He acknowledges in his work Larvae and Evolution to have borrowed the idea of hybridogenesis from the well-known process of interspecific hybridisation that take place in plants.
[10] In an article published in the esteemed journal Proceedings of the National Academy of Sciences in 2009, Williamson claimed that the body plan of the adult butterfly and its caterpillar larval stage would have evolved separately in different organisms; then, their phylogenies would eventually merge by hybridisation at a more recent point of their evolutionary history.
[13] Margulis maintained that Williamson's paper was scientifically sound and was only being censured because it didn't adhere to Darwinian orthodoxy.
"We don't ask anyone to accept Williamson's ideas – only to evaluate them on the basis of science and scholarship, not knee-jerk prejudice", said Margulis.
[12] Williamson's hypothesis was rebutted in response papers in the same journal issue by the biologists Michael W. Hart and Richard K. Grosberg[14][15] and Gonzalo Giribet (Curator of Invertebrates in the Museum of Comparative Zoology at Harvard University)[16][17] and later by Arnab De and Rituparna Bose.