One oligophagous endophagous insect has likely shifted from the native to the invasive, but none to the non-invasive Eugenia.
Key Words: biological invasion, endophagous insect, herbivore fauna, introduced species, invasive species, non-invasive species, oligophagous insects
One consensus generated from these syntheses and other more recent empirical studies is that the total number of insect herbivores, and the numbers of endophagous and oligophagous herbivores, are all reduced on introduced invasive species compared with conspecific populations in the native range or on co-occurring native congeners (Keane & Crawley 2002; Colautti et al.
One question of particular interest is whether there have been any shifts of oligophagous and/or endophagous herbivores from the native to the introduced plant congeners, and if such shifts occur more onto the non-invasive than to the invasive congeners.
We predict that (1) the total number of herbivore species will be (a) greater on the native Eugenia species than on the introduced invasive and non-invasive congeners; and (b) greater on the introduced non-invasive Eugenia than on the introduced invasive congener; (2) the number and proportion of oligophagous and endophagous herbivores will be (a) greater on the native Eugenia species than on the introduced invasive and non-invasive congeners; and (b) greater on the introduced non-invasive Eugenia than on the introduced invasive congener, and (3) fewer herbivores, particularly oligophagous and endophagous herbivores, will be shared between the native Eugenia and the introduced invasive Eugenia than between the native and introduced non-invasive Eugenia.
Insects were classified as native or exotic, oligophagous or polyphagous, and endophagous or ectophagous feeders.
In addition to the identity of the herbivores, the number of total insect herbivore species on each Eugenia species, the number and percentage of native insect herbivores, the number and percentage of endophagous vs.
Prediction 2--There will be greater numbers of oligophagous and endophagous herbivore species on native Eugenia than on introduced species.