The plant stress and plant vigor hypotheses (PVH) are two of the most widely recognized hypothesis invoked to explain differential distribution of insect herbivores among their host plants. In both cases, the emphasis is on bottomÁup processes (i.e. host-plant quality), but a recent meta-analytical review of the literature has shown that the plant stress hypothesis might have limited support among insect herbivores. In this study, we conducted a meta-analysis of the effects of plant vigor on insect herbivore abundance and survivorship by reviewing 71 published articles that explicitly tested the PVH and enabled 161 independent comparisons. Z-transform was used as the metric to standardize the results of all independent comparisons. Our quantitative results have shown that Hymenoptera (sawflies) was the most abundant group in the reviewed studies, representing 28.1% of the independent comparisons, followed by Diptera (25.1%) and Homoptera (22.6%). Amongst all the guilds studied, gall-formers were the most representative group (68.0%), whereas leaf-miners and stem-borers were underrepresented (less than 4.0% of the available comparisons). Insect herbivores were significantly more abundant on more vigorous plants (E'' 00.6432, CI 00.7558Á0.7280), but no significant effect was detected on herbivore survivorship. When herbivores were categorized into feeding guilds, effects of plant vigor on herbivore abundance were stronger for sap-suckers, leaf-miners and gall-formers. Our results have shown a strong herbivore preference for more vigorous plants, although our results do not support a preferenceÁperformance linkage.An increased number of studies in plantÁherbivore interactions have recognized that intra-plant heterogeneity affects both the distribution and the performance of herbivorous insects (Schultz 1983, Strong et al. 1984, Crawley and Akhteruzzaman 1988. The plant stress and plant vigor hypotheses are two of the most widely recognized hypotheses invoked to explain heterogeneous distributions of herbivores among their host plants (Williams and Cronin 2004). The plant stress hypothesis (PSH) proposed by White (1984) argues that herbivore abundance is higher on stressed host plants due to an increased availability of nutrients, a decreased concentration of defensive compounds and/or changes in the ratio of nutrients to chemical defenses. Evidence supporting the prediction that moderate stress benefits herbivores due to increased nutritional quality are abundant (McClure 1980, Lewis 1984, Mattson and Haack 1987 and positive relationships between insect herbivory and plant stress have been found for some tree species, crops and herbaceous plants (Mattson and Haack 1987, Heinrichs 1988). Nevertheless, some authors claim that experimental tests of the PSH have generated conflicting results (Bultman and Faeth 1987, Louda and Collinge 1992, Koricheva et al. 1998, De Bruyn et al. 2002, and many authors (Larson 1989, Koricheva et al. 1998) have championed the abandonment of the PSH and the search for alternative hypothes...