Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

FNZ 18 - Chalcidoidea (Insecta: Hymenoptera) - Introduction, and review of smaller families - Introduction

Noyes, JS; Valentine, EW 1989. Chalcidoidea (Insecta: Hymenoptera) - introduction, and review of smaller families. Fauna of New Zealand 18, 96 pages.
( ISSN 0111-5383 (print), ; no. 18. ISBN 0-477-02545-5 (print), ). Published 02 Aug 1989


The superfamily Chalcidoidea is a very large group of parasitic Hymenoptera including world-wide nearly 20 000 described species (Noyes 1978). They are well represented in nearly all parts of the world, but most groups within the superfamily appear to be most diverse in the tropics. The majority of chalcids are small or very small, and many have strongly sculptured integuments giving a strongly metallic blue, green, bronze, or purple sheen. Their coloration, sculpture, and great morphological diversity make them one of the most varied and attractive groups of Hymenoptera.

The superfamily is here considered to comprise twenty families, the Mymarommatidae being treated as a separate superfamily, the Mymarommatoidea (see p. 48). However, the limits of several of these families are poorly defined, different workers recognising different numbers of families; e.g., Riek (1970) recognised only nine families, and Nikol'skaya (1952) recognised as many as twenty-four families.

Chalcids probably exhibit a greater range of biological diversity than any other superfamily of Hymenoptera Parasitica. Most species are parasitoids, but groups of species in several families are phytophagous. Agaonidae develop only in figs, and phytophagous species also occur in the Eulophidae, Eurytomidae, Pteromalidae, Tanaostigmatidae, and Torymidae.

Parasitoid biology attains its most elaborate expression in the Chalcidoidea. There are solitary and gregarious species; ectoparasitoids and endoparasitoids; primary, secondary, and tertiary parasitoids; polyembryonic species; and species with planidial larvae. Some species are extremely polyphagous, whereas others appear to be very host-specific. All immature stages of hosts are attacked, from the egg (which may be parasitised by species of Mymaridae, Trichogrammatidae, Eulophidae, Encyrtidae, or Aphelinidae) to the pupa (attacked by several groups of Pteromalidae in particular). Chalcids attack an extremely broad range of hosts, including virtually all endopterygote orders, many exopterygotes, and some arachnids.

Chalcids are one of the most important groups in applied biological control (see Noyes 1985), and have been widely used as such in New Zealand (see below). Many species introduced for this purpose have become established as effective parasitoids of insect pests of agriculture and horticulture (see below). Several exotic species have become established accidentally, probably after being imported with plant material. These chalcids may now be associated with modified environments such as gardens, or with exotic plants, and may play an important part in limiting the development of potentially damaging insects. Some chalcids are pests because of their phytophagous habit. For example, some Eurytomidae develop in the seeds of red clover, lucerne, and acacia, and others damage the stems of grasses.

Given their importance to agriculture and horticulture in New Zealand, it is surprising that so little has been published on the New Zealand chalcid fauna. Except for a few descriptions of new genera and species - by Walker (1839), Kirby (1883a), Ashmead (1900, 1904), Cameron (1910), Timberlake (1916, 1929), Gahan (1922, 1927), Gourlay (1928), Hincks (1961), Kerrich (1964), Kerrich & Yoshimoto (1964), Tachikawa & Valentine (1969a,b, 1971), and Valentine (1966, 1971a) - our knowledge has been limited to a few papers published by Gourlay (1930a,b), Miller (1935), Cumber (1959), and Valentine (1963, 1967, 1970, 1971b) which are largely concerned with the introduced fauna. In all, up until 1984, published information on the New Zealand fauna deals with only 75 genera and 92 species (see Appendix Table 2).

The present study is based almost entirely on material which has accumulated in the New Zealand Arthropod Collection (NZAC), held by DSIR's Entomology Division in Auckland, and from an extensive Malaise trap and sweep-net survey in both the North and South islands during 1980 and 1981. Although we believe that this material is a representative sample of the chalcids to be found in New Zealand, some large areas remain comparatively poorly surveyed. For example, very little material has been seen from the Mount Egmont area (TK) or from the eastern and central North Island.

This contribution reviews to generic level the eleven families of Chalcidoidea and Mymarommatoidea which are represented in New Zealand by eleven or fewer genera. Keys to the genera of the remaining families occurring in the New Zealand subregion are included either in separate contributions to the 'Fauna of New Zealand' series (Encyrtidae - Noyes 1988; Mymaridae - Noyes & Valentine 1989) or in a review of the Australasian genera of chalcids, excluding Elasmidae, Encyrtidae, Aphelinidae, Signiphoridae, Mymaridae, and Trichogrammatidae, by Dr Z. Boucek (1988).

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