Data from: Insects on plants: explaining the paradox of low diversity within specialist herbivore guilds

Classical niche theory explains the coexistence of species through their
exploitation of different resources. Assemblages of herbivores coexisting
on a particular plant species are thus expected to be dominated by species
from host-specific guilds with narrow, coexistence-facilitating niches,
rather than by species from generalist guilds. Exactly the opposite
pattern is observed for folivores feeding on trees in New Guinea. The
least specialized mobile chewers were most species-rich, followed by the
moderately specialized semi-concealed and exposed chewers. The highly
specialized miners and mesophyll suckers were the least species-rich
guilds. The Poisson distribution of herbivore species richness among plant
species in specialized guilds and the absence of a negative correlation
between species richness in different guilds on the same plant species
suggest that these guilds are not saturated with species. We show that
herbivore assemblages are enriched with generalists because they are more
completely sampled from regional species pools. The herbivore diversity
increases as a power function of plant diversity, and the rate of increase
is inversely related to their host-specificity. The relative species
diversity among guilds is thus scale-dependent, as the importance of
specialized guilds increases with plant diversity. Specialized insect
guilds may therefore comprise a larger component of overall diversity in
the tropics (where they are also poorly known taxonomically) than in the
temperate zone, which has lower plant diversity.