The Heliconius hybrid butterfly: speciation yes, evolution no
The news headline proclaimed ‘Evolution simulated in the lab’.1 The article then went on to say that a research study published in the prestigious journal Nature last week2 had successfully recreated the South American butterfly Heliconius heurippa, which has red-orange and yellow-white stripes on its wings. They did this, the article said, by seeking to ‘recreate the evolutionary pathway’ that had given rise to it.
Other news media carried the same theme, with BBC News reporting the study demonstrates that ‘two animal species can evolve to form one’.3
But is it really ‘evolution’? A closer look at the facts shows otherwise.
Researchers had suspected that H. heurippa might be a hybrid of Heliconius cydno, which has a yellow stripe, and Heliconius melpomene, which has a red one. So the researchers interbred these two species, ‘creating a butterfly with the two-stripe pattern of H. heurippa within just three generations.’ And there was no need to physically separate the two-stripe butterflies from the others, in order to maintain the ‘purity’ of the newly bred H.heurippa. ‘Butterflies tend to choose partners that look like themselves’, said one of the researchers, Chris Jiggins of Edinburgh University. ‘So, once the new pattern was established, these individuals have tended to mate with one another and shunned their parental species.’
This is a fantastic example of rapid speciation—no surprise to creationists. However, it is not evolution, as no new genetic information has been produced. The butterflies are still butterflies, with the hybrid species simply having an assortment of genes inherited from the two parent species.
- Evolution simulated in the lab, The Australian, <http://www.theaustralian.news.com.au/story/0,20867,19484572-30417,00.html>, 16 June 2006.
- Mavárez, J., Salazar, C., Bermingham, E., Salcedo, C., Jiggins, C., and Linares, M., Speciation by hybridization in Heliconius butterflies, Nature 441 (7095):868–871, 16 June 2006.
- Two species become one in the lab, BBC News, <news.bbc.co.uk/2/hi/science/nature/5080298.stm>, 19 June 2006.