Common name: Red spider wasp
Scientific name: Sphictostethus nitidus
Māori name: ngaro wīwī
Size: 7 – 22mm long
Habitat: Forest, sand dunes, river beds, suburban backyards.
Like all spider wasps, Sphictostethus nitidius nests alone and does not live in colonies like many of its other Hymenopteran relatives. On warm summer days throughout New Zealand you may observe the female wasps running around your backyard in search of spider prey, which they use to provision their offspring. When the wasp locates a spider it repeatedly stings the spider until it is permanently paralysed, and then drags it backwards to its underground nest. The nests are dug under stones or concrete, or sometimes built in old cicada pupal chambers. The spider is dropped into an empty nest cell, after which the female will lay an egg on top of the spider’s body, and then leave the nest after plugging the hole with twigs and leaves. A few days later the egg hatches and the newly emerged larva feeds on the spider by piercing a hole into it and sucking out the juicy insides.
Although their red and gold colouration usually acts as a warning signal that repels potential bird predators, observations have been made of house sparrows and some native birds stealing the paralysed spiders from the wasps’ grasp!