‘Gogga’ is a popular Afrikaans word used mostly in a derogatory sense, to denote a creepy-crawly, a flying insect or a near relative, such as a spider, scorpion, tick or mite. People often use the word in exasperation when irritated by buzzing flies and mosquitoes, and deal with the offender by hitting, squashing, trampling or dousing it with an aerosol spray. Paradoxically, ‘gogga’ is also used as a term of endearment, yet another linguistic quirk of the Afrikaans language.
The best definition that science is able to give for an insect is ‘an animal with six legs in the adult stage’. Applying this seemingly simple statement to all the animal species, which have been discovered and described scientifically, we find that the vast majority fit this description. An inventory of Earth’s living organisms lists a total of 1,75 million species, of which not less than 1,1 million or two-thirds are insects.
But who decides what insects belong where? This is the realm of taxonomists, people whose main interest is classifying living things into different groups, according to various scientific criteria. Thus, they have to date determined that there are at least six major types of life, which they designate as ‘Kingdoms’. The two best known are plants and animals, the remaining four being more primitive and microscopic life forms. The animal Kingdom is further divided into 33 ‘Phyla’ (singular ‘Phylum’). Of these, 32 are spineless animals and one, known as the ‘Chordata’ possesses a chord or spine in its back. Humans are Chordates or more specifically, vertebrates.
Insects have no spine or internal skeleton like vertebrates, and are relegated to the ‘Class’ Insecta (or Hexapoda, meaning six-legged). Entomologists are people who study insects and they generally agree that there are 26 groups into which insects can be divided, known as ‘Orders’. These range from primitive silverfish and fish moths to socially complex termites and highly developed honey bees. Ultimately, the Orders are made up of ‘Families’ , ‘Genera’ and ‘species’, the latter generally being the final step in classification.
To give an idea of how numerous insects are, a prominent entomologist estimates the weight (or body mass) of the world’s ants to be roughly the weight of all 6 400 million humans living today, namely 320 000 million tons. More about ants and humans: the societies of both species are remarkably similar – ants and people have highly developed social systems. Both are ‘super organisms’, meaning the ability to communicate, cooperative behaviour and altruism (unselfish sacrifice by an individual to promote the interests of other individuals). Another characteristic of a super organism is that it dominates ecosystems, which ants and humans certainly do. In tropical forests ants alone make up four times the weight of all the land vertebrates (amphibians, reptiles, birds, mammals) put together. Furthermore, ants and people exert a tremendous effect on other species. We divide our labour, we are the principle turners of the soil, we are the top predators; worse still, we are constantly at war with our own species. Ants eclipse us in this respect however, as they are the most warlike of all animals. Reflect for a moment that ants and humans behaviour supports the theory that highly evolved societies having an elevated level of altruism, tending to divide into distinct groups that then proceed to fight against each. We humans are constantly at war and have been in group conflict since prehistory. This begs the question whether complex societies and war go hand-in-hand. Can ant behaviour provide humanity with any lessons? Like us, ants do some shocking, repellent things. They scavenge, they cannibalize, and they practice slavery. They do differ in one aspect (proponents of female freedom, take note): ant colonies are all female; males are tolerated for only part of the year! One lesson we can learn is that these biblically busy little creatures (‘look to the ant thou sluggard’) keep themselves fanatically clean, so ant epidemics are rare.
But other important differences also exist, benefiting the human whose weight is huge compared to the micro-mass of an ant. We are not only physically but mentally superior to ants. Ants cannot use fire, for the simple reason that the smallest, stable fire must be much larger than an ant. Ants cannot therefore carry fuel close enough to a fire to maintain it. Ants cannot use tools like, for example, a hammer because an ant-sized hammer will have too little kinetic energy to drive an ant-sized nail. Furthermore, an ant-sized book would be impossible to open because the necessarily ultra-thin pages would be held together by inter-molecular forces that are extremely powerful at that micro-scale. Moreover, ants are unable to read – they do not possess sufficient brain cells to perform this function. And…..ants cannot wash because water’s surface tension prevents adhesion (wetting) to their bodies, plus the fact that most insects’ waxy outer layer repels water. The fastidiously clean ant overcomes this disadvantage by dry-cleaning itself.
Other ‘goggas’ perform seemingly impossible feats. Mosquito-like pond skaters can literally walk on water, using the surface tension to create a contact angle with their miniscule feet, which is so high that the surface pressure prevents them from sinking. Because the force exerted by water’s surface tension is proportional to the length of a pond skater’s feet, a human weighing a million times more than a pond skater would need feet with a perimeter of more than seven kilometres to do this.
The common housefly, which pesters you to the extent that a swatter has been designed specifically to deal with it, is aerodynamically possibly the most gifted creature on Earth. What aircraft can execute six turns a second, hover instantly, fly straight up (or down or backward), somersault and land upside-down or on a vertical surface? Its brain, by the way, is smaller than a pinhead, yet the swipe of a human hand is magnitudes slower than a fly’s ability to avoid being smacked. An ardent studier of hoverflies disputes this agility however, maintaining they are the ultimate aerial performer. We will have equaled the darting hoverfly when we develop an aircraft that can hover in one spot, hurtle through the air to another point, and return directly to precisely the previous hovering point. Using advanced technology, which involves filming at super-slow motion; researchers put another acrobat, the ubiquitous fruit fly through its paces by manipulating their visual field in a closed chamber. When the film is screened, there are 6 000 images of every second of the acrobatics performed by these densely-clustered fliers to explain how they avoid mid-air collisions. Executing 90-degree turns, they employ their total of 12 muscles in combination with compound eyes, light sensors, wind-sensitive hairs and equilibrium organs on their backs that function like gyroscopes. A mid-air collision has not yet been recorded during these experiments.
Flies have been around for hundreds of millions of years. They are also the first animals to take to the air, long before birds. When you finally flatten that pestering fly with a well-aimed swipe of the swatter or triumphantly exterminate the ant colony, which is excavating your driveway, with deadly insecticide dust, remember…there are more where they come from and they will probably outlast us as a species.
Text by Dr. Hu Berry
Originally published by Venture Publications in ‘Flamingo ’August 2006