Cited research: Am. Nat. doi:10.1086/652998 (2010)

Biologists have come up with a wide range of estimates for the number of arthropod species on Earth. These invertebrates, which include insects, contribute significantly to global species richness. Andrew Hamilton at the University of Melbourne in Australia and his colleagues attempt to improve on these numbers by using two new models to estimate tropical arthropod species richness.

In both models, most of the parameters are represented by probability distributions instead of point estimates. The models predict medians of 3.7 million and 2.5 million tropical arthropods, with 90% confidence intervals of 2.0 million and 7.4 million, and 1.1 million and 5.4 million, respectively. These figures suggest that even after 250 years of taxonomy, only about 30% of the world's arthropod species have been described. L.O.-S.