Scientists force evolution in the lab



Scientists have forced a little evolution in the laboratory, controlling whether a caterpillar becomes green or black. The color of the critter was made to vary with temperature during their development. The experiment reveals the basic hormonal mechanism underlying the evolution of such dual traits, the researchers report in Monday’s issue of the journal Science. The study was done on Manduca sexta, a caterpillar commonly called the tobacco hornworm. Its larvae are normally green. A related species, Manduca quinquemaculata, becomes black or green depending on temperature. The idea was to use similar temperature shocks to evolve a similar change in M. sexta.

Similar differences show up in genetically identical ants, which can develop into queens, soldiers or workers, based on the hormones they’re exposed to early in development. Similar hormonal differences can affect the specific color of a butterfly or bird.

More here.