Opius Wesmael, 1835

The genus Opius is arguably one of the largest in the family Braconidae, though van Achterberg (1997) has attempted to split the genus into roughly two equal parts on the basis of the presence or absence of a basal tooth on the mandible. Since only a few species have been formally placed using this subdivision, I am using the broader concept of Opius (Opius sensu lato) for the few species that are know to attack fruit-infesting Tephritidae. In addition to the subgenus Bellopius, treated separately, the species included in Opius and treated below are Opius baldufi Muesebeck, Opius bucki Costa Lima, Opius downesi Gahan, Opius froggatti Fullaway, Opius mariae Tobias, and Opius tafivallensis Fischer. Most of these species seem unrelated to one another or to the other genera and species groups of Opiinae that attack fruit-infesting Tephritidae. They may thus represent independent acquisitions of tephritid parasitism in the Opiinae.

For additional information, see the Opiinae and Braconidae pages.

1. O. froggatti face:...
2. O. froggatti habitus: lateral...
3. O. froggatti thorax...
4. O. froggatti thorax: do...
No referenced distribution records have been added to the database for this OTU.
Identification of Species and Subspecies
Two of the species, Opius bucki and Opius tafivallensis, have the occipital carina absent. The occipital carina is present in the other four species treated here. Opius bucki and Opius tafivallensis are Neotropical species and are readily distinguished from one another by their coloration and propodeal sculpture. Opius tafivallensis, a black and white species with no propodeal sculpture, has been reared from a tephritid in the genus Gerrhoceras. Opius bucki, a species that is mostly yellow with some black markings, and with coarsely reticulate-rugose propodeal sculpture, was originally thought to have been reared from an unknown tephritid (but see O. bucki page). No additional information is available on these two species (see summary in Wharton and Marsh 1978).

Two of the remaining species are from the Old World and two are from the Nearctic Region. The Old World species Opius froggatti is known from Australia and New Caledonia and has been reared from at least three species of Bactrocera (Wharton and Gilstrap 1983, Carmichael et al. 2005). Opius mariae is known only from the southeastern corner of Russia, where it has been reared from Myoleja sinensis (Zia) in Lonicera fruit as well as Acidiella echinopanasis Kandybina and possibly Rhagoletis reducta Hering (Tobias 1977).

Opius baldufi and Opius downesi, the two Nearctic species, both have a short hypopygium and share identical features of the clypeus and mandibles with the true members of the genus Biosteres. The general pattern of the fore and hind wing venation is also the same, but the second submarginal cell is slightly longer, and the second metasomal tergum is striate. Based on the number of shared characteristics, it is likely that these two species will eventually be placed in or near Biosteres sensu stricto when this section of the Opiinae is revised. In the restricted sense used here, however, the known hosts of Biosteres belong almost exclusively to leaf-mining Anthomyiidae, and there are as yet no records from Tephritidae. Opius baldufi is a parasitoid of Rhagoletis basiola whereas Opius downesi has been reared from four other species: Rhagoletis berberis, Rhagoletis pomonella, Rhagoletis tabellaria, and Rhagoletis zephyria (Wharton and Marsh 1978, Maier 1981). Opius downesi has a slightly longer ovipositor than Opius baldufi. Opius baldufi has a more restricted distribution in the midwestern US and Utah whereas Opius downesi apparently occurs all across northern US and southern Canada.