
Timema cristinae (striped morph)
Credit: Bart Zijlstra www.bartzijlstra.com
The wingless, plant-feeding stick insect, Timema cristinae, occurs in two different cryptic colour morphs. One has longitudinal white stripes along its back on an otherwise green body, while the second is a uniform plain green.
The striped morph is found on Adenostoma fasciculatum, a plant with long, needle-like leaves, where the stripes help break up the outline of the insect’s body, making it resemble a cluster of green needles. In contrast, the plain green morph is found on Ceanothus spinosus, which has broader, more tree-like leaves on which conspicuous white stripes would be maladaptive.
This seems entirely sensible and, from the perspective of an intelligent designer, a perfectly reasonable way to protect stick insects from predation — setting aside, for the sake of argument, the questionable logic of designing predators to eat stick insects and then designing stick insects to avoid being eaten.
However, the means by which this cryptic colouration was achieved in populations of Timema cristinae on two different mountains, where the respective host plants grow, is more typical of the behaviour of creationism’s putative designer. In each case, the same camouflage was achieved through entirely different genetic mechanisms. This tendency to reinvent the metaphorical wheel appears to be a hallmark of creationism’s “intelligent” designer — seen, for example, in the development of different wing structures in birds and bats, different forms of insulation in mammalian fur and bird feathers, and several distinct designs for eyes.
Of course, there is no reason to expect a mindless natural process such as evolution by natural selection to respond to identical environmental pressures in precisely the same way in two geographically isolated populations. All that matters is whether the eventual adaptation — in this case, effective camouflage — is functionally comparable.