New name for common grass grub
PERHAPS our most abundant beetle, the common grass grub, was long known as Costelytra zealandica — Cz for short. Not any more.
A paper* in the New Zealand Entomologist has established that Costelytra zealandica is a rare species presumably found in forested areas of greater Wellington. It was described by Adam White (as Rhizotrogus zealandicus) in 1846.
When B.B. Given revised the New Zealand grass grub beetles (Scarabaeidae: Melolonthinae) in 1952, he thought C. zealandica was the common grass grub beetle found throughout New Zealand. However, two Spanish workers have found that Given was wrong and that the common grass grub is an undescribed species.
These researchers have named it after Given as
Costelytra giveni, CocaAbia & RomeroSamper 2016.
The natural habitat of the New Zealand grass grub was presumably native tussock grasslands, but it has since become a serious pest on introduced pastoral grassland. Both of those original habitats would have been uncommon or absent around Wellington in 1840, so the Costelytra species White described from there is most likely to be a shrubland or forest species. In light of this finding, the genus Costelytra requires revision.
*CocaAbia, M.M. & J. RomeroSamper 2016. Establishment of the identity of
Costelytra zealandica (White 1846) (Melolonthinae), a species commonly known as the New Zealand grass grub. New Zealand Entomologist 39 (2):129146.