FNZ 40 - Cixiidae (Insecta: Hemiptera: Auchenorrhyncha) - Popular summary
Larivière, M-C 1999. Cixiidae (Insecta: Hemiptera: Auchenorrhyncha). Fauna of New Zealand 40, 93 pages.
( ISSN 0111-5383 (print), ; no. 40. ISBN 0-478-09334-9 (print) ). Published 12 Nov 1999
The primitive planthopper family Cixiidae has more than 1500 known species. Probably at least twice as many species remain to be described. The family is divided into three groups of genera and species or subfamilies; only one subfamily, the Cixiinae, is known from New Zealand.
Compared with larger or warmer regions of the world, the New Zealand fauna appears relatively small (25 species, 11 genera), but what it lacks in size it makes up in uniqueness.
Because of the special nature of the fauna, New Zealand can be regarded as a biodiversity hotspot for these insects for the following reasons. Eight out of 11 known genera are found nowhere else in the world. The majority of species are restricted to islands (e.g., Three Kings and Chathams) or to small regions and remote areas of the back country. Like the Tuatara and velvet worms (Onychophora), a number of genera and species represent very ancient lineages that may have originated on Gondwanaland. Other, more recently evolved, lineages have diversified in more recent habitats such as subalpine environments (e.g., genus Semo), coastal areas and limestone caves (Confuga persephone).
The New Zealand fauna, however, did not evolve in total isolation. Three genera are shared with other regions of the world: Aka occurs also in Tasmania, and Cixius and Oliarus are cosmopolitan.
Cixiid planthoppers are graceful little insects generally ranging from 4 to 8 mm in length. They are slightly broadened and flattened and superficially resemble minute cicadas. Their head is squat with a pair of short, bristle-like antennae. Their anterior wings are slightly hardened and they usually have distinctive dark hair-bearing spots along the veins. Some New Zealand species are bright green, others are yellowish brown, greyish, or dark brown with varied colour patterns on the anterior wings and markings on head and thorax
Adults can be found feeding on a variety of trees and shrubs, or among grasses. Sometimes, especially in cold weather, adults and immatures (nymphs) may be found under stones and debris. Mating occurs in the spring. The female lays her eggs in the ground with her awl-like ovipositor. She carries a tuft of white, woolly wax at the end of her abdomen, which she distributes in the soil around or under the eggs to protect them.
Nymphs, which are mostly undescribed, typically live underground in the soil, where they feed on the root sap of grasses and other plants. Probably all the species have a similar life-cycle, with older nymphs and adults overwintering and a single generation being produced each year. One known exception is Oliarus atkinsoni which takes two years to develop from egg to adult.
In general, very little is known about the biology of the New Zealand species, and this would be an interesting area of study now that we have a better understanding of the composition of the fauna. The plants on which Cixiidae are most commonly found are flax (Phormium), grass tree (Dracophyllum), hebe, karamu (Coprosma), kiokio (Blechnum ferns), mahoe (Melicytus), ti (cabbage tree), and various grasses, rushes and sedges. Some planthoppers are also associated with beech (Nothofagus), conifers such as kauri pine (Agathis australis), red pine (Dacrydium cupressinum), yellow pine (Halocarpus biformis), totara (Podocarpus totara), and tree ferns, but it is still unclear which of these are actually used as hosts for feeding and reproduction. The best known species is Oliarus atkinsoni which reproduces on flax and is responsible for transmitting a phytoplasma disease (yellow-leaf disease) to it.
Many cixiids jump very readily with their relatively long posterior legs. Most species, however, seem to be able to leap or fly only short distances, presumably to escape danger or move between plants. In the case of Chathamaka andrei (only found on the Chathams), some individuals have reduced posterior wings and anterior wings that are welded together which prevents them from flying.
The geographical distribution of most species was undocumented before this study. We now have a good knowledge of distribution patterns, but more collecting is needed in under-surveyed areas, e.g., the Three Kings, the Chathams, Northland, the Central Volcanic Plateau, the Marlborough Sounds, mountain ranges of Nelson and Buller, Otago, Fiordland, and Stewart Island. Of the two main islands of New Zealand the North Island has the greatest number of genera (nine) and species (15), although they are not all restricted to it; five genera and seven species also occur on the South Island. Seven species are restricted to the South Island, one species to the Three Kings, and one to the Chathams. Stewart Island shares its fauna with Fiordland and Southland.
This handbook was written for a wide audience, with easy-to-follow identification keys and several illustrations and maps. It is hoped that it will generate renewed interest for this fascinating group of insects.