Extrapolations from field studies and known faunas converge on dramatically increased estimates of global microgastrine parasitoid wasp species richness (Hymenoptera: Braconidae)

1. We extrapolate a new range of estimates of the species richness of Microgastrinae (Hymenoptera: Braconidae) wasps, a diverse group of small parasitoids that attack caterpillars of Lepidoptera. 2. Our estimates, using an array of focal study faunas to provide reasonable bounds for minimum and maximum values, range from 17000 to 46000+ species. These calculations make use of a geographically relatively constant proportion of the total number of local caterpillar species to species of Microgastrinae, and extend what is known from better studied areas to those less thoroughly studied. 3. This new estimate of species richness for Microgastrinae is 8-20 times that of the approximate to 2000 currently described species, and 2-10 times greater than that of previously published estimates.