Antistrophus
rosinweed stem gall wasp
An undescribed of in the Antistrophus that induces distinctive stem-cluster on Silphium perfoliatum (cup ). Like other Antistrophus species, it likely produces only female through , with emerging in fall to lay in plant stems. The galls provide shelter and food for developing .
Pronunciation
How to pronounce Antistrophus: /ænˈtaɪstɹəfəs ˌʌndɪˈskɹaɪbd ˌpɜːfoʊˈleɪətəm stɛm klʌstər ɡæl/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Distinguished from other Antistrophus by specificity (Silphium perfoliatum vs. S. integrifolium for A. silphii or Lygodesmia juncea for A. lygodesmiaepisum) and (stem-cluster formation). The perfoliate leaves of the host plant (cup plant) provide a field identification cue. Galls differ from goldenrod ball galls (Eurosta solidaginis) in being stem-based rather than , and from oak galls in host plant and .
Habitat
Tallgrass prairie and prairie remnants; associated with Silphium perfoliatum in mesic to wet-mesic prairie conditions
Distribution
Northwestern Missouri and adjacent regions with tallgrass prairie ; likely occurs throughout the range of Silphium perfoliatum in the central United States
Seasonality
in fall; formation visible on plants during summer growing season
Host Associations
- Silphium perfoliatum - Stem-cluster induced on this ; undescribed distinct from A. silphii on S. integrifolium
Life Cycle
Parthenogenetic producing only female ; laid in stems, formation initiated by larval secretions manipulating plant growth , larval development within gall, inside gall, by chewing exit hole
Behavior
females use to inject into actively growing stem tissue; induce formation through chemical manipulation of rather than direct feeding on existing tissue
Ecological Role
formation creates microhabitat structure on prairie plants; galls may serve as food source for gall- or ; contributes to of prairie through specialized - interaction
Human Relevance
Subject of entomological research on biology and prairie dynamics; contributes to understanding of specialization and in
Similar Taxa
- Antistrophus silphiiAlso occurs on Silphium but specifically on S. integrifolium (wholeleaf rosinweed) rather than S. perfoliatum; may differ in clustering pattern and leaf differs (non-perfoliate)
- Antistrophus lygodesmiaepisumSame with similar but restricted to Lygodesmia juncea (rush skeletonplant) in loess hilltop prairies; described as pea-like on wiry stems rather than clustered on thick perfoliate stems
More Details
Undescribed Status
This represents an undescribed known from informal designation; formal taxonomic description pending. The 'perfoliatum' epithet in the working name refers to the Silphium perfoliatum with its distinctive perfoliate leaves that wrap around the stem.
Conservation Context
Like other prairie- Antistrophus , occurrence tied to remaining tallgrass prairie . S. perfoliatum more widespread than Lygodesmia juncea, potentially conferring less imperiled status than A. lygodesmiaepisum.