Consumption (mean ±1SE) of confamilial pairs of native vs exotic macrophytes by five herbivore species: (a) P. spiculifer, (b) P. canaliculata, (c) P. insularum, (d) P. haustrum, and (e) P. paludosa.

The sloping line in each figure represents the 50∶50 distribution expected if there is no preference for native versus exotic plants. The filled-in symbols indicate significant preference for one plant in that pair. Inset histograms show the mean consumption across exotic and native plant pairings. P-values from two-tailed paired T-tests are for the pooled histogram data. The triangles present in a) and e) represent comparisons including Ludwigia grandiflora and Pistia stratiotes, plants whose native distribution is in question. P-values for these two graphs are provided with (N = 9) and without (N = 7) these two data points. The a and b's designate comparisons from the North American and South American perspective, respectively.