Introduction 1997 1993 2001 2001 2005 2005 1990 1999 1980 2004 2006 1863 Pieris brassicae 1977 P. brassicae Pieris rapae 1994 1977 1991 2002 Brassica Trichogramma Pieris 2005 1994 P. rapae P. brassicae P. rapae 1985 P. brassicae P. rapae 1977 1988 1988 1988 P. rapae P. brassicae P. brassicae P. rapae 1992 1992a 2005 2001 1996 1996 2001 2001 2004 2005 1995 1999 1999 2000 2003 2004 2001 1997 2001 2004 Pieris rapae P. brassicae 2002 2006 2006 Pieris Methods and Materials Plants and Insects Brassica oleracea gemmifera P. brassicae P. rapae Chemical Analysis 1990 1992a 2001 2004 1987 1990 2 Herbivore Oviposition Preference Test Pieris a.m. p.m. a.m. p.m. Surface Application of JA P. brassicae P. rapae 2 Systemic Uptake of JA P. rapae 2 Effect of Pure JA on Oviposition Preference P. rapae Pieris 1992a 2 Bioassays with Purified Glucosinolate (GLS) Fractions 1990 P. rapae Performance of P. rapae Caterpillars P. rapae Statistical Analyses P. rapae t P. brassicae t U U Results Chemical Analysis B. oleracea 1 2 1 Table 1 Brassica oleracea 2 Compound a,b a,c Z P Glucoiberin 10.7 (6.3–21.7) 0 (0–6.0) −2.713 0.007 Sinigrin 9.3 (0–23.5) 4.2 (0–6.8) −1.774 0.076 4-Hydroxyglucobrassicin 0.7 (0–6.1) 0 (0–0) −2.207 0.027 Glucobrassicin 34.9 (18.4–98.2) 88.6 (38.6–132.5) −1.479 0.139 4-Methoxyglucobrassicin 0.5 (0–2.5) 0 (0–1.3) −1.370 0.171 Total amount of glucosinolates 64.1 (27.0–155.7) 90.0 (42.9–138.8) −0.563 0.573 a b N c N Herbivore Oviposition Preference: Surface Application of JA P. brassicae N Z P N Z P N Z P Z P 1 P. rapae 2 t t df P t df P t df P t Fig. 1 Pieris brassicae asterisks P P a b  Fig. 2 Pieris rapae B. oleracea asterisks P P t  Systemic Uptake of JA P. rapae t df P t Effect of Pure JA on Oviposition Preference t df P t 3 Fig. 3 P. rapae P t N  Bioassays with Purified Glucosinolate Fractions 2 Z N P t df P t 4 Table 2 2 Z P U Glucosinolate GLS from control plant GLS from JA-treated plant Glucoiberin 4.9 3.9 Sinigrin 3.1 5.1 4-Hydroxyglucobrassicin Not detected Not detected Glucobrassicin 16.0 81.0 4-Methoxyglucobrassicin Not detected 0.8 Fig. 4 P. rapae P t N  Performance of P. rapae Caterpillars 5 U Z P F df P Fig. 5 P. rapae open squares  Discussion P. rapae P. brassicae Spodoptera exigua Trichoplusia ni Manduca sexta 1996 1997 2000 2001 Manduca quinquemaculata S. exigua 2001 2001 2004 Brassica Brassica campestris Brassica B. oleracea Plutella xylostella 1997 B. oleracea 1994 2001 2003 2005 2005 Both butterfly species distinguish between induced and non-induced leaves, most likely based on chemical differences, as JA-induced leaves do not display herbivore presence or damage. The different levels of two out of five glucosinolates in the surface extracts may provide a chemosensory basis for the oviposition preference observed, although the isolated GLS from the two treatments yielded no differences in acceptance of the paper for oviposition. While the isolated GLS on paper stimulated oviposition behavior, they appear not to be the main cue to discriminate between the JA-induced and non-induced cabbage plants. 1993 1994 1996 2003 P. rapae P. brassicae 1992b 1996 1992b Pieris 1994 1993 2005 2000 2002 2006 2006 1999 2002 2002 2006 1992 P. rapae 2003 P. rapae B. oleracea Pieris