Short and Happy Life
The eggs of the Bogong Moth start their life cycle on the black soil plains of the Darling Downs in Southeast Queensland, west of the Great Dividing Range.
The eggs hatch into larvae/cutworm caterpillars in early spring. They dig a burrow in the dirt at the base of a plant, hide in it by day and come out at night to eat the plant. Once they are about 5 cm long, they pupate in a cocoon inside their burrow, emerging as adult moths 3–4 weeks later.
These black soil plains get too hot for the moths in summer. So when the summer storms herald their arrival with atmospheric low pressure systems, the moths take to the wing in their billions. They can flap a few hundred kilometres south each night, keeping up their strength by feeding on flowering gum trees. When the Sun comes up, they dive down to find a safe resting spot that is both dark and cool to hide in until sunset. So, in this case, the lights of a big city can trick them into landing before they should.
The journey can be fraught with natural disasters as well. Winds have been known to blow them as far off course as Melbourne and New Zealand. After flapping some 800 km along the east coast of Australia, they arrive at their cool resting place in the caves across the high Bogong Plains near Mount Bogong which (of course) is in the Bogong National Park in the Australian Alps.
Over the summer they ‘sleep’ in these caves—‘estivation’ is the insect equivalent of animal hibernation—with about 27,000 moths squashed onto each square metre of the cave walls.
After sunlight, these moths make up the second largest input of energy into the Australian Alps in summer. It’s almost ‘Meals on Wheels’ for the local animals, with all this wonderful food at their doorstep. These predators include birds (e.g. pippets, robins and ravens), spiders, reptiles, fish, mammals (especially foxes) and marsupials (e.g. the Antechinus and the Mountain Pigmy Possum).
Around February and March, they head for home. Only one in every thousand gets back there to mate. Then, after a short life with lots of travel (about 1,500 km), they die.
Tricky Flight Path
So what’s the story with moths dive-bombing the verandah?
You have to look carefully to notice this, but most of their flight path is not straight, but curved. Moths, like other nocturnal travellers, use quite a sophisticated system of Celestial Navigation to find their way. It’s called ‘Transverse Orientation’—keeping a fixed
angle on a distant source of light. And it is remarkably effective.
Suppose that the Moon is high in the northern sky, and that you want to head west for a few hours. Easy, just keep the Moon on your right (the north) and you will automatically be heading west. It works only because the Moon is so far away.
Now try navigating, not with the Moon but with a streetlight only a few metres away. When you try to keep it on your right, you will very quickly find yourself walking in a circle. And if you keep the streetlight somewhere between directly to your right and directly in front of you, you will quickly enter a death spiral and hit the post of the streetlight. This is how the moths get tricked.
Although moths have been around for many millions of years, they don’t have much evolutionary history in dealing with bright city lights at night. In Australia, the Bogong Moths leave hot Southeast Queensland every summer and flap their way about 800 km south to arrive in the cool Australian Alps in November. But the city of Canberra has blossomed into existence along their ancestral pathway. The moths get tricked by the city lights, become disoriented and head for the lights of buildings in Canberra.
Like a moth to a flame…
The wingspans of moths range in size from a tiny 4 mm to a terrifying 300 mm.
Moths are closely related to butterflies. They have a similar life cycle—egg, larva (caterpillar), pupa (chrysalis) and, finally, the imago (adult).
Trick Lights
It’s not only moths that get tricked by lights. Some baby sea turtles get tricked also. Their evolutionary imperative is that, when they hatch on shore and dig up through the sand to the surface, they head in the direction of the Moon. They hatch at night when the Moon is over the sea—which is the right direction for the baby turtles to scramble towards. However, because we humans have placed lights along the beach, some baby turtles head inland towards the lights—and die.
Moths Carry Arsenic
Bogong Moths are poisoning their summer home in the Australian Alps with arsenic that they gather from Southeast Queensland. The arsenic was brought to our attention when local scientists in the Australian Alps noticed that all plant life was dead for 30 m on the downhill side of the caves in which the Bogong Moths sleep during the summer months.
The story began in the 1920s when vast amounts of arsenic were used, not only to kill the invasive prickly pear cactus but also in general agricultural sprays. The local environment took up this arsenic.
Polluting chemicals are usually carried by wind or water or, as in this case, up the food chain. The Bogong Moths pick up the arsenic from the soil and plants when they are young and growing. On average, there is one Bogong larva in each 10 m2 of soil. They then carry this arsenic in their bodies into the caves where their density can reach 27,000 moths per square metre.
The arsenic then enters the alpine food chain in many ways. The Bogong Moths are eaten, transferring the arsenic to a range of predators. For example, the local feral foxes eat about half-a-billion moths each year. The moths defecate, dumping the arsenic-rich faeces on the ground, the rain then spreading it around. The moths also die. In some caves, the moth corpses are 1.5 m thick on the floor.
Flaming Beauty
But perhaps it’s all part of Nature’s Grand Plan. In ‘The lesson of the moth’, in Archy and Mehitabel by Don Marquis, Archy (a journalist reincarnated as a cockroach) spoke with a moth who knew it was going to die. There are many ways to die but, said the moth, ‘it is better to be happy for a moment and be burned up with beauty’.
Reference
Marquis, Don, Archy and Mehitabel, New York: New York, Anchor Books, published by Doubleday; copyright 1927, 1930, Anchor Books edition 1973, 1990.
Runner’s High
There are some people who invest in kilojoules so they can store them carefully around their middle. And there are those who invest in physical fitness, which they build up by pounding the pavement. And while the Slouches on Couches expound the virtues of watching TV or lazing under a tree reading a book, the runners pant breathlessly of their secret reward—the Runner’s High.
Now here’s something odd. Runners have always confidently claimed that the Runner’s High is due to chemicals called ‘endorphins’ released by the brain. Although there was nothing approaching real proof for this claim until February 2008, people still believed in it wholeheartedly.
How the Myth Began
Opiate drugs (e.g. opium, morphine, codeine and heroin) affect the human brain because brain cells have receptors for these drugs. This is how our brains recognise these opiates (or, indeed, how any of the cells in the body recognise any chemicals). So, on one hand, there are chemicals that you can extract from a pretty poppy that originally grew in Turkey. And, on the other hand, human brains all over the world have receptors for these chemicals. But why should there be a link? The search for endorphins began with this deceptively simple question.
In the mid-1970s, we finally found the answer. The brain makes its own opiates that are similar to the opiates found in the Opium Poppy. Some of them were called ‘endorphins’—short for ‘endogenous morphines’, i.e. ‘chemicals like morphine’ that are ‘made in the body’.
Brain Opiates
There are three main groups of opiates that the human brain makes, each coming from different precursor chemicals. They each have variable effects on the different natural opiate receptors, which include k-receptors (kappa), m-receptors (mu), d-receptors (delta) and s-receptors (sigma). These receptors are found in varying degrees in different parts of the brain.
The ‘enkephalins’ (which
means ‘in the head’) were the first natural opiates to be classified as acting on the brain. They are a breakdown product of, and come from, ‘proenkephalin’. They appear widely in the central and peripheral nervous systems and also in the adrenal medulla. They cause respiratory depression and reduced gastrointestinal motility.
The ‘dynorphins’ are another class of natural opiates. There are several types, including A-dynorphin and B-dynorphin. They come from ‘prodynorphin’ and act mainly on k-receptors on cells. They act as painkillers and antidepressants and cause physical dependence.
Finally we have the class that everybody has heard of—the ‘endorphins’. These come from ‘pro-opiomelanocortin’. Again, there are several types, including beta-endorphins, which are excellent at giving spinal-pain relief.
Running happy…
‘Runner’s High’ is said to occur when strenuous exercise takes a person over a threshold that activates endorphin production.
Endorphins are produced by the pituitary gland.
Activation of opiate receptors by endorphins regulate many functions within the body, including pain perception, internal temperature, appetite, sexual behaviour and blood pressure.
A synapse is a small gap between neurons where nerve impulses pass between nerve cells.
And the link to the Runner’s High? Well, fit people supposedly enjoy boundless energy, a zest for life and reduced stress. But the Runner’s High is something even better again. It differs considerably between individuals, but it’s described as a drug-like, elusive feeling of euphoria. It encompasses weightlessness, inner harmony, feelings of disembodiment, a total lack of anxiety or stress and, sometimes, even the occasional orgasmic sensation. In other words, it’s much better than the euphoria you feel from opening a packet of chocolate bikkies. Under the influence of the Runner’s High, some runners have even been reduced to tears at the sight of a cute puppy.
Runners began to whisper to each other about this high when jogging began to become popular in the mid-1970s. It was around this time that endorphins were discovered, so it seemed obvious that endorphins caused the high—but there was no proof.
Chinese War on Opium
Arabian traders introduced opium to China somewhere around 600 AD. In 1860, China was forced to tolerate the legalisation of opium, after losing the two Opium Wars (of 1839–1842 and 1856–1860) with Britain (which held a monopoly on the sale of opium in Asia). As a consequence, by 1906 China consumed 39,000 tonnes of the world’s total opium production of 41,000 tonnes. About one-quarter of China’s adult male population (some 13.5 million) was addicted to the stuff.
Poppy Seeds
Poppy seeds can give you a false positive for opiates in a drug screen.
Poppy seeds are commonly used as a flavouring and topping for cakes and breads. Typically, 1 g of poppy seeds carries up to 33 millionths of a gram of morphine and 14 millionths of a gram of codeine. Although these are very small quantities, modern technology can easily detect even smaller amounts.
Before 30 November 1998, the US Substance Abuse and Mental Health Services Administration had a cutoff level of 300 billionths of a gram per millilitre of urine. Two poppy seed rolls (containing 1.5 g of poppy seeds) were enough to trigger an alert. So in 1998, the cutoff level was lifted to 2,000 billionths of a gram per millilitre of urine.
The Original Morphine
Endorphins are a family of chemicals that have effects similar to morphine—except that they are made in the body. So let’s look at the source of the original opiates—the Opium Poppy.
There are about 50 different species of the poppy, scientifically called Papaver somniferum. They usually have nodding buds on a single stem, four to six flowers with petals, and grow between 1–5 m high. They include the Oriental, the Shirley, the Long-headed and, yes, the Opium Poppy. If you cut the central bulb of the poppy with a sharp blade, it will exude a soft milky sap that will harden overnight into a rubbery latex. This latex contains up to 16% morphine.
We don’t know why the Opium Poppy makes opiates. Perhaps they are a waste product, or a protective mechanism or a part of the ripening process.
The painkilling properties of the latex from the Opium Poppy have been known for millennia. Its seeds have been found in Spanish caves dating back to 4200 BC. By 3400 BC, the Sumerians were calling it Hul Gil, or ‘joy plant’. The ancient Egyptian medical textbook known as the Ebers Papyrus, written around 1500 BC, listed the latex of the Opium Poppy as a painkiller. The ancient Greeks, Romans and Persians also knew this plant well for its painkilling properties.
Opiates tend to act in one of two locations—on the central nervous system or on smooth muscle. They can relieve the pain of kidney stones and gallstones by reducing the contractility of the smooth muscle in the ducts. They can reduce a cough and relieve respiratory distress by acting on the central nervous system. They can treat diarrhoea by reducing fluid loss and relaxing the smooth muscles of the gut.
Use of Opiates
For many thousands of years, opium was the only painkiller known to medicine. When it was mixed with alcohol, it was called ‘laudanum’, which was very popular in Europe. And ‘paregoric’ was a camphorated solution of opium, used to treat diarrhoea by relaxing the smooth muscle of the gut.
Morphine was first extracted from opium in 1804, and codeine in 1832. However, heroin was obtained around 1898, by treating morphine with acetic anhydride.
Various synthetic opiates were first synthesised in the late 1930s. These include methadone and meperidine.
Discovery of Human Opiates
It was in 1960 that Choh Hao Li, a neurologist at the University of California, San Francisco, first isolated beta-endorphin. He purified it from the pituitary glands of 500 camels. But because this chemical didn’t answer the questions he was asking, he did no further work with it. (Much later, after other workers had announced their discoveries, Li went back to his original beta-endorphin. When used as a painkiller and compared to morphine, he found that it was three times more powerful when injected into the veins and 48 times more powerful when injected directly into the brain.)
By 1973 other workers had worked out that various animal brains had receptors that interacted weakly with opiates, such as morphine.
However, it was in 1975, that John Hughes and Hans Kosterlitz isolated some opiate-like chemicals from the brains of pigs. Because these chemicals were found in the head, they called them ‘enkephalins’. On a chemical level, they are all made from five amino acids stuck together to make a protein. There are two types of enkephalins—one with the amino acid ‘leucine’, the other with the amino acid ‘methionine’. Although quite addictive, they were weak at killing pain—unfortunately, the exact opposite of the result that everybody wanted.
Endorphins are Discovered
A few studies in the 1980s found endorphins in the bloodstream of people who had been running. However, there were a few problems with these studies.
First, they measured endorphins in the blood, not in the brain. So these endorphins could have been produced anywhere in the body as part of a gross stress response. Second, the levels of circulating endorphins did not relate to the level of ‘being high’ that the runners experienced.
And finally, because we are talking about the human body, the bland claim that ‘endorphins give you the Runner’s High’ is too simplistic. For one thing, the human body makes several types of opiates—endorphins are just one of them. For another, there are many types of opiate receptors that your natural opiates affect in differing degrees—and some of these opiates can make you feel unhappy or even sick. This might explain why, after a decent run, some runners feel like vomiting, rather than being ‘at one with the Godhead’ around them.
But the high was definitely real for many. Some people with Obsessive-Compulsive Disorder actually became ‘addicted’ to their regular dose of exercise. Indeed, some people use exercise as a coping mechanism—and provided that they don’t actually exercise so much that they inju
re themselves, it is probably perfectly fine.
Opium Production
In 1980, the world’s production of legal and illegal opium was about 2,000 tonnes. By 2002 it had increased to 5,000 tonnes, with Afghanistan the world’s leading producer. (Production decreased in 2001 when the Taliban placed a ban on the growing of Opium Poppies the previous year.) And by 2008, opium production in Afghanistan had increased enormously, thanks to the ongoing war against the Taliban. Afghan farmers can make much more money growing Opium Poppies than any other crop.
The Proof…
In February 2008, the neurologist Dr H. Boecker published his paper on the Runner’s High. His team in Germany measured both ‘euphoria’ and whether brain opiates were binding to various receptors in the brains of ten distance runners. The runners in the study were deliberately not told what the researchers were looking for. Typically, they were running 21.5 km in 115 minutes at an average speed of 11 kph, with their hearts beating at 144 beats per minute, compared to their regular 52 beats. The intensity of this long and continuous work-out forced the muscles to use up their stored glycogen. (Sports such as swimming, cross-country skiing and cycling produce the same effects.)
The study produced two findings. First, that the natural opiates were binding to those parts of the brain that deal with mood. Second, that there was a direct relationship between the euphoria and how the natural opiates were binding to the brain. Dr Boecker said in The New York Times: ‘You could really see the difference after two hours of running. You could see it in their faces.’
Science is Golden Page 15