Unfortunately much of what is known about the natural history of New Zealand fauna is fragmentary, largely based on anecdotal data and extrapolations made from related taxa found outside the country.
Most of the New Zealand beetle species were described between 1880 and 1923 by Thomas Broun, who named a total of 4323 species. His descriptions were based to a large extent on single specimens collected in the North Island lowlands whilst the considerably more varied South Island fauna, in particular the rich but then still largely unknown subalpine and alpine component, had only scanty treatment. Hundreds of native and foreign species have since been added, though many groups require detailed taxonomic study, especially since there are many undescribed species and some that are incorrectly assigned to Holarctic genera. The most diverse families in New Zealand are Curculionidae (1496 spp.), Staphylinidae (936 spp.), Carabidae (424 spp.), and Zopheridae (196 spp.) These groups are also well represented in other parts of the world. The least diverse families, with one endemic species each, are Eucinetidae, Heteroceridae, Chelonariidae, Bostrichidae, Phycosecidae, Monotomidae, Cucujidae, and Prostomidae. There are three endemic families (Agapythidae, Cyclaxyridae, and Metaxinidae).
The research on Coleoptera presently focuses on the systematics of microcoleoptera, revising families and documenting the diversity of fungus feeding and saproxylic species. Monography and smaller treatments include species descriptions and keys as well as phylogenetic analyses used to place endemic taxa into world classifications. Apart from descriptive systematics, additional studies include subantarctic island biogeography, evolution of diet and functional morphology, and population genetics.
