FNZ 63 - Auchenorrhyncha (Insecta: Hemiptera): catalogue - Popular summary
Larivière, M-C; Fletcher, MJ; Larochelle, A 2010. Auchenorrhyncha (Insecta: Hemiptera): catalogue. Fauna of New Zealand 63, 232 pages.
( ISSN 0111-5383 (print), ISSN 1179-7193 (online) ; no. 63. ISBN 978-0-478-34720-3 (print), ISBN 978-0-478-34721-0 (online) ). Published 16 Jun 2010
Cicadas, leafhoppers, planthoppers, and allies (Auchenorrhyncha)
The Auchenorrhyncha are generally regarded as a suborder of the Hemiptera. They include planthoppers, cicadas, froghoppers, spittlebugs, treehoppers, and leafhoppers. These insects are highly diverse and form a major component of the plant-feeding fauna of most terrestrial ecosystems. Auchenorrhyncha have adopted varied life habits on nearly all continents and islands (except Antarctica) and there may be around 42 000 species described worldwide. The world fauna is divided into roughly 30 to 40 families. The number of species of better known continental faunas such as North America, Europe or Australia may include thousands of species. Compared with these larger regions the New Zealand fauna – currently comprising 12 families, 68 genera and 196 species – may appear relatively small but what it lacks in size it makes up for in uniqueness, e.g., 82% of known species do not occur anywhere else in the world. From this point of view New Zealand can be regarded as a biodiversity “hot spot” for this group of insects. New genera and species will be discovered in the future and once fully described the New Zealand fauna may reach 300 to 350 species.
Auchenorrhyncha can be distinguished from other Hemiptera suborders on the basis of three main characteristics: sucking mouthparts in the form of a beak extending from the back of the head – the name Auchenorrhyncha literally means “neck-beaks”; relatively short and bristle-like antennae; and forewings of uniform texture (entirely membranous or leathery) resting rooflike over the abdomen.
In this volume, four questions most commonly asked about a group of insects are being answered: What, where, when and how? What Auchenorrhyncha occur in New Zealand, what is their status (e.g., native, introduced from elsewhere, pests, disease vectors)? What are the resources available to identify and study them? Where do species and genera occur (e.g., geographic distribution in New Zealand and overseas, habitats, dispersal abilities)? When are they active (e.g., seasonal activity, mating, egg-laying, wintering)? How do they live (e.g., food preferences, hostplants, natural enemies)?
New Zealand Auchenorrhyncha are generally active during the day and live in lowland to mountain forests and shrublands, although a number of groups are typically found in more open habitats, such as tussock grasslands, and in subalpine environments. Native species usually live within the confines of their natural habitats but some species also live in modified ecosystems and exotic tree plantations. Depending on families and genera, species can be predominantly active on low plants, trees and shrubs, or even the ground surface. Hostplants are known for less than 20% of species. The recognisable features and biology of the immature stages (nymphs) are unknown for the majority of species. Anecdotal evidence suggests that parasitic wasps, birds, predatory beetles, spiders, and mites may be among the major natural enemies of New Zealand Auchenorrhyncha. Overall, about 25% of the fauna is short-winged or wingless. Active dispersal by flight is therefore unlikely for these species.
The described New Zealand fauna, with 196 species, is about 13% the size of the known Australian fauna which has around 1500 species. Currently, 15 families of Auchenorrhyncha occurring in Australia are not found in New Zealand. The number of recognised introduced species in New Zealand is currently 24, or about 12% of the total fauna. No family is endemic to (exclusively occurring in) New Zealand but all ground-dwelling leafhoppers (family Myerslopiidae) are endemic, accounting for 70% of world species in this group. The three largest families in New Zealand are the leafhoppers or Cicadellidae (78 species or 40% of the fauna), cicadas or Cicadidae (34 species or 17%), and cixiid planthoppers or Cixiidae (26 species or 13%). These families are also well represented in Australia.
Most species shared with Australia and other parts of the world are cosmopolitan and probably introduced. Native species shared with regions neighbouring New Zealand are mostly in common with eastern continental Australia, to a lesser degree with Tasmania and Norfolk Island, and in some instances with Lord Howe Island and New Caledonia. Such faunal affinities may be indicative of an old Gondwanan origin. As in many parts of the world the family Cicadellidae (leafhoppers) is taxonomically diverse and this is where most faunal affinities are observed, followed by the family Delphacidae (delphacid planthoppers). At the generic level New Zealand shares 40% of its native genera with Australia (as including Tasmania, Norfolk Island, Lord Howe Island), or 20 out of 50 native genera. At the species level this is approximately 5%.
The species distribution maps provided show most species to be more widely distributed in New Zealand than previously thought. Even well-studied species occur in more areas of the country than previously recognised. Nevertheless, roughly 95 native species, or 55% of the entire native fauna, are known from ten populations or fewer. These populations are of potential interest to insect conservation.
A greater number of species (133) occur on the South Island and 64 native species are restricted to this island. A slightly lower number of species (119) occur on the North Island, including 44 native species restricted to this island. As many as 65 taxa are shared between the North and the South Island. Offshore island groups are known to harbour a limited number of native species: Chatham Islands (12), Kermadec Islands (10), Three Kings Islands (21). Auchenorrhyncha have never been recorded from New Zealand’s subantarctic islands (Antipodes, Aucklands, Bounties, Campbell Island or Snares).
On New Zealand’s main islands, the areas so far known to contain the highest diversity are the Northland, Auckland, and Wellington regions on the North Island, and the Northwest Nelson and Mid Canterbury regions on the South Island. However, some of these regions contain many species introduced from Australia and elsewhere. For the biologist, the areas known to have the greatest number of local endemics – species only found in a single region of New Zealand and nowhere else in the world – are the most interesting. This is the case of the Northland and Wellington regions on the North Island, and the Northwest Nelson, Marlborough, Mid Canterbury, Fiordland and Southland regions on the South Island. The largely unexplored and unspoilt area of Fiordland is likely to provide an even greater reservoir of endemism than currently estimated.
The regions with the largest number of introduced species are relatively warm parts of New Zealand as well as its main trading ports or agricultural areas (Auckland, Hawkes Bay, Nelson, Christchurch). Many introduced species have fully developed wings and good dispersal abilities, some are attracted to artificial lights, and most can adapt well to living in highly or partly modified environments.