Refuge theory proposes that a determinant of species richness (and percent parasitism) is the presence of host refuges. Plant structural refuges are good predictors of species richness for endophytic herbivores, but not for exophytic herbivores. For exophytic herbivores other traits such as relative abundance may provide refuge from parasitism. Using unbiased data on both relative abundance and larval parasitism of species in macrolepidopteran assemblages we tested the null hypothesis that percent parasitism was independent of abundance. Numerically subdominant species do not gain refuge from parasitism by persisting at low abundance. Parasitism was not different from what would be expected based on their numbers. Among numerically dominant species there was, nevertheless, a significant positive association between abundance and parasitism rate. However, dominant herbivores displayed high levels of parasitism even in the years when their abundance was low relative to other years. This suggests that dominant species may possess other traits that enhance their susceptibility to parasitoids. Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Ecology; Community structure; Land zones; Nearctic region; USA; North America Tachinidae; Braconidae; Ichneumonidae; Eulophidae; Lepidopteran hosts; Macrolepidoptera; Larval parasitism levels & host species relative abundance in host assemblage relationship; Maryland; Prevalence in lepidopteran host larvae & host species relative abundance relationship Macrolepidoptera (Lepidoptera); Dipteran parasites; Tachinidae; Hymenopteran parasites; Braconidae; Eulophidae & Icheumonidae; Relative abundance; Maryland; Larval parasitism levels & host species relative abundance in host assemblage relationship Semiothisa aemulataria (Geometridae ); Orgyia leucostigma (Lymantriidae ); Zale galbanata (Noctuidae ); Relative abundance; Relative abundance in host assemblage & larval parasitism levels relationship; Maryland none - not entered - no specific information