Meloe franciscanus
Van Dyke, 1928
Meloe franciscanus is a to the southwestern United States. are flightless and feed on Astragalus lentiginosus. The is notable for its highly specialized larval of solitary in the Habropoda. First described from San Francisco dunes in 1928, the species was presumed locally extirpated there due to loss but persists in other regions.

Pronunciation
How to pronounce Meloe franciscanus: /ˈmɛloʊ iː frænˈsɪkənəs/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
are flightless with reduced typical of the Meloe. Specific diagnostic features distinguishing M. franciscanus from are not documented in available sources.
Images
Habitat
Found in desert dune systems with of vegetation surrounded by barren sand. In the Mojave National Preserve, occurs on Kelso Dunes. In coastal Oregon, found in sand dune . are laid at the base of vegetation, particularly Astragalus lentiginosus.
Distribution
to the southwestern United States. Documented from the Mojave Desert in south-central California (Kelso Dunes), coastal sand dunes of Oregon, and historically from San Francisco dunes near Lake Merced. GBIF records confirm presence in North America.
Seasonality
emerge in winter months (January) at Kelso Dunes. Synchronized with of and leaf-out of Astragalus lentiginosus. hatch and aggregate in spring, coinciding with male bee activity.
Diet
feed on leaves of Astragalus lentiginosus. are that consume pollen and nectar provisions in nests, and feed on host and larvae.
Host Associations
- Habropoda pallida - in Mojave Desert
- Habropoda miserabilis - Silver in coastal Oregon and historically San Francisco
Life Cycle
Females lay in compact underground masses averaging 761 eggs. Newly hatched () emerge from soil, climb vegetation, and aggregate into compact balls. They release volatile mimicking female to attract male bees. Larvae attach to male bees, transfer to females during mating, and are carried to nest burrows where they feed on provisions and offspring. emerge the following winter.
Behavior
exhibit cooperative chemical deception: aggregated collectively release that mimic the specific blend of local . Different populations show local in allomone composition matching their specific host . Larvae adjust height on vegetation based on local male bee mate-searching height.
Ecological Role
Specialized of solitary ground-nesting . are tied to bee abundance and . Research indicates host abundance and temporal overlap are predictive of host range.
Human Relevance
Subject of extensive research on and - . Original locality near Lake Merced, San Francisco was destroyed by urban development, leading to presumed local extirpation. Rediscovery of host at restored Presidio dunes in 2019 highlighted value of restoration.
Similar Taxa
- MeloeOther Meloe share general and larval , but M. franciscanus is distinguished by its specific associations with Habropoda and documented local in chemical .
More Details
Chemical Ecology Research
Research by Saul-Gershenz, Millar and colleagues demonstrated that M. franciscanus are locally adapted to different through matching of blends to host . Populations parasitizing H. pallida in the Mojave Desert and H. miserabilis in Oregon are the same species based on molecular analysis, but produce distinct allomone blends attractive to their respective local hosts.
Conservation Status
The was described from San Francisco in 1928 but alteration eliminated the original . The 2019 rediscovery of at the Presidio demonstrated potential for recolonization following dune restoration, though the itself has not been confirmed from this locality since restoration.
Sources and further reading
- BugGuide
- Wikipedia
- GBIF taxonomy match
- iNaturalist taxon
- NCBI Taxonomy
- The Amazing Bee-Parasite Research of Leslie Saul-Gershenz | Bug Squad
- Those Incredible Digger Bees and Their Nest Parasites | Bug Squad
- A Silver Digger Bee in Flight at Bodega Head | Bug Squad
- Why Silver Digger Bees Are Like Gold | Bug Squad
- Bees, Parasites and Maybe the End? | Bug Squad
- Meloidae Holdings | Entomology Research Museum