Dropping a bomb on creationists – The Bombardier Beetle

Creationists are always trying to catch scientists out. Whether it is supposed gaps in the fossil record or our present lack of understanding regarding the origins of the universe, the religious right are quick and eager to fill every unknown that scientists are working on with the words ‘God’ and ‘design’ as alternative ‘explanations’. Darwin’s Theory of Evolution comes under attack perhaps more than any other scientific theory due to the direct contradiction between the biblical creation myths (Adam and Eve and the Fall of Man) and the overwhelming evidence that our species share a common ancestry with the other great apes: chimps, orang-utans and gorillas. The hard evidence that scientists have provided over the years is often met with incredulity and phrases like “maybe your ancestors came from monkeys, but not mine!” It should not be taken as an insult nor should it be embarrassing to acknowledge that we are descended from ancient apes (indeed we are apes). On the contrary, we should take great delight in the fact that we are intimately connected by our DNA (no matter how distant the connection may be) with every other living creature on Earth. A decade ago, the fruit fly (Drosophila melanogaster) was the second creature to have its entire genome (a complete genetic blueprint with all the information an organism needs to construct itself) mapped out. Astonishingly, according to research carried out by scientists, about 75% of known human disease genes have a recognizable match in the genetic makeup of fruit flies, and 50% of fly protein sequences have mammalian analogues (biological structures). What this means is that you share a hell of a lot of genetic information with an insect no bigger than a fingernail clipping!

People who are not scientifically literate (and even some that are, though these are few and far between) tend to point towards Intelligent Design as an alternative theory that better describes how certain features of the universe and living organisms came to be and that the results of what we see are guided by a creator and not due to the ‘undirected’ processes of Natural Selection. In evolutionary biology, creationists claim that the various components needed to make complex systems (such as an eye or brain) function correctly could not have evolved gradually over long periods of time; claiming that these separate components provide no benefit by themselves and thus entire systems must have been miraculously designed and created together at the same time. This particular argument that constitutes part of the Intelligent Design theory is known as Irreducible Complexity and proponents of this theory jibe biologists with such redundant questions as ‘what’s the use of only half an eye?’ Well, let’s ask the starfish: on the end of each arm there is a tiny, simple eye (ocellus), which has a single lens that collects and focuses light onto the retina allowing the starfish to only differentiate between light and dark. Although unable to make out shapes or colour, this primitive eye is useful for sensing movement, enabling the starfish to detect both potential prey and predators. Things that develop in slow steps can lead to increasingly complex systems, though some are easier to explain than others. One champion of creationists is the Bombardier beetle.

The Bombardier beetle (in the large family Carabidae) is the generic name for a type of ground beetle covering 5 separate tribes and over 500 separate species. Like other insects these beetles have developed tools to protect themselves from predators, but it is the incredibly complex way in which they do this that has brought them into the evolutionary spotlight and has led them to be praised by creationists as ‘evidence’ of Irreducible Complexity. When disturbed, the beetle sprays a boiling chemical solution from special glands in its abdomen into the face of its predator. The solution is created from a mixture of two reactant chemical compounds – hydroquinone and hydrogen peroxide – which are mixed together and explode in the face of their enemies. Creationists claim that any alteration in the delicate chemical balance of these two chemicals would lead to catastrophic consequences for the bombardier beetle and therefore, this extraordinarily complex defence mechanism could not possibly have gradually arisen by a step-by-step process as stated by evolution.

Well, before we jump to any conclusions let us take a closer look at the science behind this mechanism:

The two reactive chemicals – hydroquinone and hydrogen peroxide – are secreted through glands and are stored in two separate chambers found in the rear tip of the beetle’s abdomen. When attacked by a predator, the beetle contracts its muscles, forcing the two chemicals into a mixing chamber or reservoir containing water and catalytic enzymes (peroxidase), which are secreted through cells that line the walls of the chamber. When combined, these enzymes break down the hydrogen peroxide to form oxygen and water and catalyze the oxidation process of the hydroquinones, turning them into p-quinones (quinones are an organic compound formed from aromatic – ‘a chemical compound that has a flavour or odour’ – compounds such as benzene – a highly flammable liquid). This chemical break down forms free oxygen which generates enough heat to rapidly bring the solution to boiling temperatures that can surpass 100°C. As the liquid solution reaches boiling point about a fifth of it evaporates into a gas. This gas increases the pressure in the chamber, which builds up and forces the entry valves from the separate storage chambers to close, protecting the beetle’s internal organs. The pressure then forces the boiling solution through a small outlet valve and into the atmosphere with a loud popping sound caused by flash evaporation (when vapour or steam undergoes a reduction in pressure change when passed through a valve into a less pressurised environment). The bombardier beetle is able to discharge this solution about 70 times in rapid pulses that last no more than a second and can be fatal to attacking insects and spiders and, due to the temperature of the liquid, can be very painful to humans. Remarkably, the openings of some bombardier beetles (for example the African variety) have also developed nozzles at the end of their abdomens that can swivel through 270° and are able to aim at predators and be fired with considerable accuracy in many directions.

So how did this all come about? Though it all seems rather complicated, we can break it down and look at how these intricate mechanisms can (and do) develop on a gradual, step-by-step basis.  Just to recap; creationists claim that the reactant chemicals are so sensitive that any imbalance would lead to catastrophic end for the beetle meaning that this process could not have possibly arisen from a gradual evolutionary process, but must have all been ‘created’ at the same time.

There are three problems to the creationists claim, mainly:

1)      Hydroquinone and hydrogen peroxide do not actually react when mixed together unless a catalyst is added (in this case an enzyme secreted from cells that line the mixing chamber inside the beetle). In other words, any amount of these two chemicals is completely harmless to the beetle or any other insects unless a catalyst is added and therefore there is no ‘delicate’ chemical balance.

2)      The quinones are not unique to the bombardier beetle and are indeed found in most other insects and invertebrates. They are produced by cells, which harden the skin into a cuticle or exoskeleton along with an unpleasant taste making an effective deterrent to predators.

3)      The strength of the chemical reaction relies on the concentration of the hydrogen peroxide. The higher the concentration, the higher the amount of oxidization, which results in a more violent reaction.

All of these issues can easily be explained from an evolutionary perspective: As stated above, the quinones are commonly found in many insects and are produced in tiny indentations or small glands in the ‘skins’ of invertebrates. Due to the unpleasant taste, some beetles and insects have developed muscles that can contract around these glands giving them the ability to secrete larger quantities of quinones on demand in order to deter predators when they attack. The bigger these indentations, the more quinones they are able to secrete, thus making the survival rate amongst beetles with larger quinone sacs higher than those with smaller ones. Over time it is possible for these sacs to grow and develop into larger ducts which we find in the abdomen of bombardier beetles today. When predators’ resistance to these chemicals develops (see evolutionary arms race*), other quinones (such as hydroquinone) then develop. This is later mixed in with hydrogen peroxide (a common by-product of cell metabolism*)

*Cell metabolism is a set of chemical reactions that happen in cells that use energy to construct cellular components such as proteins (which form enzymes) and nucleic acids, which allow them to grow, reproduce, and maintain their structures. These chemical reactions are organized so that one chemical is transformed into another through a series of steps by a sequence of enzymes. Enzymes act as catalysts and allow these reactions to be carried out quickly and efficiently.

After mixing, these two chemicals then react with enzymes and generate heat and pressure, which produce a more reactive substance and therefore a more efficient deterrent against predators. The hydroquinone doesn’t actually need to be there at all for the explosive defence mechanism to work – the hydrogen peroxide would be quite enough – though its presence does enable a faster reaction to take place. As the enzymes break down the hydrogen peroxide into a reactive substance, they also break down the hydroquinone, which releases more oxygen, helping to fuel and speed up the reaction between the enzymes and the hydrogen peroxide, and make for a more violent chemical reaction. The real key lies in the concentration of hydrogen peroxide, which can (and best) be explained by a gradual increase over time. A lower concentration would cause a gentler reaction (with a mild temperature), which may be enough to deter an attacker (though perhaps not damage or kill it) and would also be relatively harmless to the bombardier beetle. Natural selection would favour those beetles whose solution was more effective at deterring predators, leading to a gradual shift toward a higher concentration of hydrogen peroxide and ultimately more violent reactions as well as an increase in the beetle’s own resilience to the powerful solution (perhaps due to the same increase in quinones that harden the beetles exoskeleton).

The bombardier beetle is a wonderful example of how evolutionary processes can span millennia to form extremely complex and seemingly impossible organisms through small, gradual changes and it is through the wonder of modern biological science and chemistry that we are able to understand how these changes occur.

Complexity cannot and does not occur instantaneously. You cannot throw a pile of junk metal into the air and expect it to land in the shape of a working car, which is the approach that creationists and the religious right seem to take. Darwin’s Theory of Evolution by Natural Selection is the only logical, methodical and elegant explanation we have that is able to explain the huge diversity of the natural world and all its wonders. We should not feel belittled or humiliated in accepting that our origins lie with the great apes and other mammals, with reptiles, birds, fish, insects and bacteria, but instead should find both solace and a sense of wonder. It has taken trillions of births, lives and deaths over the 3.5 billion year history of life on this Earth for us to be here. We are a lucky few indeed.

In the concluding words of that masterpiece of scientific writing from great man himself: ‘There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.’

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17 Comments on “Dropping a bomb on creationists – The Bombardier Beetle”

  1. Scary Boots Says:

    Remind me not to get into a fight with a Bombadier Beetle. Though the one you have a picture of up there looks rather elegant; I wonder if it would model for me?

    Nitpickin’: I thought the key point of an aromatic compound was the ring structure w/delocalised electrons – the smell and taste just being a common feature of molecules with benzene-like rings, rather than a necessary one? Ammonia and methane, to pick two nasty ones, smell but aren’t aromatic.


  2. Nitpickin’: I thought the key point of an aromatic compound was the ring structure w/delocalised electrons – the smell and taste just being a common feature of molecules with benzene-like rings, rather than a necessary one? Ammonia and methane, to pick two nasty ones, smell but aren’t aromatic.
    +1

  3. Cyborg Says:

    This is sad…that you can think of all that, just to deny King Jesus the credit He deserves for this incredible design…..this beetle is Created by God JUST LIKE YOU WERE CREATED BY GOD, PLEASE read Romans 1 v 18-20…you have no excuse…..God is clearly visible in Creation…PLEAS DON’T MISS IT! Jesus loves you….


    • Although I appreciate your enthusiasm and though it’s always nice to be loved by Jesus, I think you’re missing the point here. I don’t mean to offend, but it is clear from the overwhelming evidence that complex designs can ONLY arise over long periods of evolutionary time and cannot just spring up overnight as the creationist theory claims. It seems to me that it is not I who am going to all this trouble (can scientific research be counted as ‘trouble’?) to deny Jesus and/or God, but the religious-right (such as yourself) who are going to great lengths in creating/believing fantastic myths in order to bend reality to fit your own ill-informed preconceptions instead of looking at and accepting the facts.

      • Mark Nigro Says:

        You have done a good job at being factual for how things seem to function, and written well. Thank you.

        Still, I haven’t found any explanation in this article as to “Why” or “How” these complex structures come together. You have only said that they can and do, matter-of-factually, but not immediately. So how do we know this?

        As for the illustration you gave with the pile of metal parts coming into a car, are you insinuating that, given enough time and “repetition,” a car might actually come out as a result of being thrown up into the air? And then, reproduce itself accordingly?

        Furthermore, I don’t see how the 3 points you made are actually a problem for creationists, or how they can be factual and mutually exclusive to creation?

        Just looking for a little more explanation here.

      • mark Says:

        The key word is “theory” not fact.

  4. The Lord's assistant Says:

    Could one of you clever scientists tell me by what means the humble beetle would have to measure any evolutionary improvements and by what intelligence would it have to analyse it’s experiments over those millions of years in order to achieve the exact mix of liquids and gases (not to mention the inhibitor!)? because no matter how you put it, it still remains a fact that to work correctly, the combustability and timing had to be perfect to begin with or the beetle would have self-destructed several times over!


    • Ok, let’s first clear something up here. Evolution doesn’t make conscious choices; there are no conscious analyses or intelligent experimentations being carried out during evolutionary processes.
      Changes happen due to mutations that inevitably occur over huge amounts of time and throughout a vast number of populations and those mutations have a probability of being passed on based on their effectiveness in aiding survival – no matter how small the benefit may be. The beetle isn’t making any choices, nor is it experimenting. The development of species are at the mercy of their own mutations and other social pressures. That’s the first thing.

      Regarding the ‘exact mix’ of chemicals – if you actually read the article carefully, you will see that there doesn’t have to be a perfect blend of chemicals for the beetle’s defence to be effective. The bombardier beetle’s ancestors were far away from the acid-spraying beetles of today. By gradually increasing the concentration of the chemicals described the intensity of the reaction will slowly increase as will it’s effectiveness in warding off predators. Regardless of whether it’s a warm fart or a blast of boiling acid, if it has any positive effect in aiding the survival of the the beetle, the trait will have a higher chance of being passed on than those that make no difference or hinder it. We will then see a gradual, very slow shift over time with increasing concentrations of chemicals and more violent reactions until we reach the beetle of the present day.

      And in answer to your question ‘Could one of your clever scientists tell me by what means the humble would have to measure any evolutionary improvements….’

      Sure they can. Here’s one of the best doing just that… Enjoy! 🙂

  5. Scary Says:

    Oh, thought you might like this:

    “One day, on stripping bark from a dead tree, [Darwin] pinned down two rare types [of beetle], one in each hand. Suddenly he saw a third, a new species, too good to lose. His action was that of a trained egg-collector. He popped the right-hand one in his mouth. Unfortunately it was a bombardier beetle, which promptly lived up to its name by squirting a noxious boiling fluid into his throat, momentarily stunning him. He spat the beetle out, losing it on the ground, and in the confusion dropped the
    other too.”

    quoted from the biography “Darwin” by Adrian Desmon & James Moore p.59

  6. Arne Boberg Says:

    This is written in a very similar style to Dawkins’ “Blind Watchmaker”, in that there is a substantial body of information on the amazing “technical things” that go on inside the beetle (like Dawkins’ bat sonar analysis), but no explanation on how the progression occurs. Of course, the text is riddled with verbs such as “develop”, “favor”, “reproduce”, “transform”, “organize”, “catalyze”, “select”, etc. It is inferred that by sprinkling these verbs into the text that the whole process of developing such a complex creature progresses in simple steps, is automatic, and according to the author’s bias, has no guidance. The author has conspicuously left out the subject of all these verbs (as being rightfully God) and replace Him with an implied third party: “random chance”. This technique of mixing true background information with ridiculous conjecture is very popular among snake oil salesmen who market their latest miracle cure: “That’s right, ma’am, inter-cellular communication is really complex and very important, so that’s why you need to chug-a-lug our VitaBlitz 6000X.”


    • The conviction that the only two possibilities are pure random chance over evolutionary time, versus instantaneous creation-ex-nihilo by an external, anthropomorphic, omnipotent deity– that conviction is just silly. The evolutionary timespan is pretty firmly established, unless one just ignores all of modern science. The subsequent conviction about pure randomness is, basically, a faith-statement. (“We can imagine it happening purely randomly, and we’d rather not entertain any alternate explanations, so we believe that pure randomness is the explanation.”) Some outside-the-usual-boxes thinking is called for here.

  7. Murray Says:

    Rather than dropping a bomb, it would seem this article was merely a dud, that fizzled, sputtered and then died out with nary a bang at all…

  8. Mike Says:

    “I don’t mean to offend, but it is clear from the overwhelming evidence that complex designs can ONLY arise over long periods of evolutionary time and cannot just spring up overnight as the creationist theory claims.”

    I’m sorry but I saw no PROOF, everything you stated is strictly theory.

  9. Caro Says:

    Sorry to burst your bubble, but there is not ONE SHRED of evidence ever produced that ANY creature that ever lived, has “evolved”, (including dinosaurs), and that is a fact. Every fossil and every creature that has ever been found, has been found “as is”, going as far back as the oldest fossil on record. If evolution is the “answer” to life, then why is there no more “evolving” happening? Darwin himself admitted he could not prove his own theories. If man evolved from apes, why are their still apes? If horses evolved from the eohippus, then why are there still miniature horses? Who is to say that a Biblical “day” was only 24 hours? Maybe it was a million years… Jesus Rules ❤

  10. Keep Asking Questions Says:

    Interesting article. You need to be careful not to build up a straw man when representing the “religious” argument (and there are lots of different religious views just as there are lots of different scientific views).

    Most Christians I know don’t look to God to be an explanation to use where there are gaps in science but rather they believe God made everything and then engage in scientific observation and research to see how God has done it and many of them conclude he’s done it through evolution. Francis Bacon, one of the founding members of the Royal Society held this view and said that God has spoken to us through 2 books – “God has, in fact, written two books, not just one. Of course, we are all familiar with the first book he wrote, namely Scripture. But he has written a second book called creation” To take God seriously we need to read the Bible well but also engage in good science and give proper weight to both books where there does appear to be a contradiction between them.

  11. Lulu Says:

    This is great article that includes step by step evolutionary mechanisms for how its glands developed: http://www.talkorigins.org/faqs/bombardier.html

    Also, the bombadier beetle was originally brought into the evolution vs creationism discussion By Dr. Duane Gish, who distorted the facts on how the beetles’ defense mechanism works. Seems to me, distorting the truth to fit arguments of creationism is not a very Christianly thing to do.

    Our world is extensively and beautifully complex. It is much easier to say “It was designed that way!” than to take the time to understand how and why things work. Just a few hundred years ago humans believed the earth was flat and the sun revolved around it. Understanding how things work, how they evolved, does not preclude the existence of a higher being.


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