I was asked earlier today to comment on the Garden Rant blog regarding the issue of nonnative plants and insect survival, specifically in reference to Dr. Tallamy’s research. Though I haven’t read his popular book (Bringing Nature Home), I did read one of his most recent papers (DW Tallamy and KJ Shropshire, 2009. Ranking lepidopteran use of native versus introduced plants, Conservation Biology 23(4): 941-947). The authors argue that lepidopterans prefer native to alien species for egg laying. A serious problem I see in this paper is that the authors are literally comparing apples to oranges. They do not compare effects among species in the same genus (the reasoning is there aren’t enough publications to look at), but among genera. Thus, they lump at least 179 “alien” woody species into “native” woody genera and compare those to woody genera that are completely alien. There are only 112 species in the latter.
I would bet that if he separated out these 179 woody species and added them to the alien genera list his findings would be quite different.