Family common name: parasitic woodwasps
Genus: Ophrynopus Konow, 1897
The Orussidae are small, predominantly black sawflies with cylindrical bodies and globular heads (Eaton and Kaufman 2007). They are distinctive because they are the only sawfly family that is parasitic instead of phytophagous (Furniss and Carolin 1977). Current Hymenoptera phylogenies suggest that the Orussidae are the most closely related extant sawfly family to the suborder Apocrita, and specifically parasitic wasps (Vilhelmsen 2004).
Ophrynopus are 8–14 mm in length (Furniss and Carolin 1977). They share several remarkable morphological characters with other Orussidae, including antennal insertions located extremely low on the face, reduced wing venation, and a relatively long and thin ovipositor (Vilhelmsen et al. 2014). This genus is relatively rare in collections and poorly known (Blank et al. 2010b).
There are 15 extant described species worldwide (Vilhelmsen et al. 2013). The highest diversity is in South America (Smith and Middlekauff 1987). Only two species occur in North America (Taeger et al. 2010).
A key to North and Central American species of Ophrynopus is included in Middlekauff 1983.
Orussidae are morphologically distinct among sawfly families because of the body shape and location of antennae on head. Ophrynopus is easily confused with other genera of the family. It can be distinguished by the presence of longitudinal carinae between the eyes and the shape of the mesoscutellum and the maxillary palpi (Middlekauff 1983).
The Orussidae are external parasitoids of other insects. The documented hosts in South America for species of Ophrynopus include Cerambycidae beetle Oncideres germarii living in Prosopis chilensis (Chilean mesquite tree) and a Xiphydriidae sawfly Derecyrta sp. in Araucaria angustifolia (Brazilian pine) (Vilhelmsen and Smith 2002, Vilhelmsen et al. 2013). There is a Mexican record of O. nigricans emerging from a stem of Agave nelsoni containing a Prodoxus pallida moth (Smith 2006d). This association may be spurious since no other Orussidae are parasitoids of Lepidoptera (Vilhelmsen et al. 2013).
To find a suitable oviposition site, Ophrynopus females run up and down fallen or standing dead or damaged tree trunks, using their antennae to tap repetitively on the log. The behavior of running up and down, with the wings folded and effectively hidden, mimics the behavior of a carpenter ant. Whether they are able to sense a host presence in the log by chemical signals or by vibrations caused by the tapping of antennae is unclear (Powell and Turner 1975, Gourlay 1926).
World: The genus is widespread in tropical regions of Asia and the Americas. Species in East and Southeast Asia occur in Japan, Korea, south to Laos and Vietnam, and east to Indonesia and the Philippines (Vilhelmsen et al. 2013). In the Americas, Ophrynopus ranges from the very southern United States south to northern Argentina (Smith 2006d).
North America: There are two species in North America. Ophrynopus nigricans occurs in Mexico and the state of Texas (Vilhelmsen et al. 2013). Ophrynopus hansoni occurs in Costa Rica and Trinidad (Vilhelmsen 2004).
Map data from: GBIF.org (26 June 2019) GBIF Occurrence Download Ophrynopus
Details about data used for maps can be found here.