Non-native species Number of measured individuals Frequency of occurrence (%) Number of insects Difference in herbivore pressure (binary data of undamaged vs. damaged leaves in a cbind matrix) Difference in herbivore pressure (binary data of undamaged vs. damaged leaves in a cbind matrix) Difference in herbivore pressure (binary data of undamaged vs. damaged leaves in a cbind matrix)
Df Chisq P
Erigeron canadensis* 66 78.6 4131 21 9.88 0.980
Ipomoea cairica* 36 42.9 355 11 1.43 1.000
Bidens frondosa* 30 35.7 1747 9 8.76 0.460
Amaranthus spinosus* 27 32.1 1396 8 19.61 0.012
Bidens pilosa* 27 32.1 1708 8 6.16 0.629
Amaranthus retroflexus* 18 21.4 696 5 26.96 0.000
Aster subulatus* 15 17.9 19 4 1.38 0.848
Datura stramonium* 15 17.9 1098 4 100.21 0.000
Hibiscus trionum* 15 17.9 1105 4 13.21 0.010
Abutilon theophrasti* 12 14.3 3066 3 6.34 0.096
Phytolacca americana* 12 14.3 1329 3 20.57 0.000
Rhus typhina* 12 14.3 2 3 3.65 0.302
Solidago canadensis* 12 14.3 1122 3 0.52 0.914
Xanthium italicum* 12 14.3 18 3 1.02 0.798
Cyperus rotundus 9 10.7 8
Erigeron bonariensis 9 10.7 15
Flaveria bidentis 9 10.7 12
Veronica didyma 9 10.7 0
Veronica persica 9 10.7 0
Ambrosia artemisiifolia 6 7.1 1370
Cosmos bipinnata 6 7.1 173
Daucus carota 6 7.1 4
Helianthus tuberosus 6 7.1 243
Lactuca seriola 6 7.1 648
Solanum aculeatissimum 6 7.1 5
Erigeron annuus 3 3.6 320
Sonchus asper 3 3.6 133