Meloe franciscanus

Van Dyke, 1928

Meloe franciscanus is a blister beetle to the southwestern United States. are flightless and feed on Astragalus lentiginosus. The is notable for its highly specialized larval of solitary bees 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.

Ciclo Meloe franciscanus by Laura P. Zarcos. Used under a CC BY-SA 4.0 license.

Pronunciation

How to pronounce Meloe franciscanus: /ˈmɛloʊ iː frænˈsɪkənəs/

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Identification

are flightless blister beetles with reduced typical of the Meloe. Specific diagnostic features distinguishing M. franciscanus from are not documented in available sources.

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Habitat

Found in desert dune systems with patches 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

beetles emerge in winter months (January) at Kelso Dunes. Synchronized with of bees and leaf-out of Astragalus lentiginosus. Larvae hatch and aggregate in spring, coinciding with male activity.

Diet

feed on leaves of Astragalus lentiginosus. Larvae are that consume pollen and nectar provisions in nests, and feed on host and larvae.

Host Associations

Life Cycle

Females lay in compact underground masses averaging 761 eggs. Newly hatched larvae (triungulins) 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

Larvae exhibit cooperative chemical deception: aggregated triungulins 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 bees. are tied to abundance and . Research indicates host abundance and temporal overlap are predictive of host range.

Human Relevance

Subject of extensive research on chemical and - . Original type locality near Lake Merced, San Francisco was destroyed by urban development, leading to presumed local extirpation. Rediscovery of host bees at restored Presidio dunes in 2019 highlighted conservation value of restoration.

Similar Taxa

  • MeloeOther Meloe share general blister beetle and oil beetle larval , but M. franciscanus is distinguished by its specific associations with Habropoda bees and documented local in chemical mimicry.

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 bees at the Presidio demonstrated potential for recolonization following dune restoration, though the itself has not been confirmed from this locality since restoration.

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Sources and further reading