Mr. Answer Man Please Tell Us: Why Don’t Bugs Eat People’s Bones?
I the book, “Will My Cat Eat My Eyeballs” Big Questions from Tiny Mortals About Death, answers real questions received about death, dead bodies, and decomposition - why the creatures that consider skin and organs a tasty snack just don't feel the same way about our skeletons.
It’s a lovely summer day and you’re having lunch in the park. You bite into a fried chicken wing, munching on the crispy skin and juicy flesh. Is your next move cracking into the bones, crunching them like the giant in “Jack and the Beanstalk”?
If you yourself wouldn’t eat a pile of animal bones, why would you expect a beetle to show up and eat your bones? We expect too much from necrophages, the unsung heroes of the natural world. They are the death eaters, the organisms that fuel up by consuming dead and rotting things - and bless their hearts! Imagine, for a moment, what the world would look like without the assistance of the consumers of dead flesh. Corpses and carcasses everywhere. That road kill? It’s not going anywhere without the help of necrophages.
Necrophages do such a good job getting rid of dead things that we expect them to perform miracles. It’s like how if you do too good a job of cleaning your room, then your mom will expect perfection every time. Better to not set expectations so high. It’s just not worth the risk.
The corpse-nosher ranks are filled with diverse species. You have vultures, swooping down for a roadside snack. You have blowflies, which can smell death from up to 10 miles away. You have carrion beetles, which devour dried muscle. A dead human body is a wonderland of ecological niches, offering a wide range of homes and snacks for those inclined to eat. There are plenty of seats at death’s dinner table.
Remember the dermestid beetle? The helpful cuties we’d enlist to clean your parents’ skulls? Their job is to eat all the flesh off without damaging the bone. Let’s be clear: we don’t want them to eat the bone. Especially because other methods of flesh removal (like harsh chemicals) will not only hurt the bones, but might damage certain types of evidence, like marks on bones, which could be useful in criminal investigations. That’s why you bring in a colony of thousands of dermestids to do the dirty work. Plus, while you were over here complaining that they don’t eat enough bones, the beetles were also eating skin, hair, and feathers!
Why Don’t Bugs Eat People’s Bones? The simple answer is that eating bones is hard work. Not only that, but bones are not nutritionally useful to insects. Bones are mostly made of calcium, something insects just don’t need a lot of. Since they don’t need much calcium, insects like dermestids haven’t evolved to consume it or desire it. They’re about as interested in eating bones as you are.
But, here’s a dramatic twist: just because these beetles don’t usually eat bone doesn’t mean they won’t. It’s a cost-reward thing. Bones are a frustrating meal, but a meal is a meal. Peter Coffey, an agriculture educator at the University of Maryland, told me how he learned this firsthand when he used Dermestes maculatus to clean the skeleton of a stillborn lamb. Adult sheep bones are robust, “but in fetuses and newborns there are several places where fusion is not yet complete.” When he removed the lamb bones after the beetles finished cleaning them, “I noticed small round holes, about the diameter of a large larva.” It turns out beetles will go after less dense, delicate bones (like those of the stillborn lamb), but, Peter says, “there has to be a perfect storm of good environmental conditions and poor food availability before they’ll resort to bone, which would explain why it’s not more commonly observed.”
So, while dermestids and other flesh-eating bugs do not usually eat bone, if they get hungry enough, they will. Humans behave the same way. When Paris was under siege in the late 16th century, the city was starving. When people inside the city ran out of cats and dogs and rats to eat, they began disinterring bodies from the mass graves in the cemetery. They took the bones and ground them into flour to make what became known as Madame de Montpensier’s bread. Bone appetit! (Actually, maybe don’t bone appetit, as many who ate the bone bread died themselves.)
It seems like no creature out there wants to eat bone, really prefers bone. But wait, I haven’t introduced you to Osedax, or the bone worm. (I mean, it’s right there in the name, people. Osedax means “bone eater” or “bone devourer” in Latin.) Bone worms start as tiny larvae, floating out in the vast blackness of the deep ocean. Suddenly, emerging from the void above is a big ol’ dead creature, like a whale or an elephant seal. The bone worm attaches, and the feast begins. To be fair, even Osedax don’t really devour the minerals in the bone. Instead, they burrow into the bone searching for collagen and lipids to eat. After the whale is gone, the worms die, but not before they release enough larvae to travel the currents waiting for another carcass to comes along.
Bone worms aren’t picky. You could throw a cow, or your dad (don’t do that), overboard and they’d eat those bones, too. There is strong evidence that bone worms have been eating giant marine reptiles since the time of the dinosaurs. That means the whale eaters are older than whales themselves. Osedax are nature’s peak bone eaters, and they’re even sorta nice to look at, orangey-red floating tubes covering bones like a deep-sea shag carpet. Pretty amazing, given that scientist didn’t even know these creatures existed until 2002. Who knows what else is out there in the world, devouring bone?
Mental Floss / Wikipedia / Encyclopedia Britannica /
National Geographic.org / Quora /
Scientific American / Live Science / Sapiens.org /
Why Don’t Bugs Eat People’s Bones? (YouTube)
Bizarre News (we couldn’t make up stuff this good - real news story)
Citizen science discovers a new form of the northern lights
Source: University of Helsinki
Summary: Working together with space researchers, amateur photographers have discovered a new auroral form. Named 'dunes' by the hobbyists, the phenomenon is believed to be caused by waves of oxygen atoms glowing due to a stream of particles released from the sun.
In the recently published study, the origins of the dunes were tracked to a wave guide formed within the mesosphere and its boundary, the mesopause. The study also posits that this new auroral form provides researchers with a novel way to investigate conditions in the upper atmosphere.
The study was published in the first issue of the journal AGU Advances.
An unknown fingerprint appears in the sky
Minna Palmroth, Professor of Computational Space Physics at the University of Helsinki, heads a research group developing the world's most accurate simulation of the near-Earth space and space weather that cause auroral emissions.
The sun releases a steady flow of charged particles, known as the solar wind. Reaching Earth's ionised upper atmosphere, the ionosphere, they create auroral emissions by exciting atmospheric oxygen and nitrogen atoms. The excitation state is released as auroral light.
In late 2018, Palmroth published a book entitled 'Revontulibongarin opas' ('A guide for aurora borealis watchers'). The book was born out of Palmroth's cooperation with Northern Lights enthusiasts and the answers she provided to questions about the physics of the phenomenon in the hobbyists' Facebook group.
Thousands of magnificent photographs of the Northern Lights taken by hobbyists were surveyed and categorised for the book. Each auroral form is like a fingerprint, typical only of a certain phenomenon in the auroral zone. During the classification, hobbyists pointed out that a certain auroral form did not fit into any of the pre-existing categories. Palmroth set aside these unusual forms for later consideration.
By an almost unbelievable coincidence, just days after the book was published, the hobbyists saw this unusual form again and immediately informed Palmroth. The form appeared as a green-tinged and even pattern of waves resembling a striped veil of clouds or dunes on a sandy beach.
“One of the most memorable moments of our research collaboration was when the phenomenon appeared at that specific time and we were able to examine it in real time”, says Northern Lights and astronomy hobbyist Matti Helin.
Waves newly revealed by the aurora
Investigations into the phenomenon were launched, with hobbyist observations and scientific methods coming together to explain the waves.
“It was like piecing together a puzzle or conducting detective work”, says Helin. “Every day we found new images and came up with new ideas. Eventually, we got to the bottom of it...”
The phenomenon was photographed at the same time in both Laitila and Ruovesi, southwest Finland, with the same detail observed in the auroral emission in both images. Maxime Grandin, a postdoctoral researcher in Palmroth's team, identified stars behind the emission and determined the azimuths and elevations of the stars with the help of the astronomy software program Stellarium. This made it possible to use the stars as points of reference when calculating the altitude and extent of the auroral phenomenon.
Grandin found that the auroral dunes occur at a relatively low altitude of 100 kilometres, in the upper parts of the mesosphere. The wavelength of the wave field was measured to be 45 kilometres.
A total of seven similar events - where a camera had recorded the same even pattern of waves - were further identified from the 'Taivaanvahti' ('Sky Watch') service maintained by the Finnish Amateur Astronomer Association, Ursa.
The part of the auroral zone where Earth's electrically-neutral atmosphere meets the edge of space is an extremely challenging environment for satellites and other space-borne instruments. Palmroth says this is why it is one of the least studied places on our planet.
“Due to the difficulties in measuring the atmospheric phenomena occurring between 80 and 120 kilometres in altitude, we sometimes call this area 'the ignorosphere'",” she says.
The dunes were observed precisely in that particular region of the auroral zone. The observed phenomenon guided the researchers towards a middle ground between atmospheric research and space research, as the usual methodology of space physics could not explain it alone.
“The differences in brightness within the dune waves could be due to either waves in the precipitating particles coming from space, or in the underlying atmospheric oxygen atoms”, says Palmroth. “We ended up proposing that the dunes are a result of increased oxygen atom density.”
Next, the team had to determine how the variability in the density of the oxygen atoms caused by gravity waves in the atmosphere results in such an even and widespread field of waves. Normally at the altitude of study there are many different kinds of gravity waves travelling in different directions at different wavelengths, which is why they do not easily form the even wavefields exhibited by the dunes.
The Northern Lights illuminate a tidal bore
The study suggests that the phenomenon in question is a mesospheric bore, a rare and little-studied phenomenon that takes place in the mesosphere. The tidal bore phenomenon is a wave common to many rivers, where the tide travels up the river channel.
Various types of gravity wave are born in the atmosphere and then rise. In very rare cases, gravity waves can get filtered as they rise between the mesopause and an inversion layer that is intermittently formed below the mesopause. The inversion layer makes the filtered waves bend and enables them to travel long distances through the channel without attenuation.
When the oxygen atoms in the bore collide with the electrons precipitating down upon the atmosphere, they become excited. When releasing this excitation, they create the auroral light. This is why mesospheric bores - a phenomenon thus far considered a very challenging subject of research - can occasionally be seen with the naked eye.
Space researchers focus on the atmosphere
Prior to this discovery, mesospheric bores were not observed in the auroral zone, nor have they been investigated via auroral emissions.
“The auroral zone as a whole is usually discounted in studies focused on the bore, as auroral emissions impair the technique used to identify mesospheric bores", says Palmroth.”
Traditionally, researchers specialising in the atmosphere and space have largely investigated their topics of interest separate from each other. This is because there are only a handful of known mechanisms of interaction between the ionosphere bathing in the precipitating electrons, and the neutral atmosphere.
With the help of measuring devices operated by the Finnish Meteorological Institute, the dunes were found to occur simultaneously and in the same region where the electromagnetic energy originating in space is transferred to the ignorosphere.
“This could mean that the energy transmitted from space to the ionosphere may be linked with the creation of the inversion layer in the mesosphere”, says Palmroth. “In terms of physics, this would be an astounding discovery, as it would represent a new and previously unobserved mechanism of interaction between the ionosphere and the atmosphere.”
Science Daily (01/29/2020)