The Benefits of Metamorphosis

Insects show the greatest diversity of any group of multi-celled creatures. While the reasons for this are as numerous the insects themselves, it is interesting to note that "holo-metabolous" insects - those that have a pupal stage (like the chrysalis of butterflies for example) are far more numerous in terms of species than insects that are "hemi-metabolous," such as cockroaches or grasshoppers, in which the juveniles and the adults are generally quite simialr in their habits and appearance.

What advantages does being "holo-metabolous" give you, in an evolutionary sense? It means as a juvenile and adult you can live a very different sort of life, and so take advantage of the environment in many more sorts of ways, and importantly in more than available to hemi-metabolous insects. Just consider the buttefly for example - a leaf eating caterpillar disguised as a bird dropping can change in a nectar sipping flying machine with elaborate colors for warning and display.

The comparison of these two major kinds of insects over a long period of time (~300 million years) actually also provides a way to test theories of how being 'modular" in your design (having distinct physical or temporal parts to your body) may enhance your "evolvability" - or ability to evolve over the long term.

This article tackles all these issues. It is a long one, but there we are.

Click the image of the Diagram above for the PDF.