Antistrophus rufus

Antistrophus meganae

Antistrophus jeanae

Antistrophus rufus Gillette 

Larvae developing in galls in cambium and pith of flowering stems of S. laciniatum.

Biology. — Larvae develop within galls in flowering stems of S. laciniatum (for biology, see Tooker et al. 2002, Tooker and Hanks 2004a). They overwinter in dead stems, pupate in the early spring, and adults emerge in late May through late June. Although adults of both sexes have fully developed and functional wings, they do not fly readily but rather walk, occasionally taking hopping flights to nearby plants. Males emerge before females and search for mates on dead stems of the previous season, guarding areas of stem where females eventually emerge, and driving off competitors by charging or butting with the head. Females mate immediately upon emerging and then move to nearby developing stems of S. laciniatum where they oviposit in axils. As many as 20 females oviposit in a stem at the same time and require less than one minute to insert an egg. Egg load upon emergence averages —165 eggs per female. Densities of galls commonly reach hundreds per stem. Parasitic wasps are the most significant source of mortality for A. rufus larvae with rates of parasitism often exceeding 90% (Tooker and Hanks 2004a). Species of parasitoids reared from A. rufus galls include eurytomids (Eurytoma lutea Bugbee and an unidentified Eurytoma species), an ormyrid (Ormyrus labotus Walker), eupelmids (Eupelmus vesicularis [Retzius] and two unidentified Brasema species), and a pteromalid (unidentified Homoporus species; Tooker and Hanks 2004a). Populations of gall wasps are decimated when prairies are burned, but quickly recolonize (Tooker and Hanks 2004b). 

Antistrophus meganae Tooker and Hanks, new species

Diagnosis. — Larvae developing in galls in cambium and pith of flowering stems of S. terebinthinaceum. See description for further details. 

Biology. — Similar to A. rufus, but larvae develop within galls in flowering stems of S. terebinthinaceum. Adults begin emerging from stems in mid-June and continue to emerge for approximately 20 days (Tooker and Hanks 2003a). Females oviposit in stem internodes of S. terebinthinaceum after bolting. Similar to A. rufus, A. meganae larvae can suffer high parasitism rates and the same guild of parasitoids appears to attack both species (Tooker and Hanks 2004a).


Antistrophus jeanae Tooker and Hanks, new species

Diagnosis. — Larvae developing in galls in cambium and pith of flowering stems of S. perfoliatum. See description for further details.

Biology. — Similar to A. rufus, but larvae develop within flowering stems of S. perfoliatum. Adults emerge from stems for a period of about 20 days beginning in mid- May and females oviposit in stem inter- nodes after bolting. Similar to other species in the complex, parasitoids can inflict high levels of mortality on A. jeanae larvae. 

Description of the Antistrophus rufus (Hymenoptera: Cynipidae) species complex, including two new species