Center for Systematic Entomology, Gainesville, Florida


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Kurczewski FE, Abela AJ, Shimizu A. 2023. Chalcochares hirsutifemur (Banks) (Hymenoptera: Pompilidae: Pompilinae), a probable obligate parasitoid of Aptostichus Simon (Araneae: Mygalomorphae: Euctenizidae) in California. Insecta Mundi 1004: 1–13.


This is an open access article distributed under the terms of the Creative Commons, Attribution Non-Commercial License

Published on August 29, 2023 by Center for Systematic Entomology, Inc. P.O. Box 141874 Gainesville, FL 32614-1874 USA


Size equivalence, seasonal synchronicity, geospatial sympatry, habitat specificity, and host-search­ing behavior implicate the spider wasp Chalcochares hirsutifemur (Banks) (Hymenoptera: Pompilidae: Pompilinae) as an obligate parasitoid on species of the wafer-lid spider genus Aptostichus Simon (Araneae: Mygalomorphae: Euctenizidae) on coastal sandy back dunes in San Luis Obispo and Santa Barbara coun­ties, CA. This is substantiated by 2010–2022 macrophotographs, videos, and field observations. Such host evidence supports recent unpublished phylogenomic studies that place Chalcochares as a sister genus of the spider wasp tribe Aporini, in which all species are known obligate parasitoids on trapdoor spiders and related Mygalomorphae. Chalcochares hirsutifemur and C. engleharti (Banks) are separated based on morphological, geographic, and probable host spider differences. Resource partitioning on the coastal sand dunes between C. hirsutifemur and three species of smaller Aporus Spinola is proposed.