Stenodynerus krombeini
Bohart, 1953
Stenodynerus krombeini is a solitary in the Eumeninae. It is a small, cavity-nesting that provisions its nests with paralyzed as food for its . The species is difficult to distinguish from the closely related Parancistrocerus based on images of live specimens; microscopic examination is typically required for definitive identification. Males have a distinctive antennal structure with the last folded against the adjacent segment.
Pronunciation
How to pronounce Stenodynerus krombeini: //ˌstɛn.oʊˈdaɪ.nər.əs ˈkrɒm.baɪ.ni//
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Difficult to separate from Parancistrocerus based on photographs of living specimens; even with specimens under a microscope, identification is challenging. Distinguished from larger like Euodynerus hidalgo by smaller size and more patterning. Males can be identified by their distinctive antennal structure.
Appearance
Small with patterning. Males possess a distinctive antennal modification where the last is folded like a finger against the preceding segment. The is smaller and more ornately patterned than some related mason wasps such as Euodynerus hidalgo. Coloration and pattern details specific to this species are not separately documented from its close relatives.
Habitat
Cavity-nesting that utilizes pre-existing tunnels such as old borings in dead wood, hollow twigs, or artificial blocks. Associated with flowering plants that provide nectar for .
Distribution
Recorded from Colorado Springs, Colorado and Benicia, California. The broader distribution is poorly documented due to identification challenges and taxonomic synonymy with Rhynchalastor krombeini.
Seasonality
Active in June based on observations in Colorado and California. Specific is otherwise undocumented.
Diet
Females provision nests with paralyzed as larval food. feed on nectar from flowers including Indian hawthorn (Rhaphiolepsis umbellata).
Life Cycle
Nests in pre-existing cavities. are provisioned with paralyzed , an is laid, and cells are partitioned and sealed. Detailed has not been separately documented from related .
Behavior
Solitary nesting . Females hunt to provision nest . Males have been observed foraging on flowers. The is a potential for parasitic sapygid .
Ecological Role
of ; may contribute to local caterpillar control. as through nectar feeding. Serves as for parasitic in .
Human Relevance
Occasionally encountered in artificial blocks installed for solitary bees and . Not known to be aggressive; only if handled. Contributes to backyard observations.
Similar Taxa
- Parancistrocerus speciesNearly identical in appearance; cannot be reliably distinguished from S. krombeini in images of live specimens or even with microscopic examination in many cases.
- Euodynerus hidalgoLarger and less ornately patterned; more readily distinguished in the field.
More Details
Taxonomic note
Stenodynerus krombeini was originally described by Bohart in 1953. GBIF and Catalogue of Life list this name as a synonym of Rhynchalastor krombeini, though iNaturalist maintains it under Stenodynerus. The taxonomic relationship between these requires further clarification.
Identification challenges
The difficulty in distinguishing Stenodynerus from Parancistrocerus, even with specimens in hand, suggests that published records and observations may contain misidentifications.