Illustrated by Caleb Salisbury
When under attack by leaf-munching insects, many plants start manufacturing special substances which act as chemical signals to attract other species that prey on the leaf-eaters. The advantages to the plant’s ability to survive are obvious, so evolutionists will of course point to natural selection as solely responsible for the phenomenon.
Researchers were puzzled, however, to discover an unusual aspect to the story in the case of tobacco plants attacked by moth caterpillars.1 It normally takes a few hours at least for such signal chemicals to be produced. Yet the caterpillar’s enemies, called ‘big-eyed bugs’,2 came almost immediately, sensing the chemicals normally released straight away from any leaf damage. These chemicals are called green leafy volatiles (GLVs). They are released from the leaf irrespective of what is causing the damage, i.e. whether by a knife, or a caterpillar’s bite. But the big-eyed bugs only came when the GLV release was caused by caterpillars. So how could they tell the difference?
The GLVs come in two varieties or ‘isomers’, Z and E.3 Experiments showed it was the Z/E ratio that enabled the bugs to tell the difference between ‘normal’ leaf damage and a caterpillar bite. So what changed this ratio to alert the bugs? Researchers found that it was not the plant, but the caterpillars themselves that rang the dinner bell for the bugs. The ratio is changed by caterpillar saliva, which converts much of the Z-GLVs to E-GLVs.
This “weird and novel twist” is seen as a conundrum, because natural selection4 would be expected to act against something which makes an organism less fit to survive.
References and notes
- Fields, H., Caterpillars sign their own death warrants, www.sciencemag.org, 26 August 2010. Return to text.
- Geocoris spp [plural species]. Return to text.
- Note for chemistry buffs: Z means that the atoms with the highest atomic number are on the same side of a double bond, from German zusammen = together. E means they are on the opposite side, from entgegen = opposite. Return to text.
- A factual, though ultimately non-creative, process—see creation.com/muddy. Return to text.
Thanks for showing us again that God is interested in the small things He made all elements, we just messed up the concoctions.
I can see that this would not easily fit the Darwinian model, but not sure how it fits the creation model either, unless this was designed this way ,and moth caterpillars ,not being nephesh life were always as disposable.probably I am missing a something!
You may be missing something, but that is not to imply that this is a straightforward issue. For the general question of things 'designed to harm', see the relevant chapter of the Creation Answers Book (chapter also available for free download as pdf): How did 'bad things' come about? As to the issue of insects not being nephesh life, in my view there is a strong argument for that, though not all within CMI would come down on that side. There is an article in which an entomologist being interviewed on the subject muses on this same question, see Bugs, Baramins and Beauty.