Hosts or Prey
Identification
Adults (wasps) are slender and metallic dark bluish green with coppery and purplish markings. The wings are mostly clear with brown veins. The body of adults, mature larvae, and pupae is a little over 1/4 inch (6 mm) long.
Larvae are maggotlike with distinct segments. Larvae and initially pupae are pale yellow to whitish. As pupae age they darken and develop appendages folded against the body. Larvae and pupae occur hidden under bark in tunnels made by the wood-boring larvae of goldspotted oak borer, a flatheaded borer.
Life Cycle
Calosota elongata develops through four life stages: egg, larva, pupa, and adult. Several wasp larvae feed on the outside of a single late-instar (larval) goldspotted oak borer, commonly the last instar that has formed a chamber in which the immature beetle is about to pupate.
The wasp larvae consume the host's entire body except for the head capsule. The mature wasp larvae then pupate in the borer's tunnel and emerge as adults. The adult parasitoids can be active and flying from at least May into October.
Habitat
The goldspotted oak borer was first detected in California in San Diego County in 2004. Since then it has killed several tens of thousands of oaks, which has changed the plant community of certain oak woodlands.
Surveys of natural enemies were conducted to identify potential biological controls for goldspotted oak borer. In addition to various predators, two parasitoids were discovered to have colonized goldspotted oak borer in Southern California: Atanycolus simplex and C. elongata.
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To improve biological control
- Grow flowering insectary plants to provide nectar for adult natural enemies.
- Avoid the application of broad-spectrum, persistent insecticides for all pests because they are toxic to natural enemies.
See Protecting Natural Enemies and Pollinators for more information.
Species
At least six Calosota species occur in California: C. aestivalis, C. bicolorata, C. elongata, C. longiventris, C. metallica, and C. speculifrons. At least some are parasitoids of beetles, flies, or other wasps, but the biology of some is unknown. Calosota elongata is only known to parasitize goldspotted oak borer. In some publications goldspotted oak borer, Agrilus auroguttatus, is named A. coxalis. But A. coxalis is actually a different species of flatheaded borer.
More Information
- Calosota Curtis (Hymenoptera, Chalcidoidea, Eupelmidae) – Review of the New World and European fauna Including Revision of Species from the West Indies and Central and North America (PDF), ZooKeys
- Can the Destruction of California’s Oak Woodlands be Prevented? Potential for Biological Control of the Goldspotted Oak Borer, Agrilus auroguttatus, BioControl
- First Occurrence of the Goldspotted Oak Borer Parasitoid, Calosota elongata (Hymenoptera: Eupelmidae), in California, Pan-Pacific Entomologist
Scientific classification:
- Phylum: Arthropoda
- Class: Insecta
- Order: Hymenoptera
- Family: Eupelmidae
