A tachinid parasite, Triarthria spinipennis (Meigen), introduced over 50 years ago to control populations of the introduced European earwig in coastal California, is reported for the first time in California's Central Valley. Both the parasite and its host prefer cooler, more humid environments near water. Parasites were found during two consecutive years and abundance patterns within each year indicate they are multivoltine. The parasite has successfully accompanied its host's inland invasion from the coastal region of California.
Barthell, John F. and Stone, Rebekah, "Recovery of the Parasite Triarthria Spinipennis (Meigen) (Diptera: Tachinidae) from an Inland California Population of the Introduced European Earwig" (1995). Ba. Paper 78.
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