Introduction

Parastephanellus rufoornatus Thorax, dorsal view

Overal size ranges from three millimeters, for some Australian species, to almost 10 cm (4 in., incl. ovipositor), as in the Neotropical Megischus macullipenis.

Stephanids have been part of the scientific literature for the past 200 years, but are still considered a poorly known group of wasps. The last revision of the family was done by Elliott (1922). This revision is an excellent compilation of the work done on stephanids up to 1922, but its highly heterogeneous descriptions and highly simplified keys are of very limited use in recognizing stephanid species.

Part of the obscurity that surrounds the family is probably due to the fact that stephanids are not easily spotted in their natural habitat, and are only rarely collected by most of the usual collecting methods. Consequently, they are also rare in most collections.

Parastephanellus sp ovipositing (Rodd 1951) Copyright Royal Zool. Soc. NSW, Australia Used with permission

Many collectors have observed stephanids flying around or emerging from dead trees, and the name of the respective plant species is eventually mentioned on the respective labels. However, it is very rare to find records of host associations.

The biology is well known only to Schlettererius cinctipes (Cresson), from western USA (Taylor 1967a). This species develops on the larvae of Sirex noctilio (Siricidae), the pine wasp. The discovery of this association caused some surprise, since the most common assumption was that stephanids were parasitoids on Coleoptera (Roman, 1917; Rood, 1951; Townes in Muesebeck et al. 1951). Kirk (1975) reported other Sirex species as hosts to S. cinctipes. Coleoptera hosts have also been reported. Braza (1989), searching for parasitoids of the beetle Agrilus sexsignatus (Buprestidae), a pest in Eucalyptus deglupta Blume, found a species of Foenatopus, for which this author provides no further information. Townes (1949) mentions Agrilus kalshoveni as a host to the Philippine Diastephanus leucostictus, and Bluthgen (1953) reports some Xylotrechus (Cerambycidae) species as hosts of the European Stephanus serrator.

Fragmentary information is available for a few other stephanids, but for most species nothing is known. The oviposition behavior and the larva were described and illustrated by Rodd (1951) for an unidentified species of Parastephanellus.

The only attempt of using stephanids in biological control programs was done by Taylor (1967b and 1976), in Tasmania. Taylor used S. cinctipes (together with other non-stephanid parasitoids) against Sirex noctilio, the pine wasp, with good results.

This page last updated: April 21, 1998.