Species Diversity in the Third and Fourth Trophic Levels: Patterns and Mechanisms

Publisher Website
Google Scholar
Abstract
(1) Parasitoid lists generated from the primary literature for 285 species of British phytophagous insects were used to examine correlates of parasitoid species-richness patterns. (2) The number of parasitoid species supported by a herbivore was tested against eight variables describing taxonomic and ecological characteristics of hosts. Herbivore feeding niche and host-plant architecture were identified as major determinants of parasitoid richness. (3) Geographic range/extent studied, herbivore host-plant specificity, host taxonomic isolation and the number of generations per year (for Lepidoptera) had statistically significant effects on richness, but were judged to be of questionable biological importance due to sampling artefacts or interactions with other variables. (4) Mechanisms through which host-insect feeding strategy and host-plant complexity can influence parasitoid communities and the reliability of the data are discussed.