Dianthidium arizonicum
Rohwer, 1916
Arizona Pebble Bee
Dianthidium arizonicum is a of resin in the , first described by Rohwer in 1916. It is to the southwestern United States, particularly Arizona. Like other members of the Dianthidium, it is a solitary bee that constructs nests using resins. The species has been documented nesting in artificial bee blocks, indicating adaptability to human-provided nesting structures.
Pronunciation
How to pronounce Dianthidium arizonicum: //ˌdaɪˌænˈθɪdiəm ˌæ.rɪˈzoʊ.nɪkəm//
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Identification
Dianthidium arizonicum belongs to a characterized by pebble-like nest constructions made from resins. Within the genus Dianthidium, identification typically requires examination of morphological details such as the pattern and of pale markings on the , the structure of the (pollen- hairs) in females, and male . The specific epithet 'arizonicum' indicates its locality in Arizona, distinguishing it geographically from related species such as D. curvatum and D. pudicum which occur in different regions.
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Habitat
Documented from pinyon/juniper woodland in the southwestern United States. Observations indicate occurrence in areas with flowering plants suitable for pollen and nectar collection, including Heterotheca . The species has been recorded nesting in artificial blocks in nature park settings, suggesting use of pre-existing cavities in dead wood or hollow stems in natural conditions.
Distribution
Southwestern United States, with confirmed records from Arizona ( locality) and Utah. The occurs in the Colorado Plateau region and adjacent areas. Distribution records indicate presence in North America with documented observations in Coconino County, Arizona and Kane County, Utah.
Seasonality
Active during summer months. Documented observations from late June, with nesting activity recorded in June. As a solitary , are likely active during the flowering season of their plants.
Diet
feed on nectar from flowers. Females collect pollen using a (brush of hairs on the underside of the ) to provision nest for their . Documented flower visitation includes Heterotheca (showy goldenaster).
Host Associations
- Heterotheca sp. - pollen/nectar sourceDocumented flower visitation by Dianthidium (Dianthidium) sp., likely D. arizonicum given geographic context
Life Cycle
Solitary with typical nesting biology. Females construct nests in pre-existing cavities such as hollow twigs or borings in dead wood. Nest are partitioned and sealed using resins, forming distinctive pebble-like plugs. Each cell contains a pollen loaf provisioned with regurgitated nectar, upon which an is laid. develop within sealed cells, with multiple possible per season depending on climate.
Behavior
Females exhibit territorial around nest sites. Documented nesting in artificial blocks indicates adaptability to human-modified environments. The has been observed sharing bee block with other cavity-nesting including (Euodynerus hidalgo) and other bees. Like other Dianthidium, females are known to create resin plugs at nest entrances, potentially as a defense against .
Ecological Role
of flowering plants in southwestern North . As a resin , contributes to through pollen collection and transfer. Serves as for parasitic including Leucospis affinis ( ), which lays in Dianthidium nests. Nesting activities may facilitate secondary cavity use by other organisms.
Human Relevance
Has been documented utilizing artificial blocks (bee condos) installed for , demonstrating value as a target for bee enhancement. No known agricultural or economic significance. Potential for healthy pinyon/juniper woodland .
Similar Taxa
- Dianthidium curvatumOverlapping geographic range and similar resin-nesting biology; distinguished by morphological details of integumental markings and male
- Dianthidium pudicumCongeneric with similar nesting habits; D. arizonicum distinguished by Arizona locality and specific morphological characters
- Heriades spp.Other small that nest in pre-existing cavities and use resin in nest construction; distinguished by different body form and structure
More Details
Nesting Biology
Dianthidium are known as 'pebble ' or 'resin bees' for their distinctive use of resins to construct and seal nest . The resin plugs are durable and may persist in cavities for multiple seasons. Females of D. arizonicum have been documented nesting in artificial bee blocks alongside other solitary bees and , indicating the species benefits from efforts targeting .
Parasite Interactions
The Dianthidium serves as for parasitic in the , particularly Leucospis affinis. These chalcid wasps are external that lay in host nests; their attach to and consume developing larvae. The presence of D. arizonicum in concentrated nesting (such as bee blocks) may increase vulnerability to compared to dispersed natural nests.