. bistipita thereby protects the millipede from what would otherwise potentially threaten it in a hot habitat.

According to my explanation for the origins of bioluminescence in millipedes, as their evolution progressed and Motyxia colonized higher elevations that support more predators, this millipede repurposed and intensified its glow as a way to warn predators of its greater toxicity.

These findings show that even seemingly complex, intricate traits we see today may have evolved through many small steps, and from an original function unrelated to its present day role. These findings also provide insights into how the spectacular biodiversity of our planet evolved.

Different functions in different organisms

In addition providing the adaptive and defensive functions discussed here, bioluminescence also serves more than 10 other functions for various organisms.

For example, it fills other types of defensive roles, from creating smoke screens and fireworks that startle predators and give prey precious time to escape, to lighting up body parts that detach to distract predators from the organism's vulnerable structures. It can also play offensive roles, serving as a lure for predators, confusing prey and providing illumination.

Railroad worms of the genus Phrixothrix have a red bioluminescent lamp in their head and eight pairs of green lamps lining the sides of their abdomens. Because this light is invisible to its prey (since most insects are unable to see in red light), it has been hypothesized that the carnivorous Phrixothrix uses its bioluminescence as its own "private" illumination source—although it is not yet known whether Phrixothrix can see its own red light.

Many remaining mysteries

Bioluminescent organisms produce light through chemical reactions involving hundreds of various unrelated enzymes and other light-producing proteins that evolved independently in various groups of organisms.

But so far, researchers understand the biochemical reaction that produces light in only a handful of species. We know the most about how light is produced by fireflies, specifically the big dipper firefly, Photinus pyralis.

In addition, new bioluminescent creatures are still frequently being discovered—particularly on land and sea in tropical areas, and most often in coral reefs, which are among the most diverse ecosystems on Earth.

With so much still to discover about bioluminescence, various aspects of this phenomena form the bases of vibrant and active fields that are currently being researched by biochemists, entomologists, marine biologists, and engineers.

Research into bioluminescence has already produced many practical applications. Those include:

  • Helping to revolutionize our understanding of cancer by literally shining a light on what researchers could not see any other way. Scientists can make particular types of cells in laboratory animals bioluminescent—including cancer cells. Using high-tech imaging tools, researchers can track the movement of these bioluminescent cells by following the light they emit. This technique enables researchers to view proliferating and metastasizing bioluminescent cancer cells in real time, and thereby gain important insights about how cancer grows.
  • With NSF funding, Jennifer Prescher of the University of California-Irvine is creating a new way to view specific biological events, including those that involve cancer growth. Her work involves bioluminescent tools that produce light only when cells come into direct contact with one another.
  • Those tools could, for example, be applied to tumor cells and cancer-fighting immune system cells. When the different types of cells are separate, they would generate minimal light or none at all. But when one type of cell makes contact with the other, they would light up. That luminescence could help researchers test potential cancer therapies, as it would signal that cancer-fighting cells were able to successfully reach cancer cells, and could be useful for cancer therapies.
  • Revolutionizing how we study cells. NSF-funded biologist Osamu Shimomura's search for the source of the green glow of the jellyfish Aequorea victoria led him to discover a protein called green fluorescent protein (GFP). GFP is now widely used in biological and biomedical research as a fluorescent tag.
  • Researchers can label a particular type of biomolecule of interest, such as a protein, antibody, or amino acid, by chemically attaching GFP to it. They may then track the labelled biomolecules by following the green fluorescence attached to them.
  • Such tagging helps researchers track specific biological activities, such as the production of insulin and the movement of HIV proteins. In 2008, Shimomura, along with Martin Chalfie and Roger Tsien, received the Nobel Prize in Chemistry for the discovery and development of GFP.
  • Helping us find cellular activity. Enzymes responsible for bioluminescence in fireflies are used by researchers to detect ATP (adenosine triphosphate), which is an essential substance for living cells. Because ATP is ubiquitous in cells, its presence is an indicator of biological activity and can be used to determine the cleanliness of drinking water, rate of fermentation, and microbial activity of soils.
  • Providing new ways to find important ions. Many types of physiological processes trigger changes in concentrations of intracellular calcium ions, an essential component of biological processes. One way to track intracellular calcium concentrations in is to insert a type of photoprotein known as aequorininto cells. Like GFP, aequorin is derived from the jellyfish Aequorea victoria. Aequorin reacts with calcium, emitting light when it does so, which signals the element's concentration.

The next time you notice glowing animals, remember there is still much to learn about why and how their wondrous lights evolved, and how research about them may benefit society in many and varied ways.


National Science Foundation - Where Discoveries Begin

A recently rediscovered bioluminescent millipede emits a blue-green light.


July 31, 2015

As a National Science Foundation (NSF)-funded entomologist, Virginia Tech's Paul Marek has to spend much of his time in the field, hunting for rare and scientifically significant species. He's provided NSF with an inside look at a literal bug hunt, and the fascinating world of bioluminescence.

It is midnight on a winter night in 2013, and I am in the middle of a dark oak forest near San Luis Obispo, Calif. I am here, alone, with my millipede-finding ultraviolet (UV) flashlight and wanderlust to explore. My goal is to find millipedes that are bioluminescent--meaning they produce light through a chemical reaction.

As an entomologist who is fascinated by millipedes, I chose this site because back in 1967, two immature, inch-long bioluminescent millipedes were first discovered here. But between 1967 and 2013, this species had not been seen and its biology had remained a mystery.

In hot pursuit of a millipede

Looking for these 62-legged millipedes is an adventure. Their habitats are in giant sequoia forests, coastal live oak groves and mountain skunk cabbage meadows in the High Sierra of California. Collecting them requires conducting fieldwork from dusk to dawn.

These millipedes not only glow in the dark but also fluoresce--meaning that when they are illuminated with UV light, they shine a brilliant green hue. So I search the dark forest with just the purple light of a UV torch, which makes fluorescent creatures glow.

Over by a small, bubbling stream, I find one member of this enigmatic species, then two more (which were mating) and then three more. Their green fluorescence shines brightly under the UV light. I switch the light off and the millipede disappears I turn it back on and it reappears as a glowing beacon of lime green.

I excitedly, but gently, scoop up the millipedes to avoid disturbing them, which could cause them to ooze cyanide as a defense mechanism. I must place each of them into a small plastic cup with a bit of soil and leaves that provide moisture.

The millipedes that I seek hold clues about the evolution of bioluminescence and how this trait, which functions as a deterrent to predators, is rare evolutionarily and geographically.

My research team, which is funded by NSF, explores the evolution of bioluminescence in a genus known as Motyxia, the only millipedes in North America that are known to be bioluminescent.

In a previous article for NSF, I explained that Motyxia's "glow means no" to predators. That is, the green glow of nocturnal Motyxia--which are exclusively found in the Sierra Nevada Mountains of California--wards off nocturnal predators. Motyxia's bright coloring warns predators that when these millipedes feel threatened, they ooze toxins, including hydrogen cyanide, an extremely poisonous gas.

However, my recent research indicates that millipedes may not have always used bioluminescence as a defense mechanism. Rather, bioluminescence may have originated in a millipede species named Xystocheir bistipita for an entirely different function and slowly evolved into its current defensive function for Motyxia.

All in the family

Xystocheir bistipita, which was not known to be bioluminescent, had not been seen in about 50 years until I recently rediscovered this species in the oak forest near San Luis Obispo. When I rediscovered it, I surprisingly found that this species does, in fact, emit a faint glow.

In order to provide a context to the evolution of bioluminescence, my team and I sequenced the DNA of X. bistipita, and positioned it on an evolutionary tree with other species of Motyxia and their closest relatives. These and other analyses showed that X. bistipita should now be classified in the genus Motyxia along with other glowing millipedes. So in honor of its family ties, I gave X. bistipita a new name: Motyxia bistipita.

Brightening up

Our analyses also showed that the faint bioluminescence of the low-lying cousins of Motyxia bistipita--which I'll refer to as simply M. bistipita--represents an older trait than the brighter bioluminescence of their mountain relatives. In addition, millipede species that live at higher elevations exhibit the brightest bioluminescence.

Furthermore, millipedes with brighter bioluminescence have larger cyanide glands, suggesting that millipede toxicity may be linked to the intensification of their bioluminescence.

These discoveries provide the bases for a possible explanation of the evolutionary origins of bioluminescence in millipedes. Over time, bioluminescence gradually escalated from the faintly glowing species of Motyxia that live at low elevations to the brighter and more highly toxic species of Motyxia that live at high elevations.

This evolution might have occurred because millipedes that live at high elevations share their habitat with many more predators than do lower-elevation millipedes. Therefore, they need a brighter glow to advertise to predators the greater toxicity of their cyanide weapon. The more glow, the more emphatic the "No!"

Our analyses of the chemical reaction used by M. bistipita to generate its faint glow suggests that this species might not have originally acquired bioluminescence as a defense mechanism. Rather, it might have acquired its faint glow to help adapt to the dry heat of its habitat--before other Motyxia acquired bioluminescence.

Evidence for this idea includes the particular chemical reaction that M. bistipita uses to create light. This reaction neutralizes potentially harmful chemical byproducts, such as peroxides, which the millipede's body produces when it metabolizes oxygen in hot weather. Bioluminescence by M. bistipita thereby protects the millipede from what would otherwise potentially threaten it in a hot habitat.

According to my explanation for the origins of bioluminescence in millipedes, as their evolution progressed and Motyxia colonized higher elevations that support more predators, the millipede repurposed and intensified its glow as a way to warn predators of its greater toxicity.

These findings show that even seemingly complex, intricate traits we see today may have evolved through many small steps, and from an original function unrelated to its present day role. These findings also provide insights into how the spectacular biodiversity of our planet evolved.

Different functions in different organisms

In addition, providing the adaptive and defensive functions discussed here, bioluminescence also serves more than 10 other functions for various organisms.

For example, it fills other types of defensive roles, from creating smoke screens and fireworks that startle predators and give prey precious time to escape, to lighting up body parts that detach to distract predators from the organism's vulnerable structures. It can also play offensive roles, serving as a lure for predators, confusing prey and providing illumination.

Railroad worms of the genus Phrixothrix have a red bioluminescent lamp in their head and eight pairs of green lamps lining the sides of their abdomens. Because this light is invisible to its prey (since most insects are unable to see in red light), it has been hypothesized that the carnivorous Phrixothrix uses its bioluminescence as its own "private" illumination source--although it is not yet known whether Phrixothrix can see its own red light.

Many remaining mysteries

Bioluminescent organisms produce light through chemical reactions involving hundreds of various unrelated enzymes and other light-producing proteins that evolved independently in various groups of organisms.

But so far, researchers understand the biochemical reaction that produces light in only a handful of species. We know the most about how light is produced by fireflies, specifically the big dipper firefly Photinus pyralis.

In addition, new bioluminescent creatures are still frequently being discovered--particularly on land and sea in tropical areas, and most often in coral reefs, which are among the most diverse ecosystems on Earth.

With so much still to discover about bioluminescence, various aspects of this phenomena form the bases of vibrant and active fields that are currently being researched by biochemists, entomologists, marine biologists and engineers.

Societal benefits

Research into bioluminescence has already produced many practical applications. Those include:

    Helping to revolutionize our understanding of cancer by literally shining a light on what researchers could not see any other way. Scientists can make particular types of cells in laboratory animals bioluminescent--including cancer cells. Using high-tech imaging tools, researchers can track the movement of these bioluminescent cells by following the light they emit. This technique enables researchers to view proliferating and metastasizing bioluminescent cancer cells in real time, and thereby gain important insights about how cancer grows.

With NSF funding, Jennifer Prescher of the University of California, Irvine, is creating a new way to view specific biological events, including those that involve cancer growth. Her work involves bioluminescent tools that produce light only when cells come into direct contact with one another.

Those tools could, for example, be applied to tumor cells and cancer-fighting immune system cells. When the different types of cells are separate, they would generate minimal light or none at all. But when one type of cell makes contact with the other, they would light up. That luminescence could help researchers test potential cancer therapies, as it would signal that cancer-fighting cells were able to successfully reach cancer cells, and could be useful for cancer therapies.

Researchers can label a particular type of biomolecule of interest, such as a protein, antibody or amino acid, by chemically attaching GFP to it. They may then track the labelled biomolecules by following the green fluorescence attached to them.

Such tagging helps researchers track specific biological activities, such as the production of insulin and the movement of HIV proteins. In 2008, Shimomura, along with Martin Chalfie and Roger Tsien, received the Nobel Prize in Chemistry for the discovery and development of GFP.

The next time you notice glowing animals, remember there is still much to learn about why and how their wondrous lights evolved, and how research about them may benefit society in many and varied ways.

-- Paul Marek, Virginia Tech (540) 231-5653 [email protected]

Investigators
Paul Marek
Jennifer Prescher

Related Institutions/Organizations
University of California-Irvine
Virginia Polytechnic Institute and State University


The Institute for Creation Research

The Scottish island of Kerrera has produced the earliest known bug in the fossil record, a millipede. 1 It was found in Silurian System rocks recently claimed by secular scientists to be 425 million years old. 1 Unexplainably, their millipede fossil just seemed to show up, fully-formed as a completely functioning &ldquocreeping thing.&rdquo

This discovery also caused some consternation with the uniformitarian community. Secular scientists recognize that their evolutionary worldview creates some intense time crunches, forcing them to marvel at the rapid pace that evolution must have proceeded. The University of Texas reported,

&ldquoIt's a big jump from these tiny guys to very complex forest communities, and in the scheme of things, it didn't take that long," said Michael Brookfield, lead author of the paper published in Historical Biology. "It seems to be a rapid radiation of evolution from these mountain valleys, down to the lowlands, and then worldwide after that." 2

However, Brookfield, a research associate at UT Austin's Jackson School of Geosciences and his co-authors, found their millipede fossil is still 75 million years younger than the date estimated by molecular clock dating. 2

Something must be wrong with these dating techniques. Seventy-five million years is a big difference. And how did this critter evolve in the first place? Most of the fossils in Silurian and older rocks are marine in origin.

The authors leave the question of the origin of the millipedes unanswered once again. Where are the ancestors to these millipedes?

This is a recurring problem in the fossil record. No ancestors to trilobites are found in Cambrian System rocks either. 3 The list could go on and include nearly every fossil ever found. There are no ancestors to anything found in the fossil record. 4

Instead, fossils preserve a record of the progressive flooding of the continents. 4 Each fossil type shows up full-formed and functioning&mdashjust like this millipede. And even though the millipede was found in rocks dominated by marine fauna, it is no surprise to find a few land critters washed out to sea and buried with marine fossils. After all, a dinosaur was washed 70 miles offshore later in the Flood and was buried over a mile deep. 5

The global Flood offers the best explanation for this solitary millipede fossil. God used the Flood to judge the Earth, and it only happened thousands of years ago, not millions. 6

Stage image: Fossil millipede Kampecaris obanensis.
Stage image credit: British Geological Survey . Copyright © 2020. Adapted for use in accordance with federal copyright (fair use doctrine) law. Usage by ICR does not imply endorsement of copyright holders.

References
1. Brookfield, M.E. et al. 2020. Myriapod divergence times differ between molecular clock and fossil evidence: U/Pb zircon ages of the earliest fossil millipede-bearing sediments and their significance. Historical Biology. DOI: 10.1080/08912963.2020.1761351
2. University of Texas at Austin. World's oldest bug is fossil millipede from Scotland. PhysOrg. Posted on Phys.org May 28, 2020, accessed June 1, 2020.
3. Clarey, T. The Cambrian Explosion Mystery Deepens. Creation Science Update. Posted on ICR.org June 19, 2018, accessed June 1, 2020.
4. Clarey, T. 2020. Carved in Stone. Dallas, TX: Institute for Creation Research, 90-113.
5. Clarey, T. and J. J. S. Johnson. 2019. Deep-Sea Dinosaur Fossil Buries Evolution. Acts & Facts. 48 (8).
6. Cupps, V. 2019. Rethinking Radiometric Dating. Dallas, TX: Institute for Creation Research.

*Dr. Clarey is Research Associate at the Institute for Creation Research and earned his doctorate in geology from Western Michigan University.


Watch the video: millipede u0026 centipede (August 2022).