Story: Insects – overview
Page 3 – Groups few in number
To a visitor, New Zealand might seem to have few butterflies. Compared with Australia, where there are 364 species, New Zealand’s selection is small. There are fewer than 20 species of native butterfly; 12 are recognised species, but the others have not been formally described. Apart from the ubiquitous red admiral (Vanessa gonerilla), seen in parks and back gardens, native species live in more remote mountains or along rocky coasts and riverbeds.
Bees and wasps
Although most insect types are represented in New Zealand, there are some notable exceptions. Inexplicably, social insects are either absent altogether or, if they are present, they are uncommon and the number of species are few.
Social bees do not occur except where they have been deliberately introduced, but there are 28 species of solitary native bees. These are smaller than introduced bees and have short tongues, which limits the flowers they can pollinate. They gather in large numbers on the blossoms of mānuka and pōhutukawa trees.
Social wasps are not part of the native fauna, but a few exotic types have been accidentally introduced. Two species of aggressive black and yellow wasps (Vespula germanica and V. vulgaris) are now established throughout New Zealand.
Ants and termites are the only truly social insects in New Zealand. Only 11 of 39 species of ant are native. This small diversity is surprising considering the country’s proximity to Australia, where there are almost 10,000 species. Ants prefer warmth and sunshine, and climate cooling during the Pleistocene ice ages may have destroyed an earlier ant fauna in New Zealand, leaving only a few species that could tolerate the cold.
Only three species of native dry-wood termite are known in New Zealand, compared with more than 300 in Australia. Dense colonies of these small white insects, numbering many thousands, can be found inside decaying wood, usually on the forest floor. They are a primitive type of termite, lacking the impressive building skills of the more advanced species, but still with castes of soldiers, immature workers and reproducing adults. The adults are winged, and mate briefly in swarms. They then bite off their wings in order to burrow and establish new colonies.