Biology
A. jeanae induces inconspicuous, externally imperceptible galls in stems of Silphium perfoliatum (Fig. 4H) (Tooker et al. 2004; Nastasi and Deans 2021).

Distribution
Tooker et al. (2004) reported this species only from several prairie sites in Illinois (USA). Nastasi and Deans (2021) did not report additional localities. However, specimens we examined revealed records from three additional state records: Indiana, Iowa, and Wisconsin. A verifiable iNaturalist observation (https://www.inaturalist.org/observations/114414672) also records this species from Ohio; we have since examined adult gall wasps reared from the plant material from the same site, which confirmed their suspected identity (in litt.). Lastly, a specimen identified during this study (USNMENT 01822302; see complete specimen data in Suppl. material 1: table 1) confirms the occurrence of this species in Missouri (Columbia, Boone County) (see discussion). Known and potential distribution are summarized in Fig. 9.

Antistrophus jeanae Tooker & Hanks, 2004

Feeds on: Induces galls on Silphium perfoliatum L.

Distribution: United States: Illinois

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.

Antistrophus jeanae
Rosinweed cryptic stem gall wasp

Hosts: cup plant (S. perfoliatum)

Gall location and description: Galls of species in this group are cryptic, meaning they are not outwardly visible and can only be located upon dissection of a galled stem. When dissected, the stem will have numerous brown, oval-shaped chambers along the inside of the pith, each with a single insect.

Range: This species group has been found throughout the Midwestern, Eastern, and South Central United States. Like many other herb galls, this complex probably occurs throughout the entire ranges of each species’ respective host plant(s).

As with the rosinweed flower gall wasps, it was once believed that cryptic galls on rosinweeds were all induced by either of two species, Antistrophus minor and A. rufus. Recent data shows that there are multiple species of cryptic stem gall wasps on these plants, each preferring a single host plant.

Unlike other rosinweeds, compass plant (S. laciniatum) has been found to host two distinct species of cryptic stem gall wasps. These two species are found in the same habitats, and often induce galls on the same individual host plant. The reason for this bizarre occurrence is currently unknown.

Many unrelated groups of gall wasps seem to have indepdently developed the ability to induce cryptic, inconspicuous galls. The mechanism by which this has been made possible is not known, but it is likely that having hidden galls decreases the odds of attack by predators or parasites. Due to the known diversity of cryptic gall wasps and hidden nature of cryptic galls, it is quite likely that many cryptic galls have thus far evaded detection and await discovery!