Evolution and butterflies: a question

[Kenelm Philip]

	George Reiswig asked about the evolution of complete metamorphosis
in butterflies.

	According to all the evolutionary trees I have seen, Lepidoptera
split off from Trichoptera. In other words, leps as such did not have to
evolve complete metamorphosis--they already had it. Complete metamorphosis
arose about 300 million years ago in the line that produced Lepidoptera,
Diptera, Hymenoptera, Coleoptera, and others.

	There are fossil butterflies--but all are clearly assignable to
modern families.

	Reiswig also asked "Why the species clung so tenaciously to being
a winged adult is a little tough to explain." The best answer to that is
the delightful quote by C. M. Williams: "The earth-bound early stages built
enormous digestive tracts and hauled them around on caterpillar treads.
Later in the life-history these assets could be liquidated and reinvested
in the construction of an essentially new organism--a flying machine
devoted to sex."

							Ken Philip
fnkwp at aurora.alaska.edu