Introduction

Parastephanellus rufoornatus

Overal size ranges from three millimeters, for some Australian species, to almost 10 centimeters, as in the Neotropical Megischus macullipenis.

They 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. Copyright Royal Zool. Soc. NSW, Australia Used with permission

Many collectors have observed stephanids flying around dead trees, and the name of plant species from which they emerged are eventually mentioned in specimen labels. However, it is rare to find records of host associations. The biology is well known only to Schlettererius cinctipes (Cresson), from west 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 published. Braza (1989), searching for parasitoids of the beetle Agrillus sexsignatus (Buprestidae), also a pest in pine trees, found, among others, a species of Foenatopus, for which he does not give further information. Townes (1949) mentions Agrillus kalshoveni as a host to the Philippine Diastephanus leucosticus, and Bl�thgen (1953) reports some Xylotrechus (Cerambycidae) species as hosts of the European Stephanus serrator.

Fragmentary information is available for a few other stephanids, but to the great majority nothing is known. Oviposition behaviour and general aspect of 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: March 09, 1998.