CB310: Bombardier beetle evolution

Claim CB310:

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Response:

1. This is an argument from incredulity. It is based in part on an inaccurate description of how the beetle's bombardier mechanism works, but even then the argument rests solely on the lack of even looking for evidence. In fact, an evolutionary pathway that accounts for the bombardier beetle is not hard to come up with (Isaak 1997). One plausible sequence (much abbreviated) is thus:
   1. Insects produce quinones for tanning their cuticle. Quinones make them distasteful, so the insects evolve to produce more of them and to produce other defensive chemicals, including hydroquinones.
   2. The insects evolve depressions for storing quinones and muscles for ejecting them onto their surface when threatened with being eaten. The depression becomes a reservoir with secretory glands supplying hydroquinones into it. This configuration exists in many beetles, including close relatives of bombardier beetles (Forsyth 1970).
   3. Hydrogen peroxide becomes mixed with the hydroquinones. Catalases and peroxidases appear along the output passage of the reservoir, ensuring that more quinones appear in the exuded product.
   4. More catalases and peroxidases are produced, generating oxygen and producing a foamy discharge, as in the bombardier beetle Metrius contractus (Eisner et al. 2000).
   5. As the output passage becomes a hardened reaction chamber, still more catalases and peroxidases are produced, gradually becoming today's bombardier beetles.
   
   All of the steps are small or can be easily broken down into smaller ones, and all are probably selectively advantageous. Several of the intermediate stages are known to be viable by the fact that they exist in other living species.
   
   
2. Bombardier beetles illustrate other aspects of life that look undesigned:
   • With design, we expect similar forms to be created for similar functions and different forms for different functions (Morris 1974, 70). However, what we see is different forms for similar functions. Many ground beetles have very similar habits and habitats as centipedes, but their forms differ greatly. Different groups of bombardier beetles use very different mechanisms for the same function of aiming their spray (Eisner 1958; Eisner and Aneshansley 1982).
   • Some forms have no function. Some bombardier beetles have vestigial flight wings (Erwin 1970, 46,55,91,114-115,119).
   • If bombardier beetles have a purpose, then death is an integral part of it, since the beetles are predators (some, as larvae, are parasitoids, gradually eating pupae of other beetles [Erwin 1967]), and their spray is a defense against other predators. Many creationists claim that death was not part of God's design.

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