If ever there was a creature that should inherit a fear of spiders, it would be the fly. Some estimates suggest that more than 50% of them are killed and eaten by spiders every year. I often see them trapped in webs. Evolutionary psychology would teach us that the fear of spiders in humans is genetically programmed into their DNA. Many of their luminaries, from Pinker to Dawkins, to Tooby and Cosmides agree. Dr Beetle deduces that by similar reasoning, the selective pressure on flies to develop an inherited fear for spiders must be enormous: if such a thing is possible!
To test this theory, Dr Beetle obtained two empty fish tanks, 60 x 30 x 30 cm and placed them on a table. A board sat between the two tanks so there was no view between them. The fundamentals of the experiment were that ten flies were placed into each tank, and then a spider was dropped in after them. The tank without a spider acted as the control. On several occasions through the day or next morning, the behaviour and distribution of flies in both tanks was observed. Most importantly, the distribution of flies was checked from afar when first entering the room, as if you approach too fast and close, some flies will react and launch into the air. This experiment was conducted several times. The spiders used were large Black House Spiders (Badumna insignis), mortal enemy of the fly. Sometimes, spiders were alternated between tanks, or the table turned to reduce the influence of room/window effects. The flies tested included the common house fly (Musca domestica) and various blowflies (Calliphoridae).
To my surprise, the flies appeared to ignore the spider, even when it moved. I'm sure that if I had placed spider fearful humans (arachnophobics) in the room, they would be huddled and gasping in a corner furthest from the spider. Flies were often very close to the spider. On several occasions, flies would even approach or land on the spider, and the spider would kick it away. In my frustration, I added a small ball of smelly meat, to check that the flies were not acting strangely because they were scared out of their wits. To my further surprise, some of the flies alighted on the meat to feed, even with the spider lurking near by. The only avoidance responses obtained were when the spider moved within a few centimetres of the fly, but this same response could be elicited by other small objects such as a cricket, a beetle, a rolling marble, or even other flies that landed or flew close by. I would have expected some stronger reaction targeted specifically at the spider, rather than a simple 'get out of the way of something immediately close' response. Can't DNA recognize the far greater danger that eight hairy legs and two body segments poses to them (indeed and alas, a few flies were lost to the cause during these experiments)? Evolutionary psychologists tell us that it can in humans! This kind of experiment might make some neat thesis work for some post graduates, to verify my findings. Perhaps also compare lab bred flies with wild flies.
The only logical conclusion I can reach is that a fear of spiders cannot be programmed or inherited into the DNA. Perhaps evolutionary psychologists are just looking for excuses for their own fears. Can they not drill down into their own psyche past all the human delusions and teachings to the touchstone of wildness inside, where it is then easy to recognise the source of your responses? Wildness is the reality where humans do not have the right of veto, but perhaps no human can stare into that reality?
OK, perhaps humans will not grant emotional behaviour to insects. Although, they happily assign anger to wasps or aggression to bees! So if flies are not capable of emotional behaviour, then at least they should have been able to evolve some kind of avoidance behaviour that would give them some pre-warning to the enormous threat posed by spiders? The DNA in flies is not of a different chemistry to that in humans.
Some flies have adaptations that might allow them to avoid spiders or other predators. A few tephritid flies look like spiders, and when disturbed move in a zig-zag dance resembling the movements of a jumping spider. But this evolution into mimicry probably leaves no more fear in the mimic than I found in the common garden varieties of fly that I examined. The parasitic sarcophagid fly Arachnidomyia lindae even seeks out orb-weaving spiders, so it can lay eggs on her egg-sac, which its maggots can then feed upon.
So let's examine a few more facts surrounding the human fear of spiders (arachnophobia):
Many monkeys enjoy catching and eating spiders, such as the marmoset, squirrel monkey, and lion-tailed macaque. Therefore, human ancestors at least as far back as their parallel to monkeys presumably had no such fear of spiders. Less than 0.1% of the many species of spider can actually kill people. Most cause no reaction or a minor irritation like a mosquito bite. In modern Australia, only around 25 people in the last 80-100 years are known to have died from spider bite (mainly the red back spider or the Sydney funnel web spider). With a population during this time increasing from around 6 to18 million, that means a death rate of less than one in a million per year. Would such a trivial selective pressure make an impact on human evolution and their genes, and maintain that effect?
There are no dangerous or life threatening spiders in northern Europe or England. If an instinctive fear of spiders had evolved in Africa, why would such an instinct not have devolved and disappeared in these regions, in the same way that high melanin content for dark skin disappeared when it became redundant in these climates of reduced UV? There is no point in wasting energy in keeping a redundant adaptation, especially one that must have been so lightly ingrained into humans, considering its absence in other ancestral species.
The strongest arachnophobia and fear began in northern Europe, where there was the least threat. Surely this suggests the cause of the fear rode on the back of urbanisation, anthroprudism (more beetle), sterility of mind, and estrangement to insects. Most indigenous cultures had little or no fear of spiders. The fear is also less common in rural communities than for city dwellers. Some such as the Piaroa Indians of Venezuela happily catch, handle and eat tarantulas. Similarly, a number of tribes from Papua New Guinea like to eat spiders (Paul Ehrlich 2000 page 372, note 116). Similarly, tarantulas are often cooked and eaten in Cambodia. One older Hindu ritual is said to have involved throwing spiders about the bride, like confetti. Indians of Michoacan (Mexico) gathered and used the social spider Mallos gregalis around their abode as natural fly traps. An endearing term originating in Europe for the mass of spiderling threads sometimes seen floating or caught on shrubs during their dispersal, is gossamer. Studies demonstrating fears and phobias in western students and populations are hardly going to be able to separate primal behaviour from the modern fashion of loathing spiders. The learnt fear is much more common in women than men, as it has become an encouraged method for them to differentiate their femininity (playing into the hands of those who expect them to be the weaker sex). Spiders are easily portrayed as villains in many horror films such as Arachnophobia. Most parents will teach children to fear touching all and every spider. The indigenous craft of wanting to know your animal neighbours and each species differently and in detail has no real impact on a modern families' ability to find food - you just buy it at the supermarket. I would be more impressed if the demonstration of spider fears involved experiments with indigenous peoples or the Piaroa, who are not so artificial and paranoid.
One common argument meant to prove the inheritance of a fear for spiders in humans is that mosquitoes, bees and cars cause far more deaths than spiders, yet the dominant human concern is with spiders. But I can think of a number of reasons why people - who do not wish to understand - would learn to fear spiders. Mosquitoes and bees are more visible when they strike than spiders. The surprise from spiders upsets people. They make webs at night across your well trodden pathways, which are great places for a spider to place their web - they are like insect flight tunnels. But when humans walk along their favourite paths at night, they get entangled and wrapped around the face when they least expect it. Or, a spider might suddenly appear if you lift clothing or a box on the ground, or they hide in some dark corner. This compares to the mossy or bee which makes a buzzing sound and arrives in plain view. Also, spiders, or the really scary ones, are much larger than the bee or mossy. They also tend to make a mess around permanent houses with their disgusting webs and droppings. They are predators, and wrap up their dead like mummies, rather than just leave a neat and tidy red spot and itch upon the skin. They usually live in some cryptic corner where they are difficult to remove. They also look very different, and do not demonstrate the beauty of flight seen in bees or mozzies. For minds that are willing to accept phobias rather than deal with issues, spiders would be about as creepy as they get. Humans have so many issues to deal with, that the thought of spider love will invariably be at the bottom of the list. All of these reasons may fuel the learnt fear for spiders, but they are hardly sufficient events that would call evolution into action.
Cars kill far more humans than spiders, yet humans fear spiders not cars. If fears are inherited, then the reason is that there has not been sufficient time for natural selection to put a fear of cars into the genes. But I think the difference is due to other factors. To an issue plagued species, spiders are too creepy to bother coming to terms with - a modern affliction not found in most indigenous or rural communities. Most people do not fear cars because they are completely controllable and open to study by humans. They are human inventions, and such useful and obedient tools, whereas spiders have a mind of their own. The fundamental behind fear is not of danger, pain or hurt. It is of not being a part of the system affecting you - disrelation. After all, people quite often like to bungee jump, box or hurt themselves in controlled ways. People fear threats (danger), but they will also fear public speaking (no danger) where the risk is of being uncovered as a fool and therefore not really suitable to the system or majority. So what I am getting at, is that people fear spiders not because they are dangerous (which essentially, they are not), but because they are so different to the order and system of mind that people have now gotten used to.
Any self respecting attuned person with the wit to know and understand spiders could live quite happily with their presence. Education about spiders, contact with spiders, and a bit of intestinal fortitude to overcome and master your mind clings, should sooth and release the panicked human. Modern aids that help you overcome the fear include virtual reality, or controlled introduction programs to these beautiful creatures. (Article posted January 2004)