Grass Grub Beetle

Costelytra zealandica, a native of New Zealand, spinning on a spider's web.

This small (1 cm) scarab beetle is a major pest. It was a creature of lowland native grasses, but with the arrival of European farming it has greatly increased its spread. The larvae live underground feeding on the roots of grasses and other plants, causing much damage, while the adult beetles feed on the leaves of trees and shrubs. No doubt they are to blame for much of the mysterious mutilation I find.

The grubs are in the ground in large numbers here. Digging a small hole to plant a young tree or shrub will turn up several. On warm nights in late spring and early summer the beetles swarm for mating. For about half an hour after dark they buzz about furiously. Like moths they are attracted by light, and kick up a racket that sounds like hail hitting the windows. In the morning there are dead and dying beetles everywhere.

The warm conditions are ripening the berries. I can now munch my way around the garden enjoying red and black currants, and the little yellow strawberries that have an incredible flavour.