Stenodynerus ammonia

(de Saussure, 1853)

Stenodynerus ammonia is a of potter wasp in the Eumeninae. It is currently classified as a heterotypic synonym of Rhynchalastor ammonia in some taxonomic databases, reflecting ongoing taxonomic revision in this group. The species was originally described by Henri de Saussure in 1853. Like other members of Eumeninae, it is a solitary that constructs nests in pre-existing cavities. Very few observations of this species have been recorded, with only 7 observations documented on iNaturalist as of the available data.

Pronunciation

How to pronounce Stenodynerus ammonia: /stɛˌnoʊ.dɪˈnɪərəs əˈmoʊ.niə/

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Identification

Stenodynerus ammonia is difficult to distinguish from related based on external alone. According to field observations, Stenodynerus cannot reliably be separated from Parancistrocerus species from images of live specimens; microscopic examination of actual specimens is required for confident identification. The genus Stenodynerus is characterized by features of the and propodeum that require detailed examination. Specific diagnostic features for S. ammonia versus other Stenodynerus species are not documented in the available sources.

Habitat

As a cavity-nesting mason wasp, Stenodynerus ammonia likely utilizes pre-existing tunnels such as borings in dead wood, hollow twigs, or artificial structures like blocks. The single documented field observation of a congeneric or closely related (either Stenodynerus or Parancistrocerus) involved an individual entering a hole in a bee block in a residential backyard setting in Colorado.

Diet

Larval offspring of Eumeninae , including Stenodynerus, are provisioned with paralyzed caterpillars that serve as food. This has been observed in related cavity-nesting mason wasps and is characteristic of the .

Life Cycle

As a solitary in Eumeninae, the presumably involves: a female constructing or appropriating a pre-existing cavity nest; provisioning with paralyzed caterpillars; laying ; and sealing cells with partitions. The larva consumes the provisioned food, pupates within the cell, and emerges as an . Specific details for S. ammonia are not documented.

Ecological Role

As a of caterpillars, Stenodynerus ammonia contributes to regulation of lepidopteran . As a cavity-nesting , it may compete with other solitary and bees for nest sites, and its nests may be subject to by cleptoparasitic wasps such as Sapygidae.

Similar Taxa

ParancistrocerusCannot be reliably distinguished from Stenodynerus based on images of live specimens; microscopic examination required for separation.
Rhynchalastor ammoniaCurrently considered the accepted name for this in some taxonomic treatments; Stenodynerus ammonia is listed as a heterotypic synonym.

More Details

Taxonomic Uncertainty

There is significant taxonomic instability surrounding this . GBIF lists Stenodynerus ammonia as a heterotypic synonym of Rhynchalastor ammonia, while iNaturalist maintains it under Stenodynerus. The Catalogue of Life shows a complex synonymy involving Rhynchalastor ammonia paraensis. This reflects broader systematic challenges in the Eumeninae, where generic boundaries remain poorly resolved.