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We’re told that we can insert a gene to confer sterility and this trait would race like wildfire through Aedes aegypti. Why this species? Because it’s the vector of the Zika virus—along with the dengue and yellow fever viruses. The problem is that A. aegypti isn’t the only culprit. It’s just one of a dozen or more bloodsuckers that will also have to be wiped out. After we’ve driven these species to extinction, we’ll presumably move on to the Anopheles species that transmit malaria.

The post Designer nature: mosquitoes first and then what? appeared first on OUPblog.

The world recently learned that the Islamic State in Iraq (ISIS) has resurrected a biological weapon from the second century. Scorpion bombs are being lobbed into towns and villages to terrorize the inhabitants. As the story goes, this tactic was used almost 2,000 years ago against the desert stronghold of Hatra which was once a powerful, walled city 50 miles southwest of Mosul. But this historical interpretation might be just a bit too quick.

What we know from the writings of Herodian, who documented the ancient attacks by Hatrians on Roman invaders, is that the people crafted earthenware bombs loaded with “insects.” The favored hypothesis is that these devices were loaded with scorpions. And it’s true that these creatures (although not insects) were abundant in the desert. In fact, Persian kings offered bounties for these stinging arthropods to ensure the safe and pain-free passage of lucrative caravans through the region. But the local abundance of scorpions is not sufficient to draw a conclusion.

Scorpions tend toward cannibalism, so packing a bunch of these creatures into canisters for any period of time would have been (and presumably still is) a problem. According to an ancient writer, powdered monkshood could be used to sedate scorpions, although at high doses this plant extract is insecticidal (how ISIS solves this problem is not evident). But there’s another problem with the scorpion hypothesis.

A Syrian account of the siege of Hatra specified that the residents used “poisonous flying insects” to repulse the Romans. But, of course, scorpions don’t fly. One possibility is that the natural historians of yore were thinking of the scorpionfly (a flying insect in which the male genitalia curl over the back and resemble a scorpion’s tail), but these are small creatures are found in damp habitats, not deserts. Another possibility is that ancient reports of scorpions becoming airborne during high winds account for flying scorpions, although such a remarkable phenomenon hasn’t been reported by modern biologists. Finally, some scholars speculate that the clay bombshells were filled with assassin bugs, which can fly and deliver extremely painful bites.

In the end, it seems likely that the Hatrian defenders and the ISIS militants latched onto the opportunities presented by the local arthropod fauna. But why would scorpions be so terrifying then or now? These creatures deliver a painful sting to be sure, but they are only rarely deadly. The responses of the Roman invaders and the Iranian townsfolk seem disproportionate to the consequences of being stung.

To understand why panic ensues when insects (or scorpions) rain down on a village, we must appreciate the evolutionary and cultural relationships between these creatures and the human mind. Our fear of insects and their relatives is rooted in six qualities of these little beasts—and scorpions score well.

• First, our reaction arises from the capacity of these creatures to invade our homes and bodies. Scorpions, with their nocturnal activity and flattened bodies, are adept at slipping under doorsills and hiding in our shoes, closets, and furniture.
• Second, insects and their kin have the ability to evade us through quick, unpredictable movements. While scorpions might not skitter with the panache of cockroaches, they are still reasonably nimble.
• Third, many insects undergo rapid population growth and reach staggeringly large numbers which threaten our sense of individuality. While scorpions are not particulary prolific, having them scatter from exploding canisters (as described in the modern attacks), surely generates a sense of frightening abundance.
• Fourth, various arthropods can harm us both directly (biting and stinging) and indirectly (transmitting disease and destroying our property). Scorpions certainly qualify in the former sense, as they are well-prepared to deliver a dose of venom that elicits intense pain, sometimes accompanied by a slowed pulse, irregular breathing, convulsions—and occasionally, death.
• Fifth, insects and their relatives instill a disturbing sense of otherness with their alien bodies. Scorpions are hideously animalistic, even rather monstrous being like a demonic blending of a crab, spider, and a viper in terms of their form and function.
• Sixth, these creatures defy our will and control through a kind of depraved mindlessness or radical autonomy. Scorpions can appear to be like tiny robots, with their jointed bodies and legs taking them into the world without regard to fear or decency.

Perhaps it is in this last sense that scorpions most resemble the ISIS assailants. Both seem to be predators, unconstrained by ethical constraints, maniacally and unreflectively seeking to satisfy their own bestial desires. Of course, we ought not to dehumanize our enemy—no matter how brutal his actions—by equating him with insects or their kin. (This rhetorical move has been made throughout history to justify horrible treatment of other people.) But perhaps this sense of amorality accounts for our fear of both ISIS and their unwitting, arthropod conscripts.

The post Scorpion Bombs: the rest of the story appeared first on OUPblog.

        

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Entomologists estimate there to be around a quintillion individual insects on the planet–and that’s just insects. Bugs are everywhere, but how much do we really know about them? Jeff Lockwood to the rescue! Professor Lockwood is answering all your bug questions–one at a time, that is. Send your question to him care of [email protected] and he’ll do his best to find you the answer.

Do bugs feel pain? Like, how does the exoskeleton work?

Well, it’s hard to know.  But then it’s hard to know what any organism experiences.  For that matter, I’m not even sure that you feel pain—or at least that your internal, mental states are the same as mine.  This is the “other minds” problem in philosophy.  At least other people can tell us what they feel (even if we can’t be certain that their experience is the same as ours), but we can’t even ask insects.  However, we can have three rather compelling lines of evidence that our six-legged brethren feel pain.

First, insects have a nervous system that resembles ours in many ways.  That is, they see, hear, smell, taste, and feel.  Many of our pains arise from pressure, shock, heat and other stimuli administered at high levels—and insects most assuredly respond to these bodily sensations.

Insects can even detect stimuli that are outside of our sensory scope.  For example, butterflies can see ultraviolet wavelengths and bees can detect the plane of polarization of light.

Next, there are relevant biochemical similarities between insect and human nervous systems.  At least some invertebrates possess endorphins and enkephalins.  These chemicals are opioids (think opium) produced by the body to alleviate pain and stress.  So the presence of these in insects suggests that they might experience pleasure/pain.  We also know that the mechanisms of neural transmission are similar in insects and humans.  This is one of the reasons that neurotoxic insecticides also poison you along with the cockroach in your kitchen.  In fact, the organophosphate insecticides are based on the nerve gases developed during World War II.  Kinda creepy, eh?

Finally, from an evolutionary perspective the awareness of pain is an enormously adaptive mechanism.  Feeling pain when you touch something hot allows a fast response—and a learning opportunity.  So it is unreasonable to assume that pain is unique to humans.  In fact, this perception might reasonably be expected in organisms whose survival can be augmented by the experience of pain, either as part of an escape mechanism or as a basis for the capacity to learn from past experience.  Insects have lots of things inflicting damage on them (fly swatters, bug zappers, lizards, bats, entomologists, etc.) and they certainly have the ability to learn (one experiment showed that headless cockroaches can learn—which is possible because insects don’t stuff all of their neural processing into their heads, like we do).  So it seems quite reasonable that insects would have evolved the capacity to feel pain.

About 30 years ago, an eminent insect physiologist addressed the question of pain in insects.   Vincent Wigglesworth (seriously, that was his name) argued that insects experience internal, visceral pain as well as pain caused by heat and electrical shock.  However, he inferred from observations that cuticular damage did not cause pain.  For example, an insect doesn’t limp when its leg is damaged.  And this leads to your question about the exoskeleton.

The insect’s exoskeleton is, well, a skele

Entomologists estimate there to be around a quintillion individual insects on the planet--and that's just insects. Bugs are everywhere, but how much do we really know about them? Jeff Lockwood to the rescue! Professor Lockwood is answering all your bug questions--one at a time, that is. Send your question to him care of

This is the last part of Jeffrey Lockwood’s blog on the development of nerve gases from insecticide. The previous installments can be read here and here. Today he looks at nerve gases then and now.

His book, Six-Legged Soldiers: Using Insects and Weapons of War, is out now.

While the nerve gases did not realize their lethal potential in World War II (probably because the Nazis, who had a monopoly on these weapons, mistakenly believed that the Allies could reply in-kind), these chemicals had too much promise to disappear from the military scene. In the closing weeks of the war, the invading Soviet army stole the secret formula of soman and captured the massive production plant for tabun. Ecstatic with these spoils of war, the Russians dismantled, transported, and reassembled the German plant on the banks of the Volga. The machinery was back in operation a year later and by the late 1950s, the Soviets had stockpiled no less than 50,000 tons of nerve gas. While the Red Army was pumping out organophosphates as weapons, the chemists of the West were busy upping the ante.

In 1952, a British chemist synthesized an odorless toxin capable of penetrating the skin. Not only did this organophosphate have a toxicity ten times that of soman, but it was viscous enough to form poisonous puddles that would persist and produce deadly vapors for weeks (the earlier, G-agents were volatile and short-lived on the battlefield). The pinnacle of the new V-agents was VX, which became the golden child of the American chemical warfare community and tens of thousands of tons were produced and loaded into bombs and shells over the next 20 years.

All the while, agrichemical companies searched for organophosphates that were substantially more toxic to pests than they were to humans. And they finally struck insecticidal gold. Today, farmers and homeowners are intimately familiar with the chemical legacy of the nerve gases. An incredible 70 percent of all insecticides applied in the United States are organophosphates—about 73 million pounds per year. Diazinon and malathion of two of the three most commonly used home-and-garden insecticides. Worldwide sales of organophosphate insecticides approaches $3 billion, accounting for nearly 40 percent of the entire market. Malathion, the most widely used of these chemicals, has a human toxicity 15,000-times lower than its nerve gas ancestors, while still being remarkably lethal to insects. However, even the relatively safe forms of these insecticides have been used as murderous weapons.

During the struggle against apartheid in South Africa, organophospate insecticides became the weapon of choice for assassins operating within extremist factions of P.W. Botha’s violent apartheid government. Parathion—a chemical cousin of malathion—was an ideal poison, being readily available and generating a set of indistinct symptoms such as nausea, headache, vomiting, diarrhea, disorientation, confusion, and respiratory arrest. The killers quickly discovered a bizarre but wickedly effective method for delivering the poison to a political enemy: breaking into the victim’s house or hotel room and smearing the odorless, colorless insecticide onto the person’s underwear. The optimal penetration of the chemical was through the body’s largest hair follicles, conveniently located under the arms and in the crotch. If the targets of these insecticidal weapons were limited to victims of demented murderers (and the occasional, incautious farm worker) we might be somewhat relieved, but there is a much darker potential.

In 1975, the Stockholm International Peace Research Institute provided a disturbing analysis of the potential for unholy alliances between agrichemical industries and modern militaries: The possibility that chemical plants, especially those producing organophosphorus insecticides, could be converted to the production of nerve agents or other CW [chemical warfare] agents cannot be excluded…So far as plant safety measures are concerned, if a plant were producing very toxic insecticides, the safety measures would possibly differ very little from a plant producing nerve agents.

Indeed, in 1995 we learned just how easy it is to produce the evil progenitors of today’s insecticides. On March 20th, just before the height of rush hour, an apocalyptic cult called “Aleph” released sarin into the Tokyo subway system. The chemical was carried along by five high-speed trains which spread the nerve gas through the teeming subterranean tunnels. The attack was poorly conceived and executed but still managed to kill a dozen people and injure 5,000. Had the mastermind, Shoko Asahara, not been half-blind and entirely crazy, his followers might have murdered thousands.

Today sees the second part of Jeffrey A. Lockwood’s three-part account of the creation of nerve gas through the synthesizing of insecticides. Check back tomorrow for the last part.

Jeffrey Lockwood is the author of Six-Legged Soldiers: Using Insects as Weapons of War. You can read the first part of his blog here.

Schrader understood the strategic implications of his discovery. He named the chemical “tabun” and communicated his findings to Army Weapons Office in Berlin. A Nazi decree required that all inventions with military potential be reported, and they were especially keen to find a chemical that would improve on the agents used in World War I. Hitler’s objections notwithstanding, the Germans were fully aware that the Italian dictator, Benito Mussolini, had successfully used mustard gas in his 1935 invasion of Ethiopia and—more importantly—there had been no international repercussions for the week-long chemical bombardment of the African nation. The Axis powers reasonably concluded that the Geneva Protocol was a convention of convenience—and chemical weapons were still viable if used with discretion against the proper opponent.

Schrader was summoned to Berlin to demonstrate the efficacy of his chemical to the military leaders, who were amazed with the power of tabun. They watched in horrified rapture as even a minuscule dose applied to the skin of a dog or a monkey immediately caused the animal’s pupils to shrink to pinpoints, after which it frothed at the mouth, vomited, and collapsed. As the gruesome demonstration progressed, the animal began to defecate uncontrollably, its limbs twitched, its entire body convulsed, and finally it died. The entire ordeal was mercifully completed within 15 minutes, although mercy was the farthest thing from the mind of the military. They were mesmerized by this chemical’s virtues—not only did it kill within minutes (phosgene and mustard gas took hours), but it was lethal though both inhalation and skin contact. Moreover, tabun was practically odorless; the enemy would never know what was coming until the ghastly symptoms took over their bodies.

The German military moved Schrader to a new facility at Elberfeld, providing him with state-of-the-art equipment and an undisturbed setting in which to continue his research on the organophosphates. Their faith in the chemist was well placed. In 1938 he discovered sarin, a compound with what he called an “astonishingly high” toxicity. Although the etymology of tabun seems to have been lost in history, “sarin” was an acronym honoring the key scientists involved in its discovery. The formula was dutifully delivered to the Wehrmacht’s laboratories in Berlin, where tests revealed a toxicity ten times that of tabun.

The deadliest organophosphate, soman, was isolated by Dr. Richard Kuhn, who won a Nobel Prize in chemistry for his work on carotene, a precursor of vitamin A. Kuhn’s work on deadly chemicals came too late in the war for the Nazis to put his nerve gas into production. Discovered in 1944, soman completed the evil trinity of G-agents, so-named for either Germany or Gerhard (Schrader). There were two other G-agents, but these received only cryptic code-names and never became serious contenders for the Nazi’s nerve gas program. By the time of Kuhn’s discovery, the Germans were also beginning to understand why these chemicals were so lethal.

The organophosphates inhibit the enzyme responsible for breaking down acetylcholine. This chemical is the primary neurotransmitter in the human body, carrying impulses between nerve endings. Without the enzyme to deactivate the neurotransmitter, the signals continue unabated. With no way of stopping the nerves from firing, we cannot control our bowels, muscles, or breathing—and a grisly death follows in short order. But the Nazis didn’t need to know how these insecticides-cum-nerve gases worked in order to understand that they had the potential to turn the course of the war.