Resource fragmentation hypothesis
Lua error in package.lua at line 80: module 'strict' not found. The resource fragmentation hypothesis was first proposed by Janzen & Pond (1975), and says that as species richness becomes large there is not a linear increase in the number of parasitoid species that can be supported. The mechanism for this hyperbolic[disambiguation needed] relationship is suggested to be that each of the new host species are too rare to support the evolution of specialist parasitoids (Janzen & Pond, 1975). The resource fragmentation hypothesis is one of two hypotheses that seek to explain the distribution of the Ichneumonidae.
Further reading
Gauld, I., Gaston, K., & Janzen, D. (1992) Plant allelochemicals, tritrophic interactions and the anomalous diversity of tropical parasitoids: the “nasty” host hypothesis. Oikos, 65, 353-357.
Further references
Janzen, D.H. & Pond, C.M. (1975) A comparison by sweep sampling of the arthropod fauna of secondary vegetation in Michigan, England, and Costa Rica. Transactions of the Royal Entomological Society of London, 127, 33-50.