Introduction 2005 Pieris brassicae Pieris rapae Pieris napi 1982 1995 2002 P. brassicae P. rapae 1992 1992 2000 2002 Pieris Brassica Brassica oleracea Brassica nigra P. brassicae 2003 B. nigra Methods and Materials Plants B. nigra abyssinica 1975 Insects Pieris brassicae B. oleracea gemmifera B. nigra Caterpillar Position on the Plant P. brassicae 1975 Caterpillar Growth on Leaves and Flowers 1 Fig. 1 B. nigra  Preparation of Plant Samples for Glucosinolate Analysis P. brassicae Determination of Glucosinolate Content 2001a 2007 2001a 2001b 2004 1982 1984 −1 2001a Statistical Analyses 2005 Results Position on the Plant 2 P Fig. 2 B. nigra  P. brassicae Caterpillar Growth 3 P Fig. 3 P. brassicae circles squares B. nigra B. nigra  Glucosinolate Levels Pieris 2002 1 P 4 P 1 4 1 4 Table 1 B. nigra Factor Sinigrin PE GB 4OHGB 4MeOGB Time ns ns ns *** ns Tissue *** *** ns *** ns Treatment * ns ns * ns Genotype *** *** *** *** ns Tissue × genotype ** *** ns * ns Treatment means presence or absence of third-instar caterpillars feeding on flowers during 4 d. Effect of the factor “time” refers to changes over 4 d in intact plants PE = phenyethylglucosinolate; GB = glucobrassicin; 4OHGB = 4-hydroxyglucobrassicin; 4MeOGB = 4-methoxyglucobrassicin P P P Fig. 4 Concentrations of five glucosinolates (mean + SEM) in leaves and flowers of 10 plants of accession A. For both leaves and flowers, the initial concentration just before treatment, the concentration in leaves or flowers of plants damaged by feeding caterpillars during 4 d, and the concentration determined in leaves or flowers of intact plants 4 d after caterpillars were introduced on the treated plants  Discussion P. brassicae B. nigra P. brassicae 1982 P. brassicae P. brassicae B. oleracea 1984 2000 2005 1993 1996 1996 1999 2000 1996 1997 2006 1997 2001 1993 1998 2001 1988 1998 B. nigra 2005 B. nigra P. brassicae 2000 2001 2003 2004 1992 1996 2002 2004 2000 Brassica 1988 B. rapa 1999 Brassica napus 2005 2000 2003 2006 1982 1984 2003 Tyria jacobaeae Senecio jacobaea T. jacobaeae 1999 1987 1997 P. rapae B. oleracea Cladophora glomerata 1991 1997 1987 2002 Hadena bicruris Silena latifolia Microplitis tristis P. brassicae 2004 2006 2007 P. rapae 2003 2003 P. rapae B. nigra 4 P. brassicae P. rapae Brassica nigra P. rapae 2002 P. brassicae B. nigra Pieris Plutella xylostella 2000 B. nigra B. napus 1992 2001 B. napus 2004 Pieris P. brassicae P. brassicae P. rapae P. rapae P. brassicae 2003 1975 Cotesia 1996 2005 P. brassicae 1982