Burnettweldia plumbella
(Kinsey, 1920)
Beaked Twig Gall Wasp
Burnettweldia plumbella is a gall wasp that induces distinctive galls on oak trees. The was transferred from the Disholcaspis to the newly erected genus Burnettweldia in 2021. It is commonly known as the beaked twig gall wasp due to the pointed tip of the galls it produces. The has been documented on multiple oak species in western North America.
Pronunciation
How to pronounce Burnettweldia plumbella: /bɜrˈnɛt.wɛl.di.ə plʌmˈbɛl.ə/
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Identification
The beaked twig gall is distinguished by its pointed tip and bright coloration—either red or green with yellow spots. These galls are formed on twigs of specific oak , particularly blue oak, leather oak, and scrub oaks. The combination of plant, twig location, and distinctive beaked separates this species from other oak gall wasps.
Appearance
are 3–4 mm in length. The galls they induce are up to 15 mm in diameter, brightly colored in either red with yellow spots or green with yellow spots, and feature a distinctive pointed or beaked tip.
Habitat
Oak woodlands and savannas supporting oak , including blue oak (Quercus douglasii), leather oak (Quercus durata), Muller's oak, and scrub oaks (Quercus berberidifolia). Galls are formed on actively growing twigs.
Distribution
Western North America, documented in California and associated with oak native to this region.
Seasonality
Galls form in spring and summer. emerge from galls in November and December.
Host Associations
- Quercus douglasii - gall blue oak
- Quercus durata - gall leather oak
- Quercus berberidifolia - gall scrub oak
- Quercus × mulleri - gall Muller's oak
Life Cycle
Females lay in actively growing oak twigs, inducing gall formation. Larvae develop inside the gall, which provides shelter and nutrition. occurs within the gall. emerge in late autumn.
Behavior
Induces gall formation on oak twigs through chemical cues deposited during oviposition. The precise mechanism of gall induction remains unknown, though insect fluids are hypothesized to influence plant .
Ecological Role
As a gall inducer, this manipulates plant tissue development to create specialized microhabitats. The galls may serve as resources for other organisms in the oak gall , including and .
Human Relevance
The distinctive galls are of interest to naturalists and ecologists studying plant-insect interactions. No economic impact on agriculture or forestry has been documented.
Similar Taxa
- Other Disholcaspis/Burnettweldia speciesSimilar gall and associations; distinguished by specific gall shape, color pattern, and host oak
- Trichoteras tubifaciensAlso induces galls on oaks, but produces crystalline tube galls on Oregon oak rather than beaked twig galls
More Details
Taxonomic history
Originally described as Disholcaspis plumbella by Kinsey in 1920. Transferred to the new Burnettweldia in 2021 based on phylogenetic analysis.
Gall characteristics
Gall diameter up to 15 mm; color (red/green with yellow spots) observed within the .