Hazardous Insects and Spiders

The Bug Dude presents The Skeptical Entomologist

Hazardous Insects and Spiders

A look at the dangerous to humans posed by common insects, scorpions, and spiders.

INTRODUCTION

    If there's one thing that seems to really get people's attention, it's the figure of a spider or a wasp on the wall. In western societies, as many as 55% of women have arachnophobia, and 18% of men are severely afraid of spiders. [1] These fears are justified by those who dislike spiders with the fact that "spiders are dangerous, a black widow can kill a person!" While the bite of a Latrodectus can indeed kill a small child if medical treatment is not sought immediately, this hardly seems to be a valid reason for the image culture has placed on these animals. Only slightly less maligned are bees, wasps, and ants; the former two for their stings, and the latter for their tendency to invade homes. Paradoxically, people love to come across an Asian ladybird beetle (Harmonia axyridis), even though the foul smelling substance it expels onto the skin is, in fact, a poison, and itself is a ravenous predator of aphids (once again emphasizing the notion that perception is everything; our cute symbol of spring is a terrifying hunter). 

    The purpose of the essay is to argue that insects and arachnids are not as inherently dangerous as they seem. While there are many urban legends (spiders under toilet seats, soldier and camel killing solpugids), some with a basis in truth (the recurring and errant internet meme of the "spider under the toilet seat" has its roots based in the wild west, where outhouses made excellent hunting grounds for Latrodectus spiders), these are largely unsubstantiated and, even it they were true at some point, utterly irrelevant now; in the age of advanced medical technology, human deaths from these animals are incredibly rare. 

The Eight Legged Freaks Versus Man's Best Friend

     The reason that insects, spiders, and scorpions are maligned by humans may be the fact that they are so different than us. We only have four limbs, while they have a minimum of six. Many eyes, or large, complex globes of ommatidia which watch the world unblinkingly. However, the claims are often based on the animals being seen as "dangerous". I myself have experience in such a claim, being told that if my own progeny came into contact with my P. imperator or G. rosea, there would be dire consequences. How do these magnificent, miniature marvels so compel us with fear to urge us to threaten each other when another willingly keeps them in their home? 

     It is extremely bizarre (to me anyway, although that may be the Aspergers talking), at least on the face of it, that a country which loves sky diving, roller coasters, a love of guns, of fast cars and rodeos would fear a creature as small as a spider. We could crush a spider without a second thought, and when we weed, we are literally destroying their microhabitat (to quote J. Robert Opppenheimer, "And now I've become death, destroyer of worlds."), and yet they haunt our collective memory to such an extant that few other animals - most notably the shark - rival them in terms of fear factor. 

    A basic search of "dangerous animals" or "U.S. deaths caused by spiders" brings up horrifyingly specific figures. One website cites, without any real information to back it up, 100,000,000 annually; the site looks to be, fortunately, satire.[2] Distressingly, this seems to be the common theme; "spiders are dangerous, and they should be gotten rid of". One website states that the deaths caused by venomous spiders are eight times as great as deaths caused by both bees and wasps (or maybe it's the other way around; the wording is, actually, rather horrible).[3] To further add to the confusion, the CDC only inflames things by listing three venomous, medically significant spiders instead of the normal two (Latrodectus and Loxosceles reclusa); the added species is the hobo spider (Tegenaria agrestis)[4]. Still, others claim another venomous spider which lives in the United States: Cheiracanthium inclusum, the American yellow sac spider. Once you add in the fact that the occasional wandering spider from Brazil (Phoneutria), a very venomous species, occasionally stows away in shipments of bananas to supermarkets, it would seem we are living in a veritable nightmare.

The Brazilian wandering spider, sometimes called the banana spider.

    Of course, spiders aren't the only animals which have to contend with bad publicity. At least as equally feared as spiders, if not more, in some parts of the country are scorpions; in the American southwest, they are everywhere. By far the most feared is Centruroides excilicauda, the Arizona bark scorpion, which is also the only scorpion out of the 80 North American species which can be fatal to humans. But scorpions aren't the only things which give spiders a run for their money; soplugids, better known as camel spiders or sun spiders, are found worldwide, and are (also worldwide) the subject of many, rather gruesome, urban legends. Then you have bees and wasps (the only wasp I would be wary of is the tarantula hawk wasp, for reasons we shall see later), which have given chemical corporations a wide market to sell their wares to.

    But how do these animals fare when compared to other animals? The most deadly of the insects and arachnids, the spiders, kill on average 6.6 people annually (this is a rather liberal number; the more conservative estimates are zero); admittedly, these are also the cases in which very young children are bitten, and medical help is not offered to the victim. On average in the United States of America (where the 6.6 people are allegedly killed by spiders), less than 1 person is killed by grizzly bears (it seems an odd thing to say, but it's an average); one person is killed annually by a cougar.

     Dogs by far have the highest kill rate of any animal outside of humans. 31 deaths occur annually from dog attacks; the most common culprits of canine crime are pit bulls, rottweilers, dobermans, and German shepherds. People have also been run down by mix breeds, golden retrievers, labradors, St. Bernard dogs, mastiffs, American bulldogs, Alaskan malamutes, and even weimaraners. Yet people absolutely love their dogs. There are even those who claim that, despite continually topping the list in causes of fatal dog attacks, pit bulls are perfectly safe to be kept around small children and infants. This is incredibly alarming when one considers that most of these deaths involved small children, toddlers, and babies.

     These are often the same people, mind you, who absolutely hate spiders, scorpions, centipedes, and insects. Why would people hate an animals that only can kill you if you don't seek medical attention, yet leave their small toddlers around an animal with a reputation for turning on its owner? 

     To push the issue of this cognitive dissonance home, let's recap (these are for the U.S. only):

Dog breeds known to kill humans: pit bulls, rottweilers, doberman pinschers, German shepherds, mongrels, golden retrievers, St. Bernard dogs, bull mastiffs, American bulldogs, Jack Russel terriers, Alaskan malamutes, huskies, weimaraners, schnauzers, labradors, wolf-dog hybrids, great danes, American Staffordshire terrior, chow, pomeranian, airdale terrier, English sheepdog[9]

Spider species known to kill humans: Black widow, brown recluse  

Despite it's higher kill count, many people would prefer a dog

to a spider.

     As many people would assert, the basis of fear is not only due to the fact they are venomous. The human brain responds differently to different shaped objects. Even though the domestic dog (Canis lupus familiaris) is much more dangerous than a spider is, humans usually do not fear them because they are similar to us. They're bodies contain no rough angles, they don't move suddenly or in a "jerking" manner. The human brain has evolved to find animals with large eyes cute (which is why human babies have seemingly large eyes), a trait often found in dogs. Dogs also display a remarkable ability to react in ways spiders cannot; dogs display some degree of empathy, acting sad when their owner, say, displays signs of depressions. Dogs may even empathize better with humans than any other animal, including humans.[5] Spiders, on the other hand, are solitary. While dogs evolved as social animals whose survival depends on maintaining a position in a highly structured social group, spiders never had any need to evolve such behavioral traits.

     This is not to say that venomous insects and arachnids should not be taken seriously. Even if they cannot kill, their venom (wasps, ants, bees, spiders, scorpions), pedipalps (scorpions), and the "mandibles" of soplugids (actually, they are their cherlicerae) can cause intense pain in those who are stung. For example, the sting of the tarantula hawk wasp (genera Pepsis), for example, is extremely painful, and second only to that of the South American bullet ant (Paraponera); when stung by a Pepsis wasp, Justin Schmidt (who devised the Schmidt pain index for the stings of bees, wasps, and ants), described it as so painful the only thing a person can do is scream.[6] 

     Many venomous spiders have conditions named after them; Latrodectus spiders, for example, cause a condition known as latrodectism in those who have been bitten, and the experience, while not fatal, is extremely unpleasant. Even pet species of arachnids can do some damage; P. imperator does not cause any major damage with its sting, but large ones have been known to break skin with their pedipalps; New World tarantula bites are often treated as minor stab wounds as opposed to spider bites, because the majority of the damage is done by the actual bite itself when compared to the effect of the venom.
  Why we fear arthropods lies deep in our evolutionary past. That's right, before the advent of modern medicine, bites form spiders, stings from scorpions or wasps, could very well prove fatal. Studies show that humans are instinctively more afraid of dark colors, sharp angles, and unpredictable movements than smooth curves, bright colors, and predictable behaviors. The former is often found in arthropods, while the latter is found more commonly in birds and mammals (and butterflies; have you ever noticed how people hate moths but love butterflies?). According to psychologist Jon May, 

We like bright-coloured [sic] butterflies and ladybirds, but spiders are dark coloured with long, angular legs... we also are very sensitive to seeing things moving our of the corner of our eye and immediately notice it, and insects move quickly and unpredictably.[7]

     It doesn't help much when we see arthropods eating things we would generally consider animals which would eat them. It seems utterly mind-blowing that a praying mantis would catch a hummingbird, or that a spider could kill (and consume) a snake. Yet, these things happen (if Facebook is to be believed, the majority of these things happen in Australia), and their occurrence seems to throw our established "food chain" on it's head (yet another reason to adopt "food webs" instead of "food chains"). However, this really does not violate any natural order; much like any animals, many arthropod predators will take whatever they can catch.

Meanwhile, in Australia, a golden orb weaver 

(genus Nephila) consumes a small bird.

     Fear of such animals is also likely driven by a general misunderstanding of them by the public. While a person may be driven to understand the behavior of a dog, or a bird, or a fish, they may simultaneously never give two thoughts to how a spider or a wasp sees the world. As such, these organisms remain an enigma, whose behaviors are as elusive as a half-forgotten dream, who are forever seen as living in the shadows.
     Fear of insects and arachnids aren't the only remnants of our evolutionary history; the common fears of heights, enclosed spaces, and the dark once were great assets to our pre-human ancestors. But, in the 21st century, these fears no longer have any survival value; remnants of a dangerous and brutal live in nature, before we had the technology to control the environment, they can only hold us back as we go into the future. While the exotic pet trade is helping to squelch some of these unnecessary fears and negative stereotypes about invertebrates, everybody should try to learn as much as they can about spiders, insects, and scorpions.

Not to be outdone, a praying mantis (Mantis religiosa)

catches and consumes a hummingbird.

Solifugae - The Myths & the Facts

     Even few spiders instill as much fear, as much awe, and as many urban legends as Solifugae. Not an actual species, Solifugae is an order of arachnid, and a single individual is known as a solpugid. They are endemic to desert biomes, although they may also be found in grasslands and wooded areas; there are over 1,000 described species. Many species described are extant, although some are known from fossilized carcasses from the Pennsylvanian. These animals are best known for their impressive chelicerae, which appear as two large, saw-like jaws that dwarf the actual head. These large weapons are used to take down and tear apart their prey, and solpugid bites have been known to break skin and leave ragged wounds. While no species are poisonous, that hasn't stopped them from accumulating a nasty reputation.

A fossilized solpugid.

     Their Latin mean translating (roughly) into "fleeing from the sun", they have many colloquial names: sun spiders, camel spiders, wind scorpions, matevenados (deer killers in Spanish), jerrymanders (the name given to them by British soldiers in WWI), rooiman ("red man"), and baardskeerders ("bear cutters"). One of the more intimidating behaviors exhibited by solifugae is its tendency to "chase" after people. Indeed, this is one of the many myths about them returning from Iraq with the soldiers. However, this behavior is not them chasing the soldiers out of any malice or predatory intent; this is simply them seeking shelter from the desert sun. If the soldier mustered enough nerve to sit there calmly, it is likely the solpugid would simply come to rest in the shade the soldier provided.

The photo of two solpugids was authentic, although the 

accompanying text was almost entirely fictitious.

     The above picture has started circulating around the internet quite some time ago, with the following text: 

"Yuck. I sure am glad we don't have these here. Although we probably will after this war...

This picture is a perfect example of why you don't want to go to the desert. These are 2 of the biggest I've ever seen. With a vertical leap that would make a pro basketball player weep with envy (they have to be able to jump up on to a camels stomach after all), these bastards latch on and inject you with a local anesthesia so you can't feel it feeding on you. They eat flesh, not just suck out your juices like a normal spider."[8]

    First and foremost, this description is inaccurate because it places the range of solifugae as only in the middle east, when species naturally occur in the Americas. As stated earlier, these animals are also found in grassland and wooded areas, so the description is wrong on that count, as well. As far as has been observed, these animals cannot jump, let alone make vertical leaps into the air. They do not secrete any compound from their jaws, either venom or anesthetic, and when they bite you, you definitely feel it. Camel spiders have also never been known to attack camels (or deer).
     Once again, it seems that myths have been cultivated over an animal with a bizarre appearance that the general public knows very little about. To complicate the problem, the History Channel (who's expertise is "history") ran an episode of the pseudoscience show Monster Quest in which "arachnologists" scoured Middle Eastern deserts for giant solpugids, although they predictably didn't find any (which didn't seem to affect their optimism that it exists). As with many other arachnids, enthusiasts are constantly having their time preyed upon by the gullible who have been taken in by these wild falsehoods. As Winston Churchill famously said, "a lie gets halfway around the world before the truth has a chance to get its pants on."
     Another common myth about camel spiders is a truly terrifying one (or, it would be terrifying, if it were in any way accurate). This myth claims that they run parallel to military vehicles, emitting a screeching sound as they run. While utterly ridiculous, camel spiders are considered to be the fastest of all land arthropods; they have been known to reach speeds of up to ten miles per hour. They have also been known to make sounds by stidulating their chelicerae, although the resultant sound could hardly be described as a "screech".
     Nevertheless, solpugids are indeed an intimidating animal; so intimidating, in point of fact, that when one was found in the house of an English soldier, the entire family evacuated the building.

Holding a pet solifugae is surprisingly anti-climatic.

The Spider and the Toilet

     Sometimes, urban legends have their origins in real events. One of these is the recurring story of a "new, ultra-venomous" spider which seems to find the underside of toilet seats an excellent place to build a home. The spider is always portrayed as the rather beautiful two-striped Telamonia dimidiata, which is a species of jumping spider from south Asia, which is harmless to humans. The original hoax was created in 1999 by an individual named Steve Heard, because he wanted to see if a fraudulent meme would be propagated despite obvious holes in its central premise. The most recent incarnation of this meme was worded in the following manner:

"Please pass this on to everyone on your email list:  
According to an article by Dr. Beverly Clark, in the Journal of the United  Medical Association (JUMA), the mystery behind a recent spate of deaths  has been solved. If you haven't already heard about it in the news, here is  what happened. 
3 women in Chicago, turned up at hospitals over a 5 day  period, all with the same symptoms. Fever, chills, and vomiting, followed  by muscular collapse, paralysis, and finally, death.  There were no outward signs of trauma.  Autopsy results showed toxicity in the blood. These women did not know  each  other, and seemed to have nothing in common. 
It was discovered, however,  that they had all visited the same restaurant (Big Chappies, at Blare  Airport), within days of their deaths. The health department descended on  the restaurant, shutting it down. The food, water, and air conditioning  were all inspected and tested, to no avail.  The big break came when a waitress at the restaurant was rushed to the  hospital with similar symptoms. She told doctors that she had been on  vacation, and had only went to the restaurant to pick up her check. She  did not eat or drink while she was there, but had used the restroom. That is  when one toxicologist, remembering an article he had read, drove out to  the restaurant, went into the restroom, and lifted the toilet seat.  Under the seat, out of normal view, was small spider. The spider was  captured and brought back to the lab, where it was determined to be the  South American Blush Spider (arachnius gluteus), so named because of its  reddened flesh color. This spider's venom is extremely toxic, but can take  several days to take effect. They live in cold, dark, damp, climates, and  toilet rims provide just the right atmosphere. Several days later a lawyer  from Los Angeles showed up at a hospital emergency room. Before his death,  he told the doctor, that he had been away on business, had taken a flight  from New York, changing planes in Chicago, before returning home. He did  not visit Big Chappies while there. He did, as did all of the other victims,  have what was determined to be a puncture wound, on his right buttock.  Investigators discovered that the flight he was on had originated in South  America. The Civilian Aeronautics Board (CAB) ordered an immediate  inspection of the toilets of all flights from South America, and  discovered the Blush spider's nests on 4 different planes!  It is now believed that these spiders can be anywhere in the country. So  please, before you use a public toilet, lift the seat to check for  spiders.  It can save your life! And please pass this on to everyone you care about."[9]

      In today's highly sanitized world, the underside of a toilet seat would be the last place a spider would set up shop. Not only to regular cleanings keep any prey populations from accumulating in such an microhabitat, the chemicals used to clean would themselves be highly toxic to the spider, and would almost certainly kill them. Why, then does this at least seem plausible to most people who hear it?
     The story obviously plays to people's irrational fear of spiders. While the origins of this particular chain meme have origins dating only to 1999, similar incidents have occurred in older times. Most notable of these would be incidents which occurred in outhouses before the advent of indoor plumbing; seldom clean, made of wood, and outside, these would have likely seen moderate levels of prey populations. In such conditions, spiders would be likely to be found. The spider in this example would likely be Latrodectus; the immediate environment is shaded, protected, well suited for building its messy webs, and literally crawling with prey items. And when the local farmer needs to "make some room", he may of been unfortunate enough to alarm the resident spider with his genitalia, resulting in a nasty bite that, in a time before medical science became what it is today, was often fatal.
    Another, video version of this story has also been making the rounds, being promoted on Facebook and YouTube:

    The spiders in the video appear to be a species of huntsman spiders (Sparassidae), which are often quite large and, to those who lack any understanding of spider species, intimidating. They are generally considered to be harmless to humans, with defensive bites causing no major medical issues. That doesn't stop people from (1) fearing spiders even more, and (2) vowing never to use a gas station restroom again.

Bullet Ants and Pepsis Wasps

This is most definitely NOT recommended. 

 
     If you know anything about Pepsis wasps (the species in the video is Pepsis formosa), you can probably conclude the man in the above video has balls so hard that, when he falls, they crack concrete. Second only to the sting of a bullet ant, the Pepsis sting is so painful that it is, essentially, unbearable. The only thing which rivals the sting of P. formosa is the bullet ant, Paraponera clavata. P. clavata is famously used in coming of age rituals for some south american tribes. Young men looking to become full fledged men in their tribe must wear the bullet-ant-mittens twenty times.

Donning a glove of angry bullet ants. 

Could you do it?

Once again, don't try this at home. 

     If there were any insects worth fearing, it would be these, which deliver the most painful stings of any insect. Yet even these animals do not deserve to be blindly hated for what they can do.
     The bullet ants receives it common name because it has often been said that the sting is so painful that it feels as though one has been shot. While this may seem, to most, to be a blatant hyperbole, there can be no mistaking the effects of the neurotoxins on the body - those who are stung clearly feel it, and they feel it deeply. The creator of the Schmidt Pain Index described the Pepsis wasp sting as "blinding, shockingly electric. A running hair dryer has been dropped into your bubble bath." Bullet ants, he contents, feel like "fire-walking over flaming charcoal with a 3-inch rusty nail grinding into your heal."[10] Clearly, if these unscientific but humorous descriptions are correct, these animals are not to be taken lightly.
     But are they dangerous? A single animal won't kill a human, no. Once again, while these animals certainly can deliver their venomous goods, they seem to have built up a reputation that is greatly exaggerated. One can't help but wonder why the caliber is never mentioned when a bullet ant is compared to a gunshot wound. It can be easily imagined that it may feel like being shot with a .22, but the vagueness about the description could just as easily imply that it is equal to the pain of being shot in the foot with a .40 caliber pistol. It would be highly unlikely that the sting of a bullet ant would be akin to the pain felt when being shot with a .270 Winchester, but, once again, the vagueness of most of the reports doesn't rule it out. All that is said is that it feels like a "gunshot". It would seem much more likely that the reference to a "gunshot" type pain is a hyperbole, a way to describe a pain that is to exquisite for words.
     The sensation of a P. formosa sting is much more defined by those unfortunate enough to experience it. It is quite easy to imagine what it feels like to be unable to do anything but scream (and maybe roll around on the ground like a possessed person). But the sting is also reported as very ephemeral, lasting only minutes. What an oxymoron! A pain so powerful you can only scream, but it's gone in a matter of minutes. Compared to the bullet ant, which takes 12-24 hours to fully dissipate inside the body.
     Why do these animals have such powerful stings? As with all biological answers, they are found in the eons of evolution. Also, before we continue into the origins of such powerful chemical weaponry, we should probably note that the black body and bright wings of the P. formosa wasp are warning coloration against predators. It doesn't want to use the built of stores of venom for anything other than hunting tarantulas; biologically speaking, any other use of its sting would be a gross misuse of such a powerful chemical weapon. The venom is primarily for the capturing of prey, spiders such as tarantulas. The wasps venom works in such a way so that it paralyzes the spider for the remainder of its life, while still keeping it alive (wasp larvae like fresh meat); if anything could help bear the pain of such a sting, perhaps it is the knowledge that your fate is much better than the spider's. Schmidt hypothesizes that the reason for the painful sting of the Pepsis formosa (and likewise for the bullet ant) is

"making us hurt far more than any animal that size ought to be able to do. It deceives us into thinking serious damage is being done."[11]

     In a world in which Darwinian rules reign supreme, and only those most able to adapt and survive pass their genes on to the next generation, the role of such potent venom is quite obvious; if a sting is painful enough to repel a predator, your genes may be more likely to survive into the next generation. In the case of the tarantula hawk wasp, it may be hypothesized that the strength of the venom comes from the concentration of the chemical ingredients; in an environment where water is hard to come by, a venomous organism would find benefits in concentrating the venom so that less of it needs to be used, thus conserving water. The same parallel can be found in tropical and desert scorpions - often, the more dangerous scorpions are found in desert locales.

Hobo Spiders and Yellow Sac Spiders - Wrongfully Accused

     In the Pacific Northwest, there exists an invasive species so terrible, so venomous that is has quickly surpassed both the violin spider and the black widow in terms of infamy. It is the very dangerous and very aggressive hobo spider. And it must be something about its new locale that gives it its new power and aggression, because, in their native land of Europe, they're considered quite harmless.
     As comedian Tim Allen would say, back the truck up. How can an animal be incredibly deadly in the United States, but be harmless in its native land? Once again, falsehoods have left the truth in the dust. Unlike Latrodectus spiders, Pepsis wasps, or bullet ants, the medical effects of T. agrestis and C. inclusum are hotly debated among professional and amateur arachnologists. Hobo spiders have coexisted with humans for centuries, and across America, many people often come into close contact with yellow sac spiders and never notice them, let alone suffer a bite. The major difference between these two species, and the arguments surrounding their toxicity, is that T. agrestis is an invasive species whereas C. inclusum is a native spider. As such, it would seem the hobo spider is automatically more important - and therefore, more dangerous and more frightening - simply because it is new. "Black widows? Seen them lots of times. Brown recluses? Meh, SSDD. Hobo spiders? Now, that's something!"
 

Hobo Spiders

     In the United States, the argument for the toxicity of T. agrestis is based, almost entirely, on three pieces of information; a study involving rabbits, a man who was purportedly bitten by a hobo spider who developed lesions, and the fact that their Latin name agrestis was translated as meaning "aggressive", when it more accurately means "of the fields". Many are quick to take these at face value, but, alas, we do not live in a universe of black and white, and so we cannot assume these to be accurate without looking deeper into them.

     Regarding the scientific study, rabbits were submitted to T. agrestis bites and their reactions were recorded.[12] The rabbits developed sores on their skin at the site of the bite. This study was used by several governmental agencies, including the CDC, to assess the danger of this new, invasive spider, claiming it causes necrosis in humans. This then, in turn, led to the assumption that spider bites attributed to L. reclusa were really caused by hobo spiders. Subsequent studies into the toxicity of hobo spider bites has failed to reject the null hypothesis that T. agrestis venom is not medically significant; and, indeed, there have been no confirmed cases of their venom causing such a response.

     In regards to the man who was reportedly bitten by a hobo spider and developed necrotic lesions from the venom, one very important fact is often left out: the victim had a preexisting skin condition known as phlebitis, one which made him prone to similar skin lesions.[13] Once again, popular media has not helped the situation even minutely, as Animal Planet's show Infested was quick to jump on the story. Once again, skepticism is needed to determine fact from fiction; while it appears to be a documentary, it is produced for entertainment purposes.

A personal hero of mine, Arlo from Quaoar Power,

conducts a hobo spider bite test.

Yellow Sac Spiders

     The other contested spider is the yellow sac spider. Originally classified as a Clubionidae (true sac spiders) but now classified as a long-legged sac spider (Miturgidae), C. inclusum is endemic to North America, commonly found in trees and shrubs. They can have a legspan of one inch when the legs are fully extended. Like the hobo spider, it is nocturnal and does not rely on a web to catch its prey. Because of this, when humans do encounter the American yellow sac spider, it is usually because the spider has wandered into the vicinity of the person; the majority of the time, however, the spider and human never interact, despite their sometimes close proximity to each other.

     Like that vast majority of all spiders, C. inclusum is venomous. Often, when a person it bitten, nothing more than local symptoms are reported. It is worth noting that the American yellow sac spider has affected a very important industry in a rather unique way - in 2011, the species was responsible for Mazda's recall of thousands of Mazda6 automobiles; the spiders had built webs which had clogged the fuel ventilation systems. It was never determined what had caused the spiders to build webs in such a unique place.[14]

A yellow sac spider video, courtesy of Quaoar Power.

Scorpions

     Scorpions exude a menacing aura that makes them at once frightening, yet mysterious. Nocturnal hunters known for their large pedipalps, the elongated tail, and their eerie glow under a black light, several species are becoming more common to see in the pet trade. The imperial scorpion, Paninus imperator, is about at dangerous as a honeybee, but it's size and coloration make it no less intimidating to any observer. Such an appearance can play a large psychological trick on humans, and many are afraid of picking them up, despite their often docile temperament.

World's deadliest scorpion, the Indian red (Hottentatta tamulus).

     Of all described 2,000 species of scorpions, only 20-30 have venom strong enough to be considered medically significant (excluding, of course, the possibility for an allergy to the proteins in the venom).[15] Among these are the Arizona bark scorpion (Centruroides sculpturatus) and the deathstalker (Leiurus quinquestriatus). 

A video of a child stung by an Arizona bark scorpion.

What Do We Do From Here?

     The question of how to handle the reputations of venomous insects and arachnids is important, because while reputations of some are completely overblown and fictitious, other reputations are well earned. The same rule of thumb for a hobo spider cannot be applies to the deathstalker, and a scurrying camel spider would seem to be infinitely more dangerous than an almost stationary Latrodectus, although this is not the case. 

     There is nothing simple about changing the perceptions people have, especially when it's something they don't want to deal with. Arachnophobes are a good example; they have an irrational fear of spiders so great that it's a problem simply getting them to talk about them often. And, when one points out the fear is irrational, they may get defensive, accuse you of judging them, and storm out of the room (or hang up violently) in agitation. Many of these same people would look to dogs as a source of joy and comfort, even though dogs are more likely to kill them than any spider is, especially in this age of medical wonders. 

     It seems the best course of action is to tell those who fear, those who ignore, and those who love these wonderful animals to treat them with respect and dignity, never interact with them unless necessary, and to always remember that they, like us, may simply need some space.

[1] http://en.wikipedia.org/wiki/Arachnophobia#Culture

[2] http://www.angelfire.com/ultra2/spider_information/

[3] http://www.venomousspiders.net/

[4] http://www.cdc.gov/niosh/topics/spiders/
[5] http://news.discovery.com/animals/zoo-animals/dogs-empathy-humans-120831.htm
[6] "Tarantula Hawks - DesertUSA". Retrieved 2010-07-26.
[7] http://www.dailymail.co.uk/sciencetech/article-2158452/The-shape-fear--spiders-scare-Humans-hardwired-fear-angular-legs-unpredictability.html
[8] http://urbanlegends.about.com/od/spiders/ss/Camel-Spider.htm
[9] http://www.truthorfiction.com/rumors/b/bushspiders.htm#.UaBmkkBQGSo
[10] http://www.dailymail.co.uk/sciencetech/article-2148089/The-10-painful-stings-planet-self-sacrificing-man-tried-150-different-varieties-science.html
[11] http://discovermagazine.com/2003/jun/featstung#.UaB_NUBQGSo
[12]  Vest, D. K. (1987). Envenomation by Tegenaria agrestis (Walckenaer) spiders in rabbits. Toxicon 25(2):221-4.
[13] Vetter, R. S. and G. K. Isbister. (2004). Do hobo spider bites cause dermonecrotic injuries? Annals of Emergency Medicine 44:605-607.
[14] http://articles.latimes.com/2011/mar/03/business/la-fi-mazda-spider-20110304
[15] http://animals.nationalgeographic.com/animals/bugs/scorpion/

Three Poems About Spiders and Insects

Strings

It hangs, silent in

the darkness between

chrome and grey.

Patient eyes, unbound

without self-awareness,

waiting above resting 

needles.

It crouches upon itself

as it hangs inverted, 

clinging to a web of 

irregular madness.

It's pitch body, darker than tar,

spotted with the dire red

of fear, is shrouded 

in the shadows of it's home.

It cannot see the lonely

cricket as it wanders below.

Stopping, going, stopping, going.

One wrong step, it blunders into

a sticky thread which clings to it

as though it were a lost child 

which as found its mother. 

Pulled into the air,

the predator finally 

acknowledges the crickets existence.

Up, up, up to active fangs, 

watching eyes, working legs.

Within reach, silk shrouds 

a desperate cricket moments before

death is delivered through one 

well placed bite.

Latrodectus hesperus

Acheta domesticus 

From the Beginning

It has been this way from the beginning.

Seemingly unchanging, seeming 

to defy its own evolution.

Two long, elegant wings 

carry it through the air in 

its endless search for 

nutrients.

97% of the mosquitoes it sets its eyes on

will never breathe again.

Born from water, it climbed 

up the stalk of a young

grass stem where it cracked

its very own skin in one final

effort to free itself 

from the shrinking prison which
held it for so long.

Anax junius

The Running Sun 

If people know anything about it,

it is that is is to be feared.

Large slicing jaws which 

tear into skin and camels 

and deliver poison and 

kill pets. 

This is not what they are.

They are only what they are,

simple survival in harshest

conditions adult men shun.

Speeding across the sands 

in search of shades, afraid 

of the rays of the sun.

Solifugae 

Intelligence and Pain in Invertebrates (Can Invertebrates Appreciate the Pain They Feel?)

The Bug Dude presents The Skeptical Entomologist 

INTELLIGENCE AND PAIN IN INVERTEBRATES

CAN INVERTEBRATES APPRECIATE THE PAIN THEY FEEL?

INTRODUCTION

   It's a popular topic among philosophical circles, and it is becoming more of an issues in science circles as well - is the experience of pain limited to humans, or can it be found in other organisms? In this case, "other organisms" means terrestrial invertebrates; dragonflies, butterflies, leeches, spiders, centipedes, worms, and the like. Unlike philosophy, however, science gives us the unique ability to not just ponder the question, but to solve it empirically. It may be a bit off topic, but it is worth stating before we start: neuroscience is slowly displacing psychology, and with each advancement in neuroscience we know more about the way the nervous system functions. As a side effect of such advancements, perhaps the most prominent point of strain is the concept of free will; this point isn't being dredged up to make a singular point - it has a significant role to play when we examine the responses to pain in organisms.
    However, to get back on track, it must be stated that it is undeniable that all organisms respond to stimuli. Whatever organisms you poke - be they bacteria, archaea, plants, fungi, or animals - will ultimately have some sort of response. However, the problem of pain becomes infinitely more complex when the subject is animals, as one could argue that only animals could even begin to process pain as we would (as we are animals ourselves). The reason this is infinitely more complex is, not only do we know that animals are capable (at least, some are in theory) of feeling pain, but we as humans have put a name to the pain. It may seem a rather odd distinction to make, and surely it has served our species well in distinguishing ourselves from our lowly origins.
    As an entomologist and arachnologist, the area of pain I am most interested in is whether or not terrestrial arthropods feel pain (I will also extend such academic curiosity to the mollusks with which we share the land). This is tied not only with the definition of pain (concrete or abstract), but also with intelligence (can an arthropod appreciate the pain it feels?). All organisms respond to stimuli, and it appears as though all animals, or at least a wide variety of them, feel what I will term "concrete pain" in this essay - that is to say, they react to pain from an objective, interactive world. Since we know that insects at least respond to pain (a caterpillar will, for example, react differently to being nudged with a finger as opposed to pricked with a needle), the question is how such experiences in the minute world relate to intelligence. It is most certainly not an easy question to answer, and I have no doubt I will ultimately fail in any attempt to do so with this essay. In science, we are seldom completely certain, but we can make intelligent, ethical, and rational judgments based on the evidence and information we have on hand.

THE MOST BASIC OF PAINS

   Before any sort of progress can be made, or, indeed, even before we can begin to answer the question of whether or not terrestrial invertebrates experience pain, we have to first define what we mean when we say "pain". The problem of pain may be infinitely more complex for us as organisms with complex nervous systems because pain is not as simple for us as it is for, say, a tarantula. As a starting point, we should define pain in its most basic form (as that is where we will start if we wish to assign more complex pain to invertebrates). Dictionary.com defines pain as "1. physical suffering or distress, cause by illness or injury; 2. a distressing sensation" [1]. The evolutionary purpose of pain is, therefore, to inform the animal when it is taking damage; an organism cannot survive and reproduce its genes if it is maimed or killed before it has the opportunity to do so. Pain provides the organism incentive to keep itself from harm. In its most basic level, it serves as a kind of physiological smoke alarm [2]. (You can do a simple experiment at home to demonstrate this. Take the tip of a sharpened knife, and push it into your flesh. Before you break the skin, you'll feel at least some small magnitude of pain; if you don't, you should probably consult an expert). In this most basic sense, it is quite apparent that invertebrates are subject to pain, or at least to an equivalent of it: If you nudge a beetle, say, it may move a little bit; however, if you take the same beetle and damage it, it is more than likely going to move away at a greater pace. It would seem logical to assert that there is a difference between pain and simply feeling something, as there is with "higher" animals such as Homo sapiens. 

     

INTELLIGENCE IN ARTHROPODS

    If we are going to look into the concept of pain in invertebrates, we are going to have to look at the level of brain development. Brains are amazing things - all that we see, touch, feel, hear, or will ever think is, essentially, confined to the brain. True, our senses are triggered by objective experiences (being poked with a stick, smelling a flower, bumping into a wall, etc.), but our own experience of them is confined within the brain. Brain development itself seems to correlate to higher intelligence and understanding to such a degree that when we think of super-intelligent extraterrestrials, they are almost always drawn with oversize, bulging brains.
    While the size of the brain is important, it's not necessarily the size of the brain alone. A sperm whale (Physeter macrocephalus) has a much larger brain than that of a human, yet it is the human, and not the whale, which have developed a global society which is now stretching its mechanical hand into space. What's important is brain-to-body ratio. That simply means that the brain size compared to the rest of the animal is what counts, and not brain size alone. Not only does brain size count, but brain function also depends on the neuronal activity in the brain [3].

A look at the brains off two of the arthropods we shall examine: a spider (top), and bee (bottom).

SPIDERS

   In terms of invertebrates, intelligence (or, at the very least, behaviors which seem intelligent) are readily available. Lets look at spiders - some of the most intelligent spiders in the world today are jumping spiders, who have brains so large they actually extend into the legs   of the animal (that's up to 80% of body size!).[4] The most widely appreciated of the jumping spiders belong to the genus Portia, which (as luck would have it) prey on other spiders. But do they use their brains to outwit other spiders?

A Portia spider makes an excellent introductory case study.  (http://www.flickr.com/photos/weett/4346160438/)

    

    The hunting behaviors of Portia spiders are an excellent place to start looking at intelligence levels of invertebrates (the most intelligent and emotional of all invertebrates, the Cephalopods, will not be taken into account, because, for this article, we are focused on terrestrial invertebrates). Portia spiders have often been referred to as "eight legged cats" because of their hunting behaviors. They not only hunt in the open, but have been known to build prey catching webs, and have been observed invading the webs of other spiders [4]. In laboratory settings, the spiders have even been observed solving problems that involve invading webs of spiders which are, as far as can be determined, foreign to them; in the Phillipines, Portia spiders have learned to hunt spitting spiders form behind (spitting spiders themselves hunt jumping spiders). While this appears to be instinctive, it often serves as a jumping-off point (pun intended) for trial-and-error attempts, form which the spider will learn. 

Japanese scientists have discovered that jumping spiders may use "image defocus" 

to judge distance between them and their prey items. 

    Intelligent behavior is exhibited by many different species of jumping spiders. Portia spiders are not alone in the spider world in their ability for visual processing on par with those of cats (well known for their keen eyesight). Some species have been observed in laboratories to recognize and react to images on computer screens; and, as remarkable ability as it is, it isn't even a new discovery - such intelligent behaviors were first observed in the 1980s. In one case, a Portia spider even attacked the screen when it recognized another spider on screen.[5] 

A Portia spider attacks a virtual prey species in a laboratory. 

    Jumping spiders are also known to react to humans in such a way as to make them unique from other spiders. When intimidated by a finger, the zebra jumping spider (Salticus scenicus) doesn't simply run or show it's fangs, as are stereotypical among spiders. It moves according to the movements of the finger, keeping an eye on it. Yes, it will ultimately try to escape if it feels threatened, but it's first reaction is not simply a fight or flight response. It seems to be curious about what it is its facing. Curiosity, as it turns out, is well documented in jumping spiders; they seem to be curious about any new thing which enters their immediate environment. [6]
    As with most solitary animals of their size, it is difficult to determine between intelligence and instinct. Surely one can say that a jumping spider can learn from trial-and-error, much the same way more "complex" animals tend to learn. On the other hand, approaching a spitting spider from behind seems to be hard-wired into the Portia spiders' brain, so one would be hard pressed to call that true "intelligence". Likewise, attacking the screen (an experiment in wolf spiders showed that they reacted simularly to simulated images) when they discern either a prey item or a rival may not be definitive sign of intelligence - it may not be intelligent at all. Once again, it may be nothing more than instinct (it is highly likely that instinct is the explanation). Jumping spiders make a strong case that arthropods may have some degree of intelligence, but they're a far cry from exploring space anytime soon.

Video of a jumping spider hunting a honeybee. 

The perfect (violent) transition to our next arthropod example.

HONEYBEES

    Honey bees are among the most important pollinators in the world. The most interesting facets of these insects is not just their famous way of communication (through the dance floor) but also their ability to learn and remember colors. However, most people don't know about bees for that reason - they are famous because of colony collapse disorder (CCD), which has been the the subject of documentaries (The Silence of the Bees, Where Have the Bees Gone?) and movies (The Happening makes a strong reference to CCD). While that is an interesting and major course of entomological resources (involving genetically modified organisms, pesticides, and a boatload of rage), what is relevant here is the behaviors exhibited by bees.
    The unique thing about bees is that the bees responsible for foraging for food seem to spend their entire times learning.[6] This certainly seems to indicate at least some level of intelligence (remember, intelligence in this case is strictly defined as the ability to learn). One could argue that the ability for honeybees to successfully learn over their lifetime is a handy trick delivered by the blind eye of evolution, and it seems as though that would play a large part in this scenario. On the other hand, it also seems blatantly absurd: the foraging bees are reproducing their own particular genes. To understand this phenomenon, we must first look at the social structure of honeybees.
    Honeybee society revolves around the queen bee, the largest member of the hive which produces the progeny which ultimately constitute the entirety of a hive, and can live for three to five years. Queen bees are develop with the death of an existing queen, in which case a larvae (the vast majority of bees are female) are fed royal jelly.[7] (An interesting side note - in many hives which are affected with CCD, the queen bees are often still present) Once in her life, the queen will mate with a drone bee, the only male bees present in the entirety of the hive. Drones are stouter bees which are larger than the workers but smaller than the queen, with larger eyes and are unable to sting (bee stingers are modified ovipositers, which are understandably absent in male bees); it is worth noting that drone bees are haploid. Finally, the vast majority of the hive are sterile, female daughters of the queen, who perform food gathering and defense roles in the hive.
    Having reviewed the social structure of the honeybee, we can now begin to determine whether the remarkable abilities they exhibit are intelligent or if they are merely instinctual. If they are intelligent, we have to determine if such behaviors are taught or arrived at from trial and error.
    First, lets look at the ability of bees to learn over the course of their life. Evidence suggests that this may be intelligence; memory formed from a single experience can last for up to three days, and when it is enforced three or more times, it lasts for the bee's lifetime.[8] It's quite an amazing thing to think about; that an animal so many of us overlook, that so many of us may even despise, is capable of learning and remembering experiences. To further illustrate this point: in one experiment, bees were exposed to a variety of colors, one of which was attached to a sugary reward. After one trial, the bees were kept in a cage for several days. When the experiment was finally repeated a few days later, over 50% of the bees began foraging with the correct color (the one that had been associated with the sugary treat).[9] 
     Is the communication through dance intelligence? If we assert that bees are intelligent, as experiments suggest they are, are the complex physical communications intelligent as well? Two hypotheses for how bees communicate the location of productive foraging areas are as follows:

1: Honeybees "explain" the location of productive foraging areas through body movements

2: Bees use chemical signals to "explain" the location of productive foraging areas.

    By far the more accepted of the two ideas is the dance-communication proposal, which, in the interest of brevity, will be explained in the video below:

A video explaining an interesting experiment with dance-communication of honeybees. 

Karl von Frisch eventually won a Nobel Prize in Physiology or Medicine for his efforts.

    But is the dancing communication of honeybees instinctive or learned? As it turns out (most non-entomologist or insect enthusiasts would not be aware of this), the dance communication (also known as the waggle dance, or Tanzsprache, literally "dance-talk", as defined by von Frisch) is rather controversial. It is still debated whether or not it counts as actual language, which would play a major role in whether or not it is intelligence or instinct. Tanzsprache seems to signify something (the location of productive foraging areas) through a signifier (the dance itself), it lacks any form of symbols, syntax, or grammar.[10] As it seems to be only the basic possible form of communication, however amazing for arthropods, one can't help but feel that it is deeply instinctual. This is only confirmed even more when it is taken into consideration that all bee species have a Tanzsprache, although, much like human language, there seem to be different variances depending on species (in humans, the differences are due to geographical location). It is interesting to note that there is variability among the successfullness of the Tanzsprache - some honeybees can successfully find the foraging area after watching less than ten repetitions of the dance, while others seem to be unable to find it after watching over fifty.[10] 

" Bees can memorise [sic] at least six locaitons, and three paths leading to each. They can remember at least four good choices and four bad choices. These memories are not just visual; they can also remember them by smell, and the overall memory is often a mixture of smell, location and colour."[13]

    Honeybees are also an intriguing species because they seem to display, at least on some level, emotions. When exposed to negative circumstances, the bees displayed negative cognitive biases:

"Shaken bees also have lower levels of hemolyph dopamine, octopamine, and serotonin. In demonstrating state-dependent modulation of categorization in bees, and thereby a cognitive component of emotion, we show that the bees' response to a negatively valenced  [sic] event has more in common with that of vertebrates than previously thought."[15] 

DRAGONFLIES

    I previously mentioned dragonflies in my last Skeptical Entomologist post, in which I looked at homosexuality among several species. However, what is even more amazing (and, for us human "elitists" so sure of our superiority over insects, intimidating) is the recent discovery that dragonflies have the ability to engage in what is termed "selective attention". That means that, if the dragonfly is following a group of midges, for example, the predator will have the ability to focus on one individual within the swirling mass. This raises the interesting question, because the ability to focus on one thing in particular in a chaotic environment is definitely something we have long thought only occurred in animals with higher cephalization and brain-to-body ratios.
    A discovery of incredible importance in cognitive research and with applications in robotics, this arguably major announcement was made in 2012.[11] And yes, while it was slightly overshadowed by the discovery of the Higgs boson (which was a long and time consuming process, so perhaps the discovery of the Higgs deserved the spotlight), that fact does not negate its importance. The truly unique aspect of this discovery was not just that the behavior was observed in insects, but that the process by which it was possible was also discovered: the neural activity. In fact, it was the first neural activity which allowed for selective attention in any invertebrate.[11] This ability allows the dragonfly to hunt small insects - such as mosquitoes and midges - with a 97% success rate.

Dr. Steven Wiederman, one of the scientists who

 discovered the ability of selective attention in dragonflies. 

(Photo credit: David O'Carroll, University of Adelaide) 

    The dragonfly case is interesting because it further supports the assertion that the behaviors, personality, and ultimate overall character of an animal is dependent on brain function. While there may be naysayers like Deepak Chopra who will ultimately scream in the face of anybody that will listen ("The brain and the mind exist separately" is one of Chopra's most famous, and unsupported, claims), that does not detract from the essence of such a discovery. Given current knowledge about neural pathways and brain function, it is very reasonable to assume that the dragonfly's success rate at hunting would plummet horribly if this particular neural pathway was interrupted.

   DO ARTHROPODS EXHIBIT COGNITIVE ABILITIES?

    As with intelligence, the answer largely depends on how the word "cognitive" is defined. According to dictionary.com, the first definition of cognition is "1. or or pertaining to the act or process of konwing, perceiving, remembering, etc.; of or relating to cognition; 2. of or pertaining to the mental processes of perception, memory, judgement, and reasoning, as contrasted with emotional and volitional processes."[12] As the initial definition is very much in alignment with the definition of intelligence, we will use the second definition for the purpose of this essay. Can insects and spiders reason? Can they make judgments? In my opinion, the answer is decidedly yes. Spiders, such as the jumping spiders, assess situations before they attack their prey, looking for the best possible angle which maximizes jumping potential and minimizes potential injuries. If insects and spiders are so different from us, yet display at least some cognitive functions, what does that mean for their experience of pain? 

    Do insects think? If they do, it is probably not in a manner to which human would consider thinking. Higher brains provide the ability to think abstract thoughts. An insect or spider may be said to "think" if we wish to define thinking as only the processes of the brain. They certainly seem to be able to assess situations and act accordingly.

    

DEFINING THE HYPOTHESES 

    Now that we have reached the main topic of discourse for this essay - Do insects appreciate (understand) the pain they feel? - it is time to take a short break and decide on our pair of hypotheses. Take a break, get up and walk around, have a shot of Dry Fly or Buffalo Trace, and come back when you're ready.

    Ready? Good. We can now define the hypotheses we wish to test:

Null hypothesis: arthropods do not understand/appreciate the pain they experience.

Alternative hypothesis: arthropods do understand/appreciate the pain they experience.

     Now that that is settled, we may continue our discussion. First, we should start off with what we as humans experience as emotional or abstract pain, and why our illusion of free will may be clouding our judgement on the issue. 

HOW "FREE WILL" CLOUDS THE DEBATE

    If we ever wish to determine the answer to the question of arthropods understanding their pain, we must first understand what our pain is and how we, as humans, understand it. Having a much more complex social structure which allows for the spreading of memes, a higher degree of cognitive capabilities, and a far more developed sense of individual identity, our own appreciation of our pain is bound to be vastly different than that of any arthropod. Or so you would think. What if I were to propose to you that our experience of pain is, evolutionary  almost exactly the same? What if all of our cultural trappings, religious traditions, and ever-present memes were, at their very core, completely wrong? What if we're not different from the animal kingdom?

    I propose that the problem of human pain is one of the main ways our species has separated itself from the rest of the organic world - in our drive to single ourselves out as divinely special, we attributed pain only to ourselves. When it became overwhelmingly apparent that other animals feel physical pain as well, our species desperately clung to the meme that our species could experience emotional and abstract pain. As is usual when you learn more about the natural world, that idea was also smashed. Other animals, such as chimpanzees and elephants, experience emotional pain; this can be seen best when a member of their close family dies. Eventually, we came to understand it, thanks to the enthusiasm of amateur and professional biologists alike, keeping the intellectual curiosity alive.

    It seems as though the idea of insects understanding pain strikes many people even deeper. "At least," they seem to think to themselves, "at least we are different from insects! How far removed are we from the ant, and that has made us so superior!" Except, of course, that the ant has been evolving over the eons a well. As humans, we remain only partly rational, and very reluctant to accept new ideas (in fact, one of the basic tenants of scientific literacy is the replacement of private prejudice with accepting ideas based on publicly verifiable evidence) when they pop up. Our species even suffers from cognitive dissonance, in which two contradictory beliefs are held by the same individual (that is, of course, a highly simplified definition, which I will tackle in a later post).

HOW "FREE WILL" HAS FOOLED US ALL

    Before we begin, I should preface this by saying that, while free will is an illusion (or, as neuroscientist Sam Harris points out, an illusion of an illusion), we all are autonomous; that is, just because we don't have the free will we've been tricked into believing we have does not make us puppets. It simply makes us mistaken. If you wish to know more, I recommend reading Free Will by Sam Harris. 

    The concept of free will has been one of the defining characteristics of mankind; it shapes our justice system, our religions, are thoughts on personal responsibility. Essentially, this idea that we are each the conscious authors of our own actions is perhaps man's greatest intellectual lie. As I have mentioned in the beginning of this essay, psychology has been replaced with neuroscience. We can now look into the brain and understand what is going on, understand how it works, and map it. And, once again, a comfortable myth has been shattered: neuroscience is proving us that each of our individual actions are made subconsciously seven seconds before we become aware of any intent to perform said action. The famous example is the subject in a laboratory, who is asked by scientists to raise one of his hands at random; the observing scientists can not only tell when he is going to raise his hand, they can predetermine what hand he will raise. 

    This begs the question - if we are not the original authors of our thoughts, what are we? The mind - the part of the brain that we call ourselves, the conscious part - may be nothing more than a byproduct of an evolving brain; or, perhaps, it is the next step and consciousness is the direct product of a more complex brain. Whatever the initial cause, the fact remains the same - we no more consciously choose our own actions than a cricket may choose it's actions. 

    What does this mean? This means, of course, that we are essentially animals of instinct. We are doing what our evolution has allowed us to do. And while it may be much more complex than the smartest Portia spider (after all, Portia spiders don't build drive Porches), the argument can be made that it is essentially the same. After all, if we are simply observers of our own lives, watching as it plays out, than we are no more in control than the spider. 

    But, I stress again, we have deceived ourselves. We think that we are the conscious authors of our own lives, and we see arthropods as mindless, busy creatures who do nothing more than play their part. In truth, that is all humans do, although humans have the happy little ability of changing their behaviors (thanks to our highly evolved brain).

I'll just let Sam Harris himself explain the illusion of free will.

CONCLUSION 

    The answer seems to be a resounding yes. If we understand the fact that brain functions lead to behaviors, actions, emotions, and, ultimately, consciousness, then we have no other choice but to acknowledge that other animals capable of expressing anything similar to those have the ability to understand their pain. Many may find such an idea unbearably uncomfortable, but, as skeptics, it is something we have to consider. We cannot be closed minded to evidence, even if it suggests a reality contrary to what we wish reality was. Allow me to give an example: when I was a child, I used to butcher bees with one of my first childhood friends. The very fact that there is evidence which indicates they are capable of even the most rudimentary emotions leaves me utterly horrified by my past actions, leaving me feeling like quite a monster. I'm certain I am not the only one who has done such things (if it's any consolation, at the time we didn't know any better; we were ignorant of reality). But the past is the past, and we must reconcile ourselves with reality, even if it means looking back at what was (to us) a fun summer afternoon, even if it takes on a hue of brutal mania.
    To quote a study which appeared in the journal Animal Welfare,

"By closely examining the responses of invertebrates, it can be seen that they often behave in a strikingly analogous manner to vertebrates.... invertebrates such as cockroaches, flies and slugs have short- and long-term memory; have age effects on memory; have complex spatial, associative and social learning; perform appropriately in preference tests and consumer demand studies; exhibit behavioural and physiological responses indicative of pain; and, apparently, experience learned helplessness. The similarity of these responses to those of vertebrates may indicate a level of consciousness or suffering that is not normally attributed to invertebrates. This indicates that we should either be more cautious when using argument-by-analogy, or remain open-minded to the possibility that invertebrates are capable of suffering in a similar way to vertebrates."[14]

    Such a quote makes one stop to wonder. Perhaps we feel pain the exact same way an insect or spider does, but maybe the difference is that our species has the ability to ponder the pain and, ultimately, stop it. Does this knowledge mean that we can't kill insects which may be dangerous to ourselves or our families? Of course it doesn't; however, it does strongly suggest that we find a more reasonable solution than simply smashing the life out of a spider. Not only is it a crucial member of the local food web, if you squash it but fail to kill it, it may suffer.
    As animals as complex as ourselves, we need to act in an intelligent manner. This is hard, as our species is naturally a violent, xenophobic species that usually displays high levels of megalomania, typically seeing anything less than it as inferior. Even though the answer to the arthropod/pain question is important and certainly interesting, our behaviors toward them should remain the same in either case. As intelligent mammals capable of empathy, it is best to have the mental approach of utilitarianism - do the least amount of harm as possible, and do the most good as possible.
   

SUGGESTED READING

(1) http://dictionary.reference.com/browse/pain
(2) http://www.socrethics.com/Folder2/Biology.htm#C3
(3) http://curiosity.discovery.com/question/is-bigger-brain-better
(4) http://www.informatics.sussex.ac.uk/research/groups/ccnr/Papers/Downloads/Harland_Cimb2000.pdf
(5) http://www.cabinetmagazine.org/issues/25/wertheim.php
(6) http://psych.mcmaster.ca/dukas/Dukas%20%26%20Visscher%2094.pdf
(7) http://www.backyardbeekeepers.com/facts.html
(8) http://www.jneurosci.org/content/15/3/1617.full.pdf
(9) http://en.wikipedia.org/wiki/Bee_learning_and_communication#cite_note-Menzel-4
(10) http://en.wikipedia.org/wiki/Waggle_dance#cite_note-GF2009-10
(11) http://www.sciencedaily.com/releases/2012/12/121220143224.htm
(12) http://dictionary.reference.com/browse/cognitive
(13) http://bioteaching.wordpress.com/2010/05/03/insect-brains-and-animal-intelligence/
(14) http://www.scopus.com/record/display.url?eid=2-s2.0-0001460737&origin=inward&txGid=Fefoa6RxV0qF3gMVRibiJw3%3A2
(15) http://www.cell.com/current-biology/abstract/S0960-9822%2811%2900544-6