California Gall Wasp
Andricus quercuscalifornicus
Classification
- Phylum: Arthropoda
- Subphylum: Hexapoda
- Class: Insecta
- Order: Hymenoptera
- Superfamily: Cynipoidea
- Family: Cynipidae
- Tribe: Cynipini
- Genus: Andricus
- Species: quercuscalifornicus
Pronunciation
How to pronounce Andricus quercuscalifornicus: //ænˈdraɪkəs kwɜrkəsˌkælɪfɔrˈnaɪkəs//
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
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Summary
Andricus quercuscalifornicus, known as the California Gall Wasp, induces galls on oak trees, particularly the Valley Oak. It has a complex life cycle, is distributed from southern Washington to northern Mexico, and plays a crucial role in the ecosystem by supporting diverse communities of insects.
Physical Characteristics
Adult wasps are small, stout, and brown, about 5 mm long with clear wings nearly twice the length of the body. The galls are roughly spherical, varying in color from greenish to reddish or orange depending on host, age, and environmental conditions. Galls can range in size from 2–14 cm across and often contain multiple larvae as well as parasites.
Identification Tips
Look for spherical galls on the twigs of oak trees, primarily the Valley Oak (Quercus lobata). The adults are small wasps with clear wings and a stout body.
Habitat
Riparian forests, open foothill woodlands, valley savannas, plant groves, and suburban areas; primarily found on Valley Oak.
Distribution
Southern Washington through Oregon and California to northern Mexico.
Diet
Larvae feed on the gall material created by their own development from the eggs laid by the female wasp.
Life Cycle
The adult female lays eggs in the cambium layer of oak twigs in the fall. Eggs overwinter and hatch in the spring. Larvae induce galls on the tree, where they grow and pupate before emerging late summer or early fall.
Reproduction
Reproduces strictly by parthenogenesis; no male specimens have been recovered.
Predators
Many parasitoids, inquilines, and hyperparasites, as well as some birds that feed on galls and their inhabitants.
Ecosystem Role
Acts as an ecosystem engineer by inducing galls that facilitate complex insect communities and influencing the local ecology.
Collecting Methods
- Observing infested twigs for galls
- Collecting galls for examination
Preservation Methods
- Preserve galls in alcohol
- Mounting adults for collection
Evolution
Believed to have evolved specialized traits to exploit host oak species and manipulate plant growth through gall induction.
Similar Taxa
Misconceptions
Misunderstood as pests, but play an important ecological role as ecosystem engineers and facilitators of biodiversity.
Tags
- California Gall Wasp
- Hymenoptera
- Cynipidae
- Ecosystem Engineer
- Gall Inducer